rwm report no. nda/rwm/117 - geological disposal: upstream
TRANSCRIPT
NDA Report no. NDA/RWM/117
Geological DisposalUpstream OptioneeringCentralised Intermediate LevelRadioactive Waste Finishing Facility
August 2014
NDA Report no. NDA/RWM/117
Geological DisposalUpstream OptioneeringCentralised Intermediate LevelRadioactive Waste Finishing Facility
August 2014
NDA/RWM/117
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This report has been prepared by ASSIST and Nuclear Technologies under contract to the Nuclear Decommissioning Authority (NDA), Radioactive Waste Management Directorate (RWMD) and forms part of an ongoing programme of research commissioned by NDA RWMD to underpin the long-term safety of a geological disposal facility for higher-activity radioactive wastes. Before it was published RWMD became a wholly owned subsidiary of the NDA (on 1 April 2014) called Radioactive Waste Management Limited. The report has been reviewed by Radioactive Waste Management Limited. However, references to NDA and RWMD in the text have been retained as they are appropriate for the period when this research was being performed. The views expressed and conclusions drawn in this report are those of ASSIST and Nuclear Technologies and do not necessarily represent those of the NDA RWMD or Radioactive Waste Management Limited.
Conditions of Publication This report is made available under the Radioactive Waste Management Limited Transparency Policy. In line with this policy, Radioactive Waste Management Limited is seeking to make information on its activities readily available, and to enable interested parties to have access to and influence on its future programmes. The report may be freely used for non-commercial purposes. However, all commercial uses, including copying and re-publication, require permission from the Nuclear Decommissioning Authority (NDA). All copyright, database rights and other intellectual property rights reside with the NDA. Applications for permission to use the report commercially should be made to the NDA Information Manager.
Although great care has been taken to ensure the accuracy and completeness of the information contained in this publication, the NDA cannot assume any responsibility for consequences that may arise from its use by other parties.
© Nuclear Decommissioning Authority 2014. All rights reserved.
ISBN 978-1-84029-506-1
Bibliography If you would like to see other reports available from Radioactive Waste Management Limited and the NDA, a complete listing can be viewed at our website www.nda.gov.uk, or please write to our Communications department at the address below.
Feedback Readers are invited to provide feedback to the Radioactive Waste Management Limited on the contents, clarity and presentation of this report and on the means of improving the range of reports published. Feedback should be addressed to:
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email [email protected]
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Abstract The current baseline plan for many nuclear licensed sites is to treat and package waste at the site of origin to meet the Radioactive Waste Management Limited (RWM) requirements for disposal. This report considers the functions, constraints and lifecycle benefits/disbenefits of a centralised treatment or packaging (finishing) facility for intermediate level waste (ILW) arising in the UK. This work was identified as an opportunity in the RWM Upstream Optioneering work programme (Opportunity 98)1.
Potential finishing requirements were considered at a high level, by review of current or planned container and waste type combinations. A large proportion of existing waste packages are currently assumed to be fit for geological disposal and it is therefore uncertain what proportion would require further finishing. Provision for such finishing would be a risk mitigation step. Some waste packages may require further planned treatment in order to meet the requirements for geological disposal set out in the RWM Waste Package Specifications (e.g. void fill, venting). Additionally, waste that is yet to be generated through final site clearance or Sellafield decommissioning activities (after 2040) may require finishing. A wide range of finishing functions will potentially be required, including intrusive activities, such as sorting and segregation of waste and re-packaging.
A Centralised ILW Finishing Facility may help to implement greater integration across the nuclear industry through sharing of assets; however, finishing could also be provided through mobile or local facilities. A qualitative comparison was made between localised and centralised finishing, using the NDA’s Value Framework attributes, and assuming that centralised finishing only becomes viable from 2040 when a GDF is available. At present, it is not clear that a compelling business case can be made for a Centralised ILW Finishing Facility due to significant uncertainties relating to the packaged inventory at 2040 and to the finishing functions that would be required at that time.
1 Nuclear Decommissioning Authority, Upstream Optioneering Phase 2 Report, NDA Technical Note
Number 16983129, August 2012.
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Preface This report is part of an ongoing programme of research conducted by the Nuclear Decommissioning Authority (NDA) and its contractors. It is a component of the research into the implementation of geological disposal for radioactive wastes in the UK.
Geological disposal is the UK Government’s policy for the higher-activity radioactive wastes. The principle of geological disposal is to isolate the waste deep inside a suitable rock formation to ensure that no harmful quantities of radioactivity reach the surface environment. To achieve this, the waste will be placed in an engineered underground containment facility – the geological disposal facility (GDF). The facility will be designed so that natural and man-made barriers work together to minimise the escape of radioactivity. The NDA has developed a multi-barrier concept for geological disposal of higher-activity radioactive wastes. These wastes include high-level waste (HLW), spent nuclear fuel, intermediate-level (ILW) and certain low-level (LLW) radioactive wastes.
A GDF would be carefully designed and engineered to provide for ILW and LLW deep, excavated vaults together with the necessary access ways. Typically, the ILW and LLW wastes would be packaged in steel or concrete containers, usually with a cement grout, and subsequently placed in the vaults. Some time later, the vaults would be backfilled with a cement-based material, completely surrounding the waste packages. Engineered barriers would be provided by the cement grout, the containers and the backfill. Natural barriers would be provided by geological formations that surround the repository and that lie between the repository and the accessible human environment. The concept for dealing with HLW and spent nuclear fuel is slightly different in that these materials could be placed in canisters and these placed directly into deposition tunnels, again using engineered and natural barriers.
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Executive Summary The current baseline plan for nuclear licensed sites (operated by Site Licensed Companies (SLCs)) is to treat and package waste at the site of origin to meet the Radioactive Waste Management Limited (RWM) requirements for disposal. The Nuclear Decommissioning Authority’s (NDA’s) Integrated Waste Management Strategy Development Programme2
seeks to implement greater integration across the industry, in particular by sharing treatment and interim storage assets and capabilities where appropriate.
The work considers the functions, constraints and lifecycle benefits/disbenefits of a centralised treatment or packaging (finishing) facility for intermediate level waste (ILW) arising at both NDA and non-NDA sites. This was initially identified as an opportunity in the RWM Upstream Optioneering work programme (Opportunity 98)3.
A key assumption is that a Centralised ILW Finishing Facility would only need to be operational from 2040, the current baseline date for GDF availability. Therefore the study considers the finishing needs of packaged UK ILW that will exist in 2040 or be produced after that date.
By 2040, UK ILW can be grouped into four different categories, each potentially having different requirements regarding package finishing:
1. Packaged, conditioned ILW in disposal packages, in interim storage and awaiting dispatch to a GDF, or appropriate disposition if in Scotland. The waste in this group is considered not to need further treatment and/or packaging or finishing. However, there is a risk that some of these packages may have evolved while they are in storage (leading to detrimental effects) and that a proportion of them will need further finishing work. This could range from minor repairs to, in extreme cases, overpacking or re-packaging.
2. ILW in disposal packages for which further finishing work is planned in order to meet the requirements for disposal, such as encapsulation or void filling. The waste is expected to remain in the same package throughout the finishing process.
3. ILW in packages that are not intended for direct disposal, in interim storage and awaiting further processing. The waste is not in a final disposal container and further treatment and packaging is planned before geological disposal or other appropriate disposition.
4. Waste that is not yet packaged, but which is planned to be retrieved and packaged as ILW (between 2040 and 2130) as part of the Final Site Clearance (FSC) process, or through decommissioning activities at Sellafield. A wide range of finishing functions will potentially be required, including intrusive activities, such as sorting and segregation of waste and repackaging.
Functional Requirements of a Centralised ILW Finishing Facility
A review of potential finishing requirements was undertaken, using container types and waste group combinations that are currently in use or planned to be used. At this preliminary stage, the study was undertaken at a high level using generic examples; waste streams or container manufacturers have not been specified. Potential finishing requirements identified in the review included overpacking, void filling, encapsulation of unencapsulated waste, changing seals, releasing pressure, adding filters, package repair, dismantling, sorting and re-packaging, or some combination of these capabilities.
2 Nuclear Decommissioning Authority, Integrated Waste Management Strategy Development Programme,
May 2012. 3 Nuclear Decommissioning Authority, Upstream Optioneering Phase 2 Report, NDA Technical Note
Number 16983129, August 2012.
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The finishing requirements identified in the review could be provided at:
• A local finishing facility, one facility at each site where there is need. • A mobile finishing facility that could visit each site where waste package treatment
was required. Mobile waste treatment plants were considered in a separate Upstream Optioneering report, which concluded that they were unlikely to deliver any benefits and should not be pursued further4.
• A Centralised ILW Finishing Facility at a single location, to which all waste requiring finishing would be brought.
If finishing were to be provided at a Centralised ILW Finishing Facility, the facility could be divided into the following areas to provide the finishing requirements identified in the review:
• Package receipt and unloading. • Package inspection and assay. • Package treatment and processing. • Waste treatment and packaging. • Container refurbishment. • Package export.
Such a facility would also require buffer storage (both shielded and un-shielded stores) and a variety of ancillary support facilities (e.g., transport flask or transport container refurbishment, active/inactive maintenance, health physics, secondary waste treatment).
Constraints relating to package design, package weight and size, transport, lifting, throughput, interim store life, processing of secondary waste and stakeholder engagement were identified during a workshop with RWM staff..
Outline initial strategic and economic business case
An outline business case was developed to consider the potential benefits and disbenefits of carrying out all waste package finishing that is required, from 2040 onward, at a Centralised ILW Finishing Facility. The strategic case comprises the background and strategic context to the case, a summary of the current situation regarding management of packaged ILW, the case for change (benefits of making a change from the current baseline), and identifies the risks, uncertainties and constraints associated with this change.
Strategic context: The NDA Strategy II included a commitment to consider alternative waste treatment options, including multi-site and shared facilities. This is supported by the Integrated Waste Management Strategy Development Programme.
Current situation (at 2040): By 2040, UK ILW can be grouped into four categories with potentially different finishing requirements, from packaged waste in interim storage (where finishing may be needed as a risk mitigation measure) to waste from Final Site Clearance or Sellafield decommissioning that is not yet packaged. Case for change: The provision of a Centralised ILW Finishing Facility in 2040 would deliver the following benefits:
• It would provide mitigation against the risk that ILW currently packaged for GDF disposal is found not to comply with the future GDF WAC. In particular, as demand is very uncertain it may be difficult to justify the planning and construction of local
4 Radioactive Waste Management Limited, Upstream Optioneering: Technical Feasibility of Mobile Plant
for Higher Activity Wastes, NDA/RWMD/118, April 2014.
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finishing facilities on a contingency basis, whereas costs could be shared amongst waste producers if a centralised facility was available.
• It would provide flexibility in the management of problematic wastes, promoting timely hazard reduction, FSC and delicensing, and avoiding the need to extend the operation of storage facilities.
• It would make efficient use of available skills and encourage the development of a centre of excellence in treatment of waste packages, resulting in a consistent approach to waste treatment and good quality control and assurance.
• For certain waste streams, waste producers have planned to do further work on existing ILW packages in interim storage, or those yet to be made prior to GDF availability in 2040, to make them acceptable for geological disposal. Waste producers have made provision to carry out such additional work. However, a single multi-functional finishing facility could satisfy this requirement for wastes produced at multiple sites.
Provision of a centralised facility, rather than similar infrastructure provided at multiple separate sites, may provide economies of scale; however, these are uncertain because some activities will be needed at individual sites. There may also be a need for additional handling and transport of packaged waste if the centralised finishing facility is not located at a GDF, which may further offset potential economies. Uncertainties: The following uncertainties and related risks mean that it is not currently possible to develop a case for change from the existing baseline (implied in site LTPs), in which finishing is carried out on each waste-producing site:
• The location of the facility and of a GDF. There is a related risk that waste packages cannot be transported prior to finishing, and therefore that additional facilities will be needed at waste-producing sites
• The number and types of packages that may need finishing at 2040 and thereafter. • The functional requirements needed from a finishing facility. Considering the wide
range of potential functions identified, there is a risk that the plant will be so complex it cannot be made to work, or is not ALARP
• The timescales over which a finishing facility is required to operate, which will depend on GDF and decommissioning schedules.
Economic case: For each of the four categories of ILW at 2040, a qualitative comparison was made between local and centralised finishing for an example waste group (final site clearance waste at Magnox and EDF sites), using the NDA’s Value Framework attributes. Potential differentiators identified included environmental impact (construction materials, energy requirements, secondary waste production and decommissioning), safety (transport miles), long-term strategic fit (flexibility) and cost (potential for economies of scale).
Conclusions and recommendations It was concluded that it is not possible, given the current level of knowledge, to make a compelling business case for a Centralised ILW Finishing Facility, due to the uncertainties relating to the packaged inventory at 2040 and to the finishing functions that would be required at that time. It is recommended that this opportunity is revisited at a later date, once one or more of the uncertainties identified above have been resolved. It was noted that there may be an opportunity to use infrastructure, which may be in existence at 2040, at Sellafield and other licensed sites to provide the required package finishing capability. A facility for the rework of β/γ ILW packages at Sellafield is currently planned and, at other sites, treatment and packaging activities are planned between now and 2040. Consideration of the requirements for package finishing will aid discussions with waste producers on how they might make use of a centralised facility and what benefits a centralised facility would offer them.
