national strategic bat for metallic lower activity...

National Strategic BAT for Metallic Lower Activity Radioactive Wastes Final Report March 2015

Executive Summary

Purpose of this document Low Level Waste Repository Ltd (LLWR Ltd) is responsible for leading the delivery of the UK’s Low Level Waste (LLW) Strategy on behalf of the Nuclear Decommissioning Authority (the NDA). This is achieved via delivering the LLW National Waste Programme (the National Programme) through collaboration with all of the UK’s LLW producers. The National Programme therefore provides a strategic framework and associated guidance and direction to LLW management programmes for UK waste producers. An important component of the National Programme is the identification of optimised national strategies for the management of key LLW categories. These strategies are informed by Best Available Technique (BAT) studies for specific waste types. This document reports the process and outcomes for a study reviewing the BAT provisions for metallic Lower Activity Waste (LAW; including LLW and very low-level waste or VLLW). It updates the outcomes of two previous studies. Overview The aim of this National BAT study is to identify a generic national ‘baseline’ BAT option to underpin strategy for the future management of the UK’s metallic LAW. The focus of this study is on supporting UK nuclear industry waste producers, other producers of radioactive wastes including the Ministry of Defence and small producers, and treatment suppliers who maintain their own BAT studies. It is not the purpose of this study to define the management option for these wastes at each site. Each site holds specific legal and regulatory responsibility for doing so. Instead, the National BAT study identifies generic options, assessment justification and rationale that can inform and support site-specific studies. The outcomes of this ‘generic’ national strategic options assessment will also provide guidance to national strategy development. The National Programme team intend to use it as one source of information amongst others to inform the development of guidance on the production of waste producer and treatment provider metals management strategies, and to inform national strategy development directly. The strategy and the associated guidance will also recognise opportunities for integrated approaches across waste producing sites, and will identify constraints and challenges and how they are to be addressed. Process The approach followed for this BAT review was based on good practice as defined in relevant guidance documents. The main elements of BAT processes are identified as follows. • Scoping.

• Options development and initial assessment.

• Main assessment and workshop.

• Integration.

The primary aim of scoping in the BAT assessment process is for the project team and key stakeholders to develop a common level of understanding regarding the objectives and framing of the study, and the process for options generation and comparison. A scoping document was developed by the project team, and used as a basis for stakeholder engagement to test and update the process. The options development and initial assessment stage considered a detailed range of alternative treatment strategy options, on a ‘generic’ basis, i.e. considering the projected inventory for future arisings of metallic LAW across the UK rather than on a site- or waste stream-specific basis. A detailed long-list of technology options for each stage of the waste management process was identified, and following appropriate screening, combined ‘strategy options’ were constructed. The development of strategy options looked to consider each of the main stages of metallic LAW management strategies, including: enabling technologies (such as size reduction and dismantling, characterisation, initial decontamination etc.); main treatment options (surface-decontamination, melting, no treatment etc.); and end-point options (reuse, recycling, discharge and disposal options etc.). Issues such as the location of treatment were also considered, although given the generic nature of the study, this was restricted to comparison of UK and non-UK options. The main assessment and workshop phase involved the compilation of an information pack for the short-listed treatment strategy options and a technical appraisal and systematic evaluation against identified assessment attributes. This assessment was initially undertaken by experts within the project team, and then subject to detailed review through a stakeholder workshop. The outcomes of the options assessment have been summarised and documented in this report, which was provided to the stakeholders for comment prior to production of the final version. Integration is beyond the scope of this report. It reflects the process of turning the technical ‘generic’ BAT outcomes from this document into strategic guidance and associated national and site-specific plans and programmes. Outcomes Importance of early phases of waste management A key theme of the assessment concerned the need to make integrated choices across enabling approaches and main treatment options, including making early decisions based upon available data on the best prospect for waste treatment. These decisions will take account of the likelihood of achieving desired end points reflecting upper levels of the Waste Management Hierarchy. As well as considering the balance of enabling and main treatment technologies, management approaches such as buffer or decay storage and blending (but excluding dilution) need to be carefully considered to enable opportunities to deliver the desired end-points. Given the wide range of wastes within the remit of this generic study, there is not a clear dividing line between work that should be undertaken during and after decommissioning, during enabling/early waste management and main treatment phases, or on- or off-producing sites. It is important to consider the potential final end-points for different waste types throughout all programme stages.

Hierarchy of main treatment options A key conclusion from the study was that there is no one option, or combination of options, that will be BAT for all metallic wastes. For all wastes, the characteristics of individual waste streams will need to be reviewed within the context of individual producer or treatment provider strategies in order to identify BAT. For example, while a strong justification would be required, for some specific problematic LAW wastes, no treatment prior to disposal might be the BAT main treatment option. More broadly, cost disproportionality arguments may be important in evaluating BAT for lower hazard wastes. It is notable however that the majority of the volumes of metals sentenced for treatment by UK waste producers over recent years have been low activity-low level wastes (LA-LLW). More generally, the assessments indicate that it is possible to establish a hierarchy of preferred treatment options at the ‘generic’ national strategic level. The hierarchy indicates which are most likely to be associated with desirable end-points, noting that for individual waste streams with specific characteristics, applicability and proportionality arguments will apply in identifying the preferred option. The generic BAT hierarchy is summarised in Table E1. Note that the hierarchy focuses on what can be achieved for a substantial proportion of bulk metals, i.e. the majority of the inventory. Options are listed against the ‘main’ end-points they are likely to be utilised for, but it is recognised that this is a generalisation. Next Steps The BAT outcomes identified in this document, together with the associated rationale and identified wider considerations for integration into formal strategies, will be taken forward into processes to be co-ordinated by LLWR Ltd. It is this process that is intended to lead to development of the strategic guidance referred to above. Together the BAT outcomes and guidance will help inform future national and site-specific plans and programmes.

Table 2: Strategic BAT Outcomes: Hierarchy of Main Treatment Options for Metal LAW

Hierarchy End-point Options

Most

preferred on

‘generic’

basis

Release of exempt /

out-of-scope bulk

metal to market

Reclassification to exempt / out-of-scope through enhanced characterisation: For those wastes for which

initial characterisation provides confidence this can be achieved, this option offers clear benefits.

Surface-decontamination: These options, in particular mechanical surface-decontamination but also chemical

and thermal approaches, can lead to release of a range of metals without requiring subsequent treatment steps.

Melting: Melting can also lead to release of a range of metals. Where surface-decontamination and melting

options have a similar technical prospect of delivering release, wider differentiators e.g. trans-boundary

transportation are relevant.

Surface-decontamination and melting: This combination can often offer the best prospect of delivering bulk

metals for release. It is a two stage process but in practice most treatments will involve substantial enabling steps.

Reuse/recycling of

bulk contaminated

metal

Surface-decontamination: Similar to ‘release’ above, but with the reuse/recycling end-point.

Melting: Similar to ‘release’ above. Note also that some melting strategies for overseas facilities are used to

produce low contamination metals that can be recycled (and in limited cases, reused) within the nuclear industry.

Surface-decontamination and melting: Similar to ‘release’ above, but with the reuse/recycling end-point.

Disposal of bulk

metal with volume

reduction

Melting: Provides size reduction e.g. through re-forming of bulk metals, with some passivation of the waste form.

Supercompaction: Can provide size reduction for a subset of relevant malleable wastes, with limited passivation.

Least

preferred

Disposal of bulk

metal

No treatment prior to disposal:1 Remains a solution for wastes whereby it is too problematic or otherwise

disproportionate to treat them.

1 Note that in-situ disposal represents a ‘special case’ that essentially sits outside this hierarchy.

Doc No: B2010100 Metal LAW National BAT Final Report i

Contents

1 Introduction 1

1.1 Overview 1

1.2 Use of Strategic Assessments to Inform Strategy 1

1.3 Relationship with Guidance Document and Strategy Development 3

1.4 Report Development and Structure 3

2 Objectives and Context 5

2.1 Objectives 5

2.2 Waste Types 7

2.3 Existing Metallic Lower Activity Waste Management Arrangements 9

3 BAT Study Approach 11

3.1 Overview 11

3.2 Key Steps 11

4 Options and Waste Populations for Assessment 13

4.1 Overview 13

4.2 Long-list Derivation and Screening Outcomes 13

4.3 Derivation of Combined Waste Management Strategy Options 13

4.4 Waste Populations for Assessment 18

5 Assessment Process 20

5.1 Approach to the Assessment 20

5.2 ‘Location’ Element of Treatment Strategy Options 20

6 Assessment Outcomes 22

6.1 Form of Assessment 22

6.2 Importance of Choices at Early Stages of Decommissioning and Waste Management 22

6.3 Outcomes of Assessment of Combined Treatment Strategy Options 24

7 Overall Process Outcomes 33

7.1 Main Outcomes 33

7.2 Opportunities and Wider Issues for Consideration 36

8 References 37

Appendix A Existing Metallic LAW Waste Management Arrangements and Forecasts of Arisings

Appendix B Process Overview

Appendix C Outcomes of Screening: Long-list of Technology Options

Appendix D Main Assessment Process Details

Appendix E Main Assessment Matrices

Doc No: B2010100 Metal LAW National BAT Final Report 1

1 Introduction

1.1 Overview

Low Level Waste Repository Ltd (LLWR Ltd) is responsible for leading the delivery of the UK’s Low Level Waste (LLW) Strategy on behalf of the Nuclear Decommissioning Authority (the NDA). This is achieved via delivering the LLW National Waste Programme (the National Programme) through collaboration with all of the UK’s LLW producers. The National Programme leads the implementation of the National Nuclear Industry LLW Strategy, which was approved in August 2010 by the UK Government and devolved administrations (NDA, 2010). The National Programme therefore provides a strategic framework and associated guidance and direction to LLW management programmes for UK waste producers. An important component of the National Programme is the identification of optimised national strategies for the management of key LLW categories. LLWR maintains the national strategies for metal, bulk (soil and rubble), very low level (VLLW) and organic (previously termed ‘combustible’) LLW wastes on behalf of the NDA; these strategies are typically reviewed on a 5 year cycle. The National Programme also considers strategy around ‘cross-boundary’ waste issues, i.e. those that are very close to the Intermediate Level Waste (ILW)/LLW categorisation boundary, and in particular those wastes where comparatively short periods of decay storage mean that ILW may become LLW and can therefore potentially be managed as such. The more general term ‘lower activity wastes’ or LAW is adopted in the remainder of this document to describe the wastes that are within scope, and includes those wastes that might become LLW as a result of decay storage.

1.2 Use of Strategic Assessments to Inform Strategy

The development of strategies for lower activity waste categories is informed by a range of considerations. These include, for example, decommissioning plans and waste arising forecasts, the nature of waste populations within each category, the availability of commercial routes for treatment and disposal, opportunities for integration within and across industries, and sustainability over medium to longer-term timeframes. A range of further considerations are also relevant. As part of the information base supporting national strategy development for the key lower activity waste categories, the National Programme team undertake strategic or ‘generic’ options studies. The aim of these generic studies is to inform strategy development (but not to directly define strategy) and to assist future site- and waste-stream specific studies. The intention is to: • Help understanding of the range of waste streams and types within key lower

activity waste categories, and the challenges they represent;

• Explore key aspects that waste producers and treatment suppliers will need to consider in developing options studies for their own wastes;


• Identify life-cycle waste management options and key treatment and disposal techniques likely to be an important component of the output of such options studies;

• Provide a generic starting point for such future options studies, including providing an underpinning information base and a summary of key advantages and disadvantages of different waste management options;

• Alongside the main generic assessment, collate information on potential challenges and opportunities to help inform the strategy development process.

Such options assessments are high-level and generic in nature because they need to be based upon high-level aggregated waste streams and the outputs apply to a range of waste streams and to sites at different stages of their lifecycle. Nevertheless, the assessments need to remain consistent with the application of Best Available Techniques (BAT) and of the Best Practical Environmental Option2 and associated regulatory requirements and best practice guidance. This includes ensuring all key factors of relevance are considered in establishing proportionality. It is recognised however that in practice such factors vary across sites and waste streams and so can only be addressed at an overview level in this generic study. Equivalent studies have already been undertaken for organic wastes (most recently Paulley, 2014) and bulk VLLW (Donohew et al., 2009). The present study concerns metallic lower activity waste (including VLLW; defined in more detail in Section 2) for which two previous studies have been undertaken (Stevens, 2011; Rossiter, 2006). These assessments are considered robust and their outcomes have been taken into account and built upon in the current study, noting industry developments since those studies were undertaken. The review has been initiated on a shorter timescale than the standard 5 year cycle in a response to those changes and wider experience gained across the industry from implementation of the UK LLW strategy, including metals treatment, during the intervening period. This experience reflects the increase in the volumes of LLW metals that have been treated in the UK since 2006 as a result of implementation of the strategy, both at waste-producing sites and by off-site waste treatment suppliers. The review process also aimed to facilitate certain elements of National Programme planning and provided a forum for LLWR, NDA, waste producers, service providers and other stakeholders to discuss current key issues. In addition, it provided an opportunity to update the BAT study to reflect a structure and presentational approach consistent with that established in Paulley (2014). The focus of this study is on supporting UK nuclear industry waste producers, other producers of radioactive wastes including the Ministry of Defence, and small producers, and treatment suppliers who maintain their own BAT studies. As highlighted in the Scoping Workshop, it is important that the study provides as much help and guidance to waste producers and treatment suppliers as is possible and appropriate, given its role and generic nature. The scope of the generic assessment does not formally cover Naturally Occurring Radioactive Material (NORM) metal management. However, it is recognised that

2 BAT applies to the regulatory regime in England and Wales and BPEO (for strategic

choices) and BPM (Best Practicable Means) in Scotland. Regulatory guidance indicates that in practice the requirements are equivalent.


potential interactions and sensitivities with NORM industry radioactive metal waste generation may need to be explored subsequently with a view to informing future strategy development. A similar approach is taken to new-build wastes.

1.3 Relationship with Guidance Document and Strategy Development

The generic options assessment undertaken for this study will provide guidance to strategy development within the constraints outlined above. The National Programme team intends to use it as one source of information amongst others to inform the development of guidance on the production of waste-producer and treatment-provider metals management BAT assessments, and the integration of those strategies into national strategy. It is intended that the guidance shall be developed in partnership with stakeholders, who will be given the chance to input into the development process and review the outcomes. The scope of the intended guidance is described in more detail in Cassidy (2014).

1.4 Report Development and Structure

This document presents the proposed objectives, scope and process for the generic BAT study, and the outcomes from the assessment. An initial draft of a scoping version of this document was provided as input to a ‘Scoping Workshop’ (see Section 3) with stakeholders and also provided a basis for discussion and feedback with stakeholders unable to attend that workshop. The workshop provided a forum whereby scoping considerations were presented and were subject to additional input, query and challenge. Feedback from the engagements was constructive and helpful and has been used to inform the updated discussions on scope in this document, together with the separate Guidance Note (Cassidy, 2014). Following scoping, the main phase of options development, screening and assessment, was undertaken leading to formal review of draft assessment outcomes at a structured review workshop with stakeholders. The results of the workshop have been used as the basis of the final BAT outcomes recorded in this document. The report has been updated after an iteration of review by stakeholders. The rest of this report is structured as follows.

• Section 2: Overview of the objectives and context of the study.

• Section 3: Discussion on the approach utilised for the study.

• Section 4: Description of options and waste populations used to frame the assessment.

• Section 5: Description of the options appraisal process and evaluation criteria.

• Section 6: Outcomes of the options assessment.

• Section 7: Summary of overall BAT outcomes.

The discussions in the main text are supported by the following appendices. • Appendix A: Further details on existing arrangements for the management of

LAW metals in the UK.

• Appendix B: An overview of the BAT process employed.


• Appendix C: The outcomes of the screening process.

• Appendix D: Key details of the main assessment steps and criteria.

• Appendix E: Detailed description of the key outputs in terms of option assessment matrices.


2 Objectives and Context

2.1 Objectives

The aim of this study is to review the preferred generic management option or options for the UK’s metallic lower activity wastes. The primary objectives of the study are to:

• Support the National Programme’s aim to ensure that safe and effective treatment and disposal arrangements are in place and provide sufficient capacity for management of the UK’s metallic lower activity waste, enabling implementation of the National Nuclear Industry LLW Strategy;

• Identify the treatment and disposal option or options that need to be at the heart of the UK’s strategy for metallic lower activity waste; and

• Provide a framework and guidance for individual sites’ BAT assessments for treating their metallic lower activity wastes.

As part of this study, the outcomes from the equivalent studies conducted in 2006 and 2011 (Rossiter, 2006; Stevens, 2011) have been reviewed and considered, taking into account relevant industry developments in the period since they were undertaken e.g. in treatment options availability and experience of their application. The LAW metallic wastes within scope include: • all wastes that are suitable for disposal within near-surface facilities (LLW);

• including very low level and lower activity LLW wastes (referred to as VLLW/LA LLW in this study) that may be appropriate for disposal in facilities other than LLWR and Dounreay; and lower-level wastes that do require the level of protection provided by such facilities; and

• a subset of wastes that are currently classified as cross-boundary ‘higher activity wastes’ (HAW) and in their current form would require deeper disposal, or long-term interim storage in the case of Scottish wastes, but could potentially be managed as lower activity wastes after a period of decay storage.

In broad terms, this captures all wastes that (depending upon the management and treatment approach) could plausibly be disposed of to surface facilities. There are a number of fundamental Strategic Objectives that frame requirements for the identification, assessment and implementation of metal treatment options. These are drawn from UK LLW policy and strategy (Defra et al, 2007; LLWR, 2014; NDA, 2010), and include the following:

• Wastes should be treated and disposed in a manner that protects the health and safety of the workforce and the public.

• Impacts on the environment should be minimised, with practicability considerations also being taken into account.

• Ensuring consistency with the requirements and principles represented in the Waste Hierarchy, as far as is practicable.


• Minimisation of the volume of waste for disposal (and thus maximisation of the capacity of disposal facilities).

