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Radiological characterisation is a key enabling activity for the planning and implementation of nuclear facility decommissioning. Effective characterisation allows the extent, location and nature of contamination to be determined and provides crucial information for facility dismantling, the management of material and waste arisings, the protection of workers, the public and the environment, and associated cost estimations.
This report will be useful for characterisation practitioners who carry out tactical planning, preparation, optimisation and implementation of characterisation to support the decommissioning of nuclear facilities and the management of associated materials and waste. It compiles recent experience from NEA member countries in radiological characterisation, including from international experts, international case studies, an international conference, and international standards and guidance. Using this comprehensive evidence base, the report identifies relevant good practice and provides practical advice covering all stages of the characterisation process.
Activities carried out over the last three decades in relation to core-concrete interactions and melt coolability, as well as related containment failure modes, have significantly increased the level of understanding in this area. In a severe accident with little or no cooling of the reactor core, the residual decay heat in the fuel can cause the core materials to melt. One of the challenges in such cases is to determine the consequences of molten core materials causing a failure of the reactor pressure vessel. Molten corium will interact, for example, with structural concrete below the vessel. The reaction between corium and concrete, commonly referred to as MCCI (molten core concrete interaction), can be extensive and can release combustible gases. The cooling behaviour of ex-vessel melts through sprays or flooding is also complex. This report summarises the current state of the art on MCCI and melt coolability, and thus should be useful to specialists seeking to predict the consequences of severe accidents, to model developers for severe-accident computer codes and to designers of mitigation measures.
Large quantities of materials arising from the decommissioning of nuclear facilities are non-radioactive per se. An additional significant share of materials is of very low-level or low-level radioactivity and can, after having undergone treatment and a clearance process, be recycled and reused in a restricted or unrestricted way. Recycle and reuse options today provide valuable solutions to minimise radioactive waste from decommissioning and at the same time maximise the recovery of valuable materials. The NEA Co-operative Programme on Decommissioning (CPD) prepared this overview on the various approaches being undertaken by international and national organisations for the management of slightly contaminated material resulting from activities in the nuclear sector. The report draws on CPD member organisations’ experiences and practices related to recycling and reuse, which were gathered through an international survey. It provides information on improvements and changes in technologies, methodologies and regulations since the 1996 report on this subject, with the conclusions and recommendations taking into account 20 years of additional experience that will be useful for current and future practitioners. Case studies are provided to illustrate significant points of interest, for example in relation to scrap metals, concrete and soil.
The cost estimation process of decommissioning nuclear facilities has continued to evolve in recent years, with a general trend towards demonstrating greater levels of detail in the estimate and more explicit consideration of uncertainties, the latter of which may have an impact on decommissioning project costs. The 2012 report on the International Structure for Decommissioning Costing (ISDC) of Nuclear Installations, a joint recommendation by the Nuclear Energy Agency (NEA), the International Atomic Energy Agency (IAEA) and the European Commission, proposes a standardised structure of cost items for decommissioning projects that can be used either directly for the production of cost estimates or for mapping of cost items for benchmarking purposes. The ISDC, however, provides only limited guidance on the treatment of uncertainty when preparing cost estimates. Addressing Uncertainties in Cost Estimates for Decommissioning Nuclear Facilities, prepared jointly by the NEA and IAEA, is intended to complement the ISDC, assisting cost estimators and reviewers in systematically addressing uncertainties in decommissioning cost estimates. Based on experiences gained in participating countries and projects, the report describes how uncertainty and risks can be analysed and incorporated in decommissioning cost estimates, while presenting the outcomes in a transparent manner.