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List of Contents
Abstract iii
Preface iv
Executive Summary v
1 Introduction 1
1.1 Background 1
1.2 Structure of report 1
2 Project assumptions 2
3 Waste containers and package types and associated finishing requirements 3
3.1 Identification of potential waste containers 3
3.2 Identification of potential finishing requirements by waste group / container type 5
3.3 Summary of wasteform and waste package issues 8
3.4 Constraints 11
4 Potential functional requirements of a Centralised ILW Finishing Facility 13
4.1 Acceptance requirements for a Centralised ILW Finishing Facility 13
4.2 Package export criteria 14
4.3 Functional requirements of a Centralised ILW Finishing Facility 14
5 Strategic case 17
5.1 Background and strategic context 17
5.2 Situation at 2040 18
5.3 Case for change 25
5.4 Constraints 26
5.5 Risks and uncertainties 26
5.6 Scope and boundaries 27
6 Economic case 28
6.1 Credible options 28
6.2 Value Framework assessment for the example waste group 28
6.3 Comparison of credible options for different categories of waste packages 32
7 Conclusions and recommendations 36
8 References 38
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Appendix A Review of existing and planned finishing facilities A-1
A.1 Head End Cell, Harwell, UK A-1
A.2 Packaging of remote-handled ILW, Dounreay, UK A-1
A.3 GE Healthcare plant for the packaging of concrete-lined drums, UK A-1
A.4 Cigeo facility, France A-2
A.5 ZWILAG, Switzerland A-2
A.6 Central Organisation for Radioactive Waste (COVRA), Netherlands A-3
A.7 Belgoprocess, Belgium A-4
A.8 Bohunice Radioactive Waste Treatment Centre, Slovakia A-4
A.9 Summary A-5
A.10 Appendix A references A-6
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1 Introduction
1.1 Background The current baseline plan for nuclear licensed sites (operated by Site Licensed Companies (SLCs)) is to treat and package intermediate-level waste (ILW) packages at the site of origin. The processing facilities that exist in the UK are usually designed, built and operated for the treatment and packaging of a particular waste stream or group of waste streams.
Waste packages are currently packaged in accordance with the Generic Waste Package Specification (GWPS) and endorsed by the RWM disposability assessment process. Before waste packages5 can be dispatched from a site to a geological disposal facility (GDF) for disposal, the SLC would need to demonstrate that waste packages (in a suitable transport container if required) meet both the International Atomic Energy Agency (IAEA) Transport Regulations [1]), and guidance given by the Radioactive Waste Management Limited (RWM) [2] or appropriate disposition according to the Scottish Policy for the management of Higher Activity Radioactive Waste if in Scotland [3].
Waste Acceptance Criteria (WAC) for a GDF are expected to develop from RWM’s GWPS [2] as a specific site and geological disposal concept are selected. ‘Finishing’ is a term used throughout this report to refer to further treatment or packaging activities that are required to meet the GDF WAC (or alternative disposition if in Scotland). It also covers repair/rework activities as part of risk mitigation. For example, waste packages (in a suitable transport container if required) that meet the IAEA Transport Regulations, but not the requirements for disposal in a GDF, could be transported to an off-site facility for finishing to meet RWM’s disposal requirements. In the event that the waste package itself does not meet the transport requirements and a suitable transport container is not available, finishing will be required by the SLC prior to dispatch for disposal. A range of documentary evidence and inspection or monitoring data will also be required to demonstrate that the waste packages meet the GDF WAC at that time.
The Nuclear Decommissioning Authority’s (NDA’s) Integrated Waste Management Strategy Development Programme [4] seeks to implement greater integration across the industry, in particular by sharing treatment and interim storage assets and capabilities where appropriate. An opportunity identified in the RWM Upstream Optioneering work programme (Opportunity 98) relates to centrally locating waste treatment and spent fuel packaging facilities at a GDF or an alternative site [5]. This work considers opportunities for ILW only; aspects relevant to spent fuel will be considered in a separate project [6].
The aim of this report is to consider the functions, constraints and lifecycle benefits/disbenefits of a centralised treatment or packaging (finishing) facility for intermediate level waste (ILW) arising at both NDA and non-NDA sites. A business case style was adopted to present the arguments for a Centralised ILW Finishing Facility. Additional background information is therefore provided in Sections 5.1 and 5.2.
1.2 Structure of report The report is structured as follows:
• Project assumptions (Section 2).
5 A waste package is defined as the product of conditioning that includes the wasteform and any
container(s) and internal barriers (e.g. absorbing materials and liner), as prepared in accordance with requirements for handling, transport, storage and/or disposal [RWMD, Glossary, RW34-G02 Rev. 1, March 2013].
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• Identification of the wasteforms and container types (waste packages) that may require finishing (Section 3).
• Identification of the potential functional requirements of a Centralised ILW Finishing Facility (Section 4).
• A high-level strategic initial business case for a Centralised ILW Finishing Facility (Section 5). This presents the situation at 2040, the case for change, the timescales on which a change would need to be made, and identifies the risks, dependencies and constraints associated with the change.
• A high-level economic initial business case for a Centralised ILW Finishing Facility (Section 6). An example of final site clearance waste at Magnox and EDF sites is used to qualitatively identify the benefits and disbenefits of a Centralised ILW Finishing Facility, compared to the assumed baseline of localised finishing at each waste producing site, using the NDA’s Value Framework [7] criteria.
• Conclusions and recommendations (Section 7). A review of relevant experience related to the use of centralised waste processing facilities is summarised in Appendix A.
2 Project assumptions In order to bound the scope of work, the following assumptions were made:
• The location of a Centralised ILW Finishing Facility is not specified. A Centralised ILW Finishing Facility could be situated on a waste-producing site, at another site or at a GDF; it is not appropriate to determine the location at the present time.
• For the purposes of this study, a Centralised ILW Finishing Facility is not considered to be mobile. A strategic assessment of the use of mobile facilities is outside the scope of this work. Another Upstream Optioneering study examined the use of mobile ILW treatment plants [8].
• The work considers ILW arising at both NDA and non-NDA sites in the UK. • The work considers finishing of waste packages from Scottish facilities, however the
Scottish Policy for the management of Higher Activity Radioactive Waste would still apply: “the Policy allows consideration to be given to the transport of the waste from where it arises for treatment elsewhere in the UK, and to the export of the waste overseas … in line with international agreements and robust regulatory requirements” [3]. In this case, waste packages could be returned to the site of arising following finishing.
• The current RWM GWPS and guidance [2] are applicable to this study. • The amount of handling and dismantling (rework) will be minimised (i.e., as low as is
reasonably practicable (ALARP) considerations will apply and the best available technique (BAT) will be applied to waste treatment. As a result, it is unlikely to be necessary to repackage waste purely to reduce packaged waste volumes).
• Waste packages should be compliant with transport regulations to allow transport to a Centralised ILW Finishing Facility. Waste packages can be Type IP-2 transport packages, or can be transported in a Type IP-2 transport container. Alternatively waste packages can be Type B transport packages, or can be transported in a Type B transport container. In the event that a suitable transport container is not available and the waste package itself does not meet the transport requirements, further work will be required by the SLC prior to dispatch for finishing and/or disposal.
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• A Centralised ILW Finishing Facility is not expected to have a high throughput for packages requiring complicated rework (e.g., 100 packages per year) but is likely to need a higher throughput for simpler functions, such as void filling of packages.
• A Centralised ILW Finishing Facility will have a rail head on-site so that packages can be imported into the facility from SLCs and dispatched to a GDF by rail, as well as by road (or by sea, if a coastal site is selected).
• There will be no storage for waste packages at a Centralised ILW Finishing Facility, other than buffer storage, and interim storage arrangements on waste-producing sites will not be affected.
• With the exception of wastes covered by Scottish Policy, waste packages will be transported from a Centralised ILW Finishing Facility directly to a GDF in accordance with IAEA Transport Regulations [1], and not returned to the sites of origin; therefore, a Centralised ILW Finishing Facility would begin operations when a GDF is available. In this report the current baseline assumption is made that a finishing facility and a GDF will both commence operations in 2040.
• ILW arising as a result of nuclear new build activities is out of scope as this is not expected to arise until after 2100, which is assumed to be beyond the lifetime of a facility opened in 2040.
• The UK and international legislation related to the transport and disposal of ILW is unlikely to change significantly.
3 Waste containers and package types and associated finishing requirements
In this section, examples of waste containers and package types that may require finishing are identified and used to determine potential finishing requirements and constraints.
3.1 Identification of potential waste containers The wasteforms and waste packages that will be produced in the UK, and could potentially require treatment prior to disposal, were identified through review of current ILW packaging plans (based on RWM documentation [9]) and discussions with experts working in the nuclear field).
At present a variety of different waste containers6 are proposed for use; those considered within this project are grouped as follows and listed in Table 1:
• Un-shielded packages (U-ILW). • Shielded packages (S-ILW).
This review was undertaken at a generic level and, therefore, no commercial container manufacturers are identified within this report.
6 A container is the vessel into which a wasteform is placed to form a waste package suitable for handling,
transport, storage and disposal [RWMD, Glossary, RW34-G02 Rev. 1, March 2013].
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Table 1 Container types and status of transport and disposal arrangements
Waste Container Waste Type Transport Container
Disposability assessment status7
Un-shielded packages (U-ILW)
500 litre drum [10]
Solids (including Plutonium Contaminated Material (PCM)), sludges and resins
Type B container required Container endorsed
3m3 box [11], [12] Solids Type B container required Container endorsed
3m3 drum [13] Sludges and resins Type B container required Container endorsed
Enhanced 3m3 box (double skinned) Solids Type B container
required Under assessment
Temporary storage containers (various sizes)
Solids Type B or IP-2 container required Under assessment
Decommissioning boxes (various sizes)
Alpha contaminated decommissioning waste
Type B or IP-2 container required
Not currently under assessment
Shielded packages (S-ILW)
2m box (0 to 300 mm shielding) [14]
Solids Type IP-2 container Container endorsed
4m box (0 to 300 mm shielding) [15] Solids Type IP-2 container Container endorsed
6 m3 box (standard or high density) [16] Solids Type IP-2 container Container endorsed
Shielded 500 litre drum (e.g. TRU-Shield)
Solids Type IP-2 container Under assessment
500 litre Ductile Cast Iron Container (DCIC) unvented
Solids, sludges and resins
Type B container required Under assessment
DCIC unvented Solids Type IP-2 container Under assessment
DCIC vented (various sizes) Solids Type IP-2 container Not currently under
assessment
7 Green indicates that the use of this container for specific waste streams has been endorsed via the
Letter of Compliance (LoC) process, yellow indicates that an LoC submission is under assessment, and red highlights that the container is not currently under assessment; however, informal discussions may have taken place with RWM [9].
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3.2 Identification of potential finishing requirements by waste group / container type
Potential finishing requirements have been identified by considering, for each of the container types listed in Table 1, ILW groups that may need or benefit from finishing. This does not represent a comprehensive list of all waste groups/containers or issues. It is recognised that additional issues may arise during interim storage and/or dispatch of waste packages to a GDF.
3.2.1 Un-shielded packages (U-ILW)
500 litre and 3m3 stainless steel containers 500 litre drums and various types of 3m3 boxes and drums are used by a number of SLCs including Magnox Limited, Sellafield Limited, Dounreay Site Restoration Limited (DSRL) and Research Sites Restoration Limited (RSRL). The following issues have been identified with existing waste packages, which may be required to undergo finishing activities to meet the requirements for disposal in a GDF:
• Some SLCs are considering storing activated and contaminated reactor component wastes within 500 litre drums without immobilising in grout. If the requirement to minimise voidage8 is retained within the GDF WAC, void filling could be undertaken at a Centralised ILW Finishing Facility.
• Reactive metals are usually packaged in 500 litre drums or 3m3 boxes. A small number of 500 litre drums containing reactive metals have started to show signs that the wasteform is continuing to evolve with time, leading to potential detrimental effects. Packaging of waste streams containing reactive metals in 500 litre drums has been endorsed with a Final stage LoC by RWM. However, there was a caveat added that in the event of excessive degradation of the matrix due to corrosion of the Magnox metal these packages would need to be overpacked. This could be achieved by overpacking for disposal, for example, within a modified 4 drum stillage or a 3m3 box, which would enable the packages to be transported in a Standard Waste Transport Container (SWTC). If 500 litre drums were no longer to be accepted at a GDF, they would need to be dismantled and repackaged into new containers.
• Evolution issues have not currently been identified for reactive metals already packaged in 3m3 boxes. However, modified 3m3 boxes are being proposed for the future packaging wastes arising from a number of facilities on the Sellafield site where wasteform evolution (expansive corrosion) is perceived as a potential threat. In the proposed process, a liner containing grouted waste is placed into a modified 3m3 box, which is lidded and transferred to an interim store. The annulus between the liner and the side wall of the waste container is left empty to enable wasteform evolution without damaging the waste container. If required, the annulus could then be filled prior to transport to a GDF.