• Ensuring availability of technology options and their capacity to deal with waste arising schedules, including recognition of the need for appropriate flexibility in management options for decommissioning wastes.

• A presumption towards early solutions to waste management.

• Recognition of the proximity principle and waste transport issues (including trans-boundary transport policy).

• Understanding and ideally reducing lifecycle costs.

For decommissioning programmes it is often not possible to avoid lower activity waste generation and where this applies, the focus of the national strategy is on the higher levels of the waste hierarchy, with reuse, recycling and volume reduction being important considerations prior to final disposal of the residual wastes. The waste hierarchy is established in UK policy as representing best practice in guiding decisions on waste management and reducing impacts on the environment. A key further underlying consideration for this study is that many metal wastes are complex and a waste stream may include several different metal types that each need their own management strategy, at either original waste producer or waste treatment sites. It is national strategy (as detailed in NDA, 2010) and also a requirement of the regulatory regime (for example, in site environmental permits) that a BAT approach should be used in the management and control of radioactive waste disposal. BAT provides a vehicle for addressing the considerations presented above as well as wider factors. The current review will therefore be conducted using a BAT options assessment approach; although this involves going through the full process it will nevertheless capture the issues, evidence and rationale from the previous studies. As a generic BAT study, the aim of the current process is to provide an overarching rationale for the optimised management of relevant wastes. The aim is to identify a preferred ‘baseline option’ technique or techniques for the treatment of metallic lower activity waste, taking into account factors such as:

• The overall inventory of metallic lower activity waste in the UK and its main features;

• The nature and availability of the ‘main’ treatment options; and

• Combinations of options that deliver benefits given the overall objectives, including enablers such as sorting, segregation and characterisation options as precursors to the ‘main’ treatment options.

Issues such as treatment option availability, waste acceptance criteria, transport etc. are also discussed. It is not the purpose of this study to define the management option of these wastes at each site; instead each site holds specific legal and regulatory responsibilities for doing so. Therefore, the national BAT study will identify generic options, justification and rationale that will provide a framework for site-specific studies. This will be on the basis of chosen aggregated waste populations that explore the key features of wastes within the national inventory.


An aim of the generic BAT outcome and associated documentation is to facilitate sites in subsequently selecting options that are consistent in broad terms with the generic BAT principles, whilst recognising that wider considerations (e.g. nature of wastes, availability of local treatment option providers) will mean that different sites may implement different waste management approaches. These issues are already captured in individual site strategies and the updated BAT will aim to provide additional support to future site-specific issues. The current study needs to ensure that the BAT outcome recognises the spread of options that are currently being implemented by different sites and are likely to be considered in the future, even if one specific option would be preferable on an entirely ‘generic’ national basis. This generic BAT study is therefore intended to help identify preferable overall approaches to managing such wastes and identify in broad terms the key issues and considerations at a site level, without overlapping inappropriately with individual waste producer strategic decision-making. Note that waste producers here include treatment service providers, as they need to maintain their own BAT programmes to guide management of disassembled metals (for example) and secondary wastes. Existing producer-specific studies provided important input into the current BAT study. In turn, the outcomes of this process will provide significant input into future iterations of producer-specific studies, by providing framing arguments. The assessment process was also utilised to help identify opportunities for integration across organisations and (amongst other aspects) considerations such as gaps in service provision or other potential enabling strategies that could be of assistance in developing national strategy and associated guidance, as highlighted in Section 1.3.

2.2 Waste Types

The category of metallic LAW (including cross-boundary HAW; see Section 2.1) is here assumed to consist of waste streams which mainly or wholly comprise metallic solid wastes. Metals are likely to provide a substantial component of the total volume of future lower activity waste arisings in the UK. The majority of the wastes forecast to arise in the future are associated with the decommissioning of legacy facilities within the NDA portfolio, although a smaller volume of wastes is likely to be produced through other operations across the UK Nuclear Industry. Within the broad category of decommissioning metals, the majority of wastes will be iron-based (e.g. mild and stainless steels). Aluminium, copper, lead, brass and a range of other alloys are amongst the other metals that are expected to feature in the inventory of future arisings, but are projected to arise in much smaller volumes. Nevertheless, it is important that these small-volume metals are considered, as without established treatment routes underpinned by BAT, dealing with these wastes can lead to delays in bulk metal treatment and thus the overall decommissioning programme. The metal wastes include:


• Metals that are associated with surface-contamination (e.g. via contamination of coatings or contamination within the metal structure on or very close to the surface);

• Matrix-contaminated metals (embedded in the body of the metal, including those arising from neutron activation e.g. of C-13 and/or N-14 within the metal lattice, and metals containing Co-60); and

• Metals subject to both surface- and matrix-contamination.

Metals coatings, including paints and other thin coatings, rubber coatings etc., may complicate metal treatment arrangements, noting that contamination may reside in the coatings and/or the metal. An additional important component of the wastes in-scope is potential secondary wastes, including solid wastes, and gaseous and liquid effluents that might arise as a result of metal treatment. Metal wastes are frequently complex and heterogeneous. Disassembly of components can often lead to the identification of a number of different classes of metal wastes. For decommissioning of legacy facilities, it can be the case that it will not be clear until a metal component is actually disassembled exactly which waste streams will be associated with it. Therefore, heterogeneity and approaches to deal with it is an important consideration in metals waste management. More broadly, discrete items and low-volume wastes such as precious metals, need to be considered within the development of the overall strategy. However, wastes such as precious metals are too small-volume and site-specific to be addressed directly within the current generic BAT. The nature of the contamination and the heterogeneity of waste streams are particularly important in determining the types or combinations of treatment approaches that may offer benefit. Wastes that may contain some metals but that are predominately composed of other materials (organics, soil and rubble, etc.) are not within the scope of this study. These wastes are the subject of separate studies, including those noted in Section 1. The exception is where waste streams that are currently declared as ‘mixed’ wastes might yield a substantial proportion of metallic wastes if subject to a campaign of enhanced sorting and segregation. In such cases, however, it is only the potential metallic component that is within scope. The role of sorting and segregation in defining life-cycle management options is discussed in Section 4. In addition, asbestos coated metals will be addressed in a separate study. Mercury is also outside the scope of this study due to the specific challenges associated with its physical form. This study was focused on projections of future arisings from existing waste producers. However, the sensitivity of the options assessment to changes in assumptions, in particular considering the potential for wastes from new nuclear power stations, is recognised. This is intended as a practical approach given the uncertainty about the nature and rate of arising of new build wastes, and as waste volumes are likely to be smaller than the main legacy site decommissioning waste streams (see e.g. LLWR, 2014). In addition, interactions with wastes from other industries that may compete for infrastructure, in particular the treatment of NORM


wastes (DECC, 2014) will be important considerations in subsequent strategy development.

2.3 Existing Metallic Lower Activity Waste Management Arrangements

The main life-cycle management options currently pursued by metallic lower activity waste producing organisations comprise combinations of techniques, including: • Surface-decontamination, including for example:

- wiping and other simple approaches;

- water or other fluid jetting;

- surface-abrasion (e.g. shot and grit-blasting);

- chemical decontamination; etc.

• Melting, involving:

- recovery of contaminated slag and filters and release or declassification of bulk metal; or

- for a subset of specific matrix radionuclide contaminants, potentially a more limited inventory reduction, combined with volume reduction due to elimination of voidage.3

• Compaction or supercompaction (e.g. of thin malleable metal sheets in mixed waste streams); and

• Disposal (primarily of residues, including disposal and discharge of secondary wastes and effluents, and historically including disposal with no prior treatment).

Note that melting (for volume reduction) is sometimes differentiated from ‘smelting’ (separation of contaminants into slag) but this distinction is not made in this document, primarily as the process is exactly the same and it is the nature of the contamination that governs the extent to which it is transferred to slag, is released to filters in stacks via gaseous routes or is retained in the metal matrix (but with volume reduction due to elimination of voids). Size reduction of bulk metal objects (e.g. dismantling, disassembly and cutting) and sorting and segregation are important up-front components of the management approaches pursued. A brief description of the existing approaches utilised as part of life-cycle management options for metallic lower activity waste management is provided in Appendix A. Whilst these approaches are currently being actively applied by UK lower activity waste producers, this study will also consider all plausible approaches afresh to ensure the process is sufficiently comprehensive and is consistent with the approach taken in equivalent studies for other wastes. The approach to identifying options is set out in Section 4. For context, a summary of the total amount of metal wastes treated by surface-decontamination and/or melting over recent years is provided in Table 1. This shows

3 See Appendix A for a more detailed discussion of melting options.


the increase in treatment uptake over recent years. It also indicates how UK waste producers have utilised on-site, UK off-site and international facilities to successfully treat thousands of tonnes of LLW and low activity-low level (LA-LLW) metals, underpinned by site-specific BAT processes. It is also notable that the majority of the volumes of the metals treated have been in the LA-LLW category. A summary of projected future metal LLW arisings is also provided in Appendix A.

Table 1: Quantity of UK LAW metallic waste treated via the LLWR metallic waste services route for the period 2008/09 to 2013/14 (LLWR, 2014)

Year 2008/09 2009/10 2010/11 2011/12 2012/13 2013/14 Total

Tonnes processed

0 65 664 3,915 3,568 3,489 11,701


3 BAT Study Approach

3.1 Overview

The approach undertaken was based upon the application of a BAT process consistent with best practice. The aim was to be evidence-based and robust and also to recognise the importance of engagement with the range of stakeholders with an interest in this study. A further core consideration in the process design was the national generic nature of the study. Typically, site-specific BAT studies will consider a specific issue (e.g. the management of a particular waste stream) and specific options for dealing with it, which enables the assessment to efficiently draw on detailed specific information sets where available. For a national generic study a broad range of situations require consideration, therefore an evaluation in broad terms of the performance of options is appropriate. A brief summary of the process is presented below, recognising the more ‘generic’ requirements of a national study. Further details are provided in Appendix B.

3.2 Key Steps

The BAT study was designed to follow good practice for BAT assessment as defined in relevant guidance documents (EA, 2010; NISDF, 2010). The main elements of the process are identified in Figure 1.

Figure 1: Annotated Version of the Nuclear Industry Code of Practice BAT Process Diagram (after NISDF, 2010) Showing the Four Main Process Steps for This Study

These elements are addressed in the following stages:

• Study Scoping. Here the project team, assisted by stakeholders including contributions to a scoping workshop, developed a common understanding regarding the objectives, scope and context of the study, and associated assumptions and constraints. A draft scoping version of this document was provided as input to a scoping workshop with stakeholders, and to


stakeholders unable to attend that workshop. Feedback obtained has been used to inform the subsequent process as documented in this report.

• Options Screening and Initial Assessment. In this phase, a comprehensive long-list of options was developed and screened against criteria agreed during Study Scoping, in order to identify a list of detailed options that could plausibly provide benefit to treatment and management of lower activity waste metals.

• Main Assessment and Workshop. The screened list of detailed options was then used to develop a set of generic combined life-cycle management options for the main BAT assessment. Representative waste populations were identified to assist the assessment of options, which was undertaken using a qualitative multi-criteria decision-analysis (MCDA) methodology. This process was robust, systematic and evidence-based. A draft assessment of options against criteria (updated and agreed following Scoping) was undertaken by the internal project team, and then reviewed and developed in detail by stakeholders at the main stakeholder workshop. The final outcomes are captured by the following sections of this document.

• Integration. As noted previously, BAT processes typically inform rather than ‘make’ decisions. Thus, after a BAT recommendation is made, a process of integration is then required to transpose the outcomes into wider planning and associated implementation and funding decisions. The relationship of the current process to the integration and strategy development phase is also discussed in Cassidy (2014).


4 Options and Waste Populations for Assessment

4.1 Overview

In order to provide a helpful starting point for future site (including waste treatment provider) specific BAT studies for metallic LAW, and to provide meaningful input into the subsequent development of strategy, it is important this study provides a survey of all of the waste management options that are available and could provide a benefit for strategies for metallic LAW (and for post-decay storage HAW boundary wastes). It is also necessary to provide a vision for how individual waste management options can be combined into waste management strategies that cover the life-cycle of wastes, and to use the resulting combined waste management strategy options to underpin the BAT study. Individual options that do not cover the full life-cycle required to manage relevant wastes cannot be assessed on their own as they will give an incomplete picture. Generation of these waste management strategic options requires the following steps:

• Development of an options ‘long-list’ documenting all of the individual options;

• Screening of those options against criteria, to remove options that are clearly not practicable;

• Assembly of the remaining screened ‘long-list’ options into combined waste management strategy options.

In the following sections, the outcomes of these steps are described.

4.2 Long-list Derivation and Screening Outcomes

During long-list development, a wide range of resources from across the nuclear and non-nuclear industries were consulted in order to ensure the list was as comprehensive as possible. The resulting list, which covers the full range of aspects from ‘enablers’ through to main treatment and disposal/discharge options, was subsequently screened against appropriate criteria. The criteria, and the outcomes of the long-list derivation and screening processes are recorded in full in Appendix C.

4.3 Derivation of Combined Waste Management Strategy Options

4.3.1 Requirements for Combined Waste Management Strategy Options

As noted in Section 1 and elsewhere in this document, a full strategy for the management of UK’s metal LAW wastes will combine a wide range of elements. These include: 1. Consideration of enabling and main treatment technologies, and their mode

of use within decommissioning and waste management planning;

2. End-point options;


3. Locations (UK, overseas);

4. Timeframes (next five years, longer term);

5. Identifying modifiers (e.g. management strategy ‘x’ is preferred for waste-stream ‘y’ unless site-specific concerns such as ‘z’ are relevant, in which case…);

6. Opportunities (treatment technology availability in next five years and longer term, etc.); and

7. Risk management (flexibility of the strategy; response to plausible what-if scenarios e.g. unexpected treatment facility unavailability).

Aspects of the above list numbered 1 to 3 have been considered through the development of ‘treatment strategy options’, reflecting the whole waste management life-cycle. Information was also gathered during the technical assessment phase to support consideration of the elements numbered 4 to 7 in the list. Subsequently, the full range will need to be considered within the ‘integration’ phase. For the assessment phase, the following approach was adopted:

• Development and assessment of technology-based treatment strategy options (enablers, main treatment technologies, disposal options);

• Dealing with location variants using logical argument;

• Identifying timeframes of interest to the main assessment and to the wider strategy; and

• Collating information on the remaining factors through the assessment process for input into the final BAT outcome and integration phase.

The collation of strategy-relevant meta-data during the assessment is an important component of the process. It is not within the remit of this study to overlap with or pre-judge site-specific studies (as discussed elsewhere); however the process outcomes provide a framework and starting point for those studies. Potential blockers and modifiers that may need to be considered in site-specific studies were recognised when formulating National Strategic options. Questions such as the following were considered during the assessment: • How significant would transport considerations be for a typical site and

typical waste stream?

• To what extent is the viability of this option dependent on enhancing the application of enabling technologies such as sorting and segregation?

• What would prevent site ‘x’ from taking up technology ‘y’?

4.3.2 Approach to Defining Combined Waste Management Strategy Options

As noted above, a number of considerations are important in defining options for metal LAW treatment. In particular, as scoping workshop participants reinforced, there is a much finer line between enabling and pre-treatment technologies and ‘main’ treatment technologies than can be the case for other types of waste. For example, size reduction, disassembly and characterisation may be undertaken


iteratively until a waste owner is confident that the waste is characterised sufficiently to identify the best treatment route. This disassembly/characterisation process might yield a number of different metal waste types from the original component that can in turn be sentenced to different routes. In addition, characterisation requirements may differ across waste streams and at different stages. For certain wastes and process steps, intrusive characterisation may be necessary, but in other cases non-intrusive measurements, mass balance, documentation review or similar approaches may be sufficient. It was also noted that washing/jetting, wiping and other basic surface-decontamination techniques may be used to remove loose material and easily removed surface-contamination as a preparation either for more aggressive surface-decontamination (e.g. shot-blasting) or for melting. Moreover, even aggressive surface-decontamination can be a pre-treatment stage for melting, where matrix contamination is also present or melting is expected to provide more effective removal of the remaining surface-contamination. Initial surface-decontamination prior to more aggressive treatment/melting may be particularly important where the presence of loose contamination represents a potential constraint to transport safety cases that enable off-producer site disassembly and treatment. In addition, the options need to recognise that reclassification to exempt/out-of-scope through enhanced characterisation (with no further treatment) to enable release, reuse or recycling of metals represents an important option in its own right. It is also relevant to acknowledge that the role of enabling approaches including the balance of at-source and subsequent sorting, segregation and characterisation (etc.) will be very site- and waste stream-specific matters. For example, there may be requirements to undertake initial size reduction, disassembly and characterisation before it can be identified which combination of enabling approaches is needed to prepare a particular waste stream for the main treatment phase. Similarly, buffer storage might be important in order to build up enough waste for treatment to reduce costs and ensure efficiency, and decay storage might be very useful in enabling treatment as LLW waste that is initially ILW. These are also waste stream and site-specific considerations, noting that a key aim of buffer storage might be to support integration across different sites in the interests of overall efficiency and planning. Space availability for on-site buffer storage, or for storage at a nearby site, will also be an important consideration here. Therefore, whilst consideration of enabling/pre-treatment techniques in general is important within a discussion of options and associated assessments and guidance, it is not plausible to explicitly identify every possible combination of options within a generic BAT. In broad terms, the combined waste management strategy options need to:

• Capture all the main elements of life-cycle waste management options defined as being within scope;

• Appropriately represent all the ‘building block’ technologies taken forward after screening; and

• Allow sufficient simplification/grouping to make the assessment tractable.

Reflecting these perspectives, the following Figure 2 provides an overview in broad terms of a range of potential ways in which life-cycle management options for metals


can be constructed, given the enabling/pre-treatment, main treatment and disposal/final management options that remain post-screening of the ‘long-list’ of detailed options. The structure of the diagram is explained below. • Each ‘column’ within the diagram represents a key stage in the waste

management life-cycle.

