Radioactive Waste Management Ltd

Didcot, United Kingdom

Radioactive Waste Management Ltd

Didcot, United Kingdom
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Rocco S.,University of Cambridge | Woods A.W.,University of Cambridge | Harrington J.,British Geological Survey | Norris S.,Radioactive Waste Management Ltd
Geophysical Research Letters | Year: 2017

We present new experiments that identify a mechanism for episodic release of gas from a pressurized, deformable reservoir confined by a clay seal, as a result of the transition from bulk deformation to channel growth through the clay. Air is injected into the center of a thin cylindrical cell initially filled with a mixture of bentonite clay and water. For sufficiently dry mixtures, the pressure initially increases with little volume change. On reaching the yield stress of the clay-water mixture, the lid of the cell then deforms elastically and an air-filled void forms in the center of the cell as the clay is driven radially outward. With continued supply of air, the pressure continues to increase until reaching the fracture strength of the clay. A fracture-like channel then forms and migrates to the outer edge of the cell, enabling the air to escape. The pressure then falls, and the clay flows back toward the center of the cell and seals the channel so the cycle can repeat. The phenomena may be relevant at mud volcanoes. ©2016. The Authors.

Cook A.J.M.C.,University of Birmingham | Padovani C.,Radioactive Waste Management Ltd. | Davenport A.J.,University of Birmingham
Journal of the Electrochemical Society | Year: 2017

The effects of nitrate and sulfate salts on the chloride-induced atmospheric pitting corrosion of 304L and 316L stainless steel was investigated through automated deposition of droplets of magnesium and calcium salts. Nitrate was found to inhibit pitting under magnesium salt droplets when the ratio between the deposition density of nitrate anions and chloride anions was above a critical value, which was the same for both 304L and 316L. This critical ratio was found to decrease with increasing humidity. Sulfate was also observed to inhibit pitting for MgCl2 + MgSO4 mixtures, but only at higher humidities. Sulfate did not show any inhibition for CaCl2 + CaSO4 mixtures, an effect attributed to the low solubility of CaSO4. At low relative humidities, precipitation of the inhibiting salt was observed, leading in some cases to crevice-like corrosion under salt crystals. The pitting behavior was explained in terms of the thermodynamic behavior of concentrated solutions. © The Author(s) 2017. Published by ECS. All rights reserved.

Harrington J.F.,British Geological Survey | Graham C.C.,British Geological Survey | Cuss R.J.,British Geological Survey | Norris S.,Radioactive Waste Management Ltd.
Applied Clay Science | Year: 2017

In a deep geological disposal facility for radioactive waste, precompacted bentonite is proposed as a sealing material for the isolation of boreholes, disposal galleries and deposition holes. The advective movement of repository gas in bentonite has been linked to the development of new porosity and propagation of dilatant pathways. For the first time we present a detailed analysis of stress field data during the generation and evolution of a gas network. A new experimental dataset, from a highly instrumented test, clearly shows the strong coupling between stress, gas pressure and flow in bentonite. Multiple discrete propagation events are observed, demonstrating spatial variability and time-dependency as permeability within the clay develops. Analysis of the stress data before, during and after gas entry indicates a heterogeneous stress field initially develops, resulting from the development of these pathways. The flow network is dynamic and continues to spatially evolve after gas entry, such that permeability under these conditions must be time-dependent in nature. Perturbation of the stress field is significant before all major gas outflow events, presumably resulting from the requirement to propagate an effective gas network before outflow is possible. In contrast, no major flow perturbations are detected which did not correlate with fluctuations in the stress field. The controls on the distribution and geometry of the resulting flow network are unclear, as well as its long-term evolution and stability. These will be beneficial in the assessment of gas pressure evolution as part of safety case development. © 2017 British Geological Survey, a component institute of NERC

Agency: European Commission | Branch: H2020 | Program: RIA | Phase: NFRP-06-2014 | Award Amount: 9.66M | Year: 2015

The Modern2020 project aims at providing the means for developing and implementing an effective and efficient repository operational monitoring programme, taking into account the requirements of specific national programmes. The work allows advanced national radioactive waste disposal programmes to design monitoring systems suitable for deployment when repositories start operating in the next decade and supports less developed programmes and other stakeholders by illustrating how the national context can be taken into account in designing dedicated monitoring programmes tailored to their national needs. The work is established to understand what should be monitored within the frame of the wider safety cases and to provide methodology on how monitoring information can be used to support decision making and to plan for responding to monitoring results. Research and development work aims to improve and develop innovative repository monitoring techniques (wireless data transmission, alternative power supply sources, new sensors, geophysical methods) from the proof of feasibility stage to the technology development and demonstration phase. Innovative technical solutions facilitate the integration and flexibility of required monitoring components to ease the final implementation and adaptation of the monitoring system. Full-scale in-situ demonstrations of innovative monitoring techniques will further enhance the knowledge on the operational implementation of specific disposal monitoring and will demonstrate the performance of the state-of-the-art, the innovative techniques and their comparison with conventional ones. Finally, Modern2020 has the ambition to effectively engage local citizen stakeholders in the R&D monitoring activity by involving them at an early stage in a repository development programme in order to integrate their concerns and expectations into monitoring programmes.