The following issues have not been identified with existing packages. However, if they were to occur, affected packages may be required to undergo finishing:
• Wasteform degradation, leading to waste packages failing to meet one or more of the following RWM requirements: o Immobilisation of particulates. o Progressive failure during impact accidents.17 o Predictable activity release during fire accidents. o Stacking is no longer possible in the GDF.
8 Voidage limits for waste packages and GDF construction are currently being considered by RWM [17].
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• Loss of all or part of the documentation associated with the waste package, resulting in the requirement for additional assay to demonstrate compliance with the GDF WAC.
• Surface contamination, resulting from problems during interim storage, resulting in the need for decontamination or overpacking.
• Accidental damage to the waste packages, which may require rework prior to disposal in a GDF. Those damaged beyond repair may require overpacking or the contents may need to be repackaged into new containers.
• Corrosion or water damage could result in obscured package identification markings, unusable lifting features, or other issues (e.g., blinding of the vent), which may need to be rectified.
• The radionuclide inventory of the waste package may have decayed sufficiently during storage to enable the package to be disposed of using alternative routes. This could result in the requirement for additional assay to support re-routing. For a small proportion of waste packages, the activity of the contents may have increased during storage due to ingrowth of americium or accumulation of radon, which could result in the need for additional shielding or venting of gas build-up prior to transport and/or disposal.
Temporary waste storage containers A number of SLCs are considering the use of temporary containers for interim storage of operational and decommissioning waste. These containers have not been endorsed by RWM via the LoC process. To enable waste stored in these containers to be packaged for disposal, the following activities may be required:
• Transport to a finishing facility – If the finishing facility was off-site, the waste storage container would need to be approved as a transport container in its own right or would need to be compatible with an available Type IP-2 or Type B transport container. Appropriate lifting features would be required to facilitate transport, loading/unloading, and to enable handling of packages within the finishing facility.
• Assay and or monitoring to determine the radioactive inventory, as required by the GWPS [2].
• Repacking the waste into suitable containers for disposal, either in a shielded facility for beta/gamma waste requiring remote handling or in an alpha containment for plutonium or uranium contaminated wastes.
• Venting/purging of waste storage containers to release the build-up of flammable gas.
• Void filling the waste package. • Export to a GDF.
Waste producers are considering a variety of sizes for temporary waste storage containers. These storage containers (with separate transport containers if required) cannot exceed the maximum dimensions for road or rail transport. The maximum mass that can be transported on an ordinary heavy goods vehicle is 30 tonnes, so if road transport is required, there may be operational benefits in maintaining package masses below 30 tonnes [18]. Packages with masses greater than this will require transport by rail or special road transport arrangements.
3.2.2 Shielded packages (S-ILW)
2m and 4m boxes 2m and 4m boxes are primarily designed as Type IP-2 packages for the transport and disposal of reactor wastes (e.g., non-reactive metals, graphite and concrete wastes). If
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included as a requirement in the GDF WAC, void filling could be undertaken at a finishing facility, provided that the un-immobilised waste is consistent with transport requirements.
The following unplanned finishing activities may be required to ensure that these waste packages meet the requirements for disposal in a GDF:
• Decontamination of the outside of the waste package. • Repair of accidental damage to the outside of the waste package. • Repair of corrosion damage to the outside of the package. • Overpacking containers that are damaged beyond repair.
6 cubic metre concrete boxes 6 cubic metre concrete boxes are classed as disposal containers and are transported as a Type IP-2 package. They are grouted before a lid is cast on top; standard density and high density grout variants are available. At present, no finishing activities are planned for these waste packages prior to disposal.
However, following a period of interim storage, the following unplanned finishing activities may also be required to ensure that they comply with the GDF WAC:
• Assay of packages that have lost all or part of the documentation required for disposal.
• Decontamination of the outside of the box due to migration of caesium (and possibly tritium) through the concrete container walls during storage [19].
• Repair of accidental damage on the outside of the waste package (e.g., restoring damaged lifting features).
• Repair of corrosion damage to the package, e.g., as a result of atmospheric chloride-induced localised corrosion of the steel reinforcement, or concrete degradation due to carbonation [19].
• Overpacking damaged containers – An overpack could be designed and deployed to transport the 6 cubic metre concrete box to a GDF. This approach would require the design and approval of an overpack [19], which could be a flexible wrap or cover, or a more substantial container. Due to the size of the 6 cubic metre concrete box, the latter may need to be transported to a GDF on an 8-axle rail wagon or transported using special road transport arrangements [18]. If the waste package was damaged beyond repair, it could also be dismantled and repackaged for transport.
Shielded 500 litre drum The shielded 500 litre drum (e.g., TRU-Shield) has an annulus that is lined with either lead or grout. This package type is currently under consideration for endorsement via the RWM disposability assessment process.
Void filling may be required for this package, if included in the GDF WAC. Other potential finishing activities would be similar to those listed for 500 litre drums and 3m3 boxes.
Unvented Ductile Cast Iron Containers A number of SLCs are proposing the use of a variety of ductile cast iron containers (DCICs) for the interim storage of ILW. Ongoing discussions between the SLCs and RWM indicate that the following planned finishing activities may be required:
• Void filling – This could be achieved by opening the lid or opening one of the ports in the lid. The potential need to fill voids is specified as a caveat in the LoCs for these waste packages. A contingency plan may be needed if it is not possible to open the package and fill the void.
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• Addition of venting to DCICs to meet RWM requirements for disposal, including removal of any vent covers or replacement of a port closure with a vented plate.
• Testing the seal to demonstrate that it meets RWM requirements for disposal. The seal may need to be replaced if its design life is exceeded during the operational phase of the GDF.
To enable the seal to be replaced, a shielded facility will be required to remove the lid and change the seal. In the event that the seal face is damaged or corroded, the waste will need to be removed from the package and both the container and the lid decontaminated before transferring to a refurbishment facility. The refurbishment facility would need to perform the following functions:
• Re-machine the seal faces to the required tolerances. • Remove any seal residues in the seal grooves. These may also require machining. • Re-paint the container. • Re-assemble the container and test the performance of the seal.
A contingency plan may be needed if it is not possible to change the seal on the container.
Other potential finishing activities that may be required include:
• Assay of a package which has lost all or part of the documentation required for disposal.
• Repair of accidental damage to the waste package. • Decontamination of the container. • Re-painting the outside of the container. • Re-packaging.
Vented Ductile Cast Iron Containers A number of SLCs are proposing the use of vented DCICs to minimise the need to change seals and to vent waste packages prior to transport or disposal. Void filling may be required for these packages, if included as a requirement in the GDF WAC, by removal of the lid or opening of a port in the lid of the container. Other potential finishing activities for vented DCICs would be similar to those listed for unvented DCICs.
3.3 Summary of wasteform and waste package issues Table 2 contains a summary of the finishing activities that may potentially be required, based on the examples described in Section 3.2, above. For each waste package type, the categories within which it may occur are also noted; this will be discussed further in Section 5.
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Table 2 Summary of waste packages and finishing activities
Container Waste group On-site treatment process
Planned finishing activities
Other potential finishing activities
Categories in which this waste package
type may occur
Un-shielded packages (U-ILW)
500 litre drum Solids Grouting Non-encapsulation
Overpacking in the event of matrix failure Void filling
Overpacking Package repair9
1, 4
500 litre drum Sludges and resins In drum mixing Overpacking in the
event of matrix failure Overpacking Package repair9
1, 4
3m3 box Solids Grouting Non-encapsulation
Void filling Overpacking Dismantling
1, 4
3m3 drum Sludges and resins In drum mixing
Overpacking Dismantling
1, 4
Enhanced 3m3 box (double skinned) Solids
Inner liner grouted Non-encapsulation
Void filling Package repair9 Packaging into approved container
1, 4
Temporary storage containers
Decommissioning solids None
Re-packaging for disposal Void filling
3
Decommissioning boxes
Alpha contaminated decommissioning waste
None; however, probably plastic wrapped
Packaging into approved container Void filling
3
9 Package repair include activities such as surface decontamination, restoring handling features and restoring package identification.
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Container Waste group
On-site treatment process
Planned finishing activities
Other potential finishing activities
Categories in which this waste package type may
occur Shielded packages (S-ILW)
2m box (0 to 300 mm shielding) Solids Grouting
Non-encapsulation Void filling Overpacking Dismantling and re-packaging
1, 2, 4
4m box (0 to 300 mm shielding) Solids Grouting
Non-encapsulation Void filling Overpacking Dismantling and re-packaging
1, 2, 4
6m3 box (standard density or high density) Solids Grouting
Overpacking Dismantling and re-packaging
1, 4
Shielded 500 litre package (e.g., TRU-Shield)
Solids None Void filling Pressure release 1/2
DCIC unvented Type IP-2 package Grouting
Non-encapsulation
Void filling Seal change Release pressure and add filter
Overpacking Re-packaging 1/2
DCIC unvented Type B package
Void filling Seal change Release pressure and add filter
Overpacking Re-packaging 1/2
DCIC vented Void filling Overpacking Re-packaging 1/2
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3.4 Constraints Table 3 lists the constraints that are considered to affect the functional requirements of a Centralised ILW Finishing Facility. A constraint is considered to be a limitation or restriction that impedes on waste package transport, handling and operations within a Centralised ILW Finishing Facility, and constraints on the business case for such a facility.
Table 3 Constraints on a Centralised ILW Finishing Facility
Category Constraints
ALARP Any operations that take place within the Centralised ILW Finishing Facility must meet the requirements of ALARP.
Package design
Packages requiring void filling will need to have a removable lid or ports in the top face of the box that can be easily removed using remotely operated equipment. In the event that the pressure may need to be relieved within the package, where possible a safe method of achieving this should be incorporated into the original package design.
Package weight and size
This will be driven by the maximum limits for GDF operations plus the road and rail transport limits.
Transport
Waste packages will need to meet the IAEA Transport Regulations unless capable of being transported in a suitable transport container. The maximum mass that can be transported on an ordinary heavy goods vehicle is 30 tonnes. Packages with masses greater than this will require transport by rail or special road transport arrangements. The Generic Transport System Design (GTSD) currently assumes the use of a four-axle rail wagon for ILW transport packages [20]. The maximum permissible axle loading for most of the UK rail system is 22.5 tonnes per axle and this leads to a maximum loaded rail wagon mass of 90 tonnes. The current rail wagon design for the transport of ILW has a gross mass of approximately 26 tonnes which limits the maximum transport package mass to approximately 64 tonnes [20]. However, due to the stacking requirements in a GDF the gross mass of a 6 cubic metre box is further restricted to 50 tonnes [19]. It has been demonstrated that an eight-axle rail wagon could be used to transport larger waste packages [21]. The 2m box, 4m box and 6m3 waste packages are Type IP-2 packages intended to be transported without a separate transport container. If required they could be overpacked, e.g. with a flexible cover to deal with surface contamination. Larger overpacks may challenge the standard height and width restrictions for rail transport but could be moved by road under special arrangements. An SWTC could be used to transport unconditioned waste [22]. However, if transport of an existing waste package is not possible in a SWTC, further work will be required by the SLC prior to dispatch to a Centralised ILW Finishing Facility (e.g., due to excessive deformation of container). Compliance with the requirements of the IAEA Transport Regulations is demonstrated by the Package Design Safety Report (PDSR), which includes all the information required to demonstrate the safety of the
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Category Constraints transport package and establishes limits on key parameters that describe the package inventory. The PDSRs for existing designs of transport containers may need to be revised for use with unconditioned waste. There are a number of potential issues, e.g. the need to prevent loose waste from moving about in a transport package and causing “hotspots” during transport. The surface contamination of the waste package shall not exceed the limits specified in the relevant WPS [23]; the 300 series provides a specification for each standardised waste package.
Lifting
Packages requiring remote handling will need to be fitted with appropriate features that enable them to be lifted within a Centralised ILW Finishing Facility and a GDF. Alternatively a Centralised ILW Finishing Facility will need to have lifting equipment to accommodate a range of package types.
Throughput
The rate at which packages arrive at a Centralised ILW Finishing Facility will be constrained by a number of factors, including:
• The availability of transport containers (e.g. SWTCs and Type IP-2).
• The rate that packages can be extracted from SLC stores and transported to a finishing facility.
The throughput of a GDF, as it is assumed that a Centralised ILW Finishing Facility does not have any storage capacity for waste packages, other than buffer storage. The GDF throughput is currently limited by the capacities of the UILW inlet cell (2,500 transport packages per year [24]) and the drift, for LLW and SILW that requires minimal underground processing (3,900 transport packages per year [24]). The condition of waste packages in interim storage will be regularly evaluated, such that likely requirements for finishing and/or rework will become less uncertain before waste packages are due to be transferred from interim storage to a GDF. To optimise use of a Centralised ILW Finishing Facility, sufficient capacity will need to be available to avoid delay of SLC store operations.
SLC store life
The waste will be stored on waste producers’ sites in interim stores with finite lifetimes. These lifetimes may place constraints on the time by which waste producers need to empty the stores and transport waste packages to a Centralised ILW Finishing Facility or a GDF.
Processing of secondary waste
A Centralised ILW Finishing Facility will need to have the capability to process secondary radioactive waste into a form that can be disposed of in a GDF, including management of liquid effluents and gaseous discharges.
Stakeholder and planning
These can only be defined as part of the process for selecting a site for a Centralised ILW Finishing Facility.