• Different life-cycle strategy options are represented by different ways of progressing from left to right through the diagram, following the directions of the arrows.

• The diagram shows a dashed line indicating the key relationship between site Post-operational Clean-out (POCO) and decommissioning strategies and subsequent ‘waste management’ steps, reflecting the fact that they are intrinsically related. This topic is discussed further within the assessment outcomes reported in Section 6.

• The issue of use of UK vs. overseas facilities can be decoupled from the main ‘technical’ assessment of options. This discussion (see Section 5.2) can be overlaid on the outcomes of the technical assessment.

• All management options that produce solid wastes should be capable of delivering wastes that will meet the disposal waste acceptance criteria (WAC) of ‘standard’ LLW, LA LLW/VLLW or out-of-scope/exempt waste facilities. It would be reasonable to assume that most VLLW activity wastes will go to LA LLW/VLLW facilities to reduce pressure on LLWR. Then the choice between new and existing facilities will depend upon their availability and WAC. At the BAT level it is unlikely that a differentiator will be observed as both options will meet common regulatory/permitting requirements; therefore, these aspects are not reflected in the options for comparison.

• A number of management options involve the generation of aqueous and/or gaseous discharges. Therefore, discharge routes need to be recognised in the overall treatment strategies.

• The potential of blending waste for treatment is noted. Whilst waste ‘dilution’ with clean material is clearly outside regulatory expectations in the UK, it is plausible that BAT cases can be made to blend LAW or cross-boundary HAW with LLW for treatment if doing so will present clear benefits.4

• While it is plausible that some exempt/out of scope and/or lightly contaminated metals arising from treatment or reclassification to exempt/out-of-scope through enhanced characterisation could be directly reused, most likely some subsequent processing (recycling) will be required, as the metals will typically not be of the correct geometry for immediate reuse. End uses for lightly contaminated material include, for example, their use in shielding in permitted facilities.

4 Please also see the discussion in Section 6.2.4.


Figure 2: Strategic Waste Management Options for Metallic LAW (and Cross-boundary HAW). Note colours and box styles indicate similar processes/steps but are largely included for presentational reasons.


From this, the main options for assessment include:

• Reclassification to exempt/out-of-scope through enhanced characterisation → Release/reuse/recycling

• Enabling/pre-treatment → Surface-decontamination, mechanical → Release/reuse/recycling (bulk) and/or Disposal/discharge (bulk/residues as appropriate)

• Enabling/pre-treatment → Surface-decontamination, chemical → Release/reuse/recycling (bulk) and/or Disposal/discharge (bulk/residues as appropriate)

• Enabling/pre-treatment → Surface-decontamination, thermal/other → Release/reuse/recycling (bulk) and/or Disposal/discharge (bulk/residues as appropriate)

• Enabling/pre-treatment → Melting → Release/reuse/recycling (bulk) and/or Disposal/discharge (bulk/residues as appropriate)

• Enabling/pre-treatment → Supercompaction → Disposal

• Enabling/pre-treatment → No treatment prior to disposal → Disposal

Hybrids of these options are also relevant, and in particular the potential use of surface-decontamination prior to melting. The assessment needs to recognise the importance of enabling and pre-treatment approaches. However, there is a limitation to the extent to which a ‘generic’ BAT can provide specific guidance on their use. With that in mind, for the present study the main differentiators in terms of options for assessment must reflect the ‘main’ treatment stages. The above options list can then be written as:

• Reclassification to exempt/out-of-scope through enhanced characterisation for direct release/reuse/recycling.

• Surface-decontamination, mechanical.

• Surface-decontamination, chemical.

• Surface-decontamination, thermal/other.

• Melting.

• Supercompaction.

• No treatment prior to disposal.

Finally, it is noted that these options, including the combinations shown in Figure 2, have been checked against other studies, in particular Rossiter (2006) and Stevens (2011). The audit confirmed that, although presentational approaches and phraseology vary, the details of the options considered are consistent.

4.4 Waste Populations for Assessment

As described in Section 2, the UK current and forecast inventory of metal LAW, including decommissioning wastes, is extensive and heterogeneous. The nature of decommissioning wastes from legacy facilities also means there is uncertainty in arisings. On this basis, it is considered important that a set of ‘representative’ waste populations are selected that provide the basis for assessing the performance of the


main combined strategic waste management options listed above. These populations need to be generic to help ensure that the assessment covers the main issues and judgements necessary for site-specific BAT studies, and provides useful input to the subsequent development of strategy. It is also important that the waste populations used for the basis of assessment reflect, as far as is appropriate for a generic study, the practical concerns of individual waste producers and treatment suppliers. This reflects comments from the scoping workshop in recognising the complexities associated with managing heterogeneous and potentially mixed-waste streams. The following main waste populations have therefore been identified for assessment purposes.

• Surface-contaminated metals. This waste population set includes:

- ferrous metals

- lead

- aluminium

- copper and brass

- other metals and alloys

• Matrix contaminated metals.

- including matrix contaminated ferrous metals and lead, etc.

• Bulk decommissioning metal streams.

- this represents complex heterogeneous waste streams arising from practical decommissioning e.g. a mix of surface-contaminated and coated metals of various geometries

• Coated metals.

- including rubber/plastic coated metals, galvanized metals, bitumen coated metals etc.5

• Complex components.

- this represents self-contained components that if/when disassembled are likely to yield several different types of metal, and for which some basic use/characterisation information is known to help guide initial choices. Examples include heat exchangers or used fuel flasks. Small complex components e.g. electronics are not central to this example waste population considered directly here.

5 Note that asbestos coated metals will be considered within a separate stream of work, and wastes with a significant organic content were covered under the equivalent Organics BAT study (Paulley, 2014).


5 Assessment Process

5.1 Approach to the Assessment

This section provides a brief summary of the process for the assessment of the treatment strategy options. As described in Section 4, the assessment was undertaken through a three-stage process.

• Preparation of a draft assessment. This involved an initial ‘internal’ project team assessment of options against criteria for the waste populations identified.

• Review at the main workshop. The draft assessment was not intended to derive a formal proposed preferred option or options, or indeed derivation of a proposed BAT strategy. This is a matter for consideration and agreement by stakeholders. Therefore, a main project workshop was held with stakeholders to present, review, challenge and update the assessment and discuss key outcomes.

• Documentation and final review. The outcomes of the process were then captured in the present document, including an iteration of stakeholder review and update.

Further details on each of these process steps are provided in Appendix D.

5.2 ‘Location’ Element of Treatment Strategy Options

As discussed in Section 4, location options for treatment strategy components within the UK (e.g. use of facilities close to waste producers vs. central facilities) are not within the scope of the options comparison. Such aspects merit detailed discussion in the final guidance and strategy to be derived during the integration phase, and in any business cases for future developments that will be informed by the current assessment. However, in terms of a generic, technical BAT comparison of options, such considerations involve factors that are too site-specific to be meaningfully addressed. The issue of whether treatment should be undertaken within the UK or overseas is, however, not site-specific and needs to be addressed. As discussed in more detail in Appendix D, to meet general regulatory and policy requirements for transport and transfrontier shipments, the following BAT outcomes were agreed on this topic for the purposes of the present assessment:

• Wastes will typically be treated within the UK wherever there is capacity and capability to do so using a preferred technique in suitable timeframes.

• Wastes will be treated overseas where a clear waste stream-specific case can be made based upon lack of UK capacity or capability (e.g. for a technique that will clearly deliver substantial environmental benefits, such as melting, and/or capacity limitations for an option that is otherwise available in the UK) or disproportionality (e.g. in cost of the UK solution).

It is beyond the scope of the present BAT study to analyse location options in more detail. The justification for overseas treatment will nearly always be made on a site- or waste stream-specific basis. It is important to recognise that waste transport


issues can be contentious to local stakeholders and require careful consideration within relevant processes.


6 Assessment Outcomes

6.1 Form of Assessment

The assessment recognised that the outputs need to be expressed in the following ways: • Narrative outcomes for key elements of metallic LAW management

strategies (in particular concerning the initial stages of decommissioning and waste management) that are important to recognise but cannot be fully explored in a ‘generic’ BAT as they are very site- and waste stream-specific judgements; and

• The outcomes of the assessments of ‘main’ treatment options for different waste groups, and associated key advantages and disadvantages of the combined waste management strategy options they are associated with.

The outcomes of these assessment stages are summarised below.

6.2 Importance of Choices at Early Stages of Decommissioning and Waste Management

A significant component of the discussions from the initial internal assessment concerned the importance of choices at early stages of the decommissioning and waste management cycle for metallic LAW. This discussion approximately corresponds to the region to the left of the dotted line in Figure 2, although in reality the distinction is very much blurred, as described in subsequent text. It concerns the initial work that will always be undertaken at source during POCO and decommissioning, and related initial waste management steps. As highlighted earlier, it is not possible to provide a generic assessment of options for ‘enabling’ stages as so many aspects are site- and indeed waste stream-specific matters. However, in recognition of the importance of these early judgements, and in the spirit of assisting the subsequent development of guidance (see Cassidy, 2014), a brief summary of relevant considerations is provided below. Note that this primarily draws on standard industry guidance e.g. from the UK LLW strategy (NDA, 2010), supplemented by views expressed at the internal workshop. 6.2.1 Integration of decommissioning and waste management strategies and identification of end-points

In reality the difference between ‘enabling’ and ‘main treatment’ options may not be clearly distinguished; surface-decontamination can be seen as either an enabler or as a main treatment approach, for example. A key point from strategy and guidance is that whatever combinations of approaches are utilised, it is helpful to have an up-front vision of the desired (BAT) end-points for wastes in order to make sure the combination of approaches from decommissioning onwards is supportive of the overall objective. These end-points can themselves be complex: for large simple items, achieving a certain level of decontamination using a particular approach may be the required end-point; for complex decommissioning wastes, there may be several end-points, each mapped to the different metals that might be encountered during disassembly.


In this case, end-points for the waste streams likely to be generated, and associated BAT studies, are likely to be required in advance of the preparation work, ideally informed by initial characterisation estimates of the waste contents and fingerprints. 6.2.2 Importance of considering waste management in decommissioning approaches

A key requirement of the UK LLW strategy is that as much sorting, segregation and characterisation as is practicable should be undertaken at source. This is because in general initial work during decommissioning can have a substantial impact on later waste management efficiencies, and segregation at source is often the most efficient approach. However, this needs to be balanced against ALARP requirements to ensure safety, noting that the overall hazard of the wastes is low. Even where for practical reasons such enabling steps are undertaken at a location other than the source, it is important that the initial decommissioning stages as a minimum are planned to assist subsequent more detailed sorting, segregation and characterisation etc., and do not make it more difficult e.g. by unnecessary mixing of wastes. 6.2.3 Optimisation arguments in planning enabling approaches

There is an important trade-off to be considered in terms of the level of effort utilised in enabling stages and the extent to which it realises other options. For example, for some wastes, initial characterisation may suggest that a mixed waste stream can all be subject to the same main treatment step, and some further disassembly and characterisation is simply required to confirm that. Alternatively, complex wastes that are heterogeneous and for which there is limited initial characterisation data may present a more complex challenge and the end-points may be less clear. In such cases, an optimisation argument needs to be made which balances the level of preparation effort against the likelihood of realising different end-points. This argument will often reflect a ‘best estimate’ judgement on incomplete data, recognising that the level of effort expended for further characterisation should balance the likelihood of achieving additional reuse/recycling/volume reduction against the difficulty, including ALARP considerations, and the costs and other practicability considerations associated with doing so. 6.2.4 Potential value of buffer and decay storage

For some low-volume individual waste streams, it may appear uneconomic to undertake treatment due to the lack of economies of scale. However, the UK LLW strategy notes that buffer storage to allow aggregation of wastes such that the volumes then become economic to treat can be an important element of waste management strategies. This would ideally happen on-site, consistent with the at-source principle but, in particular for smaller producers, there may be integration opportunities associated with combining buffer storage solutions for low hazard wastes. In addition, it is noted that at some larger sites, available space within the licenced site area can be limited, and so an appropriate trade-off decision is typically made. Decay storage falls in to a similar category. For short-lived cross-boundary ILW, a relatively short decay period may be sufficient to allow subsequent treatment as LLW and this may have substantial overall benefits. However, this relies on the availability of appropriate decay stores. Any decay period and storage arrangements for a particular waste form would need to be determined on a case-specific basis.


Blending waste represents a final and related opportunity. Whilst waste ‘dilution’ for the purposes of declassification is clearly outside regulatory expectations in the UK, BAT cases can be made to blend LAW or cross-boundary HAW with LLW for treatment purposes, if doing so will present clear benefits in terms of overall Waste Management Hierarchy alignment. Other practicability considerations (e.g. costs) are also relevant. Note that blending here refers to mixing of wastes for combined treatment as opposed to (for example) co-disposal of discrete ILW items with LLW.

6.3 Outcomes of Assessment of Combined Treatment Strategy Options

6.3.1 Assessment against criteria

The main assessment then focused on addressing the main treatment options that can be applied to metallic LAW after completion of enabling steps. The assessment involved the options and waste populations outlined in Section 4 and the criteria set described in Appendix D. Full details of the assessments are provided in the matrices set out in Appendix E. The assessment was undertaken as follows.

• A ‘full’ assessment for an initial ‘baseline’ waste population was undertaken (surface-contaminated metals).

• Assessments were undertaken for other waste populations (matrix-contaminated metals, mixed decommissioning metals) by highlighting key differences from the ‘baseline’ waste assessment.

For ‘coated metals’ and ‘complex components’ however, it was identified that it would be more helpful to present a general discussion informed by the matrices developed for other waste populations, rather than undertaking an individual assessment. 6.3.2 Summary of assessment outcomes

The following text aims to summarise the key outcomes of the assessment of treatment strategy options against criteria for each waste population. A summary is first provided for bulk surface-contaminated wastes; subsequently, differences in assessment outcomes for the other waste populations are highlighted. For each waste population ‘No treatment prior to disposal’ is considered first, as a baseline against which to compare the advantages of alternative treatment approaches. (a) Surface-Contaminated Metals

No treatment prior to disposal

For LAW metals (and for HAW metals after decay storage), there are some advantages to not undertaking treatment prior to disposal, in that this is a broadly flexible and simple approach. However, this has the substantial disadvantage that no material is targeted for reuse or recycling, and it does not achieve diversion or volume reduction from LLWR. This has several associated implications, including:

• Not delivering benefits associated with higher levels of the Waste Management Hierarchy;


• Not being consistent with priorities from UK LLW policy and strategy and from the Landfill Directive (with exceptions, as it may be BAT for some wastes – see below);

• Cost – in particular for LLW (if not VLLW/LA-LLW) as disposal volume at LLWR is comparatively expensive; and

• The risk that capacity at the LLWR may be challenged if there is not sufficient volume reduction of wastes.

In addition, the option offers limited hazard-reduction prior to disposal, and similarly limited stabilisation of wastes in terms of their long-term environmental performance after disposal, although the process of grouting and containerisation at LLW facilities will provide some benefit. On the other hand, the option avoids energy and resource use associated with treatment and avoids the need for multiple transports by avoiding interim treatment steps. It may also facilitate early completion of the waste management cycle by involving only one main management step. A further consideration is that some level of characterisation and decontamination may be required in order to enable transport safety cases to be made. If no further treatment is intended, the burden on ensuring sufficient characterisation and initial decontamination within enabling steps is potentially increased. Nevertheless, this option must remain part of the portfolio of available approaches, as there will be some problematic low-volume wastes which are particularly challenging to treat and for which direct disposal is the best option. In addition, for VLLW and other relevant lower-activity metals that are capable of being consigned to LA-LLW facilities other than LLWR/Dounreay, direct disposal costs are much lower. The importance of the Waste Management Hierarchy and consistency with UK policy and strategy is not reduced for such wastes, but disproportionality arguments are more likely to be of relevance; this aspect is discussed in more detail in the main BAT outcomes in Section 7. Supercompaction

Supercompaction delivers benefits over no treatment prior to disposal from the perspective of volume reduction, and is a readily-available and well-understood technique. It will only be applicable to a small volume subset of metal wastes but will deliver notable volume reduction. Unlike other decontamination options, however, it will not facilitate reuse or recycling and will not lead to as substantial waste diversion from disposal. In addition, like no treatment prior to disposal, it does not offer passivation. If the supercompaction is not undertaken on site, its use may place extra burden on enabling characterisation and decontamination phases to permit transport. Also, supercompaction off-site would lead to an increased total number of transports compared to no treatment. However, for LLW disposal, costs would be reduced consistent with the volume-reduction achieved. Other treatment options Each of the remaining combined strategic options – associated with surface-decontamination, melting and reclassification to exempt / out-of-scope through enhanced characterisation – are proven to deliver substantial benefits in terms of supporting reuse and recycling, including release of exempt/out-of-scope bulk metal to the market. These benefits are often achieved by use of individual technologies within these categories, or by hybrid options (in particular, surface-decontamination followed by melting). A strong track record of using such approaches has already been established for UK producers, and volumes treated


and thus diverted from disposal have increased significantly since the 2006 BPEO (Rossiter, 2006). This confirms the validity of the 2006 work and the 2011 review (Stevens, 2011) conclusions. The changed market and treatment technology uptake is one of the reasons for the current review. Mechanical Surface-Decontamination

