Research and development for geological disposal of higher activity wastes: the role and expectations of the Environment Agency

2011 ◽  
Vol 75 (4) ◽  
pp. 2431-2437
Author(s):  
C. R. Cailes ◽  
I. Barraclough ◽  
R. E. Smith ◽  
G. Thomson
Keyword(s):  
Research And Development ◽  
Research Programme ◽  
Environmental Safety ◽  
Nuclear Industry ◽  
Geological Disposal ◽  
England And Wales ◽  
Disposal Facility ◽  
Safety Case ◽  
Environment Agency ◽  
Regulatory Decisions

AbstractThe Environment Agency is the environmental regulator for the nuclear industry in England and Wales. We aim to ensure that any future Geological Disposal Facility (GDF) will meet our standards for protecting people and the environment during development, operation and following closure. We shall only grant an environmental permit for such a facility if the GDF developer submits an Environmental Safety Case (ESC) to the Environment Agency demonstrating that the proposed GDF will meet our standards. The ESC should be based on sound science and supported by appropriate research and development. The Environment Agency undertakes its own research programme to inform its regulatory decisions.

scholarly journals Development of a Generic Safety Narrative for a UK Geological Disposal Facility

2015 ◽  
Vol 79 (6) ◽  
pp. 1633-1640 ◽  
Author(s):  
L. Bailey
Keyword(s):  
Environmental Safety ◽  
System Safety ◽  
Geological Disposal ◽  
Disposal Facility ◽  
Safety Barriers ◽  
Safety Case ◽  
The Uk ◽  
Surface Environment

AbstractThe UK has published a generic Disposal System Safety Case for a geological disposal facility (NDA, 2010) and is planning to update this in 2016. However, it is a challenge to present a meaningful safety case when the location and hence the design of a geological disposal facility are not known. Consequently, this paper describes our aim to present a narrative, explaining how we can have confidence in the long-term safety of a geological disposal facility. This narrative is based on an understanding of the environmental safety functions of a geological disposal facility and the features, events and processes (FEPs) that support them. The highest level environmental safety functions required for a geological disposal facility are isolation and containment. By isolation we mean removal of the wastes from people and the surface environment. By containment we mean retaining the radioactivity from the wastes within various parts of the disposal facility for as long as required to achieve safety. Beneath these top-level environmental safety functions we have identified generic environmental safety functions associated with each of the key safety barriers within a geological disposal facility, namely: the wasteform, the container, the local buffer or backfill, the mass backfill (in the access tunnels and service ways), the plugs and seals and the geosphere. This paper discusses the application of environmental safety functions and FEPs to building a safety narrative and explains how it is proposed to use such an approach to develop a generic environmental safety case for the UK to provide confidence in the longterm safety of a geological disposal facility after it has been sealed and closed.

Framework for an environmental safety case for geological disposal in the UK

2012 ◽  
Vol 76 (8) ◽  
pp. 3457-3464 ◽  
Author(s):  
M. J. Poole ◽  
R. Kowe
Keyword(s):  
Environmental Safety ◽  
Approval Process ◽  
Site Specific ◽  
Geological Disposal ◽  
Disposal Facility ◽  
Safety Case ◽  
The Uk ◽  
A Site

AbstractThe implementation of a geological disposal facility requires the demonstration of confidence that such a facility would be safe during both the operational period and in the long-term after the closure of such a facility. The generic environmental safety case described in this paper is the vehicle used to demonstrate an understanding of environmental safety. It will be used to prepare a site-specific environmental safety case in due course. The approach taken will be consistent with a staged development and approval process, as advocated by the environmental regulators.

scholarly journals Consequence modelling of hypothetical post-closure criticality events for spent fuel disposal

2015 ◽  
Vol 79 (6) ◽  
pp. 1505-1513 ◽  
Author(s):  
R. M. Mason ◽  
J. K. Martin ◽  
P. N. Smith ◽  
R. J. Winsley
Keyword(s):  
International Studies ◽  
Quasi Steady State ◽  
Spent Fuel ◽  
Regulatory Requirement ◽  
Geological Disposal ◽  
Waste Package ◽  
Decay Heat ◽  
Disposal Facility ◽  
Safety Case ◽  
The Uk

