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Sample records for accident management measures

  1. Effectiveness of selected accident management measures

    The spectrum of application of accident management measures and the boundary conditions for their performance are discussed. An assessment is made of the feasibility and effectiveness of selected possibilities of intervention for both types of light water reactors. Detailed descriptions are given of accident management measures (bleed and feed) on the secondary and on the primary side. Investigations have revealed that West German light water reactors have a great safety potential by flexible applicaton of the existing systems for controlling events which exceed the design basis. (orig./HP)

  2. Severe Accident Management Measures Introduced in Belgian NPP's

    In response to the Belgian Safety Authorities' request to address the severe accident issue within a decennial safety review, Tractebel, on behalf of the Belgian Utility, Electrabel, examined in detail specific severe accident topics and provided the Utility with several measures that could be implemented to reduce the risk associated with beyond-design accidents. The present paper summarizes the key elements of the approach applied in Belgium: - Presentation of plant-specific studies related to severe accident issues; - Use of PSA results; - Inputs of international R and D projects; - Selection and justification of severe accident measures; - Comparative study between possible mitigative measures; - Definition and justification of implemented severe accident management strategies. The vulnerability to severe accidents as well as the potential causes of containment failures have been identified leading to the study of possible countermeasures taking into account the combination of conservative design and post-TMI measures already implemented . A section of the paper will also be devoted to the specific study made for the selection, the sizing and the implementation of hydrogen control means. After the description of the selected measures implemented, the paper also describes the content of the 'Severe Accident Management Guidelines' developed by Tractebel for the Tihange NPPs and for the Doel NPPs. This project aimed at providing the operators with procedures or guidelines enabling to deal with complex situations not formally considered in the standard Emergency Response Guidelines, including accidents in which a significant portion of the core melts. The objective of these SAMG's programs is to indicate actions that must bring the plant to a controlled stable state and, above all, mitigate any challenges to the fission product barriers. The plant personnel must use the available plant information to determine the best severe accident management measures. Obviously

  3. Investigation on accident management measures for VVER-1000 reactors

    A consequence of a total loss of AC power supply (station blackout) leading to unavailability of major active safety systems which could not perform their safety functions is that the safety criteria ensuring a secure operation of the nuclear power plant would be violated and a consequent core heat-up with possible core degradation would occur. Currently, a study which examines the thermal-hydraulic behaviour of the plant during the early phase of the scenario is being performed. This paper focuses on the possibilities for delay or mitigation of the accident sequence to progress into a severe one by applying Accident Management Measures (AMM). The strategy 'Primary circuit depressurization' as a basic strategy, which is realized in the management of severe accidents is being investigated. By reducing the load over the vessel under severe accident conditions, prerequisites for maintaining the integrity of the primary circuit are being created. The time-margins for operators' intervention as key issues are being also assessed. The task is accomplished by applying the GRS thermal-hydraulic system code ATHLET. In addition, a comparative analysis of the accident progression for a station blackout event for both a reference German PWR and a reference VVER-1000, taking into account the plant specifics, is being performed. (authors)

  4. Implementation of severe accident management measures - Summary and conclusions

    The objectives of the meeting were: 1) to exchange information on activities in the area of SAM implementation and on the rationale for such actions, 2) to monitor progress made, 3) to identify cases of agreement or disagreement, 4) to discuss future orientations of work, 5) to make recommendations to the CSNI. Session summaries prepared by the Chairpersons and discussed by the whole writing group are given in Annex. During the first session, 'SAM Programmes Implementation', papers from one regulator and several utilities and national research institutes were presented to outline the status of implementation of SAM programmes in countries like Switzerland, Russia, Spain, Finland, Belgium and Korea. Also, the contribution of SAM to the safety of Japanese plants (in terms of core damage frequency) was quantified in a paper. One paper gave an overview on the situation regarding SAM implementation in Europe. The second session, 'SAM Approach', provided background and bases for Severe Accident Management in countries like Sweden, Japan, Germany and Switzerland, as well as for hardware features in advanced light water reactor designs, such as the European Pressurised Reactor (EPR), regarding Severe Accident Management. The third session, 'SAM Mitigation Measures', was about hardware measures, in particular those oriented towards hydrogen mitigation where fundamentally different approaches have been taken in Scandinavian countries, France, Germany and Korea. Three papers addressed specific contributions from research to provide a broader basis for the assumptions made in certain computer codes used for the assessment of plant risk arising from beyond-design accident sequences. The fourth session, 'Implementation of SAM Measures on VVER-1000 Reactors', was about the status of work on Severe Accident Management implementation in VVER reactors of existing design and in a new plant currently under construction. The overall picture is that Severe Accident Management has been

  5. EC-sponsored research activities on accident management measures

    The European Commission (EC) is currently funding, via the 1994-1998 R and D Framework Programme, a number of activities in the field of Nuclear Fission Safety (NFS), and particularly in several areas related to 'Reactor Safety Severe Accidents'. This programme continues the research activities of the previous Community Reactor Safety Programme which was carried out as a Reinforced Concerted Action (RCA) during the period 1992-1995. The group of multi-partners projects selected for financial support from the EC under Area B.5.1 of the current NFS Programme, 'Supporting Activities / Accident Management Measures' (known as the 'AMM' cluster) are basically aiming at implementing the results of severe accident research into practical Accident Management (AM) strategies. The generic objective is to exchange information and to develop a common European approach regarding aspects such as phenomena related uncertainties, possible adverse effects of operator actions on the progression of the accident, interpretation of measurements, equipment performance, instrument survival and human error under stress. This paper briefly discusses the objectives and achievements of a completed project of the 1992-1995 RCA, known as 'Accident Management Support' ('AMS'), and also presents the current status of an on-going project of the 1994-1998 NFS Programme, 'Algorithm support for accident identification and Critical safety Functions signal validation' ('ASIA'). The objectives of the 'AMS' project were (i) to define, investigate and develop means and methods to provide reliable information and diagnostics, as well as support tools for accident management, and (ii) investigate the different signal validation methodologies with emphasis on the existing instrumentation rather than on new instrumentation needs. The work started with the writing of two state-of-the-art reports (SOARs) in these two areas. In parallel to the compilation of the SOARs, and later in a second phase, specific

  6. Experimental and analytical verification of accident management measures

    Two complementary test facilities - the Upper Plenum Test Facility and the ''Primaerkreislauf'' test facility were constructed to investigate the thermal hydraulic response of a pressurized water reactor during postulated accidents. The general objective of the experimental programs is to contribute to a better understanding of accident sequences and to provide a detailed data base for the validation of computer codes, i.e. ATHLET and RELAP, the latter being used by Siemens/KWU for reactor safety analyses. A major target of the recent experimental programs has been the verification of accident management procedures, such as secondary and/or primary side bleed-and-feed. The experimental results demonstrate that secondary side bleed-and-feed is a very effective method for removing decay heat without contaminating the containment. Primary side bleed-and-feed was also shown to be a highly effective measure to ensure core cooling under beyond-design-basis conditions. This publication presents results from experiments at the Upper Plenum Test Facility and the ''Primaerkreislauf'' test facility as well as from corresponding RELAP 5/Mod 2 analyses. (orig.)