Mechanical surface-decontamination (covering a range of techniques from fluid jetting to grit/shot blasting and other abrasion techniques) is a commonly used and well-understood technique that is applied both at waste producer and at separate treatment provider sites. There is therefore capacity in the market, although careful advance planning involving producers and treatment suppliers, alongside integration with strategies for other industries (e.g. NORM) that might wish to use the same facilities, is necessary to avoid bottlenecks during peaks in decommissioning and waste production. Developing ‘new’ facilities takes time and is often costly, depending upon scale and the nature of the approaches used, although that is the case for any of the main treatment options. Compared to no treatment options, there are additional factors to manage here, such as the production of solid secondary wastes (e.g. contaminated shot/grit) or liquid effluents, and the generation of dust. It is possible that the process can also concentrate activity by removing it from surfaces onto grit and shot blast residue of much smaller volume; for wastes near the ILW boundary this needs to be carefully managed to mitigate against the generation of ILW (where this is undesirable). More broadly, as these are more advanced mechanical processes than others, there is a need to carefully manage safety risks, but it is a well-understood process and safety is appropriately managed as routine. The main technical limitations associated with mechanical surface-decontamination normally concern ensuring that wastes of appropriate geometries are supplied to the process. This requires the correct enabling steps to be in place, but also means that the process is not appropriate for some wastes for which it is not possible, or too challenging, to attain the relevant geometries. In addition, thin gauge metals, and soft metals such as lead are typically not suitable for decontamination via shot/grit blasting. As this technique is typically used to divert wastes from disposal, the disposal element of costs will be lower than for no treatment. However, treatment costs can offset some of this saving, especially if substantial precursor enabling effort is required. Sale of out-of-scope/exempt metal released to the market will also offset costs in part, although the market price fluctuates and is not usually a significant factor in reducing overall costs. Economies of scale realised by effective forward-planning, buffer storage etc. can potentially help further reduce overall costs from a waste producer’s perspective, in particular if coordinated across sites. Chemical Surface-Decontamination

Many of the same arguments for mechanical surface-decontamination apply to chemical surface-decontamination. The main differences are described below. Chemical surface-decontamination covers approaches from acid applications to the use of surfactants, and there are a range of potential delivery techniques, from dipping in baths to gas-fogging. A range of such approaches are common practice and are often practiced at waste producing sites, subject to space and expertise availability. In general there is less capacity to chemically treat wastes at off-site facilities that focus on other approaches. Some of the more advanced chemical


approaches are less technically mature than the simpler decontamination approaches practiced at decommissioning sites. There are chemical safety issues to be managed, but again doing so is standard practice. Two of the main advantages over mechanical surface-decontamination include the ability to target particular contaminants with a particular chemical technique, and also (depending upon the application approach) chemical decontamination can be much less geometry dependent; indeed, some variations can be applied to the internals of components with complex geometries. However, for other classes of contamination and metal type, mechanical approaches may offer higher decontamination levels. Often, the two are used in combination. Secondary wastes are essentially contaminated effluents to be managed within permitted discharge regimes. Chemical residues, for relevant processes, also need to be carefully managed and may constrain subsequent treatment and disposal routes. An important further factor to be aware of is the WAC of final disposal facilities for metals and residues; in particular there are strict limits on complexants within disposals at LLWR. Thermal Surface-Decontamination

Thermal surface-decontamination again shares many of the advantages, and drawbacks, of the other surface-decontamination approaches. However, this is much more of a specific or niche application, often including the use of laser ablation or thermal scarifying (e.g. to remove paint) for specific aspects of wastes. Nevertheless, it can provide an important part of an overall waste treatment strategy. As for mechanical-decontamination, it works on exposed surfaces and may require size reduction to obtain the relevant geometries. It is, however, often a more flexible, in-situ approach using equipment that can be hand-held. A subset of thermal approaches concerns the use of heat to directly treat particular metals e.g. sodium, lithium which have specific chemical hazards. In this case, the approach is a complete thermal treatment rather than a specific surface-decontamination process, but this is applicable only to a comparatively small volume of wastes. A further subset concerns the use of incineration to remove organic coatings. This is essentially the use of incineration to treat mixed-material wastes, which has been considered separately in the previous Organic Waste BAT (Paulley, 2014). Melting

Melting of surface-contaminated metals can lead to the most substantial levels of release/reuse/recycling of all the technologies listed. This may be achieved using melting as the single main treatment step, or in combination with prior surface-decontamination. When it is used in combination, this can lead to multiple handling and (if treated on more than one site) increased transports compared to single step treatments. It is arguably a complex process, but a common approach whereby risks are routinely and effectively managed. Off-gases and related effluents need to be managed via an appropriately permitted route. The main secondary waste comprises the slag produced during the melting process. The process is necessarily energy intensive.


A drawback of melting is the absence of UK-based capability and the need therefore to transport overseas and justify trans-boundary treatment. However, as noted in Section 5.2, capacity and capability arguments are available to provide the basis for such justifications, and this has not proved a barrier to melting overseas to date. The factors to balance are then related to transport processes and related costs. Although there is a need to make sure facility WAC are met (e.g. for free liquids) melting is one of the most flexible approaches in that it can deal with a wide variety of contaminants, metal types and geometries; in the latter case, the main restrictions concern transport to the melter and the size-reduction required to allow its entry into the melting process. This can reduce the burden on enabling sorting, segregation, characterisation and pre-treatment steps. Also, this process can deliver a wider range of final management routes, such as recycling of lightly-contaminated material within permitted facilities (including as part of overseas treatment). Melting can be specifically beneficial to certain wastes in that it can help de-risk complex products with ‘hot spots’. On the other hand, if used on its own, for specific classes of metals/contaminants its use can lead to homogenisation of surface-contamination throughout the metal matrix. In such circumstances this can lead to limited volume reduction while preventing further treatment opportunities. However, this risk is typically controlled by appropriate characterisation and/or pre-treatment. As for surface-decontamination options, the cost of disposal will be much reduced if decontamination is successful and leads to significant release, reuse or recycling of bulk metal. This will be offset by the treatment cost. Again an additional contribution to costs will be obtained from sale of any released exempt/out-of-scope metal. Note that if decontamination is not completely successful, and the returned metal remains contaminated, the melting and reforming process will still lead to a volume reduction. Specifically for VLLW, the assessors noted that there is a potential to use some VLLW metal as an input to feedstock to manage throughput volumes in order to aid efficiencies in operation of melting facilities. In such cases, the cost of VLLW melting could be partially offset. However, the extent of this opportunity is not clear. Reclassification to exempt/out-of-scope through enhanced characterisation

Reclassification to exempt/out-of-scope through enhanced characterisation clearly in principle presents an important opportunity to achieve release/reuse/recycling of metal without undertaking a significant main treatment process step. However, and in particular for complex geometry/fingerprint wastes, the effort required to undertake this characterisation (with associated disassembly etc.) could still be substantial. Therefore, the assessors considered this approach is most likely to be undertaken for wastes where prior knowledge from initial characterisation provides confidence there is a realistic prospect of success from characterisation effort alone. A range of inputs may be required, from desk-studies to disassembly and/or washing (for example) to allow characterisation. Given the potential for disassembly etc., there will be handling hazards to be managed; however, this is a commonly used approach and these can be managed with standard practice. In terms of cost, this is likely to deliver benefits if the effort is successful and disposal costs avoided. If it is not successful, then additional costs will have been incurred, although these may be mitigated in part if the enhanced characterisation in any case proves helpful by supporting the efficiency of subsequent treatment steps.


Specifically for VLLW, it is notable that the cost differential of down-categorising wastes will be less significant than for LLW/cross-boundary HAW. Summary of outcomes for Surface-Contaminated Metals

Reclassification to exempt/out-of-scope through enhanced characterisation clearly represents a very attractive solution for those wastes thought to be near relevant contamination boundaries. However, for most of the wastes within scope, it is likely that treatment will be necessary to deliver substantial benefits in achieving higher levels of the Waste Management Hierarchy and the associated diversion of wastes from disposal. Melting and surface-decontamination techniques offer effective approaches for achieving decontamination and diversion through proven techniques. These formed the basis of the 2006 and 2011 BPEO and review outcomes (Rossiter, 2006; Stevens, 2011) and that logic still holds. Indeed, the experience since 2006 of significant metal diversion from LLWR through the use of these approaches reinforces their value. If there is a choice to be made between melting and surface-decontamination approaches for specific wastes and both offer similar opportunities in terms of release and diversion, factors such as trans-boundary movement may favour treatment in the UK, provided capacity is available. For a subset of wastes, treatment may not be possible or practicable. In such cases, supercompaction, and direct disposal without further treatment (most likely in that order) could still be BAT. However, this is likely to be the case for a small proportion of wastes only. For VLLW/LA LLW, the same logic applies as for LLW (and decay stored cross-boundary HAW). The principles of the Waste Management Hierarchy, UK strategy and the Landfill Directive strongly favour characterisation or treatment for diversion and volume reduction. However, it is recognised that the cost savings of avoiding disposal can be much less significant. This suggests that, for a range of wastes, disproportionality arguments may be of relevance. The assessors noted that such arguments will need to be made on a case-by-case basis, reflecting the nature of particular wastes and the potential treatment routes and relative costs of achieving decontamination and final disposal. The assessors also noted that approaches such as buffer storage may help economy of scale considerations in assessing relative costs. (b) Matrix Contaminated Metals

A range of the arguments described for surface-contaminated metals also apply to matrix-contaminated metals. The primary difference is that surface-decontamination options will only be of benefit for matrix-contaminated metals if surface-contamination is also present. Of the treatment options listed, it is only melting that offers the prospect of decontamination of the metal matrix. For this reason, it is likely to feature strongly in any BAT study for bulk matrix-contaminated metals, even though its use presently relies on overseas facilities. For many contaminants, melting has the potential to realise the release/reuse/recycling benefits listed for surface-contaminated metals, with the contaminants being retained in the slag or in scrubbers and filters for off-gas systems. For certain contaminants however, such as C-14 and Co-60 that arise from activation, the contaminants may be intrinsically bound with the metal matrix; therefore decontamination rates will be lower and typically the metal ingots produced will still be contaminated. Nevertheless, the reforming process will in itself


lead to volume reduction through eliminating voids and returning regular shaped ingots. As for surface-contaminated metals, reclassification to exempt/out-of-scope through enhanced characterisation, if achievable, again offers substantial benefits. However, it is possible that assay of matrix-contaminated metals could offer additional challenges compared to surface-contamination, depending upon the nature of the process that led to the contamination, and the extent of knowledge about it and the resulting contamination levels. It is also notable that some melting routes offer the possibility of melting for recycling of lightly contaminated metal within the nuclear industry if full decontamination is not achieved. The draft assessment of the use of supercompaction or direct disposal, and of the balance of costs for VLLW/LA LLW compared to other LLW fingerprints, is similar to that for surface-contaminated metals. (c) Mixed Decommissioning Metals

This category concerns metals that remain mixed after initial enabling and decommissioning steps at source have been completed. The discussion on early stages of waste management in Section 6.2, whilst relevant to all wastes, is perhaps particularly relevant here. It was noted that, in general, mixed wastes can lead to handling complications, but this is nevertheless standard practice and can be effectively managed. For mixed metals, direct disposal without further treatment is perhaps the most ‘flexible’ approach in terms of avoiding further complications in disassembly and treatment, but with the drawbacks described previously. Further size reduction, segregation and disassembly is likely to be required for supercompaction, as there are restrictions on certain waste types that are likely to be found in mixed metals streams, and to achieve the geometries required for mechanical surface-decontamination. However, if there is sufficient characterisation data available despite the mixed nature of the waste stream, chemical approaches may offer some advantages even without the same level of segregation and disassembly, by targeting particular contaminants or coatings. More often, however, sorting and segregation would be required first. Thermal treatment success would also be dependent on enabling steps. Melting can also be a flexible approach, depending upon the nature of the mixed metal stream. Provided assurances can be made that a stream will meet WAC, it has one of the broader envelopes of the treatment processes and delivers high levels of decontamination. For waste streams with a good prospect of being treated with melting, the level of characterisation necessary to demonstrate that it meets the WAC will be one of the judgements made in ‘enabling’ phases on the extent to which initial segregation and characterisation needs to be undertaken. That is, the ‘end point’ needs to be borne in mind throughout the waste management process. This is, of course, generally true also for the other technologies and indeed other wastes (see also Section 6.2), but is perhaps particularly relevant to note here. Reclassification to exempt/out-of-scope through enhanced characterisation for the purposes of release/reuse/recycling is likely to be particularly challenging for a


mixed waste set, until it is sorted and segregated and can be treated as for other wastes. The assessors noted that the balance of costs will be influenced by where different actions are taken. As noted previously, enabling activities at source typically deliver the most substantial benefits, but this is not always true; economies of scale, availability of treatment facilities and approaches such as buffer storage can also influence efficiencies and costs. Previous comments on disproportionality arguments for VLLW/LA LLW and practicability considerations for other waste streams again apply here also. (d) Coated Metals

It was agreed during the internal assessment process that, owing to the diversity of this group and the range of different issues associated with coated metals, a separate assessment table would not be appropriate for this waste stream. Instead the issues would be better considered via a qualitative discussion drawing on the assessments for previous waste types and specific considerations to be taken into account. Specific issues and considerations that apply to coated metals, identified during the initial assessment, have been summarised in the simplified assessment table provided in Appendix E. To summarise, the advantages and disadvantages of different options for surface-contaminated metals in the main also apply here. Differences highlighted reflect the extra complexities that can be associated with coated metals, noting that a variety of coatings fall within this broad classification. Coated metals can require additional enabling/pre-treatment steps to realise the main treatment stages, e.g. disassembly and stripping, compared to some other waste classes. After disassembly/stripping, the wastes may then fall into one of the other categories (e.g. surface-contaminated), or indeed within a different class of wastes (organics, for example, if all of the contamination is associated with the stripped coating). The assessors noted that for supercompaction, limits on some material types e.g. rubber may be of relevance here. More broadly, for some complex, compactable mixed wastes which have specific coatings that can be difficult to efficiently remove, e.g. thin coated metals (such as wires), supercompaction can offer some benefits. Surface-decontamination approaches have both strengths and weaknesses for different classes of coated metals. Shot and grit blasting may not be effective for some coatings, e.g. galvanized metals (where the galvanized layer is thick enough to require very large amounts of shot) or rubber. For others (e.g. paint), blasting and other forms of mechanical surface-decontamination can offer significant benefit, in particular if the contamination is within the paint, although careful management of dust and the contaminated shot/grit (or liquid) product is required. On the other hand, as for other wastes, some geometries will be challenging. Chemical-decontamination approaches can provide significant benefit for certain coatings, but not all coatings are amenable to chemical treatment (for example, it will not remove galvanized surfaces).


Thermal surface-degradation is particularly suited to helping deal with a subset of coatings, and indeed coating stripping is one of the main applications for flame and laser scarifying. Note that incineration of wastes with organic coatings is dealt with via a different generic BAT study (Paulley, 2014). Reclassification to exempt/out-of-scope through enhanced characterisation would again yield specific advantages for particular wastes, but surface coatings may make assay more challenging, depending on the coating, and require stripping etc. Arguments about direct disposal without further treatment and VLLW/LA LLW etc. remain similar to those for surface-contaminated metals. (e) Complex Components

It was agreed by the assessors that this category would be considered via a qualitative discussion drawing on the assessments for previous waste types, rather than developing a specific options matrix. This waste category concerns mixed LAW metals within complex components (as defined in Section 4.4) where there is some prior, if not complete, knowledge of the likely makeup of the metals and the contamination fingerprints associated with them, based upon their use and history. To an extent, this category of metals can be considered to be similar to the ‘Mixed Decommissioning Metals’ waste population discussed above. However, if this is assumed to represent discrete items with some advance characterisation knowledge, it may be possible to deal with the component more efficiently. For example, it may be known in advance that the component can be easily disassembled and the contents sentenced for treatment in accordance with the BAT choices for the individual classes of metals that will be obtained during disassembly. Alternatively, it may be that enough is known of the component to sentence it as a whole to the same treatment route, e.g. melting, provided there is sufficient confidence that all contained metals/materials will meet the WAC of the treatment facility and that any transport requirements can also be met (e.g. by packaging in an appropriate container, or transporting as a discrete item with no loose contamination etc.). The choice made (as for other waste categories) will depend upon the prior characterisation knowledge of the component, based upon desk studies and enabling activities. Any additional preparation or characterisation steps will need to be undertaken consistent with supporting the intended treatment route identified as most likely to be BAT on the basis of the initial knowledge.6 Prior establishment of BAT routes for individual metal categories likely to be encountered upon disassembly will also be important for overall efficiency.

6 The discussion in Section 6.2 while generally applicable is of particular relevance for this

waste category.


7 Overall Process Outcomes

7.1 Main Outcomes

The following overall outcomes have been identified. These were derived on the basis of feedback from the main workshop and summarise the more detailed outcomes presented in Section 6, which are in turn underpinned by the tables presented in Appendix E. Importance of early phases of waste management A key theme of the assessment concerned the balance between enabling approaches and main treatment options, including the need to make early decisions based upon available data on the best prospect for waste treatment. These decisions will take account of the likelihood of achieving desired end points reflecting upper levels of the Waste Management Hierarchy, given the understanding of wastes and related uncertainties. Related plans and justifications will take into account estimates of the relative benefits of different levels of effort at enabling stages, against the main treatment technologies they will support and the final outcomes that may be achieved. Management approaches such as buffer or decay storage and blending (but excluding dilution) also need to be carefully considered, to ensure relevant opportunities are recognised. Aligned with this it is important to recognise that there is not a clear dividing line between work that should be undertaken during and after decommissioning, or during enabling/early waste management and main treatment phases, or on- or off-producing sites, given the wide range of wastes within the remit of this generic study. Assessors recognised that is it important to consider the potential final end-points for different waste types throughout all programme stages, including developing BAT cases for metal types in advance that can then be applied when complex waste streams or components are characterised, disassembled and/or treated leading to segregation. Hierarchy of main treatment options A key conclusion from the study was that there is no one option, or combination of options, that will be BAT for all metallic wastes. For all wastes, the characteristics of individual waste streams will need to be reviewed within the context of individual producer or treatment-provider strategies in order to identify BAT. For example, while a strong justification would be required, for some specific problematic LAW wastes, no treatment prior to disposal might be the BAT main treatment option. More broadly, cost disproportionality arguments may be important in evaluating BAT for lower hazard (VLLW/LA LLW) wastes, although assessors recognised that experience of treating such wastes indicates that with appropriate planning and characterisation, treatment costs are often not a disproportionate element within the overall life-cycle management spend. Indeed the majority of the volumes of metals sentenced for treatment by UK waste producers over recent years have been LA-LLW. More broadly it was recognised that UK waste producers have successfully consigned 1000s of tonnes of LLW including LA-LLW metals for treatment over recent years.