Large quantities of materials arising from the decommissioning of nuclear facilities are non-radioactive per se. An additional significant share of materials is of very low-level or low-level radioactivity and can, after having undergone treatment and a clearance process, be recycled and reused in a restricted or unrestricted way. Recycle and reuse options today provide valuable solutions to minimise radioactive waste from decommissioning and at the same time maximise the recovery of valuable materials. The NEA Co-operative Programme on Decommissioning (CPD) prepared this overview on the various approaches being undertaken by international and national organisations for the management of slightly contaminated material resulting from activities in the nuclear sector. The report draws on CPD member organisations’ experiences and practices related to recycling and reuse, which were gathered through an international survey. It provides information on improvements and changes in technologies, methodologies and regulations since the 1996 report on this subject, with the conclusions and recommendations taking into account 20 years of additional experience that will be useful for current and future practitioners. Case studies are provided to illustrate significant points of interest, for example in relation to scrap metals, concrete and soil.
The Fukushima Daiichi nuclear power plant accident has had an impact on the development of nuclear power around the world. While the accident was followed by thorough technical assessments of the safety of all operating nuclear power plants, and a general increase in safety requirements has been observed worldwide, national policy responses have been more varied. These responses have ranged from countries phasing out or accelerating decisions to phase out nuclear energy to countries reducing their reliance on nuclear power or on the contrary continuing to pursue or expand their nuclear power programmes.
This study examines changes to policies, and plans and attempts to distinguish the impact of the Fukushima Daiichi accident from other factors that have affected policymaking in relation to nuclear energy, in particular electricity market economics, financing challenges and competition from other sources (gas, coal and renewables). It also examines changes over time to long-term, quantitative country projections, which reveal interesting trends on the possible role of nuclear energy in future energy systems.
Communication has a specific role to play in the development of deep geological repositories. Building trust with the stakeholders involved in this process, particularly within the local community, is key for effective communication between the authorities and the public. There are also clear benefits to having technical experts hone their communication skills and having communication experts integrated into the development process. This report has compiled lessons from both failures and successes in communicating technical information to non-technical audiences. It addresses two key questions in particular: what is the experience base concerning the effectiveness or non-effectiveness of different tools for communicating safety case results to a non-technical audience and how can communication based on this experience be improved and included into a safety case development effort from the beginning?
Worldwide consensus exists within the international community that geological repositories can provide the necessary long-term safety and security to isolate long-lived radioactive waste from the human environment over long timescales. Such repositories are also feasible to construct using current technologies. However, proving the technical merits and safety of repositories, while satisfying societal and political requirements, has been a challenge in many countries.
Building upon the success of previous conferences held in Denver (1999), Stockholm (2003), Berne (2007) and Toronto (2012), the ICGR 2016 brought together high-level decision makers from regulatory and local government bodies, waste management organisations and public stakeholder communities to review current perspectives of geological repository development. This publication provides a synthesis of the 2016 conference on continued engagement and safe implementation of repositories, which was designed to promote information and experience sharing, particularly in the development of polices and regulatory frameworks. Repository safety, and the planning and implementation of repository programmes with societal involvement, as well as ongoing work within different international organisations, were also addressed at the conference.
Nuclear Energy Data is the Nuclear Energy Agency's annual compilation of statistics and country reports documenting nuclear power status in NEA member countries and in the OECD area. Information provided by governments includes statistics on installed generating capacity, total electricity produced by all sources and by nuclear power, nuclear energy policies and fuel cycle developments, as well as projections of nuclear generating capacity and electricity production to 2035, where available. Total electricity generation at nuclear power plants and the share of electricity production from nuclear power plants increased slightly in 2015, by 0.2% and 0.1%, respectively. Two new units were connected to the grid in 2015, in Russia and Korea; two reactors returned to operation in Japan under the new regulatory regime; and seven reactors were officially shut down – five in Japan, one in Germany and one in the United Kingdom. Governments committed to having nuclear power in the energy mix advanced plans for developing or increasing nuclear generating capacity, with the preparation of new build projects progressing in Finland, Hungary, Turkey and the United Kingdom. Further details on these and other developments are provided in the publication's numerous tables, graphs and country reports.
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