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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Geological Disposal of Nuclear Waste in Tuff: Yucca Mountain (USA) [Geological Disposal in Tuff: Yucca Mountain]

For more than three decades, the US Department of Energy has investigated the potential for permanent disposal of high-level radioactive waste and spent nuclear fuel in a deep-mined repository at Yucca Mountain, Nevada (USA). A detailed license application submitted to the US Nuclear Regulatory Commission in 2008 provides full documentation of the case for permanent disposal of nuclear waste in tuff. Furthermore, the aridity of the site and great depth to the water table provide a disposal environment and a design concept unique among deep-mined repositories currently or previously proposed worldwide.

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DOE OSTI2019

Operational Safety Analysis for Disposal Period of the Future Belgian Geological Disposal Facility - 19249

For more than 40 years, ONDRAF/NIRAS (the federal agency responsible for managing radioactive waste and enriched fissile materials in Belgium) has been studying the concept of a geological disposal facility (GDF) in poorly indurated clays as an option for the long-term management of both category B waste (low-level and intermediate-level long-lived waste - LILW-LL) and category C waste (high-level waste - HLW and spent fuel). In the absence of a policy decision, the proposed Belgian reference option for disposal of such waste is a GDF in poorly indurated clays, located at a depth between 200 m and 600 m. ONDRAF/NIRAS has developed a reference disposal concept for research, development and demonstration (RD and D) purposes. At the current stage of this program, the primary objective of ONDRAF/NIRAS is to establish the safety and feasibility of constructing, operating and closing a Geological Disposal Facility (GDF) at the conceptual design level, without any presumption about the exact location of the facility. This will be evaluated in a first version of the safety and feasibility case (SFC-1 V1) for the geological disposal of category B and C radioactive wastes. Analysis of the operational safety is an important part of the SFC-1 V1. ONDRAF/NIRAS, supported by BGE Technology GmbH, has prepared an operational safety analysis of the current GDF reference design and the processes occurring during the operation and closure period. A SWIFT methodology (Structured What If Technique) is used to identify risks and the measures required to mitigate their consequences. In parallel to this SWIFT analysis, specific attention is also given to fire risk, especially in the blind-ending disposal galleries (DG). Based on understanding of fire risk analysis, recommendations suggest using exclusively electrically driven equipment to reduce fire loads and minimize the fire hazard. In addition, strict working procedures could prevent the presence of workers between the DG dead end and equipment presenting significant fire load. The use of mobile refuge chambers should also be part of the safety concept. (authors)

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DOE OSTI2018

Regulating Operational Safety at a Future Geological Disposal Facility in the UK - 18038

The United Kingdom (UK) has generated commercial nuclear energy for over 60 years; generating a significant and varied inventory of higher activity radioactive waste (HAW). In accordance with international practice, UK Government policy for long-term management of HAW is disposal in a geological disposal facility (GDF). The nuclear materials comprising HAW include high level waste, intermediate level waste and some low level waste, not suitable for disposal to the Low Level Waste Repository. In addition, other nuclear materials may be reclassified as waste in the future and will require to be managed as HAW for disposal to a GDF; these include spent fuel, uranium and plutonium. The operator of a GDF will be required to obtain a nuclear site licence from the Office for Nuclear Regulation (ONR), as the nuclear safety and security regulator, in order to construct and operate the facility. In the period prior to submission of a licence application, ONR is working to develop its regulatory expectations and provide advice on its regulatory role with regards to a future GDF. ONR has developed regulatory guidance on operational safety, benchmarked against the relevant IAEA Safety Standards and the Western European Nuclear Regulators Association (WENRA) Safety Reference Levels for Disposal. This guidance draws upon ONR's current expectations for nuclear sites; including operational reactors, fuel manufacture and reprocessing facilities, and reactors undergoing decommissioning; and incorporates relevant good practice drawn from international programmes for geological disposal and related industries (eg mining). In addition to the technical assessment guidance, ONR has developed guidance on the licensing process specific to a GDF; providing clarity for example on when a licence will be required. A review of the standard licence conditions applied to all nuclear sites concluded no significant amendment would be required for application to a GDF. Through its voluntary agreement with Radioactive Waste Management Limited (RWM), the developer and future operator of a GDF in the UK, ONR exerts regulatory influence on the design and organisational development of the future licensee. As part of this scrutiny, ONR has assessed RWM's generic Disposal System Safety Case. Subjecting the generic design and safety case to regulatory review provides opportunity for early engagement to ensure the appropriate standards will be achieved. ONR will only grant the necessary regulatory permissions if RWM adequately demonstrates the GDF will be constructed, operated and closed safely. Future challenges faced by ONR with respect to a GDF include building and maintaining regulatory competence and confidence, and engaging effectively with the public as the UK begins its search for a suitable site to provide appropriate assurance that a GDF will be operated safely and securely. (authors)

