Results 1 - 10 of 167
Results 1 - 10 of 167. Search took: 0.023 seconds
|Sort by: date | relevance|
[en] These proceedings present the outcome of a conference on decommissioning and environmental remediation (D&ER) programmes, at which challenges, achievements and lessons learned in the implementation of such programmes during the past decade were shared and reviewed. The decision to combine D&ER in one conference reflects the significant synergies that exist between the two activities; the conference aimed to explore those synergies to foster and optimize the implementation of D&ER worldwide. Key goals were to raise awareness of the importance of addressing the legacies from past activities, to identify current priority needs and to provide recommendations on the strategies and approaches that can enable and enhance safe, secure and cost effective implementation of national and international programmes in the future. The conference was organized around seven themes: National policies and strategies; regulatory framework and standards; decision making process; technical and technological aspects; waste management; project management; and international cooperation. The publication provides a detailed synthesis of the presentations made and the panel discussions which took place during the conference. The main ideas and messages expressed and discussed at the conference are presented in the President’s report, which is included in the publication. This CD-ROM which is attached to the printed STI/PUB/1759, contains the book of abstracts, presentations and the list of participants.
[en] These proceedings present the outcome of a conference on decommissioning and environmental remediation (D&ER) programmes, at which challenges, achievements and lessons learned in the implementation of such programmes during the past decade were shared and reviewed. The decision to combine D&ER in one conference reflects the significant synergies that exist between the two activities; the conference aimed to explore those synergies to foster and optimize the implementation of D&ER worldwide. Key goals were to raise awareness of the importance of addressing the legacies from past activities, to identify current priority needs and to provide recommendations on the strategies and approaches that can enable and enhance safe, secure and cost effective implementation of national and international programmes in the future. The conference was organized around seven themes: National policies and strategies; regulatory framework and standards; decision making process; technical and technological aspects; waste management; project management; and international cooperation. The publication provides a detailed synthesis of the presentations made and the panel discussions which took place during the conference. The main ideas and messages expressed and discussed at the conference are presented in the President’s report, which is included in the publication.
[en] In the frame of this conference, it is important to bear in mind that decommissioning of nuclear facilities and environmental remediation of contaminated sites represent a considerable challenge for many countries around the world. Implementing these activities requires an integration of a variety of different aspects, including project management, use of appropriate technology, ensuring safety of people and the environment, management of waste and other residual material and facilitating societal engagement in decision making (the Conference will give special attention to this issue). Decommissioning and environmental remediation are both concerned with ensuring that facilities and sites where nuclear and radioactive materials have been produced, used or stored do not present a future safety risk to humans or the environment, and generally are made available for alternative productive uses. Decommissioning is a normal part of the lifecycle of nuclear facilities, and needs to be considered from the design stage of the facility. Environmental remediation is concerned with existing exposure from past practices; but the ultimate objective is the same and advanced planning is also very important. It is important to recognize that, without showing an ability to take care of existing liabilities; it will be difficult to demonstrate the sustainability of nuclear technologies and thereby achieve public confidence and acceptance for new nuclear build. In addition to the technical and safety aspects of decommissioning and environmental remediation, there is also an important ethical dimension: generations taking benefit from the use of nuclear technologies have to do their best to solve the issues related to the back end (such as decommissioning, remediation and management of resulting waste), avoid the transfer of undue burdens to future generations. This conference is the first IAEA conference presenting together both decommissioning and environmental remediation. In 2002 and 2006, Berlin and Athens hosted IAEA International Conferences on decommissioning; and in 1999 and 2009, Arlington and Astana hosted the IAEA International Symposium and Conference, respectively, on environmental remediation. IAEA hosted an International Experts Meeting on decommissioning and remediation after a nuclear accident in Vienna in 2013. Over the course of this timespan, significant developments have taken place and therefore it is timely to discuss the implications for national programmes and to exchange recent experiences in the global implementation of decommissioning and environmental remediation and to propose actions on advancing the implementation of programmes and on how current challenges may best be addressed.