More generally, the assessments indicate that it is possible to establish a hierarchy of preferred treatment options at the ‘generic’ national strategic level. The hierarchy indicates which are most likely to be associated with desirable end-points, noting that for individual waste streams with specific characteristics, applicability and proportionality arguments will apply. The generic BAT hierarchy is summarised in Table 2. Note that the hierarchy focuses on what can be achieved for a substantial proportion of bulk metals, i.e. the majority of the inventory. For each approach, solid secondary wastes for disposal and aqueous and gaseous effluents for discharge will be produced but for simplicity they are not represented in the table. Also, options are listed against the ‘main’ end-points they are likely to be utilised for, but it is recognised that this is a generalisation.


Table 2: Strategic BAT Outcomes: Hierarchy of Main Treatment Options for Metal LAW

Hierarchy End-point7 Options

Most

preferred

on ‘generic’

basis

Release of exempt/

out-of-scope bulk

metal to market

Reclassification to exempt/out-of-scope through enhanced characterisation: For those wastes for which

initial characterisation provides confidence this can be achieved, this option offers clear benefits.

Surface-decontamination: These options, in particular mechanical surface-decontamination but also chemical

and thermal approaches, can lead to release of a range of metals without requiring subsequent treatment steps.

Melting: Melting can also lead to release of a range of metals. Where surface-decontamination and melting

options have a similar technical prospect of delivering release, wider differentiators e.g. trans-boundary

transportation are relevant.

Surface-decontamination and melting: This combination can often offer the best prospect of delivering bulk

metals for release. It is a two stage process but in practice most treatments will involve substantial enabling steps.

Reuse/recycling of

bulk contaminated

metal

Surface-decontamination: Similar to ‘release’ above, but with the reuse/recycling end-point.

Melting: Similar to ‘release’ above. Note also that some melting strategies for overseas facilities are used to

produce low contamination metals that can be recycled (and in limited cases, reused) within the nuclear industry.

Surface-decontamination and melting: Similar to ‘release’ above, but with the reuse/recycling end-point.

Disposal of bulk

metal with volume

reduction

Melting: Provides size reduction e.g. through re-forming of bulk metals, with some passivation of the waste form.

Supercompaction: Can provide size-reduction for a subset of relevant malleable wastes, with limited passivation.

Least

preferred

Disposal of bulk

metal

No treatment prior to disposal:8 Remains a solution for wastes whereby it is too problematic or otherwise

disproportionate to treat them.

7 As discussed above, this focuses on end-points for bulk metal, recognising the need for disposal/discharge routes for secondary wastes.

8 Note that in-situ disposal represents a ‘special case’ that essentially sits outside this hierarchy.


7.2 Opportunities and Wider Issues for Consideration

Through the scoping and assessment process, information on additional issues outside the scope of a ‘generic’ BAT study, but of relevance to subsequent integration and strategy development processes, were recorded. These opportunities and wider issues are noted below.

• The need to consider more broadly, and ideally provide guidance on the use of in-situ disposal for metals and indeed other wastes, was noted.

• The use of buffer and decay storage either at producer or potentially at central or regional sites, or even at treatment supplier/disposal sites would support optimised waste management through provision of storage capacity, as providing such storage capacity can help address peaks and troughs in waste production and lead to ‘economies of scale’ in treatment.

• As decommissioning ramps up across Europe there is a potential for challenges to capacity to supply melting services, for example in the medium term. The UK may wish to explore options to address this.

• The UK NORM strategy has recently been published (DECC et al, 2014). It is possible that future NORM treatment may challenge capacity at common facilities. Alternatively, there is an opportunity that integration with NORM treatment could realise opportunities such as joint business cases for metal treatment facilities, Better alignment between industries will help planning and assist avoiding cross-industry pinch-points in capacity usage.

• Similarly as the New Build process continues and waste management plans are produced integration activities will help ensure mutual support across waste-related challenges.

• There is a need for better partnership working across the industry to ensure the ongoing robustness and viability of the supply chain, given its vital role. In support of this, enhancements to planning future waste schedules, early commitments to supply chain utilisation and learning from experience as decommissioning progresses may be important factors.

• Some options/technologies may have a role in the management of metallic LAW but for more niche applications (for example, specific technologies within the chemical decontamination and thermal decontamination categories) there may be a need for collaborative R&D to explore the opportunities presented by such technologies, including identifying where these are useful, and the organisations that will need to collaborate to realise opportunities.

• Cost is recognised as an important factor to waste generators in decision making for LAW, including for metallic wastes. There is recognition that lifecycle cost is a key measure and further work on cost norms may be of benefit (for both treatment and other aspects of the waste management lifecycle) to support waste generators in the derivation and consideration of lifecycle cost in local decision making. There is an opportunity for further consideration of this within the planned guidance development work.


8 References

Cassidy, H., 2014. National Strategic Metallic BAT: Stakeholder Scoping Workshop – Response to stakeholder engagement. LLWR document reference NWP/REP/065. Department of Energy and Climate Change (DECC), the Scottish Government, the Welsh Government and the Northern Ireland Department of the Environment, 2014. Strategy for the management of Naturally Occurring Radioactive Material (NORM) waste in the United Kingdom. Defra, DTI and the Devolved Administrations, 2007. Policy for the Long Term Management of Solid Low Level Radioactive Waste in the United Kingdom. Donohew, A., Dooley, S., Keep, M., Kruse, P., and Pugh, D., 2009. Strategic BPEO study for Very Low Level Waste. Volume 1: Final Report. ENTEC report to LLWR Ltd. Environment Agencies Requirements Working Group (EARWG), 2013. Waste Minimisation Database. http://www.rwbestpractice.co.uk/ Environment Agency (EA), 2010. Radioactive Substances Regulation: Principles of optimisation in the management and disposal of radioactive waste. Version 2.0. Environment Agency (EA) and the Scottish Environmental Protection Agency (SEPA), 2004. Guidance for the Environment Agencies’ Assessment of Best Practicable Environmental Option Studies at Nuclear Sites. LLWR, 2014. LLWR National Waste Programme: Strategic Review 2013. NWP/REP/047, Issue 2. LLWR and NDA, 2009. UK Management of Solid Low Level Radioactive Waste from the Nuclear Industry: Metal Decontamination Study. NLWS/LLWR/08 – Rev 1. Magnox Ltd, 2011. Heat Exchanger Disposal Best Available Techniques (BAT) Study. Document BNLS/REP/BD/0099/11. Nuclear Decommissioning Agency (NDA), 2010. UK Strategy for the Management of Solid Low Level Radioactive Waste from the Nuclear Industry. Nuclear Industry Safety Directors Forum (NISDF), 2010. Best Available Techniques (BAT) for the Management of the Generation and Disposal of Radioactive Wastes: A Nuclear Industry Code of Practice. Paulley, A., 2014. National Strategic BAT for Organic Low Level Radioactive Waste: Final BAT Report. Jacobs report 60X50008_01. Rossiter, D., 2006. Strategic BPEO For Metal Waste Management – Options Evaluation. Studsvik report to LLWR Ltd, P0090/TR/002 Revision A. Stevens, L., 2011. Review of Strategic Options for Metallic Waste. ENTEC report to LLWR Ltd, WMS-REP-NLWS/LLWR/25, Issue 1.

Doc No: B2010100 Metal LAW National BAT Final Report

Appendix A Existing Metallic LAW Waste Management Arrangements and Forecasts of Arisings

Size Reduction and Surface-Decontamination Sites across the nuclear industry have varying capabilities for size reduction, sorting and segregation, and decontamination. Two NDA sites operate their own large-scale decontamination facilities including ‘wheelabrator’ facilities at Sellafield and the Winfrith Abrasive Cleaning Machine. These facilities process metals that have relatively low levels of contamination and simple geometries, by cutting the metal objects to suitable sizes and geometries and then grit-blasting the surface of the metal in order to reach exemption levels. The secondary wastes (primarily blasting residues) are then disposed of via the normal lower activity waste route. Currently, any material failing to meet the ‘exemption’ criteria after processing is sentenced as LLW or LA-LLW. The Metals Recycling Facility operated by Studsvik at Lillyhall in Cumbria also utilises sorting, cutting and grit blasting techniques to achieve decontamination. The Studsvik facility in Sweden and Siempelkamp’s in Germany also provide metal surface-decontamination services, but in these cases primarily as a precursor to metal melting rather than as a separate service. Chemical surface-decontamination approaches are often used in decommissioning processes at waste generator sites, with techniques including the use of solvents and detergents. Within this category, chemical complexants are also sometimes applied, but their use is typically constrained by waste acceptance criteria for disposal sites such as the LLWR as they are persistent and influence the release behaviour of contaminants after disposal. The use of complexants and their management through the process needs to be carefully considered, as even very low residual concentrations of certain complexants can cause difficulties for final disposal of solid LLW. Metal Melting Melting facilities typically operate on a campaign basis, depending upon the nature of the metals to be processed. Often, metals for melting are subject to surface-decontamination first; although melting is also an effective method for treating many surface-contaminated wastes, undertaking both steps can maximise the volume of bulk metal for subsequent release or declassification. For matrix contamination, surface-decontamination cannot be effective by definition, unless the matrix contamination is in the main located sufficiently close to the surface such that it can be removed by abrasion and removal of the metal surface itself. During melting, most contaminants will be partitioned to the slag and separated from the bulk metal, or will be driven up the stack and captured in filters. For many contaminants, the fraction of inventory retained in the final metal will be no more than a few % and often lower than 1%. Similarly the proportion of metal that is ‘clean’ and suitable for reuse following melting is often around or greater than 95% by volume (e.g. NCRP, 2003; LLWR and NDA, 2009). For a subset of contaminants that are closely associated with the metal matrix (e.g. Co-60 or C-14 produced by activation of impurities in steels), a more notable proportion may instead remain in the bulk metal. In such cases, the metal undergoes a reduction of radiological inventory due to the proportion of


contamination that is released to slags and filters, and a reduction in volume of the final wastes due to voidage elimination. It is notable however that the majority of such activated metals are currently forecast to arise in the medium to longer term (i.e. decades from now), consistent with future reactor decommissioning schedules. There are no permitted radioactive waste metal melting facilities in the UK. Therefore a range of UK waste producers utilise melting facilities based overseas. To date these have been primarily used for ferrous metals and include: • Energy Solutions in the USA (Bear Creek);

• Siempelkamp in Germany (Krefeld), via Energy Solutions; and

• Studsvik in Sweden (Nyköping).

Supercompaction A high-force supercompactor authorised for radioactive waste treatment is located at the WAMAC facility at Sellafield, and one is also operated by Tradebe Inutec at the Winfrith site. The supercompaction process typically leads to a final puck volume that is about 30% of the raw waste volume for mixed compactable wastes. This can be useful for a small proportion of metals that are thin gauge.

End Point Options Consistent with the principles of UK LLW strategy and the outcomes of the existing strategic BAT/BPEO studies for lower activity metallic wastes (Rossiter, 2006; Stevens, 2011), bulk metals are treated and released as out-of-scope/exempt for recycling wherever practicable. Treatment for reuse e.g. of lightly contaminated metal within the nuclear industry is then also favoured over other end-points. Secondary wastes, and bulk metals that cannot be decontaminated for release, are discharged (in the case of gaseous and liquid effluents) or disposed to appropriate facilities (for solid secondary wastes and bulk metals) consistent with Permitting requirements. In addition, the potential for in-situ disposal for certain wastes should not be discounted. For solid wastes that require disposal, a range of non-engineered and engineered facilities are utilised, depending upon the nature of the wastes. Treated LLW, including stabilised slag melting residues, filters, metal ingots not suitable for release and supercompacted pucks, are disposed of to engineered facilities at either the LLWR near Drigg, Cumbria, or (specifically in the case of Dounreay and Vulcan wastes) will be disposed to the LLW facilities at Dounreay, once they are operational. Untreated metal disposals without volume reduction can also be accepted, although a strong BAT case is required. At both LLWR and Dounreay, wastes within containers are grouted (if they are not already grouted prior to receipt) and disposed of to concrete-lined vaults. The grouting and containerisation process adds significantly to the effective volume of wastes disposed. In the past, direct grouting in-situ of large metallic components has also been practiced at LLWR. A range of further commercial disposal facilities accept VLLW and LA-LLW metals. Here containerisation is not always required and disposal costs are typically much lower than for LLWR. Disposal of untreated bulk metals is practiced, although the


Landfill Directive (as well as considerations such as the Waste Management Hierarchy and associated BAT arguments) serves to discourage this wherever feasible. Examples of sites currently permitted to accept VLLW and/or LA-LLW materials for disposal are:

• Augean − East Northants Resource Management Facility.

• SITA − Clifton Marsh Landfill Site.

• FCC − Lillyhall Landfill Site.

Current Forecasts for Waste Arisings UK lower activity waste producers provide estimates of future waste arisings in support of the collation of the UK National Radioactive Waste Inventory (NDA, 2014). These estimates are subject to the significant uncertainties inherent in decommissioning historic facilities, but represent the best projections on the basis of available data and provide useful context to the present study. Projections indicate metallic wastes are likely to be one of the largest future waste streams within the lower activity waste category along with soil and rubble, and ‘unknown’ material (material for which insufficient characterisation information is available but is assumed as ‘concrete, cement and sand’ in the 2013 UKRWI) (see Figure A1). For VLLW, metals production is also significant, although the total volumes in the category are dominated by other structural materials including unknown material (assumed as concrete, cement and sand) and soil and rubble (Figure A2)9. The largest metallic waste producing organisations in the next few decades are projected to be Sellafield Ltd and Magnox Ltd, associated with the decommissioning of legacy facilities at the Sellafield site and the Magnox power stations. Other key producers will include EDF Energy Ltd, Research Sites Restoration Limited (RSRL) and Dounreay Site Restoration Limited (DSRL).

Figure A1: Forecast LLW arisings only by material content (source: LLWR Strategic Review 2013 (LLWR, 2014) – note figure assumes annual waste arisings for each waste stream have a standard composition)

9

For context, it is noted that the 2013 UKRWI (NDA, 2014) total forecast arisings of all LLW and VLLW are around 1.4 million m

3 (1.7 m te) and 2.8 million m

3 (2.9 m te) respectively.


Figure A2: Forecast VLLW arisings only by material content (source: LLWR Strategic Review 2013 (LLWR, 2014) – note figure assumes annual waste arisings for each waste stream have a standard composition)

Appendix A References LLWR, 2014. LLWR National Waste Programme: Strategic Review 2013. NWP/REP/047, Issue 2. LLWR and NDA, 2009. UK Management of Solid Low Level Radioactive Waste from the Nuclear Industry: Metal Decontamination Study. NLWS/LLWR/08 – Rev 1. NCRP, 2003. NCRP Report No. 141: Managing Potentially Radioactive Scrap Metal. Nuclear Decommissioning Agency (NDA), 2014. The 2013 UK Radioactive Waste Inventory. Rossiter, D., 2006. Strategic BPEO For Metal Waste Management – Options Evaluation. Studsvik report to LLWR Ltd, P0090/TR/002 Revision A. Stevens, L., 2011. Review of Strategic Options for Metallic Waste. ENTEC report to LLWR Ltd, WMS-REP-NLWS/LLWR/25, Issue 1.


Appendix B Process Overview

Overview The interpretation of BAT in the context of radioactive waste management has tended to adopt a broad remit, reflecting the desire to minimise, so far as is practicable, the release of radioactivity to the environment whilst also taking into account a wider range of factors. Such factors include cost-effectiveness, technological status and feasibility, operational safety, wider environmental considerations (such as energy and other resource use) and socio-economic factors (EA, 2010; EA and SEPA, 2004). This broad balance between potentially conflicting objectives is particularly relevant in the context of activities on nuclear licensed sites, where there is a legal requirement on site licensees to demonstrate that the risks associated with operations have been reduced to levels that are as low as reasonably practicable (ALARP). The Environment Agency (EA) has recognised that the demonstration of BAT (or more broadly in EA guidance, optimisation) may vary, but that in all cases the overall assessment process can be described simply as comprising two main steps: • Asking if there is anything further that can be done to reduce doses to

people; and then

• Implementing that, unless the associated detriments are grossly disproportionate to the benefits gained.

There are no definitive conventions for demonstrating gross disproportion in relation to achieving BAT; indeed, the EA considers that “sound judgment and a clear, logical argument” (EA, 2010) can be sufficient to make a successful case. Key Steps The following section sets out the four key steps for this BAT study. As mentioned in the main text, it is designed to follow good practice for BAT assessment as defined in relevant guidance documents (EA, 2010; NISDF, 2010). The main elements are identified in Figure 1 of the main text. Study Scoping The primary aim of this initial step in the BAT assessment process was for the project team and key stakeholders to develop a common understanding regarding the objectives, scope and context of the study. It was also an opportunity to define specific assumptions and constraints. This provided a basis for the initial identification and characterisation of options to be considered in the assessment. The main activities associated with Scoping were:

• Develop the overall options appraisal programme, incorporating the definition of objectives, constraints, and assumptions.

• Identify key stakeholders and develop a plan to ensure they are effectively engaged.


• Agree an approach to identifying and characterising options, including appropriate recognition of ‘enabling’ technologies (e.g. sorting and segregation) as well as primary treatment technologies, leading to an initial long-list of technologies.

• Agree a provisional set of screening criteria and constraints that can be used to short-list the options.

• Agree a provisional set of assessment criteria. These will be the factors against which the performance of options is assessed, in order to provide a basis for comparing them.

• Undertake a literature review with a view to describing the options in sufficient detail for assessment and identify any data gaps that may need to be filled in advance of the main assessment phase.

