Quintessa staff have over two centuries of collective experience related to the assessment of the safety and feasibility of the long-term management and disposal of radioactive wastes in near-surface and deep underground facilities around the world.
Quintessa's work has covered a broad range of topics throughout the information pyramid linking data to decisions, including:
Quintessa has extensive capabilities with the synthesis and interpretation of data relating to engineered barrier systems, the geosphere and biosphere.
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A key question related to engineered barriers is whether they will retain their physical and/or chemical barrier functions for a sufficient length of time. For example, Quintessa has carried out a number of projects on the long-term evolution of bentonite-based buffer and backfill materials including their chemical evolution due to interactions with cementitious leachates (Are bentonite and cement compatible as sealing materials?). This capability makes use of Quintessa's fully coupled reactive geochemical transport code Raiden.
Quintessa's Geoscience Task Force has extensive experience with the interpretation of geoscientific data and the development of conceptual and process models that integrate geological, geochemical and hydrogeological understanding of a site. Most recently a detailed re-evaluation has been made of the geology, hydrogeology and geochemistry of the area around the Dounreay Shaft (Post-Closure Safety Case for the Dounreay Shaft).
Quintessa staff have a long involvement with the interpretation of data for the evolution of the biosphere and the transfer of radionuclides in the near-surface environment, for example through the international BIOMOVS II and BIOMASS projects. For example, this has included an analysis of critical issues in biosphere modeling and site investigation, and the application of a protocol for the specification of biospheres for HLW disposal assessments.
Recent projects relating to the synthesis and interpretation of data, and conceptual and process models have included:
The long-term performance assessment of radioactive waste facilities lies at the heart of Quintessa's capabilities. Quintessa staff have been involved with all aspects of the development and application of a wide range of methodologies and models for near-surface and geological disposal facilities. Also, we have provided strategic advice, management and training (Performance assessment workshop for UKAEA staff).
Examples of some recent performance assessment work include:
Following guidance from the NEA and IAEA, a Safety Case needs to be prepared that brings together all the qualitative and quantitative arguments and understanding related to the safety of a facility. Quintessa is able to provide support in addressing the following issues:
For example, a document providing supporting arguments for the 2002 Drigg Post-Closure Safety Case, and more recently a comprehensive suite of structured Safety Case documents have been produced for the Dounreay Shaft (Post-Closure Safety Case for the Dounreay Shaft).
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There are usually various options available for managing the impact of industrial process on the environment. In making an informed decision between the available choices, it is always valuable to compare the benefits and disadvantages of each in terms of important factors such as technical performance, cost, and health, environmental and social issues. This might be done at the level of plans or programmes, in which case a Strategic Environmental Assessment or Sustainability Assessment would be carried out, or at a project level where an Environmental Impact Assessment would be appropriate. Within the UK the Best Practicable Environmental Option (BPEO) assessment method, advocated by the Royal Commission on Environmental Pollution, is widely used in the context of pollution prevention, complemented by Best Practicable Means (BPM) studies to decide upon specific technologies. Whatever the precise technique, the process helps to make clear the main differences between options, highlighting the key factors involved in making the choice of a preferred option. |
Quintessa has applied such environmental options assessment approaches to a range of situations. At a national level, Quintessa has supported the comparison of options for storage and disposal of radioactive wastes, and has developed a manual for use by environmental regulators to evaluate BPEO assessments. Also, Quintessa staff have contributed to the SAFEGROUNDS (Summary of SAFEGROUNDS guidance document) project to develop best practice guidance for the management of contaminated land on nuclear and defence sites. At a project level, Quintessa staff have led a number of BPEO studies, for example relating to the Dounreay Site Restoration Plan (Best Practicable Environmental Option for Low Level Waste at Dounreay).
At the highest level a case needs to be made for the development of a particular facility taking into account of the full range of technical, environmental, socio-economic and political factors. Quintessa has provided support to clients with important work for example through collaborative projects such as COWAM 2 (Governance in European Radioactive Waste Management - COWAM 2) on the governance of European radioactive waste management, and assessing the impact of retrievability strategies.
For more information, please contact David Hodgkinson.