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THERAMIN

Technical Training SchoolWhy use thermal treatment?

Benefits and challenges

Steve Wickham (Galson Sciences Ltd.)

12th June 2019

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Acknowledgements

THERAMIN – EC funding

Contributors to THERAMIN Work Package 2

Slimane Doudou, Emily Phipps, Adam Fuller, Liz Harvey,

Jenny Kent (Galson Sciences)

Christophe Girolde, Maxime Fournier (CEA)

Etienne Fourcy, Remy Lesachey (Orano)

All WP2 questionnaire respondents

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Outline

Waste management lifecycle

Conventional waste management routes

Thermal technologies and strategic drivers

Alignment of technologies and waste types

Benefits and challenges of thermal treatment

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Waste Management Lifecycle

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NDA Integrated

Waste

Management

Strategy, 2018

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Waste Management Lifecycle

Pre-treatment: operations prior to waste treatment (e.g., dismantling, size reduction)

Treatment: operations to improve safety, economics of waste management (e.g., volume reduction, change of physical or chemical state, concentration of activity)

Conditioning: operations to produce a waste package suitable for transport, storage or disposal (may involve immobilisation, encapsulation)

Storage: maintaining waste packages in safe confinement to ensure retrievability

Transport: movement of waste packages

Disposal: emplacement of waste packages without intention to retrieve

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Ojovan and Lee, 2014

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Radioactive Waste Treatment

Objectives of treatment respond to fundamental

principles of radioactive waste management

(IAEA, 1995)

Additional requirements of optimisation, BAT/BPM,

ALARP and the waste hierarchy

Typically the objectives of treatment are:

Volume reduction

Concentration / removal of radionuclides

Change of physical state and chemical composition

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Radioactive Waste Treatment

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Waste Type Treatment Examples

Aqueous

Liquid

Concentrate activity,

discharge remainderEvaporation, sorption, filtration

Organic

Liquid

Convert to solid,

oxidiseIncineration, absorbent polymers

Solid

Minimise volume Compaction / supercompaction

Oxidise / destroy

reactivity / convert to

inorganic form

Incineration / pyrolysis

Other thermal treatments (melting, glass

encapsulation, HIP)

Chemical /thermochemical decomposition

Remove activity Decontamination

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Immobilisation of Radioactive Wastes

Changes the form of the waste such that the resulting product can be safely handled, transported, stored and disposed of

A requirement for storage / transport / disposal

May consider as treatment or conditioning

May be applied to raw waste, as a treatment process itself, or as a conditioning/packaging step applied to the products of waste treatment

Main commercially available technologies are/have been:

Cement encapsulation (conditioning)

Bituminisation (conditioning)

Vitrification (treatment/conditioning)

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Cement Encapsulation

Main technology adopted for immobilisation of LLW and ILW

Benefits: Inexpensive and readily available

Simple, low-cost process

Cement matrix acts as a diffusion barrier and provides sorption

Can be used for sludges, liquors, dry solids

Wasteforms generally have good thermal/chemical stability

Reduces solubility of many radionuclides

Non-flammable, good compressive strength, not degraded by radiation

Many cement-encapsulated waste packages disposed (LLW/SL-ILW) or in storage pending disposal (ILW)

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Cement Encapsulation

Challenges:

Cement encapsulation leads to a ~3-fold volume

increase

− More packages, higher storage/disposal capacity requirements

→ higher cost

Some waste components interact with cement

− Reactive metals, organic ion exchange resins, and plutonium-

contaminated materials (PCM)

− Retard cement hydration reactions

− Long-term waste package degradation (gel formation, expansive

corrosion of reactive metals)

− Some legacy cemented wastes do not meet WAC /disposability

criteria

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Bituminisation

Used since the 1960s - >200,000 m3 currently

worldwide

Particularly suitable for water-soluble wastes

(e.g., bottom residues from evaporators) and

spent organic resins

Most water evaporated to produce homogeneous

bitumen compound with:

Higher waste loading than cement

Better radionuclide retention than cement

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Bituminisation

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Challenges:

Potential fire hazard

Reactive product – gas

generation, salts

Bituminised waste presents

challenges for operational and

long-term disposal safety

cases

Has become a legacy waste in

some countries, requiring

further treatment to destroy

organic component

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Vitrification Thermal treatment (vitrification) used for nuclear waste immobilisation for >50

years Belgium, France, Germany, Japan, Russia, UK, USA

Benefits: Immobilise a wide range of elements

Simple technology adapted from glass manufacturing

Small volume of resulting glassy waste form

High chemical durability of glassy wasteforms in contact with natural waters

High tolerance to radiation damage

Hazardous waste constituents immobilised by direct incorporation into the glass structure (dissolution in the melt) or by encapsulation Borosilicate glasses have been first choice for immobilisation of HLW and LLW/ILW