  7. Modeling and measuring the effects of imprecision in accident management

    This paper presents two approaches for evaluating the uncertainties inherent in accident management strategies. Current PRA methodology uses expert opinion in the assessment of rare event probabilities. The problem is that these probabilities may be difficult to estimate even though reasonable engineering judgement is applied. This occurs because expert opinion under incomplete knowledge and limited data is inherently imprecise. In this case, the concept of uncertainty about a probability value is both intuitively appealing and potentially useful. This analysis considers accident management as a decision problem (i.e. 'applying a strategy' vs. 'do nothing') and uses an influence diagram. Then, the analysis applies two approaches to evaluating imprecise node probabilities in the influence diagram: 'a fuzzy probability' and 'an interval-valued subjective probability'. For the propagation of subjective probabilities, the analysis uses a Monte-Carlo simulation approach. In case of fuzzy probabilities, fuzzy logic is applied to propagate them. We believe that these approaches can allow us to better understand uncertainties associated with severe accident management strategies, because they provide additional information regarding the implications of using imprecise input data

  8. Management of severe accidents

    The definition and the multidimensionality aspects of accident management have been reviewed. The suggested elements in the development of a programme for severe accident management have been identified and discussed. The strategies concentrate on the two tiered approaches. Operative management utilizes the plant's equipment and operators capabilities. The recovery managment concevtrates on preserving the containment, or delaying its failure, inhibiting the release, and on strategies once there has been a release. The inspiration for this paper was an excellent overview report on perspectives on managing severe accidents in commercial nuclear power plants and extending plant operating procedures into the severe accident regime; and by the most recent publication of the International Nuclear Safety Advisory Group (INSAG) considering the question of risk reduction and source term reduction through accident prevention, management and mitigation. The latter document concludes that 'active development of accident management measures by plant personnel can lead to very large reductions in source terms and risk', and goes further in considering and formulating the key issue: 'The most fruitful path to follow in reducing risk even further is through the planning of accident management.' (author)

  9. Accident management information needs

    In support of the US Nuclear Regulatory Commission (NRC) Accident Management Research Program, a methodology has been developed for identifying the plant information needs necessary for personnel involved in the management of an accident to diagnose that an accident is in progress, select and implement strategies to prevent or mitigate the accident, and monitor the effectiveness of these strategies. This report describes the methodology and presents an application of this methodology to a Pressurized Water Reactor (PWR) with a large dry containment. A risk-important severe accident sequence for a PWR is used to examine the capability of the existing measurements to supply the necessary information. The method includes an assessment of the effects of the sequence on the measurement availability including the effects of environmental conditions. The information needs and capabilities identified using this approach are also intended to form the basis for more comprehensive information needs assessment performed during the analyses and development of specific strategies for use in accident management prevention and mitigation. 3 refs., 16 figs., 7 tabs

  10. Accident management measures. Demand for action as seen by the supervising authority

    The various measures taken for accident management in the plant are to be classified into categories of nuclear law, as there are: prevention of hazards, prevention of risks, or non-preventive measures ( management of remaining risk). Screening the various measures for classification shows that most of them belong to the category of preventive action under the Atomic Energy Act. This means that these measures have to be addressed in KTA safety standards. (orig./HP)

  11. SEVERE ACCIDENT MANAGEMENT TRAINING

    The purpose of this paper is (a) to define the International Atomic Energy Agency's role in the area of severe accident management training, (b) to briefly describe the status of representative severe accident analysis tools designed to support development and validation of accident management guidelines, and more recently, simulate the accident with sufficient accuracy to support the training of technical support and reactor operator staff, and (c) provide an overview of representative design-specific accident management guidelines and training. Since accident management and the development of accident management validation and training software is a rapidly evolving area, this paper is also intended to evolve as accident management guidelines and training programs are developed to meet different reactor design requirements and individual national requirements

  12. Measures against nuclear accidents

    A select committee appointed by the Norwegian Ministry of Social Affairs put forward proposals concerning measures for the improvement of radiation protection preparedness in Norway. On the basis on an assessment of the potential radiation accident threat, the report examines the process of response, and identifies the organizational and management factors that influence that process

  13. Framework for accident management

    Accident management is an essential element of the Nuclear Regulatory Commission (NRC) Integration Plan for the closure of severe accident issues. This element will consolidate the results from other key elements; such as the Individual Plant Examination (IPE), the Containment Performance Improvement, and the Severe Accident Research Programs, in a form that can be used to enhance the safety programs for nuclear power plants. The NRC is currently conducting an Accident Management Program that is intended to aid in defining the scope and attributes of an accident management program for nuclear power plants. The accident management plan will ensure that a plant specific program is developed and implemented to promote the most effective use of available utility resources (people and hardware) to prevent and mitigate severe accidents. Hardware changes or other plant modifications to reduce the frequency of severe accidents are not a central aim of this program. To accomplish the outlined objectives, the NRC has developed an accident management framework that is comprised of five elements: (1) accident management strategies, (2) training, (3) guidance and computational aids, (4) instrumentation, and (5) delineation of decision making responsibilities. A process for the development of an accident management program has been identified using these NRC framework elements