Options Screening and Initial Assessment In this phase, the initial long-list of options identified during scoping was further developed and subject to initial assessment. The aim of the long-list was to describe all technologies that could plausibly provide a part, on their own or in conjunction with others, of an option that could potentially deliver benefits for the management of the UK’s metallic lower activity wastes against the objectives previously described. Hence ‘enabling technologies’ were identified, as well as the primary management technologies, and appropriately (and potentially independently) addressed10. The initial long-list made use of a range of information from best-practice resources, including existing site waste management plans and Integrated Waste Strategies, BAT studies, UK LLW strategy documents and generic resources such as EARWG (2013). The long-list was then screened against appropriate criteria (Section 4 of the main text) in order to remove options that were assessed as not being sufficiently credible to warrant more detailed assessment. The outcomes from the screening process were presented and tested at the main project workshop. Main Assessment and Workshop The short-list of options identified following the screening phase was used to develop a set of generic combined life-cycle management options for the main BAT assessment. These options were then subject to an initial draft assessment against the assessment criteria (see Appendix D) using a multi-criteria decision-analysis (MCDA) methodology. This process is considered robust, systematic and evidence-based. The assessment drew on the knowledge and experience of a range of specialists invited to an internal workshop. The outcomes were subsequently reviewed and developed in detail by a full range of experts at the main stakeholder workshop. A qualitative, rather than fully quantitative, scoring scheme was used within the MCDA analysis. This is based upon experience of executing high-level strategic BAT studies, whereby the complexities of the decisions involved and the uncertainties that apply do not lend themselves to quantitative scoring. Consistent

10

In this context, enabling techniques are activities that are required to render the waste stream suitable for the primary management techniques. An example of an enabling technique would be sorting of a waste stream to segregate material for melting.


with other recent generic BAT studies, the focus is therefore on identifying the key strengths and weaknesses of different options against each criterion and understanding the differentiators between options they imply and the key benefits and trade-offs. This approach has the advantage of ensuring the study focuses on the key issues and does not get bogged down in uncertainties. It is also more flexible and can more easily accommodate ‘hybrids’ (also known as combinations or sequences) of options. The assessment was conducted at a high level (national and generic). However, it provided an opportunity to collate views on the key factors that will drive site-specific preferences. To help collate views, in addition to seeking input to the main options assessment, questions such as the following were asked at the main stakeholder workshop:

• If this technique is the overall generic BAT outcome, what might stop an individual site adopting it?

• What are the enablers that would be required to open up this route for specific sites?

The aim here was to provide an indication of the way in which site-specific adoption of a generic option will occur and to help test how robust each option is to variations in waste producer considerations and assumptions, in order to support assessment of issues, opportunities and priorities. Subsequent to the workshop, the options assessment and the draft generic BAT report (i.e. this report) was updated to take account of feedback received. Workshop participants and observers will be given the chance to comment on these updates, for example to ensure factual accuracy. The report will then be updated to represent the formal outcome of this stage of the process. Integration As noted previously, BAT processes typically inform rather than ‘make’ decisions. Thus, after a BAT recommendation is made, a process of integration is then required to transpose the outcomes into wider planning and associated implementation and funding decisions. During this process, a range of wider issues and perspectives will be of relevance (e.g. annual budgets, opportunities for service provision, competition for funding, relationships with other industries and associated cross-cutting issues, etc.). It is only at the end of this process that the BAT outcomes will become a part of the formal updated national strategy. Integration will also need to include development of guidance on the way that the national generic BAT can be used to support and assist the identification of a preferred management approach for metallic wastes at site level. The planned process for the integration phase is outside the scope of the current project, but it is understood that it will be implemented utilising established procedures and engagement processes defined within the National Programme. Note on Stakeholder Engagement Effective stakeholder engagement is key to the successful outcome of the generic BAT study. A range of stakeholders need to be effectively involved, including:

• Waste producers;


• Waste management service providers (treatment and disposal);

• Regulators;

• Councils/planners; and

• NDA.

It was recognised that at the workshops regulators may prefer to take ‘active observer’ roles, providing clarification on regulatory issues, views on process and challenge to the assessment outcomes. Given the range of waste producers involved, and the local/national regulators and council/planners with an interest in sites producing these wastes, the stakeholder constituency is large. Therefore, the planned approach to effectively engaging stakeholders without overburdening either stakeholder groups or the generic BAT process itself was as described below. A subset of representative stakeholders was invited to the scoping workshop, sufficient to provide confidence that the scope and proposed study approach is likely to be acceptable to the full range. Representatives of all groups were invited to the main assessment workshop. A range of stakeholders who did not wish to join the workshops but expressed an interest were kept informed by other means e.g. by being provided with the draft and final reports, with comments invited by email or telephone. Appendix B References Cassidy, H., 2014. National Strategic Metallic BAT: Stakeholder Scoping Workshop – Response to stakeholder engagement. LLWR document reference NWP/REP/065. Environment Agencies Requirements Working Group (EARWG), 2013. Waste Minimisation Database. http://www.rwbestpractice.co.uk/. Environment Agency (EA), 2010. Radioactive Substances Regulation: Principles of optimisation in the management and disposal of radioactive waste. Version 2.0. Environment Agency (EA) and the Scottish Environmental Protection Agency (SEPA), 2004. Guidance for the Environment Agencies’ Assessment of Best Practicable Environmental Option Studies at Nuclear Sites. Environment Agencies Requirements Working Group (EARWG), 2013. Waste Minimisation Database. http://www.rwbestpractice.co.uk/. Nuclear Industry Safety Directors Forum (NISDF), 2010. Best Available Techniques (BAT) for the Management of the Generation and Disposal of Radioactive Wastes: A Nuclear Industry Code of Practice.


Appendix C Outcomes of Screening: Long-list of Technology Options

The long-list of technology options set out below has been devised in accordance with the specifications for long-list identification agreed during the scoping phase. After screening, these options were used to inform an appropriate range of combined life-cycle management options, as described in the main report text. It was agreed during scoping that ‘enabling’ approaches (e.g. sorting and segregation and characterisation technologies) should be identified and discussed separately from the ‘main’ treatment/management options. This is because the applicability of enabling technologies will typically be site- or waste stream-specific considerations that are not appropriate to address in detail here. Therefore broad categories of enabling technologies are listed below to ensure the discussion is comprehensive, but they do not need to be screened or explicitly carried forward to the main assessment phase. Similarly it was identified at the scoping phase that differences between national and international facilities need to be recognised, but that within the UK regional or local facilities should not be explicitly recognised as those choices are also likely to be governed by site-specific decisions, which are out of scope. The long-list has been drawn from a range of references, which are listed subsequently. The following screening criteria were used to ‘screen out’ detailed options from the long-list:

• Is the technology capable of being legally implemented?

• Is the technology expected to provide an environmental benefit (e.g. reducing volumes for disposal)?

• Is there confidence that potential service providers will be available to provide required treatment services within a reasonable timeframe?

• Are there clear arguments that show the cost would not be disproportionate to any benefits gained?

The results of the screening process, including the full original list and the screening outcomes, are presented in the following tables.


Table C1: Enabling Technology Options

Options Notes Screening Outcome and

Rationale

Disassembly, cutting and size reduction

Generally standard components of existing enabling approaches.

IN – standard practice.

Characterisation IN – standard practice.

Segregation IN – standard practice.

Sorting IN – standard practice.

Monitoring IN – standard practice.

Blending Combining waste streams (potentially different activities) to facilitate treatment. NB does not include purposeful dilution (not acceptable from a regulatory perspective).

IN – can be appropriate.

Pre-treatment for operations e.g. transport

e.g. capping ends of pipes which may have loose waste, wrapping or painting.


Buffer storage – on site

Storage to allow volumes to accumulate such that peaks in arisings are managed, potentially ensuring better campaign management and reducing practicability (e.g. cost) barriers to uptake of other treatments.

IN – potentially important part of strategies, and standard practice (noting can apply to a range of timeframes).

Buffer storage – off site

As above, but not at site of production, possibly used by more than one producer.

IN – potentially important for some strategies. Some individual examples of use but not at a larger scale.

‘Enhanced’ characterisation

Characterisation beyond that typically used to sentence wastes to the relevant routes, in order to maximise the amount of metal that can be immediately declassified/released.

IN – standard practice e.g. for enabling reuse/free-release etc.


Table C2: Main Treatment/Management Technology Options

Options Notes Screening

Outcome

Thermal treatment options:

Melting for unrestricted reuse (clean metal)

Treatment of metals with the aim of separating bulk metal from contaminants to be retained in slags and filters. Aim to return ‘clean’ recycled bulk metal to the market.

The term ‘smelting’ is sometimes used for treatments of this type but as the process is the same this distinction is not made here.


Melting for restricted reuse (contaminated metal)

Melting with a specific reuse in mind, e.g. use of lightly contaminated metal within construction of plant etc. on an existing nuclear licensed site.

IN – has been utilised by UK industry (e.g. via Bear Creek).

Melting for volume reduction

Some activated metals, where the contaminant is intrinsically bound within the metal matrix (e.g. C-14) may not be as effectively decontaminated as other surface- and volume-contaminated metals. However melting of metals will still lead to removal of other contaminants, reduction of the activated inventory, and also reduction in total volume of the final wastes by converting the geometry to a simple ingot form.

IN – standard practice for relevant contaminated metals.

Thermal surface-degradation

The use of directed heat/flames (e.g. flame scarifying) to remove surface coatings and contamination by combustion/state change.

IN – part of standard practice.

Laser ablation Use of lasers for surface-degradation (see also above).

IN – has been done, although mainly on higher activity wastes.

Incineration of oxidisable components e.g. coatings

Use of incineration to remove/treat coatings or other combustible elements, potentially as part of a melting option, or as a precursor to other approaches (essentially, thermal surface-degradation but within an incinerator-type facility rather than using mobile scarifiers).

IN – for specific wastes, noting WAC constraints.

Vitrification Treatment with silica etc. to produce a glassy product.

OUT – for waste streams that are not predominately metal.

Mechanical surface treatment options:

Abrasion/ blasting

The use of shot, grit, ice or other particle blasting to strip surface-contamination (in some cases, including stripping the surface of the metal to ensure contaminant removal) leading to release of ‘clean’ bulk metal (unless also matrix contaminated)

IN – standard practice

Note sand is no longer allowed as a medium – banned



Outcome

and production of a residual slag for disposal. For non-fluid abrasion, management of dust can be an important consideration. Also includes sponge as a medium.

as a blasting abrasive due to silicosis concerns.

Jetting The use of high-pressure fluids (water, gases including liquid nitrogen etc.) to strip contamination from the surface of the metal. Leads to release of ‘clean’ bulk metal (unless also matrix contaminated) and production of a residual slag for disposal and/or aqueous contaminated discharges (for some variants of water jetting).


Grinding, milling and shaving

Use of coarse grained abrasives in the form of (for example) water cooled or dry diamond grinding wheels or multiple tungsten carbide surfacing discs. Leads to release of ‘clean’ bulk metal (unless also matrix contaminated) and production of a residual slag for disposal. Can lead to contamination of the grinding/shaving equipment. Management of dust can be an important consideration.


Pigging The technique involves driving a solid body device shaped to fit a pipeline interior, or another material e.g. ice, along a pipe under pressure, with the aim of (in this application) cleaning the inside of the pipe. Pigging is perhaps most likely to be applied during the decommissioning of a plant rather than during subsequent waste treatment.

IN – standard industrial technique.

Ultrasonic Use of vibration to shed surface-contamination/coatings

OUT for bulk metal – unlikely to be used for bulk metal treatment. Potential consideration for niche/small volumes or for Post-operational Clean Out (POCO).

Chemical surface-decontamination options: Chemicals/technologies:

Complexants A complexing agent is a chemical species that complexes with contaminant ions, normally metal ions, to increase their solubility. The most common complexing agents used for decontamination include EDTA (ethylenediaminetetraacetic acid), organic acids (notably citric) and sodium or ammonium salts of the organic acids. Although they can be effective the solubility enhancements have implications for environmental releases on disposal and WAC for sites are extremely restrictive on complexant concentrations in final disposals.

Application method can be by e.g. pressure washing or flushing, or by a static process where

IN – plausibly could/does provide some benefit for some wastes in scope, but need to manage disposability concerns where relevant, especially if final wastes/residues destined for LLWR.



Outcome

chemicals are sprayed, painted or spread onto a surface within a detachable coating such as a paste, gel, foam, or strippable coating. Similar application methods can also apply to acids, bases, and surfactants and these application delivery approaches are not listed separately below.

Acids In addition to acids that act as complexing agents, strong mineral acids are useful in removing contamination from metal surfaces. They attack and dissolve metal oxide films and increase solubility of metal ions. That is, they act as solvents as well as complexants (the latter covered in the above category).


Bases Similar aims to acids, but using strong bases derived from salts rather than acids.


Powders Typically involves creating powders that comprise the reagents for an exothermic reaction that occurs upon application to the metal surface following initial exposure to heat to start the reaction. The heating and oxidation process leads to stripping of the metal surface.

OUT – not currently used in nuclear industry and potential safety issues.

However, in strategic terms worthwhile tracking development/ progress for future consideration.

Surfactants Surfactants are common to the most soaps and detergents. Surfactants are organic compounds, which make it easier for water to dissolve dirt and grease. They often contain complexing agents, but not in all cases. Surfactant liquid solutions have been developed to decontaminate metal surfaces of equipment e.g. in reprocessing facilities.


Bleaches This technique specifically considers the use of liquid bleaches as oxidation agents. For example, bleaches such as hydrogen peroxide may be used to oxidise surface layers prior to final cleaning of the metal surface using acids.

IN – solvents etc. plausible.

Low metal ion redox

Redox chemical techniques for decontaminating the inside of plants, usually comprising the use of a metal ion solution with complexing agents and/or acids. As an example, the Low Oxidation Metal Ion technique was developed by the CEGB in the early 1980s especially for decontamination of water reactor primary cooling circuits.

OUT – assumed part of post-operational clean-out rather than waste treatment; not a plausible post-POCO waste treatment technology; not currently practiced



Outcome

Organic solvents

Concerns organic solvents that dissolve organic contaminants without chemically reacting with the contaminant, and do not fit in to the above descriptions of acids, surfactants, complexants etc. Examples are paint removers containing 1,1,1-trichloroethane, trichloroethylene, xylene, petroleum ethers, and alcohols.

IN – see other solvents above – note discussion on complexants.

Supercritical fluids

A supercritical fluid is a substance at a temperature and pressure above its critical point, which demonstrates behaviours similar to both liquids and gases simultaneously. This can be a benefit to decontamination e.g. due to high gas-like diffusivities and liquid solvent-like dissolution capabilities. Supercritical CO2 and water have both been used in surface-decontamination. In the case of CO2, this will subsequently evaporate leaving the stripped contaminant behind as a residue.

OUT – plausible but not substantiated for radioactive waste use, and no confidence in availability on suitable timeframes. Unlikely to be feasible for processing significant volumes of material.

Electro-chemical decontamina-tion

This involves removal of surface-contamination by oxidation etc. by the use of electric fields. A low voltage is passed through the metal using it as an anode, and a solvent acting as the cathode. The resulting oxidation compliments the solvent in efficiently removing the contamination from the surface. Often termed electro-plating or electro-etching.

OUT for bulk metal – plausible for niche metals but no large-scale availability or demonstration.

Microbially mediated surface decontamina-tion

The use of microbes to support chemical decontamination through degradation of surface coatings and contaminants.

OUT – niche application not demonstrated for radioactive wastes and not likely to be available to treat bulk metals over suitable timeframes.

Physical stripping (adhesives)

The application of material coated with adhesives to a surface, removal of which leads to stripping of surface-contamination.

IN – does happen, a real feature of practical strategies.

Chemical surface-decontamination options: Delivery mechanisms:

Gas fogging Use of a gas fog to coat metal surfaces with complex geometries, often drying to a strippable coating for subsequent physical removal. (Can also be used as a delivery mechanism for complexants, acids, bases, and surfactants).


Dipping/ Immersion of waste items within chemical baths. IN – standard



Outcome

immersion practice.

Spraying Use of sprays to apply thin layers of decontamination agent to waste.


Wiping Considers simple approaches involving wiping with cloths infused with the decontamination agent.


Compaction options:

Supercompact-ion

Use supercompaction to enable significant volume reduction producing compacted pucks for disposal (primarily mixed wastes containing malleable metal e.g. thin sheets).

IN – controlled supercompaction to minimise voidage – thin gauge metals, wiring etc.

Low- force compaction

Compaction using approaches other than high-force compaction, most likely in-drum compaction e.g. of shredded material.

OUT – limited value for metals, even malleable metals.

Other treatment options:

Cryo-cleaning The use of liquid nitrogen or similar to quickly freeze surface material such that it becomes brittle and easy to remove. Note that liquid nitrogen blasting/cutting provides this benefit in addition to abrasive effects (see ‘jetting’ above). Vibration or other methods of applying a sharp force then cause the frozen material to fall away or shatter.

OUT – as for ultrasonic, bacterial – not plausible for bulk metal given safety issues, current availability, scalability, effort required to apply in volume in reasonable time frame. May still be used for niche applications.

Other management and storage options:

Decay storage Storage to enable cross-boundary ILW/LLW to be treated as LLW, and VLLW/LLW to be treated as VLLW etc.

IN – potentially beneficial for such wastes.

Reuse of contaminated metal within permitted/ compliant facilities

Contaminated metal could be reused in the industry, e.g. in shielding for future plants or reuse of skips etc. (includes potential reuse of material as a part of treatment abroad).

IN – favoured by waste hierarchy

No treatment option:

No treatment Direct disposal without further treatment, except possible in-situ grouting in place of final disposal.

IN – still practice and can be the only option for certain wastes



Outcome

Final disposal options:

Disposal to existing LLW facilities

i.e. LLWR/Dounreay (& Clifton Marsh). IN – standard practice.

Disposal to existing other permitted facilities

e.g. other permitted lower activity/VLLW hazardous waste facilities.


Disposal to existing/new on-site disposal facilities

Most likely surface or near-surface, elsewhere than LLWR.