Typical temperature range 1100 - 1300ºC to prevent excessive volatilisation

Main application has been to HLW from reprocessing (>23,000 t worldwide by 2011)

Operating industrial facilities for LLW/ILW in South Korea, Switzerland, Russia, USA Several other facilities for LLW/ILW in development

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Thermal Technologies for Radioactive Waste Treatment

Definition of thermal technologies (IAEA TecDoc 1527) Use heat to break down organic components of the wastes,

producing inorganic, non-flammable, chemically inert and relatively homogeneous end products; or

Destroy organic components while melting inorganic components; or

Involve the assistance or application of heat at temperatures in excess of 600ºC

Three broad technology areas considered in THERAMIN for application to LLW/ILW Treatment for volume reduction and passivation (e.g.,

incineration, pyrolysis, gasification)

Treatment/conditioning by immobilisation in glass (e.g., vitrification)

Treatment/conditioning by immobilisation in ceramic or glass-ceramic (e.g., HIP)

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Thermal Technologies

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Treatment for volume

reduction and

passivation

Treatment /

conditioning by

immobilisation in glass

Treatment /

conditioning by

immobilisation in

ceramic or glass-

ceramic

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D2.3 Technologies

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High-level process Technology Facility Country

Treatment for volume reduction and

passivation

Incineration with burner and refractory

walls

JÜV 50/2 - Jülich JEN Germany

KTE incinerator Germany

EDF CENTRACO France

Rotary kiln incineration IRIS France

Pyrolysis Belgoprocess Belgium

Thermal gasification VTT gasification Finland

Calcination Widely used France, UK

Underwater plasma incineration ELIPSE France

Hydrothermal Oxidation (HTO) DELOS France

Induction metal melter

CARLA Germany

EDF CENTRACO France

Cyclife (formerly Studsvik) Sweden

Treatment / Conditioning by immobilisation

in glass

Joule-Heated In-Container

Vitrification

In-Can Melter and DEM & MELT

(metallic inner wall), CEAFrance

GeoMelt (ceramic inner wall), NNL UK

Joule-Heated Ceramic Melter (JHCM)VEK, PAMELA (both

decommissioned)

Germany,

Belgium

Cold crucible induction melter (CCIM)La Hague CCIM and Marcoule CCIM

pilotFrance

Advanced CCIM (A-CCIM) Marcoule A-CCIM pilot France

Indirect induction (metallic wall - hot

metal pot)

VICHR Slovakia

La Hague and Sellafield France, UK

Coupled cold wall direct metal

induction melting and plasma burnerPIVIC France

Coupled cold wall direct glass

induction melting and plasma burnerSHIVA France

Refractory wall plasma burning and

melting

Retech (ZWILAG) Switzerland

EUROPLASMA – Belgoprocess Bulgaria

Tetronics UK

Treatment / Conditioning by immobilisation

in ceramic or glass-ceramic HIP

NNL – Workington and University of

SheffieldUK

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Technical Drivers for Thermal Treatment

Stable, durable wasteform

Removal / decomposition / incorporation of reactive waste constituents

Volatiles driven off

Product has limited / no water content

Product has limited / no gas generation

Product has limited / no organics or complexants

More homogeneous wasteform with well-distributed radionuclides

Opportunity for better characterisation

For some technologies, consolidated (monolithic) wasteform with low voidage and low porosity

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Strategic Drivers for Thermal Treatment

Significant reduction in the number of waste packages / containers (c.f., cement encapsulation) Reduced storage capacity, transport movements and disposal

capacity

Reduced packaging, transport, storage and disposal cost

Increased passivity that could mitigate the need for package rework Greater confidence in long-term performance for certain waste groups

Provide national/international treatment services Bespoke solutions for problematic wastes (wastes without an obvious

management route)

Contingency for reworking degraded legacy waste packages Ensure compliance with the near-surface / geological disposal WAC

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Three Hypothetical Examples

1) Thermal treatment (vitrification) as an

alternative encapsulation approach

2) Thermal treatment to remove / destroy reactive

waste constituents

3) Thermal treatment to provide enhanced

containment / controlled release of radioactivity

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Vitrification as an alternative encapsulation approach

Principal motivations are the potential for: Reduced volume of conditioned waste

Reduced plant footprint

Reduced carbon footprint

Faster processing / packaging throughput

Additional benefits are possible (e.g. reduced reactivity / gas generation)

Key product characteristics Effective waste encapsulation

Low voidage wasteform

Particular relevance to ILW streams that are not easily mixed into cement slurries e.g. metals, decommissioning wastes

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Thermal treatment to remove / destroy reactive waste constituents