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DOE OSTI2017

Recent Developments in the United Kingdom Geological Disposal Facility Programme - 17558

The United Kingdom Government remains committed to the policy of geological disposal. All major nuclear nations are actively pursuing geological disposal. It is internationally recognised that geological disposal represents the safest and most sustainable option as the end point of the management of high level waste and spent fuel considered as waste. Other countries that have also decided on a policy of geological disposal include Canada, Finland, France, Switzerland, Sweden and the United States of America. The United Kingdom Government continues to favour an approach to siting a Geological Disposal Facility that is based on the willingness of local communities to participate in the siting process. Construction and operation of a Geological Disposal Facility will be a multi-billion pound project that will provide skilled employment for hundreds of people over many decades. It will contribute greatly to the local economy and wider socio-economic framework. There are also likely to be spin-off industry benefits, infrastructure investments, benefits to local education or academic resources, and positive impacts on local service industries that support the facility and its workforce. It is also likely to involve major investments in local transport facilities and other infrastructure, which would remain after the facility had been closed. The United Kingdom Government published a renewed process for siting a Geological Disposal Facility in 2014 - the Implementing Geological Disposal White Paper. This paper discusses the status of activities in the 2014 White Paper that have been accomplished or are underway through to 2016. (authors)

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DOE OSTI2015

Update on Cigeo, the French geological disposal project - 15067

Cigeo, the French geological disposal project, is the result of 20 years of studies and research led by Andra. Following a nation-wide selection and siting process, research focused on an argillaceous formation near Bure, a village on the boundary of the Meuse and Haute-Marne departments in eastern France, for the construction of an underground research laboratory. Based on the results submitted to the French Government and Parliament in 2005, a planning act was passed in 2006, establishing geological disposal as the reference solution for managing high-level and intermediate-level long-lived waste. The act sets out guidelines for managing this waste and includes a road-map leading up to the commissioning of the geological disposal facility in 2025. A public debate was held in 2013 and the project team took note of the ensuing change requests. Meanwhile, studies and design work continue, with a particular focus on the need for optimisation and an assessment of the cost of disposal.(authors)

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DOE OSTI2015

The use of underground research facilities for the demonstration of safety of geological disposal - 15094

Many countries are progressing towards developing research programmes related to the development of geological disposal facilities and as part of these research programmes many countries have constructed or are planning to construct Underground Research Facilities (URFs). The development of the safety case for geological disposal facilities, which covers both the operational phase and the post-closure phase, is built on the acquisition and integration of all necessary data including data on the natural and engineered barriers, on the facility itself (design), on the operation of the disposal facility, and in the specific case of geological disposal facilities, the conditions at the depth of disposal relevant for both in-situ and waste emplacement states. Taking these conditions into account can make the demonstration of safety more complex and demanding than for near surface disposal facilities. Most if not all of the countries well advanced in the development of geological disposal facilities have also developed underground research facilities to support the decision processes within their disposal facility development programme. Underground Research Facilities play an essential role in the demonstration of safety of geological disposal facilities and a distinction has to be made between data acquired from surface based investigations and boreholes and those data and experiments carried out in-situ. The use of in-situ data contribute to build confidence in the demonstration of safety and contribute to public confidence and acceptance of geological disposal facilities. Further discussion will elaborate on whether to use the URF as part of a future disposal facility or not, with an emphasis on the transposition of data from the experimental site to the disposal site and how this is addressed and validated in the demonstration of safety. (authors)

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DOE OSTI2018

Engineering Design of the Geological Disposal Facility for the UK - 18074

This paper discusses plans for implementing UK government policy for the safe geological disposal of higher activity radioactive waste. In order to progress the programme for geological disposal in the absence of a specific site, RWM has developed generic, illustrative disposal system designs for three host geological environments. These geological environments are typical of those being considered in other countries and have been chosen because they represent the range that may need to be addressed when developing the Geological Disposal Facility (GDF) for the UK. This paper provides an overview of the updated 2016 design of the UK geological disposal facility and describes the processes of construction, transport, waste package receipt, handling and emplacement and the design characteristics that the disposal facility will need to include for the waste inventory. The paper provides examples of the approach to ensure confidence in safety over the GDF life cycle and discusses the challenges in the design, construction and operation of a nationally significant infrastructure project with a scheduled waste disposal of more than 150 years. (authors)

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DOE OSTI2013

Temperature-package power correlations for open-mode geologic disposal concepts.