  14. Framework for accident management

    A program is being conducted to establish those attributes of a severe accident management plan which are necessary to assure effective response to all credible severe accidents and to develop guidance for their incorporation in a plant's Accident Management Plan. This program is one part of the Accident Management Research Program being conducted by the U. S. Nuclear Regulatory Commission (NRC). The approach used in establishing attributes and developing guidance includes three steps. In the first step the general attributes of an accident management plan were identified based on: (1) the objectives established for the NRC accident management program, (2) the elements of an accident management framework identified by the NRC, and (3) a review of the processes used in developing the currently used approach for classifying and analyzing accidents. For the second step, a process was defined that uses the general attributes identified from the first step to develop an accident management plan. The third step applied the process defined in the second step at a nuclear power plant to refine and develop it into a benchmark accident management plan. Step one is completed, step two is underway and step three has not yet begun

  15. Analysis simulator, a tool for the evaluation of accident management measures

    The analysis simulator is a manifold and variable engineered tool which permits the interactive handling of very comprehensive model codes and offers the wealth of information calculated by the models in a condensed and uncluttered way by means of graphic displays. The first phase of work on the simulator concentrated on the development of interfaces, interactivity and communication. The experience gathered so far and the case study, in which an accident management measure is taken to prevent a severe accident, show both the advantages of the analysis simulator and its limitations as far as the speed of simulation, its sturdiness and the extent of the models are concerned. The continuation of work on the analysis simulator and the test control room will further extend these limits in order to fully comply with the requirements for the simulation of measures oriented towards certain aims of protection. (orig.)

  16. Proceedings of the workshop on the implementation of severe accident management measures

    The OECD/NEA Workshop on the Implementation of Severe Accident Management (SAM) Measures was hosted by the PSI (Paul Schemer Institut), by two Swiss Utilities (Kernkraftwerk Beznau and Kernkraftwerk Leibstadt), and by Electricite de France. Eighty specialists from fourteen OECD Member countries attended the meeting, as well as specialists from three non-Member economies and the European Commission. Thirty-three papers were presented in four sessions, preceded by a brief Introductory Session (two invited papers) and followed by a General Discussion. The objectives of the meeting were: 1) to exchange information on activities in the area of SAM implementation and on the rationale for such actions, 2) to monitor progress made, 3) to identify cases of agreement or disagreement, 4) to discuss future orientations of work, 5) to make recommendations to the CSNI. Session summaries prepared by the Chairpersons and discussed by the whole writing group are given in Annex. During the first session, 'SAM Programmes Implementation', papers from one regulator and several utilities and national research institutes were presented to outline the status of implementation of SAM programmes in countries like Switzerland, Russia, Spain, Finland, Belgium and Korea. Also, the contribution of SAM to the safety of Japanese plants (in terms of core damage frequency) was quantified in a paper. One paper gave an overview on the situation regarding SAM implementation in Europe. The second session, 'SAM Approach', provided background and bases for Severe Accident Management in countries like Sweden, Japan, Germany and Switzerland, as well as for hardware features in advanced light water reactor designs, such as the European Pressurised Reactor (EPR), regarding Severe Accident Management. The third session, 'SAM Mitigation Measures', was about hardware measures, in particular those oriented towards hydrogen mitigation where fundamentally different approaches have been taken in Scandinavian

  17. The management of accidents

    R. B. Ward

    2009-01-01

    Full Text Available Purpose: This author’s experiences in investigating well over a hundred accident occurrences has led to questioning how such events can be managed - - - while immediately recognising that the idea of managing accidents is an oxymoron, we don’t want to manage them, we don’t want not to manage them, what we desire is not to have to manage not-them, that is, manage matters so they don’t happen and then we don’t have to manage the consequences.Design/methodology/approach: The research will begin by defining some common classes of accidents in manufacturing industry, with examples taken from cases investigated, and by working backwards (too late, of course show how those involved could have managed these sample events so they didn’t happen, finishing with the question whether any of that can be applied to other situations.Findings: As shown that the management actions needed to prevent accidents are control of design and application of technology, and control and integration of people.Research limitations/implications: This paper has shown in some of the examples provided, management actions have been know to lead to accidents being committed by others, lower in the organization.Originality/value: Today’s management activities involve, generally, the use of technology in many forms, varying from simple tools (such as knives to the use of heavy equipment, electric power, and explosives. Against these we commit, in control of those items, the comparatively frail human mind and body, which, again generally, does succeed in controlling these resources, with (another generality by appropriate management. However, sometimes the control slips and an accident occurs.

  18. Workshop proceedings of ISAMM 2009: Implementation of severe accident management measures

    This comprehensive report published by the Paul Scherrer Institute (PSI) in Switzerland reports on a conference and workshop held in Switzerland in October 2009 dealing with Severe Accidents Management (SAM) in nuclear power stations. The workshop provided an update on the status of severe accident management measures and their implications since the OECD/CSNI workshop held in 2001 at the PSI in Switzerland. Since the 2001 workshop, additional work has been performed to integrate emergency procedures and SAM measures into risk assessments in order to better reflect operator responses to recover a plant from a damaged state. The major focus of the workshop was to address SAM measures for both operational plants and new plant designs. Also, the integration of SAM measures into contemporary/future probabilistic risk assessments was discussed. 41 papers were presented in 8 sessions. The papers addressed the following areas: 1) Current status and insights of SAM (2 sessions); 2) Probabilistic Safety Assessment (PSA) modelling issues; 3) code analysis for supporting Serious Accident Management Guidance (SAMG, 2 sessions); 4) decision making, tools, training, risk-targets and entrance to SAM; 5) design modifications for implementation of SAM; 6) physical phenomena. The last part of the workshop was devoted to the presentation of the most striking highlights of the papers in the above areas, followed by two panellists giving presentations on human and organisational aspects of SAM, their importance in relation to technical issues and the effectiveness of current SAMG implementation. The question of how consequence analyses can be used to improve the effectiveness of SAM is discussed. The contributions were presented by representatives from Austria, Germany, Japan, France, the USA, Korea, Switzerland, Finland, Hungary, Belgium, Canada, Sweden, the Czech republic, the United kingdom, the Netherlands, Spain, Slovenia and Russia. The authors state that the overall picture

  19. Workshop proceedings of ISAMM 2009: Implementation of severe accident management measures

    Guentay, S. (ed.) [Paul Scherrer Institute (PSI), Nuclear Energy and Safety Research Department, Laboratory for Thermal Hydraulics, ViIligen (Switzerland)