Agency: European Commission | Branch: H2020 | Program: CSA | Phase: NFRP-04-2014 | Award Amount: 1.79M | Year: 2015

The goal of this project is to prepare the setting up of a Joint Programming on Radioactive Waste Disposal that would be established to coordinate at the European level, national research programmes and the associated research and development (R&D) activities on geological disposal for high activity long lived radioactive waste. This action includes reviewing of all strategic aspects linked to a stepwise move towards a Joint Programming in this field. This project will involve organisations that are active in the safety, management and disposal of radioactive waste and research entities. The first step of this project will be to engage in discussion with Member States representatives in order to clarify the organisation of their national R&D consistent with the implementation of the Council Directive. The second step will be to identify existing research programmes that could contribute to the identification of common scientific objectives and activities as well as specific aspects that the organisations would like to develop in the Joint Programme. The third step will be to draft the joint Programme Document that should be the technical background of the Joint Programming. The outcomes of the project will be (i) a preliminary evaluation of a potential in-kind and financial commitment of organisations, (ii) a Programme Document consisting of large programmes focused on key priorities of WMOs, TSOs side and Research Entities and (iii) a Summary report comprising a proposal for the implementation of this Joint Programming. This action will lead to the further integration of the interested research community and hence help to maintain and develop the EU leadership in knowledge and expertise for innovative radioactive waste management solutions that effectively matches public expectations. Moreover, it will further reinforce and make the interaction at EU level between WMOs, TSOs, industry, policy makers and the research community more effective.

Agency: European Commission | Branch: FP7 | Program: CP | Phase: Fission-2012-1.1.1 | Award Amount: 15.74M | Year: 2012

DOPAS aims to improve the adequacy and consistency regarding industrial feasibility of plugs and seals, the measurement of their characteristics, the control of their behavior over time in repository conditions and also their hydraulic performance acceptable with respect to the safety objectives. This DOPAS project addresses the design basis, reference designs and strategies to demonstrate the compliance of the reference designs to the design basis, for plugs and seals in geological disposal facilities. The project focuses on shaft seals for salt rock (German repository concept), tunnel plugs for clay rock (French and Swiss repository concepts), and tunnel plugs for crystalline rock (Czech, Finnish and Swedish repository concepts). Five different demonstration experiments are part of the project and will take place in Sweden, France, Finland, Czech Republic and Germany. They are in different state-of-development. The Swedish demonstrator will be constructed prior to start of the DOPAS project and will basically provide experience on demonstration of compliance of reference design to the design basis. German demonstrator will be installed after the DOPAS project and will focus on demonstration of suitability by performance assessment. The French, Finnish, Swedish,German and the Czech experiments will address developments in all phases of design basis, reference designs and strategies to demonstrate compliance of reference designs to design basis. The studied concepts will be developed in the DOPASs five thematic scientific/technological work packages, which each integrate the results of the individual experiments. The DOPAS project is derived from the IGD-TPs Strategic Research Agenda that points out the topic of plug and seals as a first priority issue for joint European RTD projects.

Lever D.,Amec Foster Wheeler | Vines S.,Radioactive Waste Management Ltd
Mineralogical Magazine | Year: 2015

Carbon-14 is a key radionuclide in the assessment of the safety of a geological disposal facility because of the calculated assessment of the radiological consequences of gaseous carbon-14-bearing species. Radioactive Waste Management Limited has established an Integrated Project Team (IPT) in which partners are working together to develop an holistic approach to carbon-14 management in the disposal system. We have used an 'AND' approach to structure and prioritize our technical work. For a waste stream to be of concern, there has to be a significant inventory, AND carbon-14-bearing gas has to be generated, AND this gas has to be entrained by bulk gas, AND it has to migrate through the engineered barriers, AND it has to migrate through the overlying geological environment (either as gas or in solution), AND there have to be consequences in the biosphere. We are also using this approach to consider alternative treatment, packaging and design options. © 2016 by Walter de Gruyter Berlin/Boston.

Padovani C.,Radioactive Waste Management Ltd
Corrosion Engineering Science and Technology | Year: 2014

Radioactive Waste Management Limited (RWM), formerly the Radioactive Waste Management Directorate of the UK Nuclear Decommissioning Authority (NDA RWMD), has a continuing programme of research and development to support the safe disposal of radioactive wastes in a geological disposal facility (GDF). This paper describes the part of RWM's research programme aimed at developing a robust understanding of the durability of container materials for a variety of potential wastes. It includes background information, a summary of relevant past and continuing R&D projects and, to a more limited extent, links to relevant scientific literature produced elsewhere. The paper considers separately the case of intermediate level waste (ILW), for which container materials are better defined, durability requirements are less stringent and the development of the disposal system in the UK is more mature, and that of high level waste (HLW) and spent fuel, for which a broader range of disposal options is being considered, durability requirements are more stringent and information available in the UK is currently largely based on international developments. © 2014 Institute of Materials, Minerals and Mining.

McCall A.,Radioactive Waste Management Ltd | Cairns M.,Radioactive Waste Management Ltd
15th International High-Level Radioactive Waste Management Conference 2015, IHLRWM 2015 | Year: 2015

The UK has a range of high heat generating wastes including legacy spent fuel, vitrified HLW and potentially new build spent fuels that may require geological disposal. The heat generated by legacy wastes and potential future wastes must be taken into account in the design of a UK Geological Disposal Facility. In the absence of a specific disposal site, RWM is developing generic disposal solutions for these wastes that take due account of high thermal loads in view of the uncertainties that are inherent in the absence of a specific site. To facilitate planning decisions and hazard reduction, RWM operates the Disposability Assessment Process. This is used to provide advice to waste producing organisations on approaches to waste packaging and interim storage to ensure compatibility with future geological disposal requirements, whilst taking due account of uncertainty.

Bailey L.,Radioactive Waste Management Ltd
Mineralogical Magazine | Year: 2015

The 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. © 2016 by Walter de Gruyter Berlin/Boston.

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