Logistical simulation of spent nuclear fuel (SNF) management in the U.S. combines storage, transportation and disposal elements to evaluate schedule, cost and other resources needed for all major operations leading to final geologic disposal. Geologic repository reference options are associated with limits on waste package thermal power output at emplacement, in order to meet limits on peak temperature for certain key engineered and natural barriers. These package power limits are used in logistical simulation software such as CALVIN, as threshold requirements that must be met by means of decay storage or SNF blending in waste packages, before emplacement in a repository. Geologic repository reference options include enclosed modes developed for crystalline rock, clay or shale, and salt. In addition, a further need has been addressed for open modes in which SNF can be emplaced in a repository, then ventilated for decades or longer to remove heat, prior to permanent repository closure. For each open mode disposal concept there are specified durations for surface decay storage (prior to emplacement), repository ventilation, and repository closure operations. This study simulates those steps for several timing cases, and for SNF with three fuel-burnup characteristics, to develop package power limits at which waste packages can be emplaced without exceeding specified temperature limits many years later after permanent closure. The results are presented in the form of correlations that span a range of package power and peak postclosure temperature, for each open-mode disposal concept, and for each timing case. Given a particular temperature limit value, the corresponding package power limit for each case can be selected for use in CALVIN and similar tools.

Hardin, Ernest.↗
DOE OSTI2018

Framework for The Analysis of US Permanent Geologic Disposal Options for Radioactive Waste

The U.S. study of permanent geologic disposal options of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) provided a technical basis for informing policy decisions regarding strategies for the management and disposal of radioactive waste requiring geologic isolation through the evaluation of potential impacts of waste forms on the feasibility and performance of representative generic concepts for geologic disposal. The goal of the study was to help inform relevant policy questions including: Is a "one-size-fits-all" repository a good strategic option for disposal? Do different waste types and forms perform differently enough in different disposal concepts that they warrant different treatment? Do some disposal concepts perform significantly better with or without specific waste types or forms?

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DOE OSTI2013

Geological Disposal Concept Selection Aligned with a Voluntarism Process - 13538

The UK's Radioactive Waste Management Directorate (RWMD) is currently at a generic stage in its implementation programme. The UK site selection process is a voluntarist process and, as yet, no communities have decided to participate. RWMD has set out a process to describe how a geological disposal concept would be selected for the range of higher activity wastes in the UK inventory, including major steps and decision making points, aligned with the stages of the UK site selection process. A platform of information is being developed on geological disposal concepts at various stages of implementation internationally and, in order to build on international experience, RWMD is developing its approach to technology transfer. The UK has a range of different types of higher activity wastes with different characteristics; therefore a range of geological disposal concepts may be needed. In addition to identifying key aspects for considering the compatibility of different engineered barrier systems for different types of waste, RWMD is developing a methodology to determine minimum separation distances between disposal modules in a co-located geological disposal facility. RWMD's approach to geological disposal concept selection is intended to be flexible, recognising the long term nature of the project. RWMD is also committed to keeping alternative radioactive waste management options under review; an approach has been developed and periodic reviews of alternative options will be published. (authors)

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DOE OSTI2012

The Belgian Research and Development Feasibility Programme for the Geological Disposal of High-Level and Long-Lived Radioactive Waste - 12338

ONDRAF/NIRAS, the Belgian Agency for Radioactive Waste and Enriched Fissile Materials, considers geological disposal in the poorly indurated Boom Clay as the reference solution for the long-term management of high-level and/or long-lived radioactive waste. To develop a safety concept and design for geological disposal, ONDRAF/NIRAS follows an iterative process demonstrating that the repository will be both safe and feasible to implement. This process is called the safety strategy. A part of the safety strategy is the feasibility programme which aims at demonstrating, at a conceptual level, that the proposed geological disposal system can be constructed, operated and progressively closed. The followed methodology is based on the substantiation of a hierarchy of feasibility statements. These statements cover all activities from the removal of primary waste packages from interim storage buildings to the closure of the disposal site and a period of institutional control. They focus on engineering practicability, health and safety and environmental considerations, costs and quality assurance issues. A 4 year research project to support the R and D feasibility programme was launched in 2009 with several international partners coordinated by ONDRAF/NIRAS. It aims at confirming that there are no fundamental flaws or show-stoppers in the feasibility of building and operating the facilities for geological disposal in the Boom Clay. (authors)

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DOE OSTI2012

Implementing Geological Disposal of Radioactive Waste Technology Platform From the Strategic Research Agenda to its Deployment - 12015

