Browse by: "E"
Index
Title Index
Year Index
The Integration Group for the Safety Case (IGSC) of the Nuclear Energy Agency (NEA) is co-sponsoring a project with the European Commission to develop a greater understanding of how to achieve the necessary integration for successful design, construction, testing, modelling and performance assessment of engineered barrier systems (EBS). These proceedings include the main findings and presented papers from the second workshop of the EC-NEA EBS project, which covered inter alia research and development work on pre- and post-closure processes; thermal management; thermal, hydraulic, mechanical and chemical process models; and repository design. The workshop was hosted by the US Department of Energy in Las Vegas, USA, on 14-17 September 2004.
This report presents the outcomes of a joint NEA-EC workshop, organised in Oxford on 25-27 September 2002 and hosted by United Kingdom Nirex Limited. The main objectives of the workshop were to provide a status report on engineered barrier systems in various national radioactive waste management programmes considering deep geological disposal; to establish the value to member countries of a project on EBS; and to define such a project’s scope, timetable and modus operandi.
These proceedings present the main findings from, and the papers delivered at, the fourth NEA-EC workshop on Engineered Barrier Systems (EBS), which took place in Tokyo, Japan, in September 2006. This final workshop of the series focused on strategies and methods to demonstrate that EBS designs will fulfill he relevant requirements for long-term safety, engineering feasibility and quality assurance. The workshop highlighted that large-scale experiments have confirmed the feasibility of techniques for manufacturing and installing engineered components in disposal systems and have also provided valuable lessons to improve designs and refine practical aspects to construct and implement EBS.
In the deep disposal of radioactive waste, the presence of several barriers serving complementary safety functions enhances confidence that the waste will be isolated and contained to protect human health and the environment. The barriers include the natural geological barrier and the engineered barrier system (EBS). The EBS itself may comprise a variety of sub-systems or components, such as the waste form, container, buffer, backfill, seals and plugs. These proceedings include the main findings and presented papers from the third NEA-EC workshop on engineered barrier systems, which focused on the role of EBS modelling in the safety case for deep disposal. The workshop examined the modelling tools currently available and identified complex areas of assessment in which further dialogue is needed.
Repositories for the disposal of radioactive waste generally rely on a multi-barrier system to isolate the waste from the biosphere. This multi-barrier system typically comprises the natural geological barrier provided by the repository host rock and an engineered barrier system (EBS).
The EBS project being conducted by the NEA Integration Group for the Safety Case (IGSC) seeks to clarify the role that an EBS can play in the overall safety case for a deep geological repository. It is in this context that the European Commission and the NEA have prepared the present report, which describes the state of the art for engineered barrier systems and provides a common basis of understanding from which to plan future programmes. It is based on answers to a questionnaire received from 13 countries and 17 organisations.
The world’s nuclear power reactors are ageing, with the majority approaching the end of their planned operational lifetimes in the coming years. The adequacy of funding for decommissioning and radioactive waste management (RMW) thus increasingly commands the attention of decision-makers.
This report by the OECD Nuclear Energy Agency (NEA) combines a solid conceptual framework with the insights from twelve case studies of NEA member countries to propose a new approach to the adequacy of funding that is both robust and flexible.
Current funding systems in NEA countries are overall adequate. The challenges ahead however are formidable: decommissioning and RWM are moving from design to implementation, returns on assets are low and societal preferences can evolve. The very long-term nature of the solutions, in particular for radioactive waste disposal, is also not easily compatible with the economic lifetimes of the original liability holders.
This requires that all elements of the system – accrued funds, expected future returns, the lifetimes of nuclear power plants, the expected costs of politically sustainable technical solutions and the liabilities for residual risks – are reviewed and realigned at regular intervals. Complementing existing approaches with such a circular approach will strengthen funding arrangements and ensure their adequacy for decades to come.
Environmental activities in uranium mining and milling are becoming increasingly important owing to: - the stricter requirements for new facilities being imposed by many countries in the form of environmental clearance approvals; - the large number of uranium production facilities which have been taken out of operation recently; - and, the restoration and reclamation measures that are being considered for many old sites which have been closed permanently.
This book provides an overview of environmental activities related to uranium production based on survey responses from 29 countries. It discusses environmental and safety activities related to the closure and remediation of formerly utilised sites; the operation, monitoring and control of producing sites; and the planning, licensing and authorisation of new facilities. It includes an overview of the reported interests of specialists working in the field, including sensitivity of ecosystems, environmental impact assessment, emissions to air and water, work environment, radiation safety, waste handling and disposal, mine and mill decommissioning and site restoration, and the regulation of these activities.
Environmental remediation activities in uranium mines and mills have become increasingly important in the last few decades due to the large number of facilities which have been taken out of operation, the growing interest in remediating previously abandoned sites and the increasingly strict environmental regulations that are being put in place. Remediation programmes are being implemented to ensure the return of affected areas to previously existing environmental conditions or to a land use that will be sustainable in the long term and acceptable to all stakeholders.