AbstractIn support of the Radioactive Waste Management (RWM) safety case for a geological disposal facility (GDF) in the UK, there is a regulatory requirement to consider the likelihood and consequences of nuclear criticality. Waste packages are designed to ensure that criticality is not possible during the transport and operational phases of a GDF and for a significant period post-closure. However, over longer post-closure timescales, conditions in the GDF will evolve.For waste packages containing spent fuel, it can be shown that, under certain conditions, package flooding could result in a type of criticality event referred to as 'quasi-steady-state' (QSS). Although unlikely, this defines a 'what-if' scenario for understanding the potential consequences of post-closure criticality. This paper provides an overview of a methodology to understand QSS criticality and its application to a spent fuel waste package.The power of such a hypothetical criticality event is typically estimated to be a few kilowatts: comparable with international studies of similar systems and the decay heat for which waste packages are designed. This work has built confidence in the methodology and supports RWM's demonstration that post-closure criticality is not a significant concern.

Update on the Review of the LLWR 2011 Environmental Safety Case

2013 ◽  
Author(s):  
Richard Cummings ◽  
Amy Huntington ◽  
John Shevelan ◽  
Andrew J. Baker ◽  
Trevor Sumerling ◽  
...  
Keyword(s):  
Environmental Safety ◽  
Acceptance Criteria ◽  
Low Level ◽  
Additional Work ◽  
Local Stakeholders ◽  
Safety Case ◽  
Waste Repository ◽  
Environment Agency ◽  
The Uk

The UK Low Level Waste Repository has submitted a fully revised Environmental Safety Case (ESC) to the Environment Agency for the continued operation of the site. The Environment Agency is reviewing the submission. As part of the review of the ESC, we have been engaging with the Environment Agency to answer questions and provide further clarification where required. Once the review is complete, LLWR will apply for a revised permit for the continued operation of the site. We are required by our current Permit to operate the site in accordance with the assumptions of the ESC. We have developed a process for the implementation and maintenance of the ESC as a ‘live’ safety case under formal change control, and the development of waste acceptance arrangements identified as necessary to ensure that the repository is operated in a safe and optimised way, consistent with the assumptions and results of the ESC. Engagement with waste consignors has been essential in the development of revised waste acceptance criteria. Additional work has also been carried out in the development of an Article 37 submission, presenting the ESC to local stakeholders and developing of waste emplacement strategies.

scholarly journals Understanding the likelihood and consequences of post-closure criticality in a geological disposal facility

2015 ◽  
Vol 79 (6) ◽  
pp. 1551-1561 ◽  
Author(s):  
R. J. Winsley ◽  
T. D. Baldwin ◽  
T. W. Hicks ◽  
R. M. Mason ◽  
P. N. Smith
Keyword(s):  
Spent Fuel ◽  
Geological Disposal ◽  
Safe Disposal ◽  
Waste Package ◽  
Disposal Facility ◽  
Safety Case ◽  
Operational Phase ◽  
Strength Rock ◽  
Criticality Safety

AbstractA geological disposal facility (GDF) will include fissile materials that could, under certain conditions, lead to criticality. Demonstration of criticality safety therefore forms an important part of a GDF's safety case.Containment provided by the waste package will contribute to criticality safety during package transport and the GDF operational phase. The GDF multiple-barrier system will ensure that criticality is prevented for some time after facility closure. However, on longer post-closure timescales, conditions in the GDF will evolve and it is necessary to demonstrate: an understanding of the conditions under which criticality could occur; the likelihood of such conditions occurring; and the consequences of criticality should it occur.Work has addressed disposal of all of the UK's higher-activity wastes in three illustrative geologies. This paper, however, focuses on presenting results to support safe disposal of spent fuel, plutonium and highlyenriched uranium in higher-strength rock.The results support a safety case assertion that post-closure criticality is of low likelihood and, if it was to occur, the consequences would be tolerable.