Lack of information available to finishing plant operators
The operators of a Centralised ILW Finishing Facility require sufficient information about the waste packages to enable the plant to operate safely.
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4 Potential functional requirements of a Centralised ILW Finishing Facility
In this section, the likely waste acceptance and export criteria and potential functionality needed at a Centralised ILW Finishing Facility are specified.
4.1 Acceptance requirements for a Centralised ILW Finishing Facility The facility will need to be able to accept waste packages in varying states, for example packages with loose lids, pressurised containers, containers with holes, bulges, splits, extensive corrosion, uneven loads and damaged lifting features. For the purposes of finishing, it will also need to be able to handle packages with loose, dispersible activity and unusual handling features. The facility will also need to be able to accept and unload waste packages transported within the range of available transport containers.
To enable transport of waste packages to a Centralised ILW Finishing Facility, the proposed waste package (in a suitable transport container if required) will need to meet the IAEA Transport Regulations. As an example, it is expected that 500 litre drums and 3m3 boxes will be loaded into SWTCs and therefore the waste producers / consignors will need to demonstrate that these packages will not compromise the performance of the SWTC. If this cannot be achieved it will be necessary to treat the package at the local site of waste arising, unless special arrangements can be made to transport the waste package.
4.1.1 Waste containers A Centralised ILW Finishing Facility should be able to process a wide range of ILW packages and transport containers. This should include:
• Containers that have been endorsed via the RWM disposability assessment process: o 500 litre drums (top lifting or in stillages). o 3m3 boxes and drums. o Low density and high density 6m3 concrete boxes, which meet Type IP-2
package transport requirements. o 2m and 4m boxes, which meet Type IP-2 package transport requirements.
• Containers under consideration/assessment by RWM: o Unvented DCICs (Type B or Type IP-2 containers). o Vented DCICs which meet Type IP-2 package transport requirements. o Stainless steel robust containers. o Shielded metal-lined Type IP-2 containers (e.g., TRU-Shield).
• Other containers: o Temporary storage containers. o Decommissioning waste boxes.
It is recognised that additional container types may be introduced in future and the flexibility to process new package variants would be beneficial.
4.1.2 Waste types A Centralised ILW Finishing Facility will potentially need to handle all types of ILW. This will include shielded facilities for high beta/gamma waste and alpha containment facilities to handle plutonium and uranium contaminated material.
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4.2 Package export criteria On leaving a Centralised ILW Finishing Facility, waste packages should meet the RWM disposability requirements as specified in the WAC and guidance documents. If the Centralised ILW Finishing Facility is located at another nuclear licensed site, the finished package should meet the transport regulations. As the wasteform may have been altered during finishing and a different consignor would be responsible for transport from a Centralised ILW Finishing Facility, new transport approvals may be required.
It is assumed that a Centralised ILW Finishing Facility and a GDF will be linked by a conventional rail system. This will enable packages up to 85 tonnes to be easily transferred to a GDF. It is noted that the range of transport containers currently being considered by RWM is heavier (gross weight up to 130 tonnes); these could be transported using an 8-axle rail wagon.
4.3 Functional requirements of a Centralised ILW Finishing Facility Based on the issues and activities identified throughout Section 3, a Centralised ILW Finishing Facility could comprise the following areas:
• Package receipt and unloading. • Package inspection and assay. • Container treatment and processing. • Waste treatment and packaging. • Container refurbishment. • Export facility. • Ancillary support facilities.
The functions that may be needed at a Centralised ILW Finishing Facility are listed in Table 4 and illustrated using a simplified process flow diagram (Figure 1). It is noted that, as the facility may need to handle contaminated packages in both the package receipt and waste processing areas, separate areas may be needed for contamination control.
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Figure 1 Process flow diagram showing potential functions of a Centralised ILW Finishing Facility
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Table 4 Potential functions of a Centralised ILW Finishing Facility
Area Sub area Functions required for both planned and other potential finishing activities
Package receipt area Road and rail connection.
Transport flask or transport container unloading area
Shielded area Unload all types of packages.
Package inspection and assay area Shielded area
Non-intrusive inspection of packages. Assay and monitoring facility. Measurement of contamination levels. Identification of packages without clear numerical identification. Assay to determine content of packages with no historical documentation.
500 litre drum and 3m3 box/drum processing area
Shielded area Void filling. Decontamination. Overpacking. Package repair. Package dismantling and re-packaging.
Plutonium and uranium (alpha) containment
DCIC processing area Shielded area
Seal replacement. Depressurisation (or confirmation of no pressure).
DCIC refurbishing area
Ventilated containment
Decontamination. Void filling.
Non active area
Cleaning/sealing faces. Vent fitting. Re-machining sealing faces. Painting outside surfaces. Void filling.
2m box, 4m box, and 6m3 box processing area
Ventilated containment
Void filling. Decontamination. Overpacking.
Shielded area
Package repair to meet disposal requirements. Dismantling and re-packaging the waste. Assay and monitoring. Decontamination.
Waste treatment area Shielded area
Including for example polymer encapsulation, sorting, segregation, compaction, thermal, and other processes (ILW treatment tool-kit). Treatment of problematic wastes, requiring additional treatment.
Waste container re-packaging plant Shielded area
Loading waste into disposal containers. Void filling. Assay and monitoring. Decontamination.
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Area Sub area Functions required for both planned and other potential finishing activities
Plutonium and uranium (alpha) containment
Void filling. Decontamination. Package repair. Package dismantling and re-packaging.
Transport flask or transport container loading area
Shielded area
Decontamination. Loading 500 litre drums into stillages. Loading stillages and 3m3 boxes into SWTCs. Pressure testing of sealed transport packages.
Package export area
Road and rail export area
Assay and monitoring. Load all types of packages.
In addition to the above areas, the facility will require buffer storage (both shielded and un-shielded stores) and the following ancillary facilities:
• Transport flask or transport container refurbishment area (for decontamination, refurbishment and testing functions).
• Active maintenance facilities. • Inactive maintenance facilities. • Health physics support facilities. • Ventilation plant. • Secondary waste treatment facility. • Security. • Changing facilities. • Canteen. • Car parks. • Marshalling yard.
5 Strategic case Sections 5 and 6 build on the information presented in Sections 3 and 4 to provide an Initial Business Case for a Centralised ILW Finishing Facility. These sections provide the Strategic Case (Section 5) and a high-level Economic Case (Section 6) as defined in Treasury Guidance [25]. The objective is to consider the potential benefits and disbenefits of centralised finishing compared to localised finishing, and to consider whether it is possible, given the current level of knowledge, to make a compelling business case for a Centralised ILW Finishing Facility. The draft case and Value Framework assessment was developed by the project team and discussed and agreed with RWM staff at a workshop.
The Strategic Case comprises the background and strategic context to the case (Section 5.1), a summary of the current situation regarding management of packaged ILW (Section 5.2), presents the case for change (Section 5.3), and identifies the risks, dependencies and constraints associated with this change (Sections 5.4 and 5.5). Interfaces with other work areas and strategies are also recognised in Section 5.6.
5.1 Background and strategic context The NDA’s Strategy 2 document (April 2011) included a commitment to consider alternative waste treatment options, including multi-site and shared facilities [26]:
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“Diverse radioactive waste management and disposal solutions will be pursued where these offer benefits over previous arrangements. We will also investigate opportunities to share waste management infrastructure across the estate and with other waste producers where we can see benefit.” “We are exploring the possibility of developing alternative waste treatment capabilities that will help to provide a more flexible and cost-effective approach to the management of higher activity wastes (HAW)10. The work will help to determine how and where the main opportunities exist…”
The NDA’s IWM Strategy Development Programme [4] seeks to implement greater integration of waste management across the NDA estate, in particular by sharing treatment and interim storage assets and capabilities, and calls for:
“…flexibility in the management of radioactive waste, widening the range of suitable treatment processes and providing strategic guidance on the impact of waste packaging solutions on long-term storage and disposal.”
The overarching NDA strategy is to convert the HAW inventory into a form that can be safely and securely stored for many decades. At the appropriate time the stored waste in England and Wales will be transported to and disposed of in a GDF.
At most NDA nuclear licensed sites, the baseline plan is to treat and package waste at the site of origin so that the packaged waste meets the RWM requirements for disposal. When a GDF becomes available to receive waste, it will be necessary to confirm that the existing packaged waste still meets the GDF WAC. It is possible that a proportion of the packaged waste inventory will not meet these criteria, either because packages have evolved during storage, leading to detrimental effects, or because the GDF WAC have changed. In either case, further package finishing will need to be carried out. This Strategic Case sets out the case for a Centralised ILW Finishing Facility to be established, where such additional finishing could be implemented.
Further information on the background and context of this work is provided in Section 1.
5.2 Situation at 2040 Although the Strategic Case would normally start with a summary of the current situation, and any shortcomings of this situation that the proposed change would address, this business case focuses on a waste treatment need that would arise at the time that a GDF becomes available. This is the earliest time that a finishing facility could begin to operate, based on the assumption that packages would be exported directly to a GDF. Consistent with current NDA baseline assumptions, it is assumed that the date at which a GDF becomes available is 2040, and this section summarises the expected situation in terms of packaged ILW at that time.
By 2040, UK ILW can be grouped into four different categories, each potentially having different requirements regarding package finishing:
1. Packaged, conditioned ILW in disposal packages, currently in interim storage and awaiting dispatch to a GDF, or appropriate disposition if in Scotland. The waste in this group is considered not to need further treatment or finishing. However, there is a risk that some of these packages may have evolved while they are in storage and that a proportion of them will need further finishing work. This could range from minor repairs to, in extreme cases, overpacking or re-packaging.
10 Higher Activity Waste (HAW) refers to all radioactive material that has no further use that falls into the
following categories: vitrified High Level Waste (HLW), Intermediate Level Waste (ILW) and a relatively small volume of Low Level Waste (LLW) that is not deemed suitable for disposal at the LLWR or the LLW facility at Dounreay.
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2. ILW in potential disposal packages for which further finishing work is planned, such as encapsulation or void filling. The waste is expected to remain in the same package throughout the finishing process.
3. ILW in packages that are not intended for direct disposal, in interim storage and awaiting further processing. The waste is not in a final disposal container and further treatment and packaging is planned before GDF disposal or other appropriate disposition.
4. Waste that is not yet packaged, but which is planned to be retrieved and packaged as ILW (between 2040 and 2130) as part of the FSC process and Sellafield decommissioning activities. For example:
o Activated and/or contaminated steel and other metals. o Activated and/or contaminated concrete plus steel in the reinforcement. o Activated and/or contaminated graphite. o Activated and/or contaminated asbestos. o Problematic wastes11 i.e., small quantities of problem materials. This could
include, for example, contaminated oils, sealed sources, or other unknowns. Category (1) waste packages are expected to be fit for GDF disposal but are found not to be; it is uncertain what proportion would require finishing. Provision for such finishing would be a risk mitigation step. Risks may include degradation of packages in interim storage, or the establishment of more onerous GDF WAC following site and disposal concept selection. Category (2) waste packages would require further planned finishing in order to provide full containment of wastes. Several groups of wastes from different waste-producing sites fall into this category. Category (3) waste packages must be repackaged or overpacked and this may involve opening of waste packages or handling of raw waste within the facility. Category (4) involves waste that is in general yet to be generated through FSC and Sellafield decommissioning activities after 2040 and may require a range of finishing activities.
A brief summary of the packaged waste types expected to be in existence in 2040 at the various NDA nuclear licensed sites and some non-NDA sites (e.g., EDF and MOD) is followed by a summary of waste groups and container types under each of the four categories defined above (Table 5).
5.2.1 Dounreay Sites Restoration Limited All ILW (operational and decommissioning) is expected to be packaged and in safe interim storage on site by 2025 [27]. This includes some mixed ILW that has been packaged but not encapsulated (in 200 litre drums or shielded lead-lined (TRU-shield) containers).
Long term management of DSRL ILW will be compliant with Scottish Government policy and emerging strategy [3].
5.2.2 Magnox Limited Two main classes of container and packaging approaches are currently in the Magnox baseline plans (LTP13). These two groups are expected to be in storage at Magnox sites in 2040, awaiting dispatch to a GDF [28]:
• Encapsulation in stainless steel containers (500 litre drums and 3m3 boxes) and overpacking (if extra shielding is required or to enable handling) – Trawsfynydd and Hunterston A.
11 These wastes have properties that prevent them from being managed through existing or currently
planned waste routes on the site of arising, or for which there is a lack of characterisation or provenance that prevents their management, or makes their management uncertain.
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• Containerisation in DCICs with conditioning (drying) as required – Bradwell, Berkeley, Chapelcross, Dungeness A, Hinkley Point A, Oldbury, Sizewell A and Wylfa [29].
By 2040, all Magnox sites will be in care and maintenance (C&M). Operational ILW will be packaged and ready for transport to the GDF, assuming no changes in RWM or regulatory requirements.
Two ILW stores for encapsulated waste have already been built (at Hunterston A and Trawsfynydd). The current Magnox LTP13 is to construct a suitable store for DCICs on each of the remaining Magnox sites by 2020. However, Magnox is considering consolidation of storage and Fuel Element Debris (FED) dissolution arrangements with stores at Berkeley, Bradwell and Hinkley Point and possible sharing arrangements with EDF Energy [29].