Principal motivations are the potential to: ‘Pre-react’ waste so that it is inert during storage and disposal –

avoid detrimental interactions with other wastes

Enhanced passive safety of wasteform improves operational safety case – in keeping with ALARP principles

Minimise potential requirement for repackaging

Various approaches could be applied Vitrification – may require pre-treatment step to break down

waste constituents

Incineration

Gasification / pyrolysis

Hydrothermal oxidation

Principally relevant for wastes with a high organic, liquid or reactive metal content, including oils, solvents,…

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Additional appeal if there are also strong drivers to minimise volume reduction

• Product does not contain any matrix formers

• But may require further treatment to be disposable

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Thermal treatment for enhanced containment

Not necessarily required for ILW, but potentially relevant for other inventory components, such as separated Pu Long-term safety case for disposal relies on minimising likelihood

and consequences of criticality

Principal motivations are the potential to: Limit the release of radionuclides such as Pu-239 for a long time

after disposal (and spread releases over time)

Control the accumulation of fissile material

Key product characteristics Durable wasteform – likely to be a ceramic / glass-ceramic

Homogeneity, with waste radionuclides well distributed

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Application of Thermal Treatment

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The Choice of Treatment Route is Important

Product characteristics vary considerably depending on the

raw waste characteristics and the thermal treatment route

employed

Waste may fully react and be incorporated in a glass or ceramic

matrix

Waste constituents may be encapsulated by the matrix

Some techniques (e.g. pyrolysis) cause thermal decomposition

but do not produce a consolidated solid product

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What Makes a Disposable Product?

Depends on waste acceptance criteria (WAC) at the relevant disposal facility

Geological disposal: may depend on generic disposability criteria – influences operation of treatment / conditioning facility

For near-surface disposal: meet WAC for relevant facility

Near-surface disposability

In UK, disposal routes to LLWR / VLLW facilities established for active products from Geomelt trials

Extension to larger volumes / more active waste uncertain

Key issues: concentration of activity; discrete items

− Implications for dose associated with human intrusion scenarios

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THErmal treatment for RAdioactive waste MINimisation and hazard reduction (THERAMIN)

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Alignment of Waste Characteristics and Treatment Route

Work has been

conducted under

THERAMIN WP2

to match waste

groups to thermal

treatment routes

Viability matrix

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Generic Waste Groups

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Waste Group Definition

Cement-conditioned solid wasteWastes which have been conditioned in a cementitious matrix. The nature of the original raw waste is

varied.

Bitumen-conditioned waste Wastes which have been conditioned in a bitumen matrix. The nature of the original raw waste is varied.

Polymer-conditioned waste Wastes which have been conditioned in a polymer matrix. The nature of the original raw waste is varied.

Metallic waste (pure or high content) Waste containing pure metal or metal mixed with other materials.

Alpha waste (including PCM)Material contaminated with alpha-emitting radionuclides (e.g. plutonium, uranium, etc.). This waste

includes PCM.

Miscellaneous contaminated solid

waste (including PVC)Other miscellaneous solid waste that is non-metallic, e.g. maintenance wastes, contaminated gravel,

concrete, etc.

Inorganic ion exchange materialIon exchange materials used for the removal of soluble radionuclides (e.g. caesium) from liquid waste

(e.g. irradiated fuel cooling pond water). Example inorganic resins include: zeolites, Ionsiv® and clays

Organic ion exchange materialIon exchange materials composed of high-molecular-weight polyelectrolytes. They are also used for the

removal of soluble radionuclides from solution.

Sludge and concentratesIncludes bulk sludge, residuals, and concentrates. Sludges arise in tanks, sumps and ponds, and

comprise a mixture of materials in particulate form.

Hazardous or Chemotoxic waste Wastes which have chemotoxic properties (e.g. Be, Cd, Hg) or which are hazardous (e.g. asbestos)

FiltersFilters are used to remove radionuclides and particulates from contaminated air or other media. Example

filters include: HEPA, charcoal filters, and cartridge filters used to remove radionuclides and particulates

from active effluent.

GraphiteWaste graphite from decommissioning of reactors that used graphite as part of the reactor design. This

could include core graphite or graphite debris from the fuel assemblies.