Disposal to other new off-site permitted facilities

Most likely surface or near-surface, elsewhere than currently permitted UK facilities.


Interim storage for higher activity wastes

Recognises the potential for interim storage of ILW wastes for later treatment once it has decayed to LLW.

IN – could be valuable for cross-boundary wastes.

Table C3: Location Option Variants

Options Notes

Screening

Outcome

Treatment in the UK11

Location variant that applies to any of the above options.

IN.

Treatment overseas

Location variant that applies to any of the above options.

IN.

Disposal in the UK

Alternatives are not feasible for legal reasons. IN.

Appendix C References Donohew, A., Dooley, S., Keep, M., Kruse, P., and Pugh, D., 2009. Strategic BPEO Study for Very Low Level Waste. Volume 1: Final Report. ENTEC report to LLWR Ltd. Egan, M., Paulley, A., and Towler, G., 2008. Treatment of Plutonium Contaminated Material at Sellafield: Best Practicable Environmental Option Study. Quintessa report to Sellafield, QRS-1372A-1 v2.0.

11

NB treatment could be via existing permitted facilities, new permitted facilities, or ‘hazardous’ waste facilities upgraded to achieve permitting to accept radioactive waste


Environment Agencies Requirements Working Group (EARWG), 2013. Waste Minimisation Database. http://www.rwbestpractice.co.uk/. LLWR and NDA, 2009. UK Management of Solid Low Level Radioactive Waste from the Nuclear Industry: Metal Decontamination Study. NLWS/LLWR/08 Revision 1. LLWR and NDA, 2011. UK Management of Solid Low Level Radioactive Waste from the Nuclear Industry: Low Level Waste Strategic Review. NLWS/LLWR/16 Issue 3. Paulley, A., Towler, G., and Collier, D., 2014. National Strategic BAT for Metallic Low Level Radioactive Waste: Scoping Report. Version 1.0. Jacobs report for LLWR Ltd B2010100_01. Paulley, A., and Collier, D., 2007. Treatment of Low-Level Waste Metals at Sellafield: External Stakeholder Workshop. Quintessa report to Jacobs/Sellafield, QRS-1369B-TN6 v1.0. Rossiter, D., 2006. Strategic BPEO For Metal Waste Management – Options Evaluation. Studsvik report P0090/TR/002. Stevens, L., 2011. Review of Strategic Options for Metal Waste. LLWR Report WMS-REP-NLWS/LLWR/25.


Appendix D Main Assessment Process Details

Approach to the Assessment and the Main Workshop As discussed in the main text, the assessment of the treatment strategy options was undertaken using a three-stage process, outlined below. Preparation of a Draft Assessment A draft assessment of options against criteria for defined waste populations was undertaken through an expert workshop held at the Westlakes Hotel, Gosforth, on 22nd October 2014, involving members of the LLWR/Jacobs/Quintessa ‘internal’ project team. Participants also included waste treatment experts from outside the core project team to introduce an element of independent challenge. This was then further developed by off-line additions, refinement and review. As described in the main text, there are a number of waste streams within the metallic LAW category with differing characteristics. While similar waste treatments will be available, the balance of arguments (e.g. reflecting the value of avoiding LLW disposal volumes, as contrasted with VLLW volumes) will differ. The draft assessment sought to recognise these key differences, without making the assessment too complex. Therefore, the approach was taken to first select the highest volume single LLW waste stream (surface-contaminated metals) and undertake a full assessment for that waste stream. Then, the assessors were asked to answer the following questions: • For each of the assessment criteria, how does the assessment change for

VLLW?

• For each of the other waste streams, how does the assessment change?

This process was systematic, in that every combination of waste stream and criteria was considered, but having a ‘baseline’ established ensured the process was efficient. Also, many of the differentiators are common across several waste streams. The draft assessment was therefore conducted via the following steps: • Review of the options for assessment.

• Review of key assumptions.

• The ‘location’ element of treatment options.

• Review of assessment criteria, and ‘key questions’ intended to help guide the assessment.

• Identification of a waste stream for the ‘baseline’ assessment (surface-contaminated metals).

• Assessment of the strengths and weaknesses (and therefore differentiators) of each treatment option against each criterion. Development of an assessment matrix capturing the assessment.


• Modification of the assessment matrix to identify changes for VLLW.

• Systematic review of the baseline assessment matrix to identify what changes for other wastes.

• Identification of key themes.

Review at the Main Workshop The draft assessment was not intended to derive a formal proposed preferred option or options, or indeed derivation of a proposed BAT strategy. This is a matter for consideration and agreement by stakeholders, informed by the detailed assessment following review at the main workshop. It was considered important that the ‘internal’ assessment did not pre-judge the outcome; its role was rather to help collate and assess the evidence required to inform that judgement. The draft assessment was therefore presented at the main stakeholder workshop, held in Manchester on 19th November 2014, in order to: • Describe the logic and rationale for the options formulation and assessment

process.

• Invite detailed discussion, comment and feedback.

• Elicit views on the relative importance of differentiators against relevant criteria of interest.

• Provide the basis for an updated final assessment incorporating feedback received.

• Discuss the key elements of the final strategy.

Documentation and Final Review The final options assessment, and the statement on the main features of the BAT outcome agreed at the workshop, was then finalised as described in the remainder of this document. In doing so feedback from workshop participants was obtained and used to inform final updates. ‘Location’ Element of Treatment Strategy Options As discussed in the main text, location options for treatment strategy components within the UK (e.g. use of facilities close to waste producers vs. central facilities) are not within the scope of the options comparison. Such aspects merit detailed discussion in the final strategy to be derived during the integration phase, and in any business cases for future developments that will be informed by the current assessment. However, in terms of a generic, technical BAT comparison of options, such considerations involve factors that are too site-specific to be meaningfully addressed. The issue of whether treatment should be undertaken within the UK or overseas is, however, not site-specific and needs to be addressed. In addition to meeting general regulatory requirements for transport, any treatment strategy involving the use of overseas treatment facilities would need to satisfy the requirements of the UK Transfrontier Shipment of Radioactive Waste and Spent Fuel Regulations 2008. Moreover, when deciding whether to authorise the export of radioactive waste for treatment overseas, the EA and SEPA are obliged to take into


account Government policy (e.g. DEFRA et al., 2007) as well as the requirements of the regulations. The current UK policy on export of low-level radioactive wastes establishes guidelines that offer somewhat more flexibility than those previously in place (Cmd 2919, 1995). Specific considerations relating to UK policy include:

• A presumption towards solutions local to the point of arising, based on the proximity principle and minimisation of unnecessary waste transports.

• A presumption towards self-sufficiency in waste management. That is to say, a case for transfrontier shipment requires demonstration that the required treatment of the wastes concerned cannot practicably be undertaken in the UK. If an equivalent UK option is available, the default regulatory position will tend to be that export is unnecessary.

• A presumption in favour of ‘early solutions’. If UK options are unlikely to be capable of delivering final disposition of the wastes on a timely basis, due to capacity issues or simply unavailability of a key technology in the UK, and overseas solutions are readily available, this could represent a significant consideration in relation to determining the outcome of an options assessment.

For the present assessment, the following BAT outcomes were agreed on the topic of location of treatment. • Wastes will typically be treated within the UK wherever there is capacity and

capability to do so using a preferred technique on suitable timeframes.

• Wastes will be treated overseas where a clear waste stream-specific case can be made based upon lack of UK capacity or capability (e.g. for a technique that will clearly deliver substantial environmental benefits, such as melting, and/or capacity limitations for of an option that is otherwise available in the UK) or disproportionality (e.g. in cost of the UK solution).

It is beyond the scope of the present BAT study to analyse location options in more detail. The justification for overseas treatment will nearly always be made on a site- or waste stream-specific basis. It is important to recognise that waste transport issues can be contentious to local stakeholders and require careful consideration within relevant processes. Criteria and ‘Key Questions’ On the basis of past experience and good practice, a criteria set was identified that falls within the following ‘standard’ broad criteria headings: • Safety and Security.

• Environmental Impact.

• Technical Feasibility.

• Community Impacts

• Financial Cost.


The detailed criteria set was reviewed and agreed at the scoping workshop, including the addition or modification of several criteria from that originally proposed prior to the workshop. It is presented in full below. Prior to the assessment phase, a number of ‘key questions’ were formulated. These summarise key elements of each criteria group that need to be addressed in assessing differentiators between options:

• Safety and Security

- Will the option help minimise health and safety risks associated with waste management – will it offer any advantages/disadvantages in terms of ease/cost of ensuring operations are ALARP?12

• Environmental Impact

- Does the option help deliver key elements of the Waste Management Hierarchy? Does it lead to volume reduction and/or de-classification whilst delivering a project with the required longevity? Are there secondary effects e.g. secondary wastes and/or significant resource use? What are the transport impacts and risks?

• Technical Feasibility

- Is the option consistent with national and NDA strategies? Is there confidence in timely availability of treatment routes, longevity of supply, and the proven performance of those routes? Is the option robust to uncertainties in the nature and rate of arisings of wastes? Is trans-boundary transport required?

• Community Impacts

- Will the option have advantages or disadvantages for relevant communities, e.g. jobs, local spends or other impacts? Will it reduce the burden on future generations?

• Financial Cost

- Will the option involve significant up-front and/or lifetime costs?

Detailed Criteria List Safety and Security (1) Acceptable rate of achieving passive control. The capacity to deliver a safe, passive wasteform for existing wastes within acceptable timescales. (2) Avoidance of implementation hazards. The extent to which there may be significant health and safety hazards associated with their implementation. Whilst the requirement to demonstrate ALARP in implementation will always be respected, a treatment alternative presenting lower operational hazards to the workforce will (all other things being equal) tend be preferred over one that involves more hazardous working conditions. Includes risks associated with transport steps.

12

Note that security aspects were considered but did not provide substantial differentiation between options for these waste types.


Environmental Impact (3) Minimising off-site impact (humans, other flora and fauna, other environmental receptors). The objective of minimising the environmental footprint, taking account of secondary wastes and effluent discharges. (4) Conditioned waste volume. The projected extent to which they are considered capable of minimising the final conditioned wasteform. (5) Confidence in product. The confidence that can be placed in achieving a stable final wasteform, capable of meeting waste acceptance criteria for disposal. (6) Resource use. The extent of life-cycle energy or material costs associated with the option. Includes energy use for transport. Technical Feasibility (7) Consistency with existing NDA and other waste producer strategies. Does the option support or conflict with existing strategies? Would it open up commercial opportunities for sites that would be of value in future strategy development? (8) Strategy flexibility. Does the option rely upon a particular facility, or the creation of a new facility? Is it only a short-term solution, or does it have strong potential for the longer-term? (9) Operability and maintainability. The extent to which technology options are considered simple to operate and maintain, and will reliably process the waste volumes involved. (10) Confidence in process viability. The confidence that can be placed in the technical maturity of the process and its capability to deliver a satisfactory final waste product. This takes into account the nature of the wastes involved as well as process operating experience with similar types of waste materials and radioactivity content, in the UK and overseas. (11) Availability of treatment routes. Considers the current (or potential future) availability of plants to process wastes, and whether they are likely to offer sufficient throughput capacity. Includes arguments on trans-boundary transports for treatment routes available internationally. (12) Robustness to uncertainties and variation in feed characteristics. The capability of an option to accommodate conceivable variations in feed characteristics (i.e. the extent to which they will be able to deal with a wide range of waste streams within the overall metallic lower activity waste category) with minimal rejection or breakdown. (13) Footprint. The area of land required by a facility and its services will be particularly relevant if it is to be placed within an existing licensed site. (14) Planning processes. Comparison with the relevant Development Plan Documents, which comprise the Regional Spatial Strategy, the Minerals and Waste Development Framework and the district Local Development Frameworks. They are also assessed for conformity with national policies, such as those set out in National Policy Statements, Planning Policy Statements and Minerals Planning Guidance.


Community Impacts (15) Socio-economic implications. Management strategies may potentially be differentiated in terms of their implications for the support for local supply chains, the number and skill level of local jobs associated with operating and maintaining treatment plants, etc. (16) Burden and sustainability. Includes ‘intergenerational equity’ i.e. not undertaking actions now, and indeed avoiding non-action, that may lead to burden on future generations. Financial Cost (17) Affordability. Short and medium term costs associated with any necessary construction, commissioning and operation. (18) Lifetime costs. Lifetime cost relates not only to the cost of implementing the waste treatment process, but also the costs of final disposal. Hence options that minimise the volume of conditioned waste requiring disposal may also be more favourable from a lifetime cost perspective. Note on evaluation of costs It is noted that cost considerations will be important, though at a very high level. Experience of costs associated with running existing facilities will be relevant, but detailed breakdowns will not be helpful given uncertainties in likely future waste stream characteristics. Rather, order of magnitude costs to establish any key differentiators will be the focus of attention. The fluctuating value of steel on the open market may be a further consideration. Further consideration of cost issues will be given through the planned development of guidance and subsequent strategy as outlined in Cassidy (2014). It is noted that waste producers and treatment providers requested at the scoping workshop guidance concerning establishing when costs are disproportionate to benefits. However, this is considered a very case-specific matter; regulatory guidance reflects the need to make a suitable case on the basis of the features of an individual situation. Instead the final guidance shall refer to case studies that indicate how decisions have been made in past BAT studies including noting how cost-benefit issues were addressed. Appendix D References Defra, DTI and the Devolved Administrations, 2007. Policy for the Long Term Management of Solid Low Level Radioactive Waste in the United Kingdom.


Appendix E Main Assessment Matrices

Assessment tables for the main waste categories are provided in this Appendix. A specific shortened assessment table for Coated Metals is provided first.

LAW Metal Waste: Surface-Contaminated (VLLW in italics)

Safety and Security Environmental Impact Technical Feasibility Community Impacts Financial Cost Options

No (main) treatment + disposal

Minimum handling so minimum contact time – potentially lower dose to workforce

Where in-situ disposal is appropriate, likely to minimise overall health and safety risk

Minimal reduction in intrinsic hazard or security risk prior to disposal – increased total public dose / environmental risk

Minimal decrease in total time period of hazard/risk

Depending on type of contamination (need to ensure no loose contamination etc) increased pressure on characterisation enabling steps to demonstrate compliance with transport requirements

Minimal secondary waste prior to disposal

No transport movements to interim treatment facilities, so reduced number of overall transports

Potential to achieve disposal earlier than for other technologies

No reduction in environmental hazard prior to disposal

Least preferred from Waste Management Hierarchy perspective

No reduction in disposal volume – maximum volume taken up at disposal facility – indeed with conditioning/void filling/containerisation, total volume can increase

For VLLW/LA LLW, inconsistent with Landfill Directive

Technically the least complex, in principle

Requires minimum characterisation effort – except that required for WAC

Does not address transport challenges for loose contamination on its own

No treatment means for some wastes higher likelihood of not meeting WAC for certain materials and disposal facility combinations – potential not to be consistent with disposal route requirements

Least preferred from the perspective of the national LLW strategy and policy (as no reduction in disposal volume) where other options are available

Need to ensure no free liquids

Community (or socio-economics) factors recognised as a fundamental factor of high importance

However, in broad terms the technical assessment of the options identified here did not identify strong differentiators between options (all have similar community impacts – scale of jobs created etc) except if volumes are not reduced and a second LLWR is required, which may significantly impact on the hosting community– May be viewed as positive (jobs/investment) or negative

(transport impacts, perception)

(See specific comment below on melting)

Low treatment costs

High disposal costs especially to an engineered vault, offset (at least in part) by no treatment costs

Lifecycle costs need to be considered in operator BAT

In-situ and VLLW/LA LLW costs for disposal are much lower

Costs for higher activity wastes maybe significantly higher

No (main) treatment

Supercompac-tion

Limited reduction in intrinsic hazard or security risk prior to disposal – increased total public dose / environmental risk

Limited decrease in total time period of hazard/risk


Reduction in volume prior to disposal but not as much as for other technologies

Limited reduction in environmental hazard prior to disposal

Increased transport movements if off-site facilities are to be used, compared to direct disposal however additional transport not likely to be significant

Energy use – although not significant compared to more complex options e.g. melting

Some secondary waste, but limited and discharged through existing routes

Standard practice - feasibility of technique demonstrated for compactable classes of waste

Transport challenges for loose contamination – need enabling steps

Not suitable for wastes other than thin malleable / mixed wastes

No passivation means for some wastes higher likelihood of not meeting WAC for certain materials and disposal facility combinations – potential not to be consistent with disposal route requirements

Involves treatment costs and disposal costs but for disposal to engineered vaults in particular, likely to be lower overall cost compared to no treatment

Supercomp-action

Table E1: Assessment Outcomes for Surface-Contaminated Metals

Mechanical surface-decontaminat-ion

Increased safety issues to manage – e.g. mobilised activity, dust / gas generation.

Increased conventional and radiological safety risk compared to no treatment, due to complexity of process, enhanced contact times and manual elements of work dependent on the technology used

Including extra handling if two-stage surface-decontamination then melting approach utilised

But reduction in intrinsic hazard and associated public/environmental dose/risk prior to disposal

However, a commonly used approach – risks can be managed

Compared to no treatment, significant improvements in terms of potential to release exempt metal for reuse or recycling, and for reuse within the industry


Generation of secondary wastes – depending upon type of mechanical approach, contaminated shot/grit residues, contact machinery, dust, liquid/gas effluents

Some treatments / materials can concentrate surface-contamination leading to higher activity residues – but only an issue for specific subset of wastes e.g. higher activity LLW near ILW boundary

Need to ensure final waste volume for disposal is a significant decrease – adding shot / grit etc can increase original volume if out-of-scope/exempt targets not met – particularly relevant to higher activity LLW or transboundary ILW

Some secondary waste can be disposed/discharged through existing routes

On site surface-decontamination can enable transport for off-site treatment

Flexible - can be used as a pre-treatment rather than main treatment. Frequently used to de-classify waste as out of scope / exempt – but for some wastes other techniques, e.g. melting may be associated with higher confidence in achieving de-classification

May need additional pre-treatment /characterisation in order to be able to fully decontaminate: For example cutting / size reduction - geometrically limited - requires exposed surfaces

A range of mechanical processes are very well proven

Can be usefully employed as a pre-treatment for melting to maximise volume reduction

Consistent with policy/strategy requirements

Secondary wastes typically meet disposal facility WAC – especially for off-site treatment, will need initial characterisation and other enabling effort to show meets treatment facility WAC, but that is common to all treatment options

In practice capability and capacity vary – needs good planning

If required, time to implement ‘new’ technologies/ facilities can be challenging within budget cycles etc.