The dismantling of the reactors and reactor buildings will be deferred until FSC (the date of which ranges from 2075 to 2105, depending on site). New infrastructure for managing ILW will be required at FSC, but this has not been specified in detail. A C&M Hub will manage the Magnox sites throughout C&M, including the emptying and decommissioning of ILW stores, prior to FSC.
5.2.3 Research Sites Restoration Limited All RSRL waste will be located at Harwell in 2040 – transported from Winfrith by 202312. The current baseline plan (LTP13) is for all RSRL ILW to be packaged, encapsulated and held in storage (either in the Harwell ILW Store or the Harwell Vault Store) from 2025 to 2040 [30, 31]. Encapsulation of Harwell remote handled ILW in 500 litre drums is planned to occur in the on-site Waste Encapsulation Plant. Therefore, by 2040 all RSRL operational ILW and reactor decommissioning wastes will be encapsulated in disposal containers and awaiting dispatch to a GDF for disposal.
5.2.4 Sellafield Limited Some ILW is already grout-encapsulated in stainless steel 500-litre drums (e.g., in the Magnox Encapsulation Plant (MEP)) and has been placed in interim storage facilities on site (e.g. Encapsulated Product Stores (EPS1, EPS2), Waste Encapsulation Plant and Waste Treatment Complex). Some carbon steel drums and non-standard boxes containing unencapsulated waste are currently in interim storage [32]. Some ILW from LP&LS is being retrieved into temporary storage containers, which are planned to be conditioned and packaged in 3m3 boxes in a new waste treatment facility [32].
All reprocessing activities, as well as Post-Operational Clean Out (POCO) wastes (except for the already contracted storage of fuel and POCO of associated plants), will cease by about 2030. Decommissioning of the majority of associated facilities will commence shortly thereafter and be largely complete by 2090 [33]. Sellafield Limited has plans to use 3m3 containers to package decommissioning ILW. In order to achieve this, a new ILW encapsulation plant will be constructed from 2015 – 2025 and several Encapsulated Product Stores with associated import/export facilities (Comprehensive Import/Export Facility) will be operational from 2018 onwards.
Figure 2 provides, as an example, some of the ILW processing plants and stores that are expected to be at the Sellafield site at 2040. A store emptying schedule has been developed and a specification for an ILW finishing facility is currently being developed by Sellafield Ltd.
12 Due to the planning consent conditions set for the Harwell ILW Store, there is a requirement
to transfer a specified portion of nuclear materials to Sellafield before Winfrith ILW can be transferred to Harwell [41].
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Figure 2 Sellafield ILW programme, showing packaging plants and stores for ILW that will be at Sellafield in 2040 [32]
5.2.5 EDF Energy EDF Energy, through the site licence company EDF Energy Nuclear Generation Ltd, operates seven Advanced Gas-cooled Reactor (AGR) power stations and one Pressurised Water Reactor (PWR) power station.
EDF’s current strategy is for ILW at the AGR reactor sites to be retrieved, conditioned and packaged on-site on a campaign basis throughout the operational phase. The packages are stored in an interim ILW store for the duration of operations. The stored ILW packages would be removed from the ILW store when a GDF is available.
It is expected that ILW to be disposed of from EDF’s AGR sites will already be packaged for disposal from 2040 [33]. It is uncertain at this point whether this waste would require further finishing prior to disposal. New facilities are planned to be built on each AGR site ~85 years after the end of generation for retrieval and packaging of FSC wastes (e.g., from reactor dismantling) for disposal.
At the PWR Sizewell B site, DCICs are proposed for the packaging of ILW resins [34].
5.2.6 Ministry of Defence (MOD) and Atomic Weapons Establishment (AWE) The MOD produces radioactive wastes through decommissioning programmes and research and development activities.
A consultation is currently ongoing regarding the management of ILW from submarines [35], and no ILW will be removed from any submarine until an ILW storage solution is agreed.
For ILW from the Atomic Weapons Establishment (AWE), the proposed packaging process includes retrieval and characterisation of drums of wastes and whole-drum high-force compaction (“supercompaction”). The supercompacted drums will then be packaged into
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standard 500 litre drums [36]. AWE will remain operational and producing PCM until at least 2060 and will store ILW in interim waste stores on site through to 2105. Between 2060 and 2070, AWE will implement a project to provide a retrieval and packaging capability to facilitate ILW export, including the handling equipment required to get the conditioned ILW packages into SWTCs and onto transport vehicles for dispatch to a GDF.
5.2.7 Summary of situation at 2040 The situation with regards to ILW at 2040 is summarised in Table 5.
Table 5 Categories of packaged and to-be-packaged waste at 2040
Category Finishing Requirements Waste Groups or Container Types in Existence at 2040
1. Packaged, conditioned ILW in disposal packages, awaiting dispatch to a GDF, or alternative disposition consistent with Scottish Policy
In principal, wastes in this group are ready for direct dispatch for disposal in a GDF. However, it is possible that some packages will have evolved in storage and therefore some additional finishing may be needed as a contingency measure. Rework of existing packages could be needed to fix unexpected damage (e.g. to bolts/identifiers), contamination (e.g. surface), evolution (e.g., container corrosion, wasteform expansion) during interim storage. Void filling and/or venting of existing waste packages (e.g., of DCICs) may be needed and will depend on the WAC that are defined for the specific geological environment at the GDF site.
DSRL: Most ILW encapsulated and packaged for disposition. Magnox Ltd: Encapsulated ILW in storage at Hunterston A and Trawsfynydd. Shielded, unvented DCICs (may require void filling as a contingency).
RSRL: All RSRL ILW encapsulated in disposal containers.
Sellafield Ltd: ILW conditioned and packaged for disposal (e.g., Sellafield MEP packaged waste in storage in EPS1 and EPS2).
2. ILW in disposal packages for which further finishing work is planned
Some of these packages already exist (e.g., unencapsulated waste in disposal packages), or may be generated in the period from the present to 2040. The required finishing work is already specified and included in current lifetime plans.
DSRL: Mixed activated and contaminated metals unencapsulated in 200 litre or 500 litre drums (e.g., TRU-Shield) (may require void filling as a contingency). MOD: Submarine Dismantling Project – reactor pressure vessels. Drummed alpha-contaminated ILW from AWE Sellafield Ltd: Silos Direct Encapsulation Plant (SDP) wastes.
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Category Finishing Requirements Waste Groups or Container Types in Existence at 2040
3. ILW in packages not intended for disposal and awaiting further planned waste processing
Raw waste not in disposal containers (e.g. temporary storage and/or transport containers) to be transported to a finishing facility for conditioning and packaging. Finishing requirements are likely to be extensive and varied, and could involve re-packaging waste or overpacking existing packages. The required finishing work is already specified and included in current lifetime plans.
Sellafield Ltd: • Advanced gas-cooled
reactor stainless steel, graphite.
• MBGW packages - most (stainless steel) MBGW packages may be disposable, but the mild steel packages are not currently considered to be disposable.
• Waste from the Legacy Ponds and Silos (LP&LS) facilities packaged in Project Boxes.
• Zeolite skips.
4. Final Site Clearance (FSC) wastes
Waste that is not yet packaged, but which is planned to be retrieved and packaged as ILW (between 2040 and 2130) as part of the FSC process. Finishing requirements are likely to be extensive and varied, and could involve grout or polymer encapsulation.
All sites: FSC / decommissioning wastes (e.g. concrete, steel and graphite).
5.2.8 Baseline Assumptions for Export of ILW to a GDF Figure 3, below, illustrates the schedules assumed by SLCs for the dispatch of ILW packages from nuclear sites to the GDF in the period 2040 to 2130. It illustrates the latest assumptions of SLCs as documented in lifetime plans and has not been optimised. A related RWM study is examining ways to improve the schedule through more accurately representing the latest requirements of waste producers and the GDF operator and taking account of the upstream and downstream operational risks and opportunities [5].
The schedule shows that there is an earlier period of activity anticipated in the period 2040-2050, near the start of GDF operations, when the Magnox, RSRL and EDF sites plan to export ILW that has been in interim storage. It is assumed that by 2040, all operational and decommissioning waste will be packaged for disposal at RSRL, DSRL and Magnox sites. The other main period of ILW export from reactor sites is post-2070 when most FSC wastes are generated and exported to the GDF. Sellafield exports waste continuously throughout the period shown in Figure 3 (2040-2130). In terms of volume of packaged waste, Sellafield dominates the inventory.
In terms of developing a case for a Centralised ILW Finishing Facility at 2040, the important waste streams are those scheduled for export to a GDF between 2040 and 2050. These will include wastes in Categories (1), (2) and (3) in Table 5, and although the largest volume will be at Sellafield, these wastes will be located at a wide variety of nuclear sites including all Magnox and EDF sites, DSRL and RSRL. At later times, wastes are expected to arise mainly from Sellafield until ~2070 onwards, and therefore there is less of a driver for centralisation.
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Figure 3 Indicative GDF receipt schedule (as of end of March 2014) The colours indicate SLC groupings, the darker bar reflects the periods during which ILW dispatch is planned (store
emptying and/or final site clearance). Only sites in England and Wales are shown because final management of Scottish wastes remains uncertain in the light of Scottish policy development
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5.3 Case for change As discussed and summarised in Sections 3 and 5.2, significant volumes of ILW will have been packaged and placed into interim storage by 2040. In many cases, the current baseline strategy involves the assumption that packaged waste that is fit for geological disposal at the time of packaging will still satisfy the requirements for geological disposal in the period 2040 to 2050. This assumption hinges on two critical requirements:
• That the disposability assessment process at the time of packaging can accurately foretell the future GDF WAC. This requirement assumes that the GDF WAC will not change significantly from the generic considerations currently used to make disposability assessments, due to significant changes in disposal concept or geological host rock or regulatory requirements.
• That the packages have not evolved significantly during the period of interim storage and are still considered to be directly disposable. By 2040, some ILW packages that are assumed packaged for disposal will have been in storage for approximately 50 years. A small number of ILW packages are already showing signs of evolution that may be detrimental to package performance.
There is clearly a risk that one or both of these requirements will not be met, and in this case, further package finishing work would be needed. Such a facility could be provided locally, centrally or via mobile facilities; in Section 6.1, it is noted that mobile waste treatment plants were unlikely to deliver any benefits and should not be pursued further [37].
The condition of waste packages in interim storage will be regularly monitored, such that major degradation and significant requirements for finishing and/or rework are likely to be recognised before waste packages are due to be transferred from interim storage to a GDF. However, monitoring is constrained by store operational conditions, and it is likely that, upon removal from interim storage, less obvious degradation features may come to light and there may be a need to carry out package remediation at relatively short notice. Such rework of packages may be needed due to unexpected damage (e.g. to bolts/identifiers), contamination (e.g. surface), or evolution (e.g., container corrosion, wasteform expansion) during interim storage.
Such work is not identified in the lifetime plans of all waste producers so a finishing facility with the capability to make waste packages comply with the relevant GDF WAC would provide mitigation against the risk that ILW currently packaged for GDF disposal is found not to comply with the future GDF WAC. In particular, as demand is very uncertain it may be difficult to justify the planning and construction of local finishing facilities on a contingency basis, whereas costs could be shared amongst waste producers if a centralised facility was available.
A centralised facility would make efficient use of available skills and encourage the development of a centre of excellence in treatment of waste packages, resulting in a consistent approach to waste treatment and good quality control and assurance.
By 2040, there would also be a need to provide package finishing for waste packages in Categories (2) and (3) of Table 5. The finishing requirements are not yet known, although some provision is assumed to be included in the lifetime plans of the relevant waste producer; however, a single multi-functional finishing facility could satisfy the requirements for wastes produced at multiple sites. A Centralised ILW Finishing Facility, capable of providing a range of package finishing capability, could also provide flexibility in the management of problematic wastes, promoting timely hazard reduction, FSC and delicensing, and avoiding the need to extend the operation of storage facilities.
For certain waste streams, waste producers have planned to do further work on existing ILW packages in interim storage, or those yet to be made prior to GDF availability in 2040,
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to make them acceptable for geological disposal. Provision of a centralised facility, rather than similar infrastructure provided at separate sites, may provide economies of scale. Nevertheless, some waste sorting, segregation, characterisation and packing activities will be needed at some individual sites, particularly during the generation and management of future FSC and Sellafield decommissioning wastes (Category (4)), which will also need packaging at various times after 2040. There may also be a need for additional handling of packages and additional transport of packaged waste if the centralised facility is not located at a GDF. If located at a GDF, there may be potential to combine with other planned facilities, such as the Transport Container Maintenance Facility, which may reduce the potential for duplication of handling facilities. A facility for the rework of β/γ ILW packages at Sellafield is currently planned [38]; this facility is expected to be available from 2035 to the end of Sellafield ILW exports to a GDF, (assumed to be in 2108). At other sites, treatment and packaging activities are planned between now and 2040. It remains to be seen whether this infrastructure, which will be in existence at 2040, could provide the required package finishing capability, or whether additional capacity or a Centralised ILW Finishing Facility would be a preferred option. The risks and uncertainties identified in Section 5.5, below, need to be resolved before a compelling case for change can be made.