The consequences of hypothetical post-closure criticality

2012 ◽  
Vol 76 (8) ◽  
pp. 3155-3163 ◽  
Author(s):  
R. M. Mason ◽  
P. N. Smith ◽  
B. D. Turland ◽  
C. P. Jackson
Keyword(s):  
Initial Distribution ◽  
Fissile Material ◽  
Chain Reaction ◽  
Geological Disposal ◽  
Significant Period ◽  
Disposal Facility ◽  
Critical Configuration ◽  
Environment Agency ◽  
Local Accumulation

AbstractThe Environment Agency Guidance on Requirements for Authorisation (GRA) of a geological disposal facility (GDF) requires a demonstration that "the possibility of a local accumulation of fissile material such as to produce a neutron chain reaction is not a significant concern." A neutron chain reaction that is just self-sustaining is also known as critical.Waste packages can be designed to ensure that criticality is impossible during the transport and operational phases of a GDF, and for a significant period post-closure. Over longer times, however, packages may degrade, and groundwater flows could lead to a localized accumulation of fissile material. Hence, even though the initial distribution of materials would need to change substantially, criticality cannot be ruled out completely.This paper describes how an accumulation of fissile material could, hypothetically, lead to a critical configuration; how such a system could evolve; what the local consequences could be; and how the engineered and geological barriers could be affected. The conclusion from studies to date is that, even for large (and very unlikely) fissile accumulations, the consequences of a post-closure criticality event are not a significant concern.

NDA Generic Research Programme for Higher Activity Waste Management Issues

2009 ◽  
Author(s):  
James McKinney ◽  
Melanie Brownridge
Keyword(s):  
Waste Management ◽  
Research And Development ◽  
Nuclear Waste ◽  
Research Programme ◽  
Nuclear Industry ◽  
Official Journal ◽  
Waste Processing ◽  
Management Research ◽  
Material Characterisation ◽  
Management Issues

NDA has a responsibility to ensure decommissioning activities are sufficiently technically underpinned and appropriate Research and Development (R&D) is carried out. The NDA funds research and development (R&D) indirectly via the Site Licence Companies (SLCs) or directly. The main component of directly funded R&D is the NDA Direct Research Portfolio (DRP). The DRP is split into four framework areas: • University Interactions; • Waste Processing; • Material Characterisation; • Actinide and Strategic Nuclear Materials. These four framework areas were competed through an Official Journal of European Union (OJEU) process in 2008. Although all four areas involve waste management, Waste Processing and Material Characterisation specifically deal with Higher Activity Waste (HAW) waste management issues. The Waste Processing area was awarded to three groups: (i) National Nuclear Laboratory (NNL), (ii) Consortium led by Hyder Consulting Ltd, and (iii) Consortium led by UKAEA Ltd. The Material Characterisation area was awarded to three groups: (i) NNL, (ii) Serco, and (iii) Consortium led by UKAEA Ltd. The initial work in Waste Processing and Material Characterisation was centred on establishing a forward research programme to address the generic needs of the UK civil nuclear industry and the NDA strategic drivers for waste management and land quality. This has been achieved by the four main framework contractors from the Waste Processing and Materials Characterisation areas working together with the NDA to identify the key research themes and begin the development of the NDA’s HAW Management Research Programme. The process also involves active engagement with both industry and regulators via the Nuclear Waste Research Forum (NWRF). The NDA’s HAW Management Research Programme includes a number of themes: • Optimisation of Interim Store Operation & Design; • Alternative Waste Encapsulants; • Waste Package Integrity; • Alternative Waste treatment methods; • Alternative storage and disposal options; • Integrated waste management solutions; • Materials characterisation. The NDA, with additional support from its framework contractors and the Nuclear Waste Research Forum, is now developing a more detailed scope for each research theme and prioritising the research projects to ensure alignment with its strategic development programme.