Shot/grit / abrasion not appropriate for thin gauge metals, or soft metals e.g. lead

Introduces an additional risk step (manual handling, use of aggressive mechanical approaches etc) – but can be managed with standard arrangements

For a range of wastes surface-treatment will reduce overall waste heterogeneity by removing surface material/fingerprint potentially leaving homogenous metal

Lower disposal costs for final product compared to no treatment

Cost of treatment (+ possible pre-treatment). Disposal costs for secondary wastes

Potential economies of scale – a large proportion of future wastes could benefit, and bulk scheduling could bring costs down

Potential cost benefits of reuse/recycling/release where achieved (sale of metal, avoiding import of new materials, etc). Cost benefits demonstrated in recent campaigns for a range of wastes including VLLW/LALLW

Mechanical surface-decontamin-ation

Chemical surface-decontaminat-ion

Involves application of hazardous chemicals

Increased conventional and radiological safety risk compared to no treatment due to enhanced complexity of process and enhanced contact times and movements

Experience of use of a range of (typically simpler) chemical approaches – risks can be managed



Need to address both radiological and chemical hazards

Secondary waste (aqueous and gaseous) – need to ensure can be disposed/discharged through existing routes

Improved accessibility for decontamination compared to mechanical – less geometrically limited

Can be targeted for specific contaminants (e.g. PWR primary loops) – although note post-operational clean-up basically out of scope here

Broadly consistent with policy/strategy requirements

Time to implement ‘new’ technologies / facilities can be challenging within budget cycles etc.

Organisational factors and site facilities may constrain or enable ability to use – need space and expertise, etc

In practice capability and capacity vary – needs good planning, and depends upon complexity of the chemical approach utilised

Chemical residues may constrain subsequent treatment and disposal



Currently limited availability for off-site treatment

Additional permit constraints may apply with use of chemicals

Use of novel chemicals may be more challenging in terms of maintaining process throughput, demonstrating WAC met for final wastes for disposal/discharge

Some technologies in this class relatively immature – others

Lower disposal costs for final product compared to no volume reduction



Potential cost benefits of reuse/recycling/release where achieved (sale of metal, avoiding import of new materials, etc)

Chemical surface-decontamin-ation

commonly used

Introduces an additional risk step (for aggressive chemicals etc) – but can be managed with standard approaches, particularly for less aggressive chemical applications


Note no UK capacity for melting means additional transport burdens for several communities – however this has typically been successfully addressed

Thermal surface-decontaminat-ion / thermal treatment

Involves use of potentially hazardous thermal based technique – need to manage conventional safety issues

Increased conventional and radiological safety risk compared to no treatment due to enhanced contact times and complexity of process

However, risks can be managed



Management/treatment of secondary wastes required– off-gas, solids

Can be used in-situ – flexible

Can avoid generation of problematic secondary wastes e.g. via combustion of surface matter

May need additional pre-treatment /characterisation in order to be able to fully decontaminate: For example cutting / size reduction - geometrically limited - requires exposed surfaces but does not necessarily require line-of-sight to contamination

Niche application – restricted applicability – but beneficial for a specific subset of wastes

Introduces an additional risk step (dealing with potential high temperature process) – but can be managed with standard approaches


Specific benefits for thermal treatment of particular metals (not just surface-decontamination) – e.g. sodium, lithium which have specific chemical hazards


Niche application – useful for specific applications, but at the bulk scale, potentially cost prohibitive

Thermal surface decontamin-ation / thermal treatment

Melting Potential operational hazards due to complexity of process, heat and off-gases involved

Increased conventional and radiological safety risk compared to no treatment, due to complexity of process, enhanced contact times and manual elements of work

Can involve multiple handling due to pre-preparation first e.g. mechanical surface-decontamination


More automated process than for others

Significant volume reduction and maximum release for recycling/reuse/exempt – in particular in combination with mechanical surface approaches

Potential for recycling, maximising exemption means addresses key Waste Management Hierarchy requirements

Gaseous emissions need to be managed

Some secondary waste, but limited and disposed/discharged through existing routes

No UK capacity at present – means additional transport requirements to overseas facilities

High energy utilisation

Established technology, although only available through overseas suppliers at present

Flexible – e.g. possibly useful where WAC not met for surface-treatment – wider range of materials / properties acceptable

Improved decontamination factors compared to other approaches - broadly consistent with policy/strategy requirements

For many wastes the highest confidence individual technique for achieving declassification/release

Flexibility to address complex / mixed / inaccessible geometries

De-risks ‘hot spots’ in decontaminated product

Could be overkill for some materials / forms of surface-contamination

Often most effective when used in combination with surface-decontamination

If used on its own can result in mixing / homogenisation – surface-contamination not released can end up within matrix – need to consider applicability etc

Transboundary movements currently required

VLLW – potential use as input to mixed stock for operational efficiency benefits

Introduces an additional risk step (associated with dealing with high temperature treatment etc)– but can be managed with standard approaches




Comparable costs with other treatments


VLLW – potential mixed stock opportunities

Melting

Reclassification to exempt / out-of-scope through enhanced characterisat-ion



Key aims are directly relevant to the Waste Management Hierarchy – minimising volumes of waste for treatment and disposal

Potential to reduce transport requirements etc also

Small volume of secondary wastes

Best use of permitted facilities

Requires prior expectation that wastes are close to limits e.g. for exemption – unlikely to be beneficial for a subset of wastes not near limits

Can require more dismantling and other work to allow enhanced characterisation than for some other techniques (although for many wastes requirements will be similar to e.g. surface-decontamination or melting preparation steps)

Bespoke work that can require desk work / specific management approaches / specialist technical capability

Once reclassified no further work required

Potentially very cost effective if declassification achieved

Potential cost risks if doesn’t achieve objectives – may simply be additional cost


VLLW – cost differential of further declassification less substantial


LAW Metal Waste: Matrix-Contaminated (VLLW in italics)






















However, in broad terms the technical assessment of the options identified here did not identify strong differentiators between options (all have similar community impacts – scale of jobs created etc) except if volumes are not reduced and a second LLWR is required, which may significantly impact on the hosting community– May be viewed as positive (jobs/investment) or

negative (transport impacts, perception)


Low treatment costs





No (main) treatment

Supercompac-tion











Not suitable for wastes other than thin malleable / mixed wastes. Most matrix contaminated waste not expected to be thin and malleable.



Supercomp-action



Increased conventional and radiological safety risk compared to no treatment, due to complexity of process, enhanced contact times and manual elements of work dependent on the technology used including extra handling if two-stage surface-decontamination then melting approach utilised

Including extra handling if two-stage surface-decontamination then melting approach utilised

But reduction in intrinsic



Generation of secondary wastes – depending upon type of mechanical approach, contaminated shot/grit residues, contact machinery, dust, liquid/gas effluents

Some treatments / materials can concentrate surface-contamination leading to higher activity residues –













Table E2: Assessment Outcomes for Matrix-Contaminated Metals

hazard and associated public/environmental dose/risk prior to disposal


but only an issue for specific subset of wastes e.g. higher activity LLW near ILW boundary



For matrix contamination, normally used prior to melting – additional transport, and secondary wastes from both processes

In combination with melting, can deliver significant volume reduction



Shot/grit / abrasion not appropriate for soft metals e.g. lead



Needs to be used in combination with melting to fully treat matrix contaminated metals, but can provide an important contribution if surface-contamination also present (possible that in specific cases, surface-decontamination alone could be sufficient to allow reuse/recycling of matrix contaminated metal within industry)

For matrix contamination, combined costs of two processes (melting also required)

Costs will be influenced by where segregation, characterisation, size reduction etc undertaken – at source (ideal) or at another site



Increased conventional and radiological safety risk compared to no treatment due to enhanced complexity of process and enhanced contact times and movements including extra handling if two-stage surface-decontamination then melting approach utilised







In combination with melting, can deliver significant volume reduction













Some technologies in this class relatively immature – others commonly used



Needs to be used in combination with melting to fully treat matrix contaminated metals, but can provide an important contribution if surface-contamination also present (possible that in specific cases, surface-decontamination alone could be sufficient to allow reuse/recycling of matrix contaminated metal within industry)

More common that mechanical surface-decontamination is used prior








to melting – or both approaches employed in combination

Note no UK capacity for melting means additional transport burdens for several communities – however this has typically been successfully addressed



Increased conventional and radiological safety risk compared to no treatment due to enhanced contact times and complexity of process including extra handling if two-stage surface-decontamination then melting approach utilised














Needs to be used in combination with melting to fully treat matrix contaminated metals, but can provide an important contribution if surface contamination also present (possible that in specific cases, surface decontamination alone could be sufficient to allow reuse/recycling of matrix contaminated metal within industry)

More common that mechanical surface decontamination is used prior to melting – or both approaches employed in combination






Increased conventional and radiological safety risk compared to no treatment, due to complexity of process, enhanced contact times and manual elements of work including extra handling if two-stage surface-decontamination then melting approach utilised




Significant volume reduction and maximum release for recycling/reuse/exempt – in particular in combination with mechanical surface approaches – the only approach that can plausibly decontaminate matrix metals

Can be used for activated as well as volumetrically contaminated metals, although main benefit for activated metals (specifically) will be re-forming and size-reducing, as majority of contamination will tend to stay within matrix






When used with surface-decontamination precursor, additional transport, and secondary


Flexible – e.g. possibly useful where WAC not met for surface treatment – wider range of materials / properties acceptable

Improved decontamination factors compared to other approaches - broadly consistent with policy/strategy requirements











Often used in combination with surface-decontamination to realise full benefits






When used with surface-decontamination, combined costs of two processes


Melting

wastes from both processes The only approach that can plausibly decontaminate matrix metals

Volume reduction for ‘activated’ metals

Limited available capability for activated metals due to nature of radionuclides.

Lack of indigenous capability means availability is subject to external (overseas) policies and programmes.

Concentration of activity in secondary waste means that careful management of waste inputs / outputs is required.












Can be more challenging for matrix contaminated metals that are more difficult to assay





Potential for higher assay costs for matrix contaminated metals


LAW Metal Waste: Mixed Decom. Metals

(VLLW in italics)





















Greatest flexibility to accept mixed wastes with minimum up-front sorting, segregation and characterisation

High voidage in this waste type makes poor use of disposal facility capacity and may challenge waste acceptability for disposal


However, in broad terms the technical assessment of the options identified here did not identify strong differentiators between options (all have similar community impacts – scale of jobs created etc) except if volumes are not reduced and a second LLWR is required, which may significantly impact on the hosting community– May be viewed as positive (jobs/investment) or

negative (transport impacts, perception)


Low treatment costs





No (main) treatment

Supercompac-tion




All main treatment options – in principle, complex wastes can mean handling challenges, but that applies whether undertaken at source or at another site – not a differentiator (except for no treatment)








Not suitable for wastes other than thin malleable / mixed wastes


Limited applicability for mixed metallic wastes, most of which will not be compactable

Requires careful control and management (not all waste metals suitable for supercompaction)

All main treatment options - where possible, desired end-point should be used to work out best balance of on-site and off-site sorting/segregation/etc, and main treatment

Flexible - can be used as a pre-treatment rather than main treatment


Costs will be influenced by where segregation, characterisation, size reduction etc. undertaken – at source (ideal) or at another site

Supercomp-action



Increased conventional and radiological safety risk compared to no treatment, due to complexity of process, enhanced contact times and manual elements of work dependent on the technology used

Including extra handling if two-



Generation of secondary wastes –










Table E3: Assessment Outcomes for Mixed Metals


(VLLW in italics)


stage surface-decontamination then melting approach utilised

But reduction in intrinsic hazard and associated public/environmental dose/risk prior to disposal


All main treatment options – in principle complex wastes can mean handling challenges, but that applies whether undertaken at source or at another site – not a differentiator (except for no treatment)

depending upon type of mechanical approach, contaminated shot/grit residues, contact machinery, dust, liquid/gas effluents

Some treatments / materials can concentrate surface-contamination leading to higher activity residues – but only an issue for specific subset of wastes e.g. higher activity LLW near ILW boundary



Will provide volume reduction for a range of components of mixed waste streams, provided they are first segregated and disassembled into appropriate geometries





Shot/grit / abrasion not appropriate for soft metals e.g. lead



Can be used for a range of wastes types – if surface-contaminated and of appropriate geometry

In practice, significant sorting, segregation, characterisation size reduction etc necessary to enable use of mechanical approaches for components of mixed waste streams

All treatment options - where possible, desired end-point should be used to work out best balance of on-site and off-site sorting/segregation/etc, and main treatment

More challenging to assure reclassification as exempt / out-of-scope owing to reduced provenance on origin / location of contamination for mixed wastes.

Some techniques may not be feasible for mixed wastes (for example, where there are mixed fingerprints)

May not necessarily be enough by itself to achieve objectives (as waste may not be purely surface-contaminated) – would require use in combination with other techniques in this case.

More challenging to achieve for wastes particularly at the higher end of the radiological spectrum. Limited infrastructure to manage such higher activity LLW is available





Increased conventional and radiological safety risk compared to no treatment due to enhanced complexity of process and enhanced contact times and movements







Can provide decontamination for a range of surface-contaminated metals within mixed waste














Costs will be influenced by where segregation, characterisation, size



(VLLW in italics)


streams without being overly geometry dependent, although that depends in turn on chemical and application method

Depending on nature of mixed waste streams may need different chemicals for different wastes within the mixed stream – may not be flexible




Some technologies in this class relatively immature – others commonly used



Will not work with galvanized coated material, and some other forms of coatings

Could plausibly provide a contribution to treating a mixed stream provided sufficient disassembly, sorting, segregation and characterisation is undertaken first


Note no UK capacity for melting means additional transport burdens for several communities –

reduction etc undertaken – at source (ideal) or at another site



Increased conventional and radiological safety risk compared to no treatment due to enhanced contact times and complexity of process














Could plausibly provide a contribution to treating a mixed stream provided sufficient disassembly, sorting, segregation and characterisation is undertaken first – then may help with certain coatings






Increased conventional and radiological safety risk compared

Significant volume reduction and maximum release for recycling/reuse/exempt – in particular in combination with mechanical surface approaches


Flexible – e.g. possibly useful where WAC not met for surface-treatment – wider range of materials / properties acceptable

Improved decontamination factors compared to other approaches - broadly


Cost of treatment (+ possible pre-treatment). Disposal

Melting


(VLLW in italics)


to no treatment, due to complexity of process, enhanced contact times and manual elements of work










For some mixed wastes, potential to provide a ‘bulk’ treatment option provided mainly metallic and enough characterisation to prove meets WAC

consistent with policy/strategy requirements











Of the ‘treatment’ options, the most likely to be able to deal with bulk mixed wastes – if predominately metal. Potentially the most flexible treatment option

Enables 100% sampling of homogenised product during process, supporting enhanced reclassification of bulk metal post treatment as exempt / out-of-scope

However, WAC likely to again require sorting, segregation, disassembly, surface-decontamination etc first – portfolio of such options may be required as precursor

Lack of indigenous capability means availability is subject to external (overseas) policies and programmes


however this has typically been successfully addressed

costs for secondary wastes
















Likely to be additionally challenging for mixed metals, and in particular, mixed fingerprints







Table E4: Assessment Outcomes for Coated Metals

Type of

coating Considerations/issues

Paint • Assess as surface-contaminated waste unless paint is known to be lead-containing.

• For lead-containing wastes, apply surface-contaminated waste table but notes that there are potential constraints on melting due to the lead content. Removal of the paint (e.g. by mechanical or thermal means) may be required to enable melting.

• Specific chemical surface-decontamination options will be appropriate for some paints (and indeed other coatings) – need to match the correct chemical/application technique to the properties of the waste.

• Note that certain surface-decontamination options (e.g. thermal laser/flame scarifying) are particularly suited to paint removal.

• Management of dust etc. will be important for mechanical removal of paint, especially if the paint is contaminated. Similarly careful management of shot/grit associated with paint removal will be necessary for relevant options.

• For this and other coatings: ‘Enhanced characterisation’ may be more challenging than for other wastes, due to potential extra difficulties in assay.

Galvanised metal

• Consider appropriate table (surface, matrix or mixed) but recognise that:

- Mechanical surface-decontamination such as shot blasting may be more challenging for galvanised metal and (in particular for metals with comparatively thick galvanized layers) and may produce challenging secondary waste that requires management (i.e. high zinc containing secondary waste).

- Due to the need for careful management of gaseous secondary waste, there may be limitations on capability/capacity for metal melting.

• Chemical surface- decontamination may not work for galvanised metals.

Plastic and rubber coated (including wiring)

• Consider appropriate table (surface, matrix or mixed) but recognise that:

- Mechanical surface-decontamination and melting are often challenging for this waste type due to the different chemical/physical characteristics of the coating, and due to the geometries involved (e.g. wiring).

- Enabling steps such as removal of the coating through mechanical, chemical or thermal means may be required to facilitate metal melting.

- Disassembly/stripping for preparation can be additionally complex.

• Where the waste stream is potentially suited for incineration due to the balance of organics to metals, this waste falls under the ‘Organics’ BAT.

Bitumen coated

• Issues and considerations similar to plastic/rubber coated metal, but potentially suitable for melting without removal of the coating.

• Older material can often be successfully stripped using mechanical means (subject to the geometry and accessibility of the waste).


Type of

coating Considerations/issues

Asbestos • Out-of-scope – to be considered in specific studies.