5.4 Constraints Specific constraints related to the functionality of a Centralised ILW Finishing Facility are identified in Section 3.4. Constraints relating to waste package transport to the facility would not apply to localised or mobile finishing facilities.
Stakeholder engagement and planning permission requirements may potentially be constraints to the business case if it were to be developed further, but at the current level of maturity of the case, these are not considered.
5.5 Risks and uncertainties The following risks to the business case have been identified concerning the provision of a Centralised ILW Finishing Facility:
• There is a risk that a proportion of packaged ILW is likely to require further finishing work to meet the GDF WAC prior to geological disposal. Such work is not covered in all existing lifetime plans.
• The location is unknown and therefore the facility could be sited at a GDF or at a waste-producing site. The site of the facility will influence the transport requirements, both in terms of transporting packages for finishing, and afterwards to the GDF. There is a risk that packages cannot be transported, and therefore that additional facilities will be needed at waste-producing sites and the centralised facility will have additional functions or capacity that are available but not used as intended.
• Considering the functional requirements identified in Section 4, there is a risk that if a wide range of functions are required, the plant will be so complex it cannot be made to work, or is not ALARP. Additionally, it may not be practical to carry out all of the processes required, or significant R&D may be required to support the operations.
There are various uncertainties relating to the function and strategic context of a Centralised ILW Finishing Facility. Some of these uncertainties can be related to the package categories in Table 5:
• The functional requirements are not certain. The finishing facility could be designed to enact simple package repairs, encapsulation of unencapsulated waste,
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overpacking degraded or failed packages, or unpacking, sorting and re-packaging operations, or some combination of these capabilities.
• Demand and throughput are uncertain - the number and types of packages that may need finishing at 2040 and thereafter, including the extent to which packages in category (1) may have evolved or degraded during interim storage to the extent that there is a need for finishing. It is uncertain how many packages in categories (2) and (3) will still require finishing at 2040.
• The provision for management of wastes locally at waste-producing sites is uncertain. If some infrastructure is anyway needed it may be cheaper and logistically easier to finish waste packages there. Even if a Centralised ILW Finishing Facility is established, its functions may be duplicated by waste management activities that have to be implemented at local waste-producing sites. This is particularly the case for FSC wastes that may still need to be characterised, size-reduced, treated and packaged at the site of origin, before they are moved to a central finishing facility for final packaging. This may result in duplication of handling activities, and removal of supposed economies of scale resulting from having a single facility, rather than multiple facilities.
• The GDF WAC – Waste packages are currently packaged in accordance with the GWPS. The GDF WAC may develop over time as a specific site is selected and the disposal concept evolves. Packages in category (2) may not need finishing, for example, if voidage is not a significant issue for the disposal concept selected for those waste packages.
• The timescales over which a finishing facility is required to operate may change, depending on GDF and decommissioning schedules. The present assumption is that a GDF will become available to receive ILW in 2040.
• Limited information is available for non-NDA sites and minor waste producers are not considered in this business case; however, if a case can be made for centralised finishing of significant ILW groups, smaller volumes held at a range of sites may be considered for inclusion. This is likely to strengthen the case, resulting in increased benefits and a range of potential commercial options for operation of the facility.
5.6 Scope and boundaries This business case has interfaces with work going on in various other areas of RWM, NDA and the SLCs:
• Technical feasibility of mobile waste treatment plants and mobile characterisation plants, with regard to higher activity waste [8]. This project is one of the opportunities in the Upstream Optioneering programme [5]. It examined the constraints on a mobile facility imposed by transport regulations/infrastructure, and analysing the approaches and strategies that could be deployed within the identified constraints.
• An ongoing RWM study is examining ways to improve the GDF receipt schedule through more accurately representing the latest requirements of waste producers and the GDF operator, and taking account of the upstream and downstream operational risks and opportunities.
• The NDA has recently developed a business case for an NDA-funded thermal treatment demonstration facility, which includes its development, operation and decommissioning, and the future influence it may have on industrial-scale thermal treatment of HAW, in particular ILW [39]. The business case focuses on the waste groups for which thermal treatment offers the greatest strategic benefit (e.g., PCM and mobile wastes such as resins and sludges).
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• A parallel study, currently being undertaken by Sellafield Limited, is considering potential product finishing techniques for an evolving package, including the timing, techniques and implications of product finishing options.
6 Economic case The economic case presents credible options for finishing of waste packages, using an example waste group. The credible options are selected in Section 6.1 and compared against the NDA Value Framework criteria [25] in Section 6.2, using an example waste group to identify key differentiators. In Section 6.3, the key differentiators are used to compare the credible options for each category of packaged ILW.
6.1 Credible options Table 5 specifies four categories of packaged ILW that will exist from 2040 onwards. All of these represent categories that will require finishing as part of the current waste management plans, or which may require finishing as a contingency measure, and all may therefore benefit from the availability of a Centralised ILW Finishing Facility.
By 2040, most waste should fall in categories (1) and (4), as most of the waste in Categories (2) and (3) should already have been processed and packaged to be ready for GDF disposal. However, it is possible that waste in categories (2) and (3) may remain to be finished in 2040, and that a Centralised ILW Finishing Facility could supply this requirement.
Two credible strategic options for finishing facilities that can provide the required capability for ILW in the four categories have been considered:
• A centralised facility providing various functions, including overpacking, encapsulation and waste package remediation (located at a GDF, at a single waste-producing site or a new site).
• Local finishing facilities at each waste-producing site (the current baseline option for Categories (2), (3) and (4)).
As noted in Section 2, the use of mobile finishing facilities are out of scope and therefore not considered. Mobile waste treatment plants were considered in a separate Upstream Optioneering report, which concluded that they were unlikely to deliver any benefits and should not be pursued further [40]. The two remaining options, centralised finishing or local finishing, are first considered against a range of Value Framework criteria, based on EGG08 guidance [7]. The two finishing facility options are first compared using an example waste group from category (4) – FSC wastes at Magnox and EDF sites.
6.2 Value Framework assessment for the example waste group The credible option of having a Centralised ILW Finishing Facility in operation from 2040 has been considered relative to the baseline option (implied in site LTPs), in which finishing is carried out on each site individually. To help the assessment, a flow chart and table comparing the activities included in both options have been prepared and are shown in Figure 4 and Table 6, respectively.
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Figure 4 An example showing the steps included in the two options, based on the steps involved in management of FSC wastes
Table 6 Comparison of the stages in the waste management lifecycle for
the option of local finishing (the present baseline) and a Centralised ILW Finishing Facility. Additional steps are shown in blue italic text
Baseline (Localised Finishing) Centralised ILW Finishing Facility
Retrieval, characterisation, sorting, segregation and size reduction (if needed)
Retrieval, characterisation, sorting, segregation and size reduction (if needed)
Packing into disposal containers Packing into disposal containers
Grout encapsulation to void fill Assay and monitoring
Assay and monitoring Loading for transport (assuming disposal container is a Type IP-2 package)
Loading for transport (assuming disposal container is a Type IP-2 package) Transport to a centralised facility
Transport to a GDF Unloading and package receipt
Receipt at a GDF Inspection and assay
Disposal Grout encapsulation to void fill
Assay and monitoring
Loading for transport
Transport to a GDF
Receipt at a GDF
Disposal
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A description of the Value Framework attributes and identification of the likely key differentiators is given in Table 7. The assessment has been conducted qualitatively, by comparing the Centralised ILW Finishing Facility to the provision of a local finishing facility at each individual site for waste packages in the example waste group.
Table 7 Value Framework criteria and project-specific definitions of attributes
Value Framework
Criteria Project-specific definition of
attributes Differentiation
Hazard Reduction
Impact of alternative finishing facility strategies on hazard
No differentiation – centralised or local finishing facility will have similar impact on hazard reduction
Security Covered by the attributes for hazard reduction and cost No differentiation
Safety (operator dose uptake, conventional safety, transport miles)
The radiological dose to workers may be qualitatively considered by comparing the number of waste handling and transport steps relative to the baseline
No significant differentiation – centralised facility option may require extra handling
Conventional operational safety, qualitatively considered by comparing the number of operations conducted (e.g. construction and decommissioning of facilities)
Centralised facility involves less construction, but additional handling at local site and central site
Transport distance to finishing facility and GDF will determine conventional safety detriment
Additional construction materials may need to be transported for the baseline, where multiple plants are required on each site Transport distance is likely to differentiate but not included because GDF location not known
Environmental impact (radiological and non-radiological discharges, material requirements and secondary waste)
Extra transport miles as a result of moving waste packages and / or construction materials would result in greater CO2 emissions (not quantified)
Non-radiological discharges to the environment
Discharges to the environment are likely to depend on the volume of waste requiring finishing and the processes involved, rather than the location
Material and energy requirements for operation of the ILW finishing facility (e.g. grout, packaging materials, decontamination agents)
May favour centralised facility – unlikely to strongly differentiate – same total waste volume will be processed in either option
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Value Framework
Criteria Project-specific definition of
attributes Differentiation
Secondary radioactive waste management and disposal arrangements
May favour centralised facility, unless waste-producing sites have existing treatment facilities If the centralised facility was located at a GDF or a sire without such facilities, new plant would be required
The material requirements for construction, and waste volumes generated during decommissioning of the ILW finishing facility(ies)
Likely to favour a Centralised ILW Finishing Facility over multiple on-site finishing facilities
Socio-economic
Staff and contractors employed and spend in local area
Number of staff involved may slightly favour multiple local facilities Maintenance of skilled workforce may favour centralised facility
Timescales
The timescales for the development and operation of finishing facilities will be driven by external factors, such as GDF scheduling
Not considered to differentiate
Long-term strategic fit
Functionality and flexibility of finishing facilities
A Centralised ILW Finishing Facility is likely to have more functionality than localised facilities which offer more opportunities to select the best process in each case
Throughput (m3/year) will depend on waste group and finishing requirements. Campaign working for different waste package types, based on planned GDF receipt schedule, could efficiently manage throughput
Finishing facilities, whether central or local, will be designed to deliver required throughput. However, periods of very low throughput at a centralised facility could incur extra costs to avoid mothballing
Indicative lifetime volumes of waste to be treated by an ILW finishing facility (m3)
Unlikely to differentiate between scenarios as facilities would be designed to deliver required volume
Cost Comparative lifetime cost of centralised and local facilities
Economies of scale may favour a centralised facility on a cost per packaged waste volume basis
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From Tables 6 and 7, it is clear that only a small number of criteria provide clear differentiation between centralised and local options. Of these, one of the clearest involves transport, but this cannot be assessed because the location of the GDF, as well as the location of the Centralised ILW Finishing Facility, is not yet known, and therefore criteria related to location, such as transport, have not been assessed. Other than transport, the other criteria that most clearly differentiate are related to the additional flexibility provided by a centralised facility, and the economies of scale afforded by a centralised facility, involving cost, material requirements and waste generated.
6.3 Comparison of credible options for different categories of waste packages
The assessment now focuses on comparing the option of a Centralised ILW Finishing Facility with the option of having multiple local site finishing facilities. An assessment is made for each of the four categories of waste defined in Table 5, and only against the attributes for which there is clear differentiation in Table 7. The assessment is summarised in Table 8.
Table 7 shows that a key differentiating factor between the provision of a Centralised ILW Finishing Facility for all UK waste, and local finishing facilities located as needed at individual waste-producing sites, is connected with economies of scale. A single centralised facility is likely to be less demanding in terms of construction materials, energy requirements, secondary waste production, decommissioning and overall cost than multiple individual facilities. However, it is uncertain how many local waste management activities, and associated local infrastructure, will in any case be needed at the waste-producing sites (Section 5.5), particularly for the management of FSC wastes. If facilities are in any case needed locally, the benefits, in terms of economies of scale, of having a further centralised finishing plant are less obvious.
The other key differentiating factors in Table 7 relate to the flexibility that a centralised facility would provide. Local facilities at individual waste-producing sites are likely to cater for local waste management needs. They may be specific to particular, site-specific waste streams and package types, and not be amenable to finishing packaged waste from other sites, owing to mismatch of waste handling equipment or operational safety issues, for example. On the other hand, a centralised facility would be designed to cater for the full range of waste and package types requiring finishing, and would be inherently more flexible than several local facilities, each tailored to their own site. This would be advantageous if unforeseen finishing work is needed, due to package evolution.
Factors related to transport of waste packages and materials (both the number of trips and the distances involved) contribute to Safety and Environment attributes. However, because the location of the GDF and the Centralised ILW Finishing Facility are not yet known, it is not currently possible to include this factor in the assessment. If the Centralised ILW Finishing Facility were to be located at a different location to the GDF, this option’s increased handling arrangements would involve significantly more transport and double-handling than the option involving local finishing only, particularly for the large waste volumes expected during final site clearance.
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Table 8 Evaluation of the baseline option (multiple local finishing facilities) with a Centralised ILW Finishing Facility, considering only those Value Framework attributes that are likely to differentiate
Value Framework Criteria
Project-specific definition of attributes Local finishing facilities Centralised ILW Finishing Facility
Safety (operator dose uptake, conventional safety, transport miles)
The radiological dose to workers may be qualitatively considered by comparing the number of waste handling and transport steps relative to the baseline
Waste packages would need to be handled prior to dispatch and on arrival at a GDF. Additional handling may be needed during the finishing process.