A Structured Programme of Research into the Chemical Aspects of Radioactive Waste Disposal

1986 ◽  
Vol 84 ◽  
Author(s):  
D. Read ◽  
A.A. Krol ◽  
B.G.J. Thompson
Keyword(s):  
Radioactive Waste ◽  
Research Programme ◽  
Nuclear Industry ◽  
Radioactive Waste Disposal ◽  
Current Status ◽  
Future Research ◽  
Deterministic Models ◽  
Safety Case ◽  
Intermediate Level Radioactive Waste ◽  
The Uk

AbstractThe UK Department of the Environment (DOE) is developing an independent capability to assess proposals made by the nuclear industry for the underground disposal of low and intermediate level radioactive waste. Modelling chemical processes forms an integral part of the underlying DOE research programme which includes the development of probabilistic risk assessment codes, more detailed deterministic models and supporting field and laboratory studies, in a co-ordinated, hierarchical approach. This paper summarises the results of a survey on the current status of this and related research, with emphasis on the assessment of a safety case for shallow land disposal of low level waste in about two years time. Shortcomings in existing work are identified, and a structured programme for future research described.

Developments in UK Regulation of Nuclear Wastes

2003 ◽  
Author(s):  
Stuart Newstead ◽  
Mick Bacon ◽  
Jim Cochrane
Keyword(s):  
Waste Management ◽  
Environmental Safety ◽  
Management Options ◽  
Regulatory Oversight ◽  
Nuclear Site ◽  
Management Plans ◽  
Safety Case ◽  
Environment Agency ◽  
The Uk

The UK has a significant nuclear legacy arising from Government funded work going back to the 1940s. Government is proposing radical changes to current arrangements to tackle this legacy, clean-up nuclear sites and develop its policy for managing solid radioactive waste. As part of these developments the Nuclear Installations Inspectorate of the Health & Safety Executive, the Scottish Environment Protection Agency and the Environment Agency are putting in place joint working arrangements to improve the regulation of intermediate level radioactive wastes (ILW). The aim is to ensure that ILW is managed in a sustainable way taking into account long-term environmental considerations. These arrangements provide for improved regulatory oversight of (i) proposals from nuclear site licensees to condition ILW, and (ii) the work by Nirex to develop further its phased disposal concept (PDC). The regulators will scrutinise: • ILW conditioning proposals: This involves assessing site waste management plans, waste management options (e.g. BPEO assessments), conceptual designs and functional specifications for waste conditioning plants, detailed designs, construction, commissioning and operation of the plants, and the state of waste packages. • Nirex’s on-going work: This involves examining Nirex’s PDC, its application to ILW conditioning proposals and associated Letters of Comfort/Letters of Advice (LoC/LoA) and the possible future development of an environmental safety case for an eventual repository. A description is given of the regulators’ process associated with these new arrangements.

Comparison of a post-closure transient criticality model with the Oklo natural reactors

2012 ◽  
Vol 76 (8) ◽  
pp. 3145-3153 ◽  
Author(s):  
R. M. Mason ◽  
J. K. Martin ◽  
P. N. Smith ◽  
B. D. Turland
Keyword(s):  
Steady State ◽  
Observational Evidence ◽  
Fissile Material ◽  
Quasi Steady State ◽  
Natural Analogue ◽  
System Safety ◽  
Geological Disposal ◽  
Disposal Facility ◽  
Safety Case ◽  
Modelling Approach

AbstractIn support of the disposal system safety case for a geological disposal facility (GDF) there is a requirement to consider 'what-if' hypothetical scenarios for post-closure nuclear criticality. Although all such scenarios are considered very unlikely, one 'what-if' scenario is the mobilization of fissile material from a number of waste packages and its slow accumulation within the GDF or the immediate surroundings. Should sufficient fissile material accumulate a quasi-steady-state (QSS) transient criticality event could result. A computer model has been developed to understand the evolution and consequences of such an event.Since a postulated QSS criticality could persist for many millennia, building confidence in the modelling approach is difficult. However, the Oklo natural reactors in Africa operated for similar durations around two billion years ago, providing a natural analogue for comparison. This paper describes the modelling approach, its application to hypothetical criticality events for a GDF, and how the model can be compared to Oklo. The model results are found to be in agreement with the observational evidence from Oklo, building confidence in the use of the QSS model to simulate postulated post-closure criticality events in GDFs.

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