    2010-10-15

    This comprehensive report published by the Paul Scherrer Institute (PSI) in Switzerland reports on a conference and workshop held in Switzerland in October 2009 dealing with Severe Accidents Management (SAM) in nuclear power stations. The workshop provided an update on the status of severe accident management measures and their implications since the OECD/CSNI workshop held in 2001 at the PSI in Switzerland. Since the 2001 workshop, additional work has been performed to integrate emergency procedures and SAM measures into risk assessments in order to better reflect operator responses to recover a plant from a damaged state. The major focus of the workshop was to address SAM measures for both operational plants and new plant designs. Also, the integration of SAM measures into contemporary/future probabilistic risk assessments was discussed. 41 papers were presented in 8 sessions. The papers addressed the following areas: 1) Current status and insights of SAM (2 sessions); 2) Probabilistic Safety Assessment (PSA) modelling issues; 3) code analysis for supporting Serious Accident Management Guidance (SAMG, 2 sessions); 4) decision making, tools, training, risk-targets and entrance to SAM; 5) design modifications for implementation of SAM; 6) physical phenomena. The last part of the workshop was devoted to the presentation of the most striking highlights of the papers in the above areas, followed by two panellists giving presentations on human and organisational aspects of SAM, their importance in relation to technical issues and the effectiveness of current SAMG implementation. The question of how consequence analyses can be used to improve the effectiveness of SAM is discussed. The contributions were presented by representatives from Austria, Germany, Japan, France, the USA, Korea, Switzerland, Finland, Hungary, Belgium, Canada, Sweden, the Czech republic, the United kingdom, the Netherlands, Spain, Slovenia and Russia. The authors state that the overall picture

  20. Accident and emergency management

    There is an increasing potential for severe accidents as the industrial development tends towards large, centralised production units. In several industries this has led to the formation of large organisations which are prepared for accidents fighting and for emergency management. The functioning of these organisations critically depends upon efficient decision making and exchange of information. This project is aimed at securing and possibly improving the functionality and efficiency of the accident and emergency management by verifying, demonstrating, and validating the possible use of advanced information technology in the organisations mentioned above. With the nuclear industry in focus the project consists of five main activities: 1) The study and detailed analysis of accident and emergency scenarios based on records from incidents and rills in nuclear installations. 2) Development of a conceptual understanding of accident and emergency management with emphasis on distributed decision making, information flow, and control structure sthat are involved. 3) Development of a general experimental methodology for evaluating the effects of different kinds of decision aids and forms of organisation for emergency management systems with distributed decision making. 4) Development and test of a prototype system for a limited part of an accident and emergency organisation to demonstrate the potential use of computer and communication systems, data-base and knowledge base technology, and applications of expert systems and methods used in artificial intelligence. 5) Production of guidelines for the introduction of advanced information technology in the organisations based on evaluation and validation of the prototype system. (author)

  1. Applicability of Phebus FP results to severe accident safety evaluations and management measures

    The international Phebus FP (Fission Product) programme is the largest research programme in the world investigating core degradation and radioactive product release should a core meltdown accident occur in a light water reactor plant. Three integral experiments have already been performed. The experimental database obtained so far contains a wealth of information to validate the computer codes used for safety and accident management assessment

  2. Opportunities for international cooperation in nuclear accident preparedness and management: Procedural and organizational measures

    In this paper we address a difficult problem: How can we create and maintain preparedness for nuclear accidents? Our research has shown that this can be broken down into two questions: (1) How can we maintain the resources and expertise necessary to manage an accident once it occurs? and (2) How can we develop plans that will help in actually managing an accident once it occurs? It is apparently beyond the means of ordinary human organizations to maintain the capability to respond to a rare event. (A rare event is defined as something like an accident that only happens once every five years or so, somewhere in the world.) Other more immediate pressures tend to capture the resources that should, in a cost/benefit sense, be devoted to maintaining the capability. This paper demonstrates that some of the important factors behind that phenomenon can be mitigated by an international body that promotes and enforces preparedness. Therefore this problem provides a unique opportunity for international cooperation: an international organization promoting and enforcing preparedness could help save us from our own organizational failings. Developing useful accident management plans can be viewed as a human performance problem. It can be restated: how can we support and off-load the accident managers so that their tasks are more feasible? This question reveals the decision analytic perspective of this paper. That is, we look at the problem managing a nuclear accident by focusing on the decision makers, the accident managers: how do we create a decision frame for the accident managers to best help them manage? The decision frame is outlined and discussed. 9 refs

  3. The vver severe accident management

    The basic approach to the VVER safety management is based on the defence-in-depth principle the main idea of which is the multiplicity of physical barriers on the way of dangerous propagation on the one hand and the diversity of measures to protect each of them on the other hand. The main events of severe accident with loss of core cooling at NPP with WWER can be represented as a sequence of NPP states, in which each subsequent state is more severe than the previous one. The following sequence of states of the accident progression is supposed to be realistic and the most probable: -) loss of efficient core cooling; -) core melting, relocation of the molten core to the lower head and molten pool formation, -) reactor vessel damage, and -) containment damage and fission products release. The objectives of accident management at the design basis stage, the determining factors and appropriate determining parameters of processes are formulated in this paper. The same approach is used for the estimation of processes parameters at beyond design basis accident progression. The accident management goals and the determining factors and parameters are also listed in that case which is characterized by the loss of integrity of the fuel cladding. The accident management goal at the stage of core melt relocation implies the need for an efficient core-catcher

  4. European Union research in safety of LWRs with emphasis on accident management measures

    On April 26th 1994 the European Union (EU) adopted via a Council Decision a multiannual programme for community activities in the field of nuclear research and training for the period 1994 to 1998. This programme continued the EU research activities of the 1992-1995 Reactor Safety Programme which was carried out as a Reinforced Concerted Action (RCA), and which covered mainly research activities in the area of severe accident phenomena, both for the existing and next-generation light water reactors. The 1994-1998 Framework programme includes activities regarding Research and Technological Development (R and TD), such as demonstration projects, international cooperation, dissemination and optimization of results, as well as training, in a wide range of scientific fields, including nuclear fission safety and controlled thermonuclear fusion. The 1994-1998 specific programme for nuclear fission safety has five main activity areas: (i) Exploring Innovative Approaches, (ii) Reactor Safety, (iii) Radioactive Waste Management, Disposal, and Decommissioning, (iv) Radiological Impact on Man and Environment, and (v) Mastering Events of the past. The specific topics included in this work programme were chosen in consultation with the EU Joint Research Centres (JRC), and with experts in the different fields taking into account the needs of the end users of the Community research, i.e. vendors, utilities and licensing and regulators authorities. This paper briefly discusses the objectives and achievements of the 1992-1995 RCA and also describes the projects being (or to be) implemented as part of the 1994-1995 programme in the areas of Reactor Safety/Severe Accidents, particularly those related to Accident Management (AM) Measures. In addition to this, some relevant projects related to AM which have been funded via independent PHARE/TACIS assistance programmes will also be mentioned