Depending on the location of a Centralised ILW Finishing Facility relative to the GDF, additional waste handling and transport steps may be required.
Conventional operational safety, qualitatively considered by comparing the number of operations conducted (e.g. construction and decommissioning of facilities).
Local finishing would be needed on each waste-producing site where finishing is needed. Multiple local finishing facilities would need to be constructed and decommissioned.
A Centralised ILW Finishing Facility would involve less construction and decommissioning compared with multiple local facilities.
Environmental impact (radiological and non-radiological discharges, material requirements and secondary waste)
Material and energy requirements for operation of the ILW finishing facility (e.g. grout, packaging materials, decontamination agents).
Multiple local finishing facilities would be needed, each with their own material and energy requirements.
A Centralised ILW Finishing Facility would have lower material and energy requirements, in total.
Secondary radioactive waste management and disposal arrangements.
Multiple local finishing facilities would be needed, each producing their own secondary radioactive waste streams (although treatment facilities may already be present at waste-producing sites).
A Centralised ILW Finishing Facility may generate less secondary radioactive waste.
The material requirements for construction of and waste volumes generated during decommissioning of the ILW finishing facility(ies).
Multiple local finishing facilities would be needed, each with their own material requirements and decommissioning waste volumes.
A Centralised ILW Finishing Facility would require less material, and would in total, generate less total decommissioning waste.
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Value Framework Criteria
Project-specific definition of attributes Local finishing facilities Centralised ILW Finishing Facility
Long-term strategic fit Functionality and flexibility of finishing facilities.
Local finishing facilities likely to be tailored to local waste needs. Local needs may be insufficient to justify construction of a facility, especially if only to meet an un-quantified need for repair (contingency option).
A Centralised ILW Finishing Facility would be likely to be more flexible and would cater for a wide range of package types and finishing needs. This could be more effective as a contingency option.
Cost A comparative approach is proposed, considering only differentiating factors.
Multiple local facilities likely to be more expensive. Note that local demand may be low or contingent (depending on need for repair). Cost may be unsustainable in these circumstances.
A Centralised ILW Finishing Facility is likely to exhibit economies of scale. As a contingency option, costs could be shared amongst waste producers.
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Having identified the benefits and disbenefits of a Centralised ILW Finishing Facility in comparison with localised facilities, it is now possible to consider these in relation to the four specific categories of waste package listed in Table 5.
1. ILW in disposal containers that are currently assumed to be ready for GDF disposal, but that may need additional finishing. In this category, the finishing facility would be used to mitigate the risk that some of the packages currently expected to go for direct GDF disposal are in fact unable to meet the GDF WAC. With regard to this category of packaged waste, a Centralised ILW Finishing Facility is strongly preferred over localised facilities. This is because a centralised facility is likely to have far greater flexibility (long-term strategic fit attribute) and would be better suited to package remediation. Additionally, as demand is very uncertain it may be hard to justify the planning and use of local facilities on a contingency basis, whereas costs could be shared amongst waste producers if a centralised facility was available. Packages requiring additional finishing are likely to arise without warning, may involve essentially any waste stream and package type, and could require a variety of types of intervention. Therefore, more effective mitigation would be provided by a more flexible facility. Moreover, the current NDA baseline does not envisage any further finishing requirements for packages in this category, and the baseline option of providing local facilities at each site could be considered not credible for this particular finishing need. Therefore, provision of a centralised facility addresses a current strategic risk and is the favoured option for this category of packages.
2. ILW currently in disposal containers where further finishing work is planned. Given that intervention is already planned, finishing facilities for packages in this category are assumed to be in current baseline plans for the sites where these wastes are currently held, and the work should be carried out by 2040. This includes ILW in 500-litre drums in the Harwell vault store where a local cementation plant is in development, and various Sellafield LP&LS wastes where further intervention is planned, making use of local waste treatment facilities. Given that plans for these local facilities are relatively mature, and some facilities are in active development, it is not clear if providing a central facility to finish these wastes would result in any economies of scale, or if there would be any real need for further finishing at 2040. On the contrary, there is a risk that there would be duplication of facilities, coupled with additional transport and waste handling if a centralised facility was built to finish wastes in this category. Therefore for wastes in this category, it is likely that local waste processing, as already planned, is the favoured option if a facility has already been constructed; otherwise a centralised facility may be the better option.
3. ILW not currently in disposal containers where further waste treatment and packaging work is planned. In this case, a range of activities is potentially needed to generate packaged waste ready for GDF disposal, potentially including waste treatment and re-packaging the waste in disposal containers. For waste in this category, although the further stages of treatment are already included in lifetime plans, these plans are sometimes less mature, and the details of waste treatment, packaging and finishing activities to have been completed by 2040 may be specified in less detail. It may be more likely that the necessary waste treatment and packaging operations could be provided by a centralised facility without necessarily risking duplication of facilities. In this case, economies of scale could mean that a single centralised facility is favoured, if the waste packages can be transported prior to finishing.
4. ILW that is yet to be generated that will arise as a result of FSC activities. Of the four waste categories, this is the one that will be generated the furthest into the future and there are therefore considerable uncertainties regarding what local waste
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management activities will be needed at the sites where the waste will arise. On the one hand, it may be necessary to carry out significant characterisation, size reduction, treatment and packaging locally. On the other, only limited management at local sites of arising may be needed. Whether local or centralised waste finishing is preferred will depend on which of these end-members is closest to the real situation. At the present time, it is not possible to make a definitive judgement whether a centralised facility is favoured.
7 Conclusions and recommendations At this stage, it is not clear that a compelling business case can be made for a Centralised ILW Finishing Facility. The provision of a Centralised ILW Finishing Facility in 2040 would deliver the following benefits:
• It would provide mitigation against the risk that ILW currently packaged for GDF disposal is found not to comply with the future GDF WAC. In particular, as demand is very uncertain it may be difficult to justify the planning and construction of local finishing facilities on a contingency basis, whereas costs could be shared amongst waste producers if a centralised facility was available.
• It would provide flexibility in the management of problematic wastes, promoting timely hazard reduction, FSC and delicensing, and avoiding the need to extend the operation of storage facilities.
• It would make efficient use of available skills and encourage the development of a centre of excellence in treatment of waste packages, resulting in a consistent approach to waste treatment and good quality control and assurance.
• For certain waste streams, waste producers have planned to do further work on existing ILW packages in interim storage, or those yet to be made prior to GDF availability in 2040, to make them acceptable for geological disposal and a single multi-functional finishing facility could satisfy this requirement for wastes produced at multiple sites.
However, the following uncertainties and related risks mean that it is not currently possible to support a case for change from the existing baseline (implied in site LTPs), in which finishing is carried out on each waste-producing site:
• The location of a GDF, and whether it is feasible to locate a Centralised ILW Finishing Facility at that site. The site of the facility will influence the transport requirements, both in terms of transporting packages for finishing, and afterwards to the GDF. There is a risk that packages cannot be transported, and therefore that additional facilities will be needed at waste-producing sites and the centralised facility will have additional functions or capacity that are available but not used as intended.
• The number and types of waste packages that may need finishing at 2040 and thereafter, including the extent to which packages in category (1) may have evolved or degraded during interim storage to the extent that there is a need for finishing. It is uncertain how many packages in categories (2) and (3) will still require finishing at 2040, as this is dependent on the requirements in the GDF WAC. Regarding FSC wastes (category (4)), it is currently uncertain to what extent waste management activities and infrastructure would in any case be needed locally at waste-producing sites.
• The functionality needed at a finishing facility, which is linked to a better understanding of the waste package inventory that may require finishing. Considering the functional requirements identified in Section 4, there is a risk that the plant is so complex it cannot be made to work, or is not ALARP. Additionally, it may not be practical to carry out all of the processes required.
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It is recommended that this opportunity is revisited at a later date, once one or more of these key uncertainties have been resolved. It was noted that there may be an opportunity to use infrastructure, which may be in existence at 2040, at Sellafield and other licensed sites to provide the required package finishing capability. A facility for the rework of β/γ ILW packages at Sellafield is currently planned and, at other sites, treatment and packaging activities are planned between now and 2040. It remains to be seen whether this infrastructure, which will be in existence at 2040, could provide the required package finishing capability.
Consideration of the requirements for package finishing will aid discussions with waste producers on how they might make use of a centralised facility and what benefits a centralised facility would offer them. It may also be useful to discuss the potential gap in provision for finishing of Category (1) ILW packages with SLCs and non-NDA waste producers.
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8 References
1 International Atomic Energy Agency, IAEA Safety Standards: Regulations for the
Safe Transport of Radioactive Material, 2012 Edition. Specific Safety Requirements, No. SSR-6.
2 Nuclear Decommissioning Authority, Geological Disposal: Generic Waste Package Specification, NDA/RWMD/067, March 2012.
3 The Scottish Government, Scotland’s Higher Activity Radioactive Waste Policy, Edinburgh, 2011.
4 Nuclear Decommissioning Authority, Integrated Waste Management Strategy Development Programme, May 2012.
5 Nuclear Decommissioning Authority, Upstream Optioneering Phase 2 Report, NDA Technical Note Number 16983129, August 2012.
6 Nuclear Decommissioning Authority, Upstream Optioneering Update January 2014, NDA Technical Note Number 21172220, January 2014.
7 Nuclear Decommissioning Authority, NDA Guidance and Expectations for Business Cases and Value Management, Document no. EGG08, Revision 8, March 2013.
8 Radioactive Waste Management Limited, Upstream Optioneering: Technical Feasibility of Mobile Plant for Higher Activity Wastes, NDA/RWMD/118, April 2014.
9 Nuclear Decommissioning Authority, RWMD Interactions with Waste Packagers on Plans for Packaging Radioactive Wastes April 2012 - March 2013, NDA/RWMD/102, July 2013.
10 Nuclear Decommissioning Authority, Waste Package Specification for 500 litre Drum Waste Packages, WPSGD No. WPS/300/03, 2013.
11 Nuclear Decommissioning Authority, Waste Package Specification for Corner Lifting Variant of 3 Cubic Metre Box Waste Package, WPSGD No. WPS/315/03, 2013.
12 Nuclear Decommissioning Authority, Waste Package Specification for Side-Lifting Variants of 3 Cubic Metre Box Waste Package, WPSGD No. WPS/310/004, 2013.
13 Nuclear Decommissioning Authority, Waste Package Specification for 3 cubic Metre Drum Waste Package, WPSGD No. WPS/320/04, 2013.
14 Nuclear Decommissioning Authority, Waste Package Specification for 2 Metre Box Waste Package, WPSGD No. WPS/350/03, 2013.
15 Nuclear Decommissioning Authority, Waste Package Specification for 4 Metre Box Waste Packages, WPSGD No. WPS/330/03, 2013.
16 Nuclear Decommissioning Authority, Waste Package Specification for 6 Cubic Metre Concrete Box Waste Packages, WPSGD No. WPS/360/01, 2013.
17 Towler, G., Baldwin, T., Paulley, A. and Wilson, J., An Initial Evaluation of the Nature and Amount of Voidage Associated with an ILW GDF, Report no. ASSIST-1547B-R1 V1.0, 2012.
18 Nuclear Decommissioning Authority, Waste Package Specification and Guidance Documentation: WPS/730 4 Metre Box Waste Package Specification, Explanatory Material and Design Guidelines, Number 8766538, March 2008.
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19 Nuclear Decommissioning Authority, Upstream Optioneering: Overview and Uses
of the 6 Cubic Metre Concrete Box, NDA Technical Note No 18959097, March 2013.
20 Nuclear Decommissioning Authority, Geological Disposal: Generic Transport Systems Design, NDA/RWMD/046, 2010.
21 Ridley, M., A Review of the Use of 8-axle Rail Wagons (Type KXA-C) on the UK Rail Network, International Nuclear Services Report no. TD/EDS/R/10/225 for RWMD, November 2010.
22 G. Steel, E. Morgan-Warren, Feasibility Study for the Use of the SWTC to Transport Unconditioned Intermediate Level Waste, AREVA RMC R10-019(C), Issue 1, March 2010.
23 www.nda.gov.uk/rwmd/producers/detail.cfm#specifications.
24 Nuclear Decommissioning Authority, Geological Disposal: Generic Disposal Facility Designs, NDA Report NDA/RWMD/048, December 2010.
25 Nuclear Decommissioning Authority, NDA Guidance for the Production of Business Cases, Doc No. EGG08, Rev 7, December 2010.
26 Nuclear Decommissioning Authority, Strategy Effective from April 2011, ISBN 978-1-905985-26-5, 2011.
27 Dounreay Site Restoration Limited, Dounreay ‘Interim’ Integrated Waste Strategy, WSU/Strategy/P033(08), Issue 6, March 2010.
28 Nuclear Decommissioning Authority, Magnox Limited and Energy Solutions, Magnox Plan Summary: Magnox Lifetime Plan 2013, March 2013.
29 Magnox Limited, Optimising the Number and Location of Interim Intermediate Level Waste (ILW) Storage Facilities on Magnox Limited and EDF Energy Sites in England and Wales, Credible Options: Summary Paper, May 2013.