[en] Nuclear activities have been undertaken on a significant scale since the Second Word War, initially associated with the production of atomic weapons, and then, from the 1950s, also involving facilities for the production of electricity and numerous other activities undertaken for civilian purposes. At that time little attention was paid to how these facilities should eventually be dismantled, nor how sites contaminated because of uranium mining, weapons testing, accidental releases and indeed due to practices involving substantial amounts of naturally occurring radioactive material, should be remediated. The last two decades have witnessed growing efforts to deal with these liabilities, particularly in States with nuclear power programmes. It is now common practice that initial plans for the decommissioning of licensed nuclear facilities, and associated cost estimates, are developed as part of the initial licensing process, recognizing that this is normal step in the facility lifecycle. Similar considerations of the entire lifecycle of facilities are generally currently applied at the development stage for new uranium mines. This evolution has occurred for several different reasons, including increasing interest and also pressure from society that principles of environmental sustainability are applied to all industrial activities, e.g. in line with the sustainable development agenda of the United Nations. This suggests, among other things, that sites hosting retired facilities should be made safe and be made available for other social and economic uses. This issue has strong ethical dimensions: the generations which gained benefit from the use of nuclear energy should, where reasonably practicable, not pass the burden of addressing the associated legacies to future generations. The very large level of participation at this conference, which has been attended by 540 persons representing 54 countries and four international organizations, provides strong evidence of current levels of awareness and interest among Member States, relevant organizations and people on the need to provide safe, environmentally sound and cost effective solutions for implementing decommissioning and environmental remediation programmes worldwide.
[en] Nuclear power plants usually have a typical design life of 40 years which can be extended up to 60 years. At the end of their operating life-times, they need to be decommissioned to ensure the safety. The design and operational management of early nuclear power plants were given inadequate consideration for the decommissioning resulted in difficulty in dismantling reactor, large amounts of waste, and high costs when implementing decommissioning. Decommissioning has become an important issue that has hindered the development of nuclear power. Safety analysis report is a major technical document reviewed by regulatory authority, and therefore should include the relevant content on facilitating decommissioning. China National Nuclear Safety Administration has asked the operator to prepare an independent chapter (Chapter 20) for describing design features and operational measures to facilitate decommissioning in safety analysis report for nuclear power plants in 2013. This paper introduces the format and content of the newly developed Chapter 20 of the safety analysis reports for academic exchanges.
[en] The Nuclear Energy Commission (NEC) nationally coordinates the activities related to the use of radioactive minerals and nuclear energy, implementing of nuclear technology, developing and researching of nuclear technology, ensuring of nuclear and radiation protection and safety. The NEC is currently working on national policies and regulations related to the decommissioning and remediation of the legacy sites. Mineral Resources Authority of Mongolia (MRAM) issues, suspends and cancels the licenses for radioactive minerals’ exploration and mining. General Agency for Specialized Inspection (GASI) regulates the activities related to the use of radioactive minerals and nuclear energy, implementing of nuclear technology, ensuring of nuclear and radiation protection and safety and responsible to make correction of the revealed irregularities. GASI issues permits and approvals and also responsible inspections for sub provinces and major entities in Ulaanbaatar. GASI admits Nuclear and Radiation Regulatory Authority (NRRA) to its structure. NRRA has divisions of Nuclear Inspection and Radiation Inspection. GASI administrates Metropolitan Inspection Agency (MIA). MIA admits Nuclear and Radiation Regulatory Division (NRRD) to its structure. MIA responsible inspection focused in Ulaanbaatar. Ministry of Environment, Green Development and Tourism of Mongolia reviews and approves Environmental Impact assessment. Laws of Mongolia on environmental protection, water, environmental impact assessment and other regulations (including Basic Regulation on Radiation Protection and Safety (2015), Regulation on Management of Radioactive Waste from Mining and Milling of Ores (2015) etc.) are effective.