  5. Accident management insights after the Fukushima Daiichi NPP accident

    The Fukushima Daiichi nuclear power plant (NPP) accident, that took place on 11 March 2011, initiated a significant number of activities at the national and international levels to reassess the safety of existing NPPs, evaluate the sufficiency of technical means and administrative measures available for emergency response, and develop recommendations for increasing the robustness of NPPs to withstand extreme external events and beyond design basis accidents. The OECD Nuclear Energy Agency (NEA) is working closely with its member and partner countries to examine the causes of the accident and to identify lessons learnt with a view to the appropriate follow-up actions to be taken by the nuclear safety community. Accident management is a priority area of work for the NEA to address lessons being learnt from the accident at the Fukushima Daiichi NPP following the recommendations of Committee on Nuclear Regulatory Activities (CNRA), Committee on the Safety of Nuclear Installations (CSNI), and Committee on Radiation Protection and Public Health (CRPPH). Considering the importance of these issues, the CNRA authorised the formation of a task group on accident management (TGAM) in June 2012 to review the regulatory framework for accident management following the Fukushima Daiichi NPP accident. The task group was requested to assess the NEA member countries needs and challenges in light of the accident from a regulatory point of view. The general objectives of the TGAM review were to consider: - enhancements of on-site accident management procedures and guidelines based on lessons learnt from the Fukushima Daiichi NPP accident; - decision-making and guiding principles in emergency situations; - guidance for instrumentation, equipment and supplies for addressing long-term aspects of accident management; - guidance and implementation when taking extreme measures for accident management. The report is built on the existing bases for capabilities to respond to design basis

  6. Assessment of accident management measures on early in-vessel station blackout sequence at VVER-1000 pressurized water reactors

    Tusheva, P., E-mail: p.tusheva@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Reactor Safety Division, POB 51 01 19, 01314 Dresden (Germany); Schäfer, F., E-mail: f.schaefer@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Reactor Safety Division, POB 51 01 19, 01314 Dresden (Germany); Reinke, N., E-mail: nils.reinke@grs.de [Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH, Schwertnergasse 1, 50667 Cologne (Germany); Kamenov, Al., E-mail: alkamenov@npp.bg [Kozloduy NPP Plc., 3321 Kozloduy (Bulgaria); Mladenov, I., E-mail: ivanmladenov@abv.bg [Kozloduy NPP Plc., 3321 Kozloduy (Bulgaria); Kamenov, K., E-mail: k_kamenov@npp.bg [Kozloduy NPP Plc., 3321 Kozloduy (Bulgaria); Kliem, S., E-mail: s.kliem@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Reactor Safety Division, POB 51 01 19, 01314 Dresden (Germany)

    2014-10-01

    Highlights: • Accident management procedures for a station blackout scenario are investigated. • Secondary and primary side countermeasures are compared. • In-depth analyses of the plant behaviour and estimation of time margins. • Insights into the physical phenomena which can influence the passive feeding. • Assessment of the effectiveness of the applied bleed and feed procedures. - Abstract: In the process of elaboration and evaluation of severe accident management guidelines, the assessment of the accident management measures and procedures plays an important role. This paper investigates the early in-vessel phase accident progression of a hypothetical station blackout scenario for a generic VVER-1000 pressurized water reactor. The study focuses on the following accident management measures: primary side depressurization with passive safety systems injection, secondary side depressurization with passive feeding from the feedwater system, and a combination of the both procedures. The analyses have been done with the mechanistic computer code ATHLET. The simulations give in-depth analyses of the reactor system behaviour, assessment of the time margins till heating up of the reactor core and insights into physical phenomena which can influence the passive feeding procedures for cooling of the reactor core. The simulation results show that such accident management measures can significantly prolong the time till core degradation. Maximum delay for core heat up can be achieved by sequentially realization of the secondary and primary side bleed and feed strategies. Due to reversed heat transfer in the steam generators or caused by the depressurization itself a part of the injected water is evaporated. Evaporation or flashing in the feedwater system can lead to an intermittent water injection, thus reducing the effectiveness of the feeding procedure.

  7. Assessment of accident management measures on early in-vessel station blackout sequence at VVER-1000 pressurized water reactors

    Highlights: • Accident management procedures for a station blackout scenario are investigated. • Secondary and primary side countermeasures are compared. • In-depth analyses of the plant behaviour and estimation of time margins. • Insights into the physical phenomena which can influence the passive feeding. • Assessment of the effectiveness of the applied bleed and feed procedures. - Abstract: In the process of elaboration and evaluation of severe accident management guidelines, the assessment of the accident management measures and procedures plays an important role. This paper investigates the early in-vessel phase accident progression of a hypothetical station blackout scenario for a generic VVER-1000 pressurized water reactor. The study focuses on the following accident management measures: primary side depressurization with passive safety systems injection, secondary side depressurization with passive feeding from the feedwater system, and a combination of the both procedures. The analyses have been done with the mechanistic computer code ATHLET. The simulations give in-depth analyses of the reactor system behaviour, assessment of the time margins till heating up of the reactor core and insights into physical phenomena which can influence the passive feeding procedures for cooling of the reactor core. The simulation results show that such accident management measures can significantly prolong the time till core degradation. Maximum delay for core heat up can be achieved by sequentially realization of the secondary and primary side bleed and feed strategies. Due to reversed heat transfer in the steam generators or caused by the depressurization itself a part of the injected water is evaporated. Evaporation or flashing in the feedwater system can lead to an intermittent water injection, thus reducing the effectiveness of the feeding procedure

  8. Use of PSA and severe accident assessment results for the accident management

    The objectives for this study are to investigate the basic principle or methodology which is applicable to accident management, by using the results of PSA and severe accident research, and also facilitate the preparation of accidents management program in the future. This study was performed as follows: derivation of measures for core damage prevention, derivation of measures for accident mitigation, application of computerized tool to assess severe accident management