Several European waste management organizations (WMOs) have initiated a technology platform for accelerating the implementation of deep geological disposal of radioactive waste in Europe. The most advanced waste management programmes in Europe (i.e. Finland, Sweden, and France) have already started or are prepared to start the licensing process of deep geological disposal facilities within the next decade. A technology platform called Implementing Geological Disposal of Radioactive Waste Technology Platform (IGD-TP) was launched in November 2009. A shared vision report for the platform was published stating that: 'Our vision is that by 2025, the first geological disposal facilities for spent fuel, high-level waste, and other long-lived radioactive waste will be operating safely in Europe'. In 2011, the IGD-TP had eleven WMO members and about 70 participants from academia, research, and the industry committed to its vision. The IGD-TP has started to become a tool for reducing overlapping work, to produce savings in total costs of research and implementation and to make better use of existing competence and research infrastructures. The main contributor to this is the deployment of the IGD-TP's newly published Strategic Research Agenda (SRA). The work undertaken for the SRA defined the pending research, development and demonstration (RD and D) issues and needs. The SRA document describing the identified issues that could be worked on collaboratively was published in July 2011. It is available on the project's public web site (www.igdtp.eu). The SRA was organized around 7 Key Topics covering the Safety Case, Waste forms and their behaviour, Technical feasibility and long-term performance of repository components, Development strategy of the repository, Safety of construction and operations, Monitoring, and Governance and stakeholder involvement. Individual Topics were prioritized within the Key Topics. Cross-cutting activities like Education and Training or Knowledge Management as well as activities remaining specific for the WMOs were as well identified in the document. For example, each WMO has to develop their own waste acceptance rules, and plan for the economics and the funding of their waste management programmes. The challenge at hand for the IGD-TP is to deploy the SRA. This is carried out by agreeing on a Deployment Plan (DP) that guides organizing the concrete joint activities between the WMOs and the other participants of the IGD-TP. The first DP points out the coordinated RD and D projects and other activities that need to be launched to produce these results over the next four to five years (by the end of 2016). The DP also describes general principles for how the joint work can be organised and funded. (authors)

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DOE OSTI2012

International Socio-Technical Challenges for Geological Disposal (InSOTEC): Project Aims and Preliminary Results - 12236

InSOTEC is a social sciences research project which aims to generate a better understanding of the complex interplay between the technical and the social in radioactive waste management and, in particular, in the design and implementation of geological disposal. It currently investigates and analyses the most striking socio-technical challenges to implementing geological disposal of radioactive waste in 14 national programs. A focus is put on situations and issues where the relationship between the technical and social components is still unstable, ambiguous and controversial, and where negotiations are taking place in terms of problem definitions and preferred solutions. Such negotiations can vary from relatively minor contestation, over mild commotion, to strong and open conflicts. Concrete examples of socio-technical challenges are: the question of siting, introducing the notion of reversibility / retrievability into the concept of geological disposal, or monitoring for confidence building. In a second stage the InSOTEC partners aim to develop a fine-grained understanding of how the technical and the social influence, shape, build upon each other in the case of radioactive waste management and the design and implementation of geological disposal. How are socio-technical combinations in this field translated and materialized into the solutions finally adopted? With what kinds of tools and instruments are they being integrated? Complementary to providing better theoretical insight into these socio-technical challenges/combinations, InSOTEC aims to provide concrete suggestions on how to address these within national and international contexts. To this end, InSOTEC will deliver insights into how mechanisms for interaction between the technical community and a broad range of socio-political actors could be developed. (authors)

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DOE OSTI2025

International Collaboration Activities in Geologic Disposal R&D: Spent Fuel and High-Level Waste Disposition (FY25 Progress Report)

This report describes the FY25 status of international collaboration on geologic disposal research and development (R&D) in the Office of Spent Fuel and High-Level Waste Disposition (SFHLWD) in the U.S. Department of Energy’s (DOE) Office of Nuclear Energy (NE). The mission of this office is to provide confidence in the safe long-term management of the nation’s spent nuclear fuel and high-level radioactive waste by reducing uncertainty and advancing technology for extended storage, transportation, and geologic disposal. R&D in geologic disposal is administered in SFHLWD’s Disposal R&D Campaign.