This report provides a summary of the most relevant issues and practices in remediation programmes of uranium production facilities and an overview of activities and plans in reporting countries. It covers the areas of site characterisation, dismantling and decommissioning, waste management facilities, water remediation, long-term stewardship and monitoring, policies and regulations, and costs. The country profiles of remediation activities and plans include information considered to be important by the country and are based on survey responses provided by 22 countries (12 OECD and 10 non-OECD countries).
Confidence among both technical experts and the public in the safety of deep geologic repositories for radioactive waste is a key element in the successful development of the repositories. This report presents the approaches and arguments that are currently used in OECD countries to establish and communicate confidence in their safety. It evaluates the state of the art for obtaining, presenting and demonstrating confidence in long-term safety, and makes recommendations on future directions and initiatives to be taken for improving confidence.
It has been widely recognised among researchers that speciation data are essential for proper and reliable modelling of radionuclide behaviour, which is studied inter alia in the context of radioactive waste management. Participants at the OECD/NEA workshop on "Evaluation of Speciation Technology" reviewed the various techniques used to identify different species of actinide and fission product elements present in nuclear waste and nuclear reprocessing streams. The review takes into account the advantages, disadvantages and limitations of the various methods in relation to their field of application. Recommendations for future R&D are also provided. These proceedings will primarily be of interest to chemists specialised in separation techniques and radioactive waste management experts.
The OECD Nuclear Energy Agency (NEA) has actively participated in discussions with the International Commission on Radiological Protection (ICRP) regarding the development of new recommendations that will replace those in ICRP Publication 60, which has long served as the international standard in this field. Part of this development process has involved the organisation of seven international workshops, including the First and Second Asian Regional Conferences on the Evolution of the System of Radiological Protection which took place in Tokyo, Japan in October 2002 and July 2004. The Third Asian Regional Conference was held on 5-6 July 2006, also in Tokyo. These proceedings summarise the results and key discussions of the Third Asian Regional Conference.
One of the main challenges facing radiological protection experts is how to integrate radiological protection within modern concepts of and approaches to risk governance. It is within this context that the International Commission on Radiological Protection (ICRP) decided to develop new general recommendations to replace its Publication 60 recommendations of 1990. In the process of developing these new recommendations, the views of the ICRP have evolved significantly, largely due to stakeholder involvement that has been actively solicited by the ICRP. In this regard, it was upheld during the First Asian Regional Conference organised by the NEA in October 2002 that the implementation of the new system must allow for regional, societal and cultural differences.
In order to ensure appropriate consideration of these differences, the NEA organised the Second Asian Regional Conference on the Evolution of the System of Radiological Protection. Held in Tokyo on 28-29 July 2004, the conference included presentations by the ICRP Chair as well as by radiological experts from Australia, China, Japan and Korea. Within their specific cultural and socio-political milieu, Asia-Pacific and western ways of thought on how to improve the current system of radiological protection were presented and discussed. These ways of thinking, along with a summary of the conference results, are described in these proceedings.
The NEA has a long tradition of expertise in the area of nuclear emergency policy, planning, preparedness and management. Through its activities in this field, it offers member countries unbiased assistance on nuclear preparedness matters, with a view to facilitating improvements in nuclear emergency preparedness strategies and response at the international level. A central approach to this has been the preparation and conduct of the International Nuclear Emergency Exercise (INEX) series.
The Fifth International Nuclear Emergency Exercise (INEX-5) was developed specifically in response to member countries’ desire to test and demonstrate the value of changes put in place following the Fukushima Daiichi nuclear power plant accident. Exercise objectives focused on notification, communication and interfaces related to catastrophic events involving ionising radiation and/or radioactive material. The exercise was held during 2015 and 2016, with 22 countries participating in the exercise.
This report summarises the major evaluation outcomes of the national and regional exercises, policy level outcomes, recommendations and follow-up activities emerging from INEX-5 and the discussions at the INEX-5 International Workshop. A set of key needs were identified in areas such as real-time communication and information sharing among countries and international partners, improving crossborder and international co-ordination of protective measures and considering the mental health impacts on populations when implementing protective measures.
This report aims to highlight the needs of integral experiments in the field of nuclear criticality safety, and to identify the available experimental facilities where such experiments could be performed.
In order to identify existing experimental needs, the NEA surveyed international nuclear criticality safety (NCS) practitioners and members of the Working Party on Nuclear Criticality Safety (WPNCS). Responses were received from eight organisations and five countries (Canada, the Czech Republic, France, Japan and the United States); additional responses were also sent by four organisations in two countries (Switzerland and the United Kingdom).
The survey results were examined by the WPNCS Subgroup on Experimental Needs for Criticality Safety Purposes (SG-5), which ranked the 25 identified needs in terms of priority as well as describing these needs in detail. A dedicated section of the report describes the existing proprietary experiments that might be used to meet some of the identified needs. Another section highlights some of the many facilities available to perform some of the prioritised criticality experiments.