  9. Accident management approach in Armenia

    In this lecture the accident management approach in Armenian NPP (ANPP) Unit 2 is described. List of BDBAs had been developed by OKB Gydropress in 1994. 13 accident sequences were included in this list. The relevant analyses had been performed in VNIIAES and the 'Guidelines on operator actions for beyond design basis accident (BDBA) management at ANPP Unit 2' had been prepared. These instructions are discussed

  10. Accident management insights from IPE's

    In response to the U.S. Nuclear Regulatory Commission's Generic Letter 88-20, each utility in the U.S.A. has undertaken a probabilistic severe accident study of each plant. This paper provides a high level summary of the generic PWR accident management insights that have been obtained from the IPE reports. More importantly, the paper details some of the limitations of the IPE studies with respect to accident management. The IPE studies and the methodology used was designed to provide a best estimate of the potential for a severe accident and/or for severe consequences from a core damage accident. The accepted methodology employs a number of assumptions to make the objective attainable with a reasonable expenditure of resources. However, some of the assumptions represent limitations with respect to developing an accident management program based solely on the IPE and its results. (author)

  11. Computerised severe accident management aids

    The OECD Halden Reactor Project in Norway is running two development projects in the area of computerised accident management in cooperation with the Swedish nuclear plant Forsmark unit 2. Also other nuclear organisations in the Nordic countries take part in the projects. The SAS II system is installed at Forsmark and is now being validated against the plant compact simulator and is later to be installed in the plant control room. It is designed to follow all defined critical safety functions in the same manner as is done in the functionally oriented Emergency Operating Procedures. The shift supervisor thus uses SAS II as a complementary information system after a plant disturbance . The plant operators still use the ordinary instrumentation and the event oriented procedures. This gives to a high extent both redundancy and diversity in information channels and in procedures. Further, a new system is under discussion which goes a step further in accident management than SAS II. It is called the Computerised Accident Management Support (CAMS) system. The objective is to make a computerised tool that can assist both the control room crew and the technical support centre in accident mitigation, especially in the early stages of an accident where the integrity of the core still can be maintained if proper counteractions to the accident sequence are taken. In CAMS another approach is taken than in SAS II by putting the process parameters in focus. A more elaborate signal validation is proposed. The validated signals are input to models that calculates mass and energy balances of the primary system. Among parameters calculated are residual heat. Experiences from these two approaches to computerised accident management support are presented and discussed. In summary: The original project proposal aimed particularly for operator and TSC support during severe accidents. In the CAMS design proposal we have, however, promoted the SMABRE code which is not designed for such

  12. Radiation protection management in Fukushima Daiichi NPS and post-accident measures

    Fukushima Daiichi Nuclear Power Station was hit by the big earthquake and tsunami, which caused the station black out and subsequent loss of cooling functions for reactor and spent fuel pools (SFPs). Consequently the fuels were damaged, hydrogen explosion blew off top of the reactor buildings and radioactive materials were released to the atmosphere and the ocean. Tsunami and power loss caused many difficulties of monitoring, dose management, and radiation protection of workers. For example, the radiation management system was down and about 5,000 Alarm Pocket Dosimeters (APDs) and their battery chargers could not be used. Due to the insufficient number of APDs, one representative of each working team had a dosimeter under the limited conditions. Through the accident, we got following lessons learned; (1) Reinforcing monitoring posts, (2) Preparing more radiation protection equipment, (3) Establishing emergency access control centre, and (4) Education and training in radiation protection. (author)

  13. CAMS: Computerized Accident Management Support

    The OECD Halden Reactor Project has initiated a new research programme on computerised accident management support, the so-called CAMS project (CAMS = Computerized Accident Management Support). This work will investigate the possibilities for developing systems which provide more extensive support to the control room staff and technical support centre than the existing SPDS (Safety Parameter Display System) type of systems. The CAMS project will utilize available simulator codes and the capabilities of computerized tools to assist the plant staff during the various accident stages including: identification of the accident state, assessment of the future development of the accident, and planning accident mitigation strategies. This research programme aims at establishing a prototype system which can be used for experimental testing of the concept and serve as a tool for training and education in accident management. The CAMS prototype should provide support to the staff when the plant is in a normal state, in a disturbance sate, and in an accident state. Even though better support in an accident state is the main goal of the project, it is felt to be important that the staff is familiar with the use of the system during normal operation, when they utilize the system during transients

  14. Severe accident management. Prevention and Mitigation

    Effective planning for the management of severe accidents at nuclear power plants can produce both a reduction in the frequency of such accidents as well as the ability to mitigate their consequences if and when they should occur. This report provides an overview of accident management activities in OECD countries. It also presents the conclusions of a group of international experts regarding the development of accident management methods, the integration of accident management planning into reactor operations, and the benefits of accident management

  15. Accident management measures. Demand for action as seen by the supervising authority; Massnahmen des anlageninternen Notfallschutzes - Handlungsbedarf aus behoerdlicher Sicht

    Wolter, W. [Ministerium fuer Finanzen und Energie des Landes Schleswig-Holstein, Kiel (Germany)

    1994-07-01

    The various measures taken for accident management in the plant are to be classified into categories of nuclear law, as there are: prevention of hazards, prevention of risks, or non-preventive measures ( management of remaining risk). Screening the various measures for classification shows that most of them belong to the category of preventive action under the Atomic Energy Act. This means that these measures have to be addressed in KTA safety standards. (orig./HP) [Deutsch] Die rechtliche Einordnung jeder einzelnen Massnahmen des anlageninternen Notfallschutzes in eine der atomrechtlichen Kategorien Gefahrenabwehr, Risikovorsorge oder Nichtvorsorge (Restrisikomassnahme) ist erforderlich. Eine ueberschlaegige Betrachtung fuehrt zu dem Ergebnis, dass zahlreiche technische Massnahmen des anlageninternen Notfallschutzes dem atomrechtlichen Vorsorgebegriff zuzuordnen sind (Risikovorsorge). Sofern Massnahmen des anlageninternen Notfallschutzes der atomrechtlichen Vorsorge zuzuordenen sind, sind sie zwingend auch im KTA-Regelwerk zu verankern. (orig./HP)