30 Nuclear Decommissioning Authority, Research Sites Restoration Limited and Babcock, Harwell Long Range Plan 2012 – 2050.
31 Nuclear Decommissioning Authority, Research Sites Restoration Limited and Babcock, Winfrith Long Range Plan 2012 – 2024.
32 Nuclear Decommissioning Authority, Sellafield Limited and Nuclear Management Partners, Sellafield Plan, Issue 1, August 2011.
33 Nuclear Decommissioning Authority and Department of Climate Change, 2013 UK Radioactive Waste Inventory: Scenario for Future Radioactive Waste and Materials Arisings, URN 14D041, NDA/ST/STY(14)0009, February 2014.
34 Nuclear Decommissioning Authority and Magnox Limited, ILW Storage and FED Treatment Optimisation Study, http://www.nda.gov.uk/documents/upload/Intermediate-Level-Waste-ILW-Storage-and-Fuel-Element-Debris-FED-Treatment-Optimisation-Study-November-2013.pdf.
35 Ministry of Defence, Submarine Dismantling Project: MOD’s Response to Consultation, Bristol, March 2013.
36 Ministry of Defence, MOD Waste Management Strategy, UK, 2010.
37 Radioactive Waste Management Limited, Upstream Optioneering: Technical Feasibility of Mobile Plant for Higher Activity Wastes, NDA/RWMD/118, April 2014.
38 Sellafield Ltd, Sellafield Integrated Waste Strategy – Update to Version 2, June 2008.
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39 S.M. Wickham, J.E. Kent, M.T. Harrison, N.R. Gribble, N.C. Hyatt, M.J. Ojovan
and R.J. Hand, Development of a Thermal Treatment Demonstration Facility for Radioactive Wastes, Nuclear Decommissioning Authority, SMS/TS/D1-HAW-P/002-BC, March 2014.
40 Radioactive Waste Management Limited, Upstream Optioneering: Technical Feasibility of Mobile Plant for Higher Activity Wastes, NDA/RWMD/118, April 2014.
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Appendix A Review of existing and planned finishing facilities A review of experience on finishing facilities, or activities typical of finishing, was undertaken to inform the list of functions that may be required at a UK Centralised ILW Finishing Facility. It is recognised that legislation and classifications of radioactive waste differ between countries; nevertheless the information obtained provides evidence of facilities where ‘finishing’ functions are carried out. The following facilities are discussed in this review:
• Head End Cell, Harwell. • Packaging of remote handled ILW, Dounreay. • UK Packaging of concrete-lined drums. • Cigeo Project, France. • ZWILAG, Switzerland. • Central Organisation for Radioactive Waste (COVRA), Netherlands. • Belgoprocess, Belgium. • Bohunice RAW Treatment Centre, Slovakia.
A.1 Head End Cell, Harwell, UK The Head End Cell (HEC) in the Solid Waste Complex at Harwell is a multi-functional facility capable of processing a wide range of wastes. It is currently operated by RSRL to treat research wastes from their legacy stores (e.g., segregation, processing and packaging of RHILW from the tube stores into 500 litre drums) [41, 42]. Finishing will be required for the wastes packed in the HEC, possibly at Sellafielld’s waste encapsulation plant. The existing design has a very low throughput and can only accept small items. This facility has introduced new processes including size reduction, polymer encapsulation and compaction capability [43].
A.2 Packaging of remote-handled ILW, Dounreay, UK To avoid the need for constructing a new encapsulation plant and shielded store, Dounreay Site Restoration Limited (DSRL) has sought Conceptual stage disposability assessment endorsement from RWM for proposals for the packaging of Dounreay remote handled ILW (RHILW) in double-skinned, lead-lined 500 litre drums [44]. The majority of this waste has already been packed into 200 litre drums which are stored at Dounreay. The remainder is yet to be packed.
The ‘stocks’ waste which is already packed is held (unencapsulated) within 200 litre drums, which are themselves overpacked. It is proposed that these wastes would be retained within these current layers of containment, with one 200 litre drum and its overpack being placed in each double-skinned, lead-lined 500 litre container. It is proposed that the ‘arisings’ wastes would be directly packed into double-skinned, lead-lined 500 litre containers.
Although the proposals do not include encapsulation of these wastes, the submission refers to the potential to add cementitious grout to the packages at a later date, should this be found to be necessary. For arising wastes this would lead to direct encapsulation, for stocks wastes the result would be entombment of the overpack within the double-skinned, lead-lined 500 litre container.
A.3 GE Healthcare plant for the packaging of concrete-lined drums, UK In the past, GE Healthcare has unpacked some concrete-lined LLW drums and sorted and segregated the contents leading to volume reduction [45]. Concrete-encapsulated waste
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drums (concrete-lined drums) were mostly created prior to 1980 for sea disposal. Since sea dumping became outlawed, these packages have been stored at the sites of generation. The wastes within the concrete-lined drums are varied and, if unencapsulated, may contain voids, free liquids and non-passivated wastes. Sorting and segregation is not feasible for any drums containing waste that is already cement-encapsulated.
A.4 Cigeo facility, France Radioactive waste packages in France are produced by the French nuclear utility Électricité de France (EDF), the fuel cycle company Areva and the nuclear research and development agency the Commissariat à l'énergie atomique et aux énergies alternatives (CEA). The Cigeo project, led by Andra, refers to the development of an underground facility located in the Meuse/Haute Marne area in eastern France to store high- and intermediate-level radioactive wastes. The first conceptual study phase was conducted during 2012 and a public consultation took place in 2013.
There will be surface facilities at the site for operations such as waste package receipt and inspection. Upon arriving at the proposed French geological disposal facility, waste package processing will consist of the following steps:
• Unload waste package from transport container. • Controlled inspection of waste package (e.g., active and inactive gamma/neutron
interrogation, temperature and measurements of dose rates). Some waste packages will be randomly monitored by intrusive means (sampling). A cell will be dedicated to re-filling the hole left by the sample.
• Placement of waste package into overpacks for disposal. The disposal overpack consists of a crate that can contain up to six waste packages with a lid bolted on top. Currently, the overpack does not contribute to the containment but it is envisaged that these will be grout filled. Overpacks will be manufactured externally and delivered on site.
• Once bolted, the overpacks will be transferred underground for disposal. To date, it is not yet decided whether a re-packaging facility is required or not. Non-compliant waste packages may be sent back to the producer. However, it is a requirement that waste packages must be able to be retrieved from the facility up to 100 years after their emplacement. This could be made necessary by an incident underground (fire, package drop etc.) or by the detection of high contamination levels in the disposal vaults. A retrieved package may have to be re-manufactured at the surface facilities.
A.5 ZWILAG, Switzerland All categories of radioactive waste generated in Switzerland are processed and temporarily stored in the ZWILAG facility and the neighbouring federal interim storage facility. The facility is separated into the following plants (as illustrated in Figure A.1):
• The plasma plant permits the processing of combustible materials, the melting of metallic parts, concrete and other solid matter and the vitrifying of organic and inorganic matter in the residue ready for final storage [46].
• The conditioning plant is used to decontaminate the waste so that some of the waste can be recycled as conventional waste. As the waste delivered to the facility can be very different with regard to composition, consistency, packaging and weight, mechanical separation methods and abrasive treatment methods are supplemented by other processes, such as electrolytic and chemical cleaning processes [47].
• The facility also contains a hot cell where storage casks can be checked and repaired or fuel rods can be inspected and unloaded [48].
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• The site also contains storage buildings for different wastes, pending treatment and transport for disposal.
The different facilities are linked to one another by a container transport system, which also includes the waste reception facility and neighbouring stations where the waste is analysed. The facility where the waste conditioned for final storage and waste free of radioactive materials are checked is also located in the conditioning plant.
Figure A.1 An overview of the facilities at ZWILAG [49]
A.6 Central Organisation for Radioactive Waste (COVRA), Netherlands COVRA provides sustainable management of Dutch radioactive waste. The organisation collects, processes and stores all radioactive waste in the Netherlands. The COVRA facility offers a number of processing/treatment techniques for different wastes and contains various storage facilities; as shown in Figure A.2. Low- and intermediate-level waste is processed (e.g. incineration, compaction, chemical or electrochemical separation and drying) in the on-site treatment facility and conditioned (i.e., cemented) in 200 litre and 1000 litre drums prior to storage, for 100 years [50].
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Figure A.2 An overview of the facilities at COVRA. 1. Office (Kantoor), 2. ILW treatment facility (Verweking lag middle radioacief afval), 3. ILW storage facility (Opslag lag en middle radioactief afval), 4. HLW treatment and storage facility (Hoog radioactief afval), 5. Depleted uranium store (Opslag verarmd uranium) and 6. Store for NORM waste (Opslag NORM)
A.7 Belgoprocess, Belgium Belgoprocess operate a waste conditioning, processing and interim storage in Mol-Dessel, Belgium. The following services are offered [51]:
• Feasibility tests and demonstration runs in existing facilities. • Research, development and technical demonstrations of process control
techniques. • Characterisation - chemical, physical and radiological - of waste streams. • Capability to process low, intermediate and high-level solid and liquid waste,
including radium- and alpha-bearing waste.
A.8 Bohunice Radioactive Waste Treatment Centre, Slovakia The Bohunice Radioactive Waste Treatment Centre is the main centre of processing technologies in Slovakia. The centre comprises the following radioactive waste treatment and processing facilities [52]:
• Solid radioactive waste separation facility. • Compaction for reducing the volume of incombustible waste. • Incineration facility reducing the volume of solid and liquid combustible radioactive
waste. • Liquid radioactive waste concentration facility and the cementation facility for
reinforcement.
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• Stabilisation of concentrated waste, other liquid RAW, solid reinforced waste and solid non-compressible waste.
The Bohunice Radioactive Waste Treatment Centre also comprises sorting lines, transportation systems, radiation control laboratory equipment, including monitoring systems. The final product of the whole radioactive waste treatment process are fibre-reinforced concrete containers filled with a cement mixture or with freely loaded solid waste encapsulated with a cement mixture, ready for permanent storage in the National Radioactive Waste Repository in Mochovce.
A.9 Summary This review helped to identify evidence of facilities where ‘finishing’ is carried out. The term finishing refers to activities relating to waste processing, conditioning, overpacking and repacking. The information obtained indicates that most facilities deal with finishing on a waste specific basis and there is less evidence of package driven finishing. Table 9 below summarises the main finishing functions from each.
Table 9 Summary table of ‘finishing’ experience from existing and planned facilities
Facility Evidence of finishing functions
Head End Cell Treatment functions - size reduction, polymer encapsulation and compaction.
RHILW packaging at Dounreay
Re-packaging.
GE Healthcare plant for the packaging of concrete-lined drums
Size reduction, sorting and re-packaging.
Cigeo Overpacking. Potential re-packaging functions required.
ZWILAG Treatment functions – plasma, mechanical separation methods and abrasive treatment methods.
COVRA Treatment functions - incineration, compaction, chemical or electrochemical separation and drying. Waste conditioning – cementation facility. Packaging into 200 and 500 litre drums.
Belgoprocess Range of characterisation, processing, treatment and storage functions.
Bohunice RAW Treatment Centre
Treatment functions – separation, high-pressure press, incineration and liquid radioactive waste concentration. Waste conditioning – cementation facility.
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A.10 Appendix A references
41 Research Sites Restoration Ltd, Integrated Waste Strategy, NDA/038/IWS, Issue 3
March 2011.
42 S. Doudou, C. Hamblin, C. Jones, J. McTeer, T. Turner and S. Wickham, Optimum Packaging Approach for Disposal of Decommissioning Waste Arisings, ASSIST, R13-95(A), Issue 1, August 2013.
43 Radioactive Waste Management Directorate, Geological Disposal Upstream Optioneering: Integrated Waste Processing Report, March 2013.
44 Nuclear Decommissioning Authority, Packaging of Dounreay RHILW in TRU-Shield Containers (Conceptual Stage) Summary of Assessment Report, June 2011.
45 Nuclear Decommissioning Authority, Geological Disposal: Phase 2 Upstream Optioneering Report, August 2012.
46 ZWILAG, Plasma Plant, http://www.zwilag.ch/en/plasma-plant-_content---1--1047.html, accessed 18 Feb. 14.
47 ZWILAG, Conditioning Plant, http://www.zwilag.ch/en/conditioning-plant-_content---1--1051.html, accessed 18 Feb. 14.
48 ZWILAG, Hot Cell, http://www.zwilag.ch/en/hot-cell-_content---1--1056.html, accessed 18 Feb. 14.
49 ZWILAG, Safety Locked Up, http://www.zwilag.ch/upload/cms/user/Zwilag_Prospekt_EN.PDF, accessed 18 Feb. 14.
50 International Atomic Energy Agency, Provision for the Application of the IAEA Safety Standards, Peer Review of the Radioactive Waste Management Activities of COVRA, Netherlands, Safety Standards Applications Series No. 8., November – December 2009.
51 Belgoprocess, Capabilities [What we do], http://www.belgoprocess.be/eng/Capabilities.htm, accessed 18 March 2014.
52 Javys, Bohunice RAW Treatment Centre, http://www.javys.sk/en/nuclear-facilities/raw-processing-and-treatment-technology/bohunice-raw-treatment-center, accessed 18 Feb. 14.