[en] After having operated numerous nuclear facilities since the 1950s, the CEA (French Atomic and Alternative Energies Commission) must now manage the dismantling of those which have reached the end of their lifetime. These high priority actions have led to the creation of an R&D dismantling division which aims at providing innovative tools, including intervention scenario simulation. Simulation is a good means of visualizing highly radioactive environments where humans cannot enter, of testing different technical alternatives, and of training workers prior to interventions. For a few years, the CEA has developed a generic simulation platform based on virtual reality (VR) technologies, usable on any decommissioning project. On this platform, different kinds of simulation can be run: physics, kinematics, virtual human simulation and dose-rate calculation. All these modules are embedded in a software called iDROP, taking into account the whole aspects involved in nuclear operations in a single simulation. This paper describes the different application cases where VR simulation has been used to design dismantling operations, presents the lessons learnt from these different implementations.
[en] The Magnox Swarf Storage Silos (MSSS) has been used to hold intermediate level waste primarily from Magnox fuel decanning, for decades. The aging facility poses an intolerable environmental hazard and the waste within needs to be retrieved to allow decommissioning of the facility. The previous strategic approach led to complex engineering solutions and a perception of potentially significant consequences from hydrogen or ignition events from the presence of reactive materials within the waste. The main issues affecting retrieval of the waste are centred on limited understanding of both the current composition of the waste and the behaviours likely to be exhibited during retrievals and processing. The two main risks considered within the reactive materials work were: - Generation and evolution of hydrogen gas; - Presence of self-igniting (pyrophoric) materials leading to waste fire. A combination of broad research and empirical experiments has led to improved understanding of the corrosion processes in MSSS. A more accurate picture of the waste inventory at retrieval has been developed, as well as a more realistic basis for waste behaviour during retrieval and downstream processing. The research and development focused initially on the corrosion mechanisms of uranium and magnesium; this was used to model the waste tipping, storage and planned retrievals. The predicted waste container payloads are now expected to present a significantly lower hydrogen and pyrophoric challenge than the previously assumed basis. Investigations into the reactivity of the more hazardous components, such as uranium hydride, which might cause problems for safety and engineering followed. Technical specialists carried out assessments on the formation, survival and reactivity of these reactive materials in order to evaluate the pessimisms constraining the design process, and to identify opportunities to reduce these restrictions.
[en] AECOM is an international leading provider of fully integrated engineering, construction, programme management, operations, nuclear decommissioning, waste management and technical services to public and private clients. AECOM, through its dedicated strategic business unit “Nuclear & Environment” has been managing the operations and clean-up of high hazard, complex nuclear sites for over 30 years - this has included the decommissioning of 20 reactors, cleanup of 1,290 waste sites and the operation of the only licensed deep geological repository in the world. This paper draws on the vast experience we’ve gained over 150 “site-years” of managing complex, high hazard sites. After a brief description of AECOM, the paper highlights some of our major representative projects involving decommissioning of production and commercial reactors as well as nuclear fuel cycle facilities, clean-up and remediation of nuclear and hazardous sites, and waste management. A wide range of challenges, either common or unique to the sites, generated by routine operations, off-normal events or accident situations, has allowed AECOM to accumulate a wealth of lessons learned. A summary of these are in the final part of the paper under the theme Experience Leads to Improved Performance.
[en] Based on the design, the cooling pond (CP) is a source of technical water intake for the Chernobyl NPP needs. The CP was constructed by creating an artificial embanking dam at floodplain area of Prypiat River. The CP water volume is designed for cooling of four ChNPP Units in the electrical power generation mode. At the stage of decommissioning this object is redundant and subject to decommissioning. As of today there is no necessity of the Plant in such “technological object” as a cooling pond. Works on the level lowering in the CP can be commenced after constructing the dams at inlet and outlet channels. As a result of the beyond-design-basis accident at the ChNPP in 1986, radioactive aerosols and dispersed fuel particles from the destroyed reactor were deposited onto the CP surface, and contaminated waters from the Plant’s technical supply systems were discharged. Due to the level lowering in the cooling pond, the SSE ChNPP administration fulfilled organizational and technical activities on radiation protection. The results of the conducted radiation monitoring show the absence of negative impact of the cooling pond slopes’ drying process on the radiation situation in a case of possible further lowering of the water level.