  16. Severe accidents at nuclear power plants. Their risk assessment and accident management

    This document is to explain the severe accident issues. Severe Accidents are defined as accidents which are far beyond the design basis and result in severe damage of the core. Accidents at Three Mild Island in USA and at Chernobyl in former Soviet Union are examples of severe accidents. The causes and progressions of the accidents as well as the actions taken are described. Probabilistic Safety Assessment (PSA) is a method to estimate the risk of severe accidents at nuclear reactors. The methodology for PSA is briefly described and current status on its application to safety related issues is introduced. The acceptability of the risks which inherently accompany every technology is then discussed. Finally, provision of accident management in Japan is introduced, including the description of accident management measures proposed for BWRs and PWRs. (author)

  17. Severe accident management concept for LWRS

    Although the advanced built-in engineered safety features and the highly trained personnel have led to extremely low probabilities of core melt accidents, there is a common understanding that even for such very unlikely accidents the plant operators must have the ability and means to mitigate the consequences of such events. This paper outlines a concept for the management of severe accidents based on 1) Computer simulations. 2) Various strategies based on core and containment damage states. 3) Calculational Aids. 4) Procedures. 5) Technical basis report. 6) Training. 7) Drills. The major benefit of this concept is the fact that there is no dedicated operating manual for severe accidents; rather the required mitigative strategies and measures are incorporated into existing accident management manuals leading to truly integrated accident management at the plant. At present this concept is going to be implemented in the NPP Geogen. Although this approach is primarily developed for existing PWRs it is also applicable to other LWRs including new NPP designs. Specific features of the plant can be taken into account by an adaptation of the concept. (authors)

  18. Severe accident management guidelines tool

    Severe Accident is addressed by means of a great number of documents such as guidelines, calculation aids and diagnostic trees. The response methodology often requires the use of several documents at the same time while Technical Support Centre members need to assess the appropriate set of equipment within the adequate mitigation strategies. In order to facilitate the response, TECNATOM has developed SAMG TOOL, initially named GGAS TOOL, which is an easy to use computer program that clearly improves and accelerates the severe accident management. The software is designed with powerful features that allow the users to focus on the decision-making process. Consequently, SAMG TOOL significantly improves the severe accident training, ensuring a better response under a real situation. The software is already installed in several Spanish Nuclear Power Plants and trainees claim that the methodology can be followed easier with it, especially because guidelines, calculation aids, equipment information and strategies availability can be accessed immediately (authors)

  19. Accident management strategy focusing on the software area

    Tokyo Electric Power Company has already conducted individual plant examination (IPE) and worked out specific accident management strategies. In addition to hardware projects which will be carried out in due order from now on, we have studied the software aspects of accident management, including personnel education and training in relevant subjects. Based on the results of these studies, a decision has been made on the work sharing between the main control room (MCR) and technical support center (TSC) in implementing accident management. We have also decided on a improvement of guidelines and manuals, such as emergency operation procedures (EOP) and accident management guidelines (AMG), and on a basic policy on personnel education and training in accident management. Following this decision, our future efforts will be focused on improving software measures in combination with hardware measures to work out a well-balanced accident management program. (author)

  20. The management of radioactive waste from accidents

    Two accident case histories are reviewed - the Three Mile Island (TMI-2) reactor accident in 1979 and the Seveso accident in 1976. The status of the decontamination and radioactive waste management operations at TMI-2 as at 1986 is presented. 1986 estimates of reactor accident and recovery costs are given. 12 refs., 8 tabs

  1. The measurement of accident-proneness

    As, Sicco van

    2001-01-01

    This paper deals with the measurement of accident-proneness. Accidents seem easy to observe, however accident-proneness is difficult to measure. In this paper I first define the concept of accident-proneness, and I develop an instrument to measure it. The research is mainly executed within chemical

  2. Severe accident analysis methodology in support of accident management

    The author addresses the implementation at BELGATOM of a generic severe accident analysis methodology, which is intended to support strategic decisions and to provide quantitative information in support of severe accident management. The analysis methodology is based on a combination of severe accident code calculations, generic phenomenological information (experimental evidence from various test facilities regarding issues beyond present code capabilities) and detailed plant-specific technical information

  3. Verification of accident management strategies at the Forsmark plant

    Due to government requirements severe accident mitigating measures were implemented at the Swedish State Power Board nuclear power plants in 1988. These measures included protection against early containment impairment, highly redundant containment spray and filtered venting of the containment. We also developed accident management strategies and corresponding documents to counteract a severe accident situation. This paper describes the accident management strategies and documents at the Forsmark nuclear power plant, the verification process of the basic approach, and our ongoing program for further development and verification of the accident management program. In summary: From the beginning it was emphasized that it was not only mitigating measures implemented, it was an accident mitigation program, including new EOP's and education and training. This program was implemented, as required by the Swedish government in the end of 1988. Since that time the accident management strategy has been validated, verified and further developed. As a general conclusion, the implemented accident management program has reached a fair degree of completeness at the Forsmark plant. It is expected that in the case a hypothetical accident would occur the envisaged strategy would handle the accident in such a way that the radiological consequences would be insignificant and radiation exposure to the personnel would be within ICRP recommendations. To reach and keep this goal it is imperative that a mental preparedness is always present. This is achieved with a continuous education, training and analyses

  4. Stress in accident and post-accident management at Chernobyl

    The effects of the Chernobyl nuclear accident on the psychology of the affected population have been much discussed. The psychological dimension has been advanced as a factor explaining the emergence, from 1990 onwards, of a post-accident crisis in the main CIS countries affected. This article presents the conclusions of a series of European studies, which focused on the consequences of the Chernobyl accident. These studies show that the psychological and social effects associated with the post-accident situation arise from the interdependency of a number of complex factors exerting a deleterious effect on the population. We shall first attempt to characterise the stress phenomena observed among the population affected by the accident. Secondly, we will be presenting an anlysis of the various factors that have contributed to the emerging psychological and social features of population reaction to the accident and in post-accident phases, while not neglecting the effects of the pre-accident situation on the target population. Thirdly, we shall devote some initial consideration to the conditions that might be conducive to better management of post-accident stress. In conclusion, we shall emphasise the need to restore confidence among the population generally. (Author)