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DOE OSTI2015

Cost Estimation Inputs for Spent Nuclear Fuel Geologic Disposal Concepts

A set of 16 geologic disposal concepts is described in sufficient detail for rough-order-of-magnitude repository cost estimates, for disposal of spent nuclear reactor fuel in generic crystalline, argillaceous, and salt host geologic media. The description includes total length, diameter, and volume for all underground shafts, ramps, drifts and large-diameter borings. Basic types of ground support are specified. Total repository capacity is assumed to be approximately 140,000 MT of spent fuel, but concepts are described in terms of modular panels each containing 10,000 MT. Waste packaging is described, and the materials and outer dimensions for disposal overpacks are given. The manner of emplacement is specified, with any additional fixturing, lining, buffer materials, and backfill needed. Thermal limits for waste package emplacement or repository closure are given, as appropriate for enclosed and open emplacement modes, respectively. The 16 disposal concepts are based on disposal concept studies performed for the Used Fuel Disposition R&D program between 2011 and 2014, and the accompanying engineering analyses.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2015

Analysis of the likelihood of post-closure criticality in a geological disposal facility - 14349

Radioactive Waste Management (RWM) is responsible for implementing geological disposal of the UK's higher activity radioactive wastes. These wastes include significant quantities of fissile nuclides and, therefore, demonstration of the criticality safety of the wastes under disposal conditions forms an important component of RWM's disposal system safety case. At the time of disposal, controls will ensure that all waste packages are sub-critical, and the containment provided by the engineered barrier system of a geological disposal facility (GDF) will ensure that criticality is prevented for some time after disposal. However, as waste packages begin to degrade, fissile and other materials may be mobilised, which could affect the potential for criticality. Therefore, the possibility for the evolution of conditions in a GDF to result in criticality requires assessment. RWM established the 'Likelihood of Criticality' research project to develop qualitative and quantitative arguments to demonstrate that criticality after closure of a GDF is unlikely. The project included consideration of the criticality safety of disposal concepts for intermediate and high level waste, spent fuel, separated plutonium and highly-enriched uranium in different generic geological settings. The results are underpinned by the construction of post-closure criticality scenarios that have been evaluated using high-level judgments about scenario credibility as well as modelling of evolving conditions in a GDF. In the latter case, a probabilistic modelling approach has been undertaken to address uncertainty in the calculation of concentrations and masses of fissile material that could occur at potential accumulation sites. The potential for criticality has been judged based on comparisons of the calculated fissile masses with minimum values required for criticality at different locations in the barrier system. This paper explains the novel approach taken to evaluating the likelihood of criticality in a GDF based on the probabilistic modelling of waste package evolution and plutonium and uranium migration. The role of this research in RWM's work to demonstrate the criticality safety of a GDF in the UK is presented in a companion paper, which also draws on the results of a parallel research project that demonstrates that, even if a criticality were to occur, then its consequences would be insignificant to GDF performance. (authors)

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DOE OSTI2015

Understanding the consequences of hypothetical post-closure transient criticality in a geological disposal facility - 14439

Radioactive Waste Management (RWM) is responsible for implementing geological disposal of the UK's higher-activity radioactive wastes. These wastes include significant quantities of fissile nuclides and, therefore, demonstration of criticality safety for the wastes under disposal conditions forms an important component of RWM's disposal system safety case. At the time of disposal all waste packages will be safely sub-critical. Containment provided by the engineered barrier system of a geological disposal facility (GDF) will ensure that criticality is not possible for some time after disposal. However, as waste packages degrade, fissile and other materials may be mobilised, which could affect the potential for criticality. Although the likelihood of a critical configuration developing is demonstrably low, it cannot be assumed to be zero over long post-closure timescales. The UK environment agencies' Guidance on Requirements for Authorisation for a GDF includes a specific requirement to consider the consequences of hypothetical 'what-if' post-closure criticality. RWM has undertaken a programme of research to model and understand the consequences of hypothetical post-closure criticality events. Initially focused on the scenario of fissile material relocation and accumulation following intermediate level waste (ILW) disposal, two bespoke computer models were developed. The quasi-steady-state (QSS) model considered critical systems maintained by accumulation of fissile materials where the temperature feedback remains negative throughout the transient. The rapid transient model (RTM) considered systems with positive temperature feedback. The QSS model development included a successful comparison with the Oklo natural reactors. With a requirement to consider post-closure criticality for a wider range of potential waste types under different illustrative disposal concepts, the initial transient criticality models had some limitations. For the QSS model this was the assumption of fixed geometry, while the complex functional inputs required in the RTM were not readily available for different materials. For the QSS model this paper describes the model development to allow changing volume; this has enabled its application to 'what-if' scenarios of flooding within a spent fuel waste package and the slumping of a stack of ILW packages. For rapid transient criticality this paper explains how the development of a simpler 'bounding approach' model to complement the RTM has enabled transient criticality analysis for a wider range of host materials. The role of this research in demonstrating post-closure criticality safety of a GDF in the UK is presented in a companion paper which also draws on the results of a parallel research project to demonstrate that the likelihood of post-closure criticality is low. (authors)

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