Organic liquids and oils Contaminated liquid waste which contains organics such as oils or solvents

Other liquid waste (e.g. Chrompik) Contaminated aqueous liquids which do not contain organics

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Task 2.2 – Strategic Analysis and Database Report

Brief descriptions of national context, programme status, and waste classifications in each country

Data gathering approach and database development

Analysis of waste to identify benefits of thermal treatment, as well as risks and barriers

Benefits could include volume reduction, passivation / remove chemical reactivity, increase GDF acceptability, reduce packaging and storage requirements, reduce costs

Identify currently planned management route and strategic benefits that could result from thermal treatment

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Existing Wastes (excl. Ukraine)

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Future Wastes

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Benefits – generic waste group matrix: Example

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Metric

Conditioned Waste

Cement-conditioned wasteBitumen-conditioned

waste

Polymer-conditioned

waste

BEL FIN FRA DEU CHE GRB BEL FIN LTU CHE CHE

Be

nef

its

Increase in wasteformstability (plus storage/disposal compatibility)

() ()

Waste volumereduction

Commercialapplication of thermal treatment technologies

Provision of (alternative) treatment routes

Cost savings

Useful for learning from experience to apply to other waste streams

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Challenges – generic waste group matrix: Example

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Metric

Conditioned wastes

Cement-conditioned wasteBitumen-conditioned

waste

Polymer-conditioned

waste

BEL FIN FRA DEU CHE GRB BEL FIN LTU CHE CHE

Ris

ks a

nd

bar

rie

rs

Lack of characterisation data

Requirement to stop ASR

Large numbers of packages needing treatment

Delays to national waste management programmes

Waste segregation

α-contamination

Increased costs/timescales

ALARP issues re waste handling

Physical and/or chemical properties of wastes

Regulatory issues

Transport restrictions

Final disposal requirements for residues following treatment unclear

Waste recovery issues

Fissile content/criticality risks

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Benefits of Thermal Treatment (1/2)

An overall increase in wasteform stability, leading to increased disposability

Elimination of organics

Chemical passivation by destroying or transforming reactive constituents

Elimination of gels formed by cement degradation

Immobilisation of corrosive / mobile species (e.g., chloride)

Volume reduction of wastes

More significant for raw (unconditioned) wastes that still require packaging for ongoing storage/disposal

Savings on storage/disposal space, transport requirements and container purchasing costs

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Benefits of Thermal Treatment (2/2)

Provision of (alternative) management routes

Potential solution for problematic wastes

Alternative to existing technologies

Can potentially accept a wide range of waste inputs - offers advantages over less flexible options

− Contingency for degrading legacy waste packages

Cooperation with other countries with similar challenges could provide a mutually beneficial solution

Cost savings

Realised throughout the waste treatment and disposal lifecycle

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Challenges – Some Pre-Treatment Issues

Lack of characterisation data

Demonstration of compliance with some key operational safety criteria may be hard to accomplish, particularly for legacy conditioned wastes

Some wastes may require segregation prior to treatment

Will increase the complexity of the treatment processing route

May have implications for keeping doses to workers ALARP

Some waste streams may be difficult to transport to a treatment facility

Difficulty of waste retrieval

Advantage of wastes that can be pumped (liquids, sludges, slurries)

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Challenges – Some Treatment Issues

Radiological risks and/or doses during treatment Ease of making relevant safety cases for thermal

Wastes containing high levels of certain radionuclides (e.g., alpha-contamination) may be more difficult to deal with More stringent off gas mitigation needs and criticality concerns

May add to operational complexity of thermal process

Waste composition and heterogeneity May need to include additives within the waste stream

before/during treatment in order to achieve a satisfactory final product

May limit the efficiency / practicability of a thermal process

Scale of process Large volume waste streams would require a different scale of

treatment process to smaller waste streams

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Challenges – Some Post-Treatment Issues

What post-treatment work is needed to ensure

disposability?

Particularly relevant to incineration / pyrolysis /

gasification

Radiological risks and/or dose issues may arise

Treatment may concentrate activity and produce a more

active waste product

Is a final disposal route currently available for all

wasteforms?

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Challenges – Some Strategic Issues

Implementing a thermal treatment option may increase costs and/or timescales, at least temporarily, over the baseline management option

Existing cementation plants may be able to process wastes quicker and more cheaply than would be achieved by building a new thermal treatment facility

The desired properties of the final wasteform and overall cost implications may help to make the case for thermal

Industrial application of thermal treatment technologies

Long lead times

Potentially high upfront investment costs

Making an acceptable safety case at any stage of the process

− E.g., where feed wastes are highly heterogeneous and/or poorly characterised

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Case for Thermal Treatment of LLW/ILW

High durability product with good disposability Little if any risk of requiring any rework prior to disposal

Reactive components destroyed

Reduces operational and long term storage, transport and disposal risks

Potentially significant volume reduction and higher waste loading compared with conventional technologies Benefit for the organic and inorganic, solid and wet wastes

Relatively generic technology - can be applied to a wide range of waste streams Economies of scale

Opportunities to treat problematic wastes, legacy wastes

Alternative to existing technologies

Cost savings for storage, packaging, disposal

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Any Questions?

THERAMIN WP2 Lead

Steve Wickham

+44 (1572) 770 649

smw@galson-sciences.co.uk

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