  5. Development of TRAIN for accident management

    Severe accident management can be defined as the use of existing and alternative resources, systems, and actions to prevent or mitigate a core-melt accident in nuclear power plants. TRAIN (Training pRogram for AMP In NPP), developed for training control room staff and the technical group, is introduced in this paper. The TRAIN composes of phenomenological knowledge base (KB), accident sequence KB and accident management procedures with AM strategy control diagrams and information needs. This TRAIN might contribute to training them by obtaining phenomenological knowledge of severe accidents, understanding plant vulnerabilities, and solving problems under high stress. (author)

  6. The screening approach for review of accident management programmes

    In this lecture the screening approach for review of accident management programmes are presented. It contains objective trees for accident management: logic structure of the approach; objectives and safety functions for accident management; safety principles

  7. Containment severe accident management - selected strategies

    The OECD Nuclear Energy Agency (NEA) organized in June 1994, in collaboration with the Swedish Nuclear Power Inspectorate (SKI), a Specialist Meeting on Selected Containment Severe Accident Management Strategies, to discuss their feasibility, effectiveness, benefits and drawbacks, and long-term impact. The meeting focused on water reactors, mainly on existing systems. The technical content covered topics such as general aspects of accident management strategies in OECD Member countries, hydrogen management techniques and other containment accident management strategies, surveillance and protection of the containment function. The main conclusions of the meeting are summarized in the paper. (author)

  8. Strategy generation in accident management support

    An increased interest for research in the field of Accident Management can be noted. Several international programmes have been started in order to be able to understand the basic physical and chemical phenomena in accident conditions. A feasibility study has shown that it would be possible to design and develop a computerized support system for plant staff in accident situations. To achieve this goal the Halden Project has initiated a research programme on Computerized Accident Management Support (CAMS project). The aim is to utilize the capabilities of computerized tools to support the plant staff during the various accident stages. The system will include identification of the accident state, assessment of the future development of the accident and planning of accident mitigation strategies. A prototype is developed to support operators and the Technical Support Centre in decision making during serious accident in nuclear power plants. A rule based system has been built to take care of the strategy generation. This system assists plant personnel in planning control proposals and mitigation strategies from normal operation to severe accident conditions. The ideal of a safety objective tree and knowledge from the emergency procedures have been used. Future prediction requires good state identification of the plant status and some knowledge about the history of some critical variables. The information needs to be validated as well. Accurate calculations in simulators and a large database including all important information form the plant will help the strategy planning. (author). 12 refs, 2 figs

  9. On preparation for accident management in LWR power stations

    Nuclear Safety Commission received the report from Reactor Safety General Examination Committee which investigated the policy of executing the preparation for accident management. The basic policy on the preparation for accident management was decided by Nuclear Safety Commission in May, 1992. This Examination Committee investigated the policy of executing the preparation for accident management, which had been reported from the administrative office, and as the result, it judged the policy as adequate, therefore, the report is made. The course to the foundation of subcommittee is reported. The basic policy of the examination on accident management by the subcommittee conforming to the decision by Nuclear Safety Commission, the measures of accident management which were extracted for BWR and PWR facilities, the examination of the technical adequacy of selecting accident sequences in BWR and PWR facilities and the countermeasures to them, the adequacy of the evaluation of the possibility of executing accident management measures and their effectiveness and the adequacy of the evaluation of effect to existing safety functions, the preparation of operation procedure manual, and education and training plan are reported. (K.I.)

  10. SAMSON: Severe Accident Management System Online Network

    SAMSON, Severe Accident Management System Online Network, is a computational tool used in the event of a nuclear power plant accident by accident managers in the Technical Support Centers (TSC) and Emergency Offsite Facilities (EOF). SAMSON examines over 150 status points monitored by nuclear power plant process computers during a severe accident and makes predictions about when core damage, support plate failure, and reactor vessel failure will occur. These predictions are based on the current state of the plant assuming that all safety equipment not already operating will fail. The status points analyzed include radiation levels, flow rates, pressure levels, temperatures and water levels. SAMSON uses an expert system as well as neural networks trained with the back propagation learning algorithm to make predictions. Previous training on data from accident analysis code allows SAMSON to associate different states in the plant with different times to critical failures. The accidents currently recognized by SAMSON include steam generator tube ruptures (SGTR), with breaks ranging from one tube to eights tubes, and loss of coolant accidents (LOCA), with breaks ranging from 0.001 square feet in size to breaks 3.0 square feet. SAMSON contains several neural networks for each accident type and break size, and chooses the correct network after accident classification by in expert system. SAMSON also provides information concerning the status of plant sensors and recovery strategies

  11. A Methodology for Probabilistic Accident Management

    While techniques have been developed to tackle different tasks in accident management, there have been very few attempts to develop an on-line operator assistance tool for accident management and none that can be found in the literature that uses probabilistic arguments, which are important in today's licensing climate. The state/parameter estimation capability of the dynamic system doctor (DSD) approach is combined with the dynamic event-tree generation capability of the integrated safety assessment (ISA) methodology to address this issue. The DSD uses the cell-to-cell mapping technique for system representation that models the system evolution in terms of probability of transitions in time between sets of user-defined parameter/state variable magnitude intervals (cells) within a user-specified time interval (e.g., data sampling interval). The cell-to-cell transition probabilities are obtained from the given system model. The ISA follows the system dynamics in tree form and braches every time a setpoint for system/operator intervention is exceeded. The combined approach (a) can automatically account for uncertainties in the monitored system state, inputs, and modeling uncertainties through the appropriate choice of the cells, as well as providing a probabilistic measure to rank the likelihood of possible system states in view of these uncertainties; (b) allows flexibility in system representation; (c) yields the lower and upper bounds on the estimated values of state variables/parameters as well as their expected values; and (d) leads to fewer branchings in the dynamic event-tree generation. Using a simple but realistic pressurizer model, the potential use of the DSD-ISA methodology for on-line probabilistic accident management is illustrated

  12. Investigation of accident management strategies for VVER-1000-Type reactors

    The goal of this work is the search for an optimal accident management strategy to prevent containment failure and to stop the core/concrete interaction from hindering cavity bottom melt-through on the one hand and from ending the ex-vessel source term increase on the other hand, i.e., to terminate the accident. The work is based on the results of previous studies of physical and chemical phenomena during different accident scenarios for VVER-1000-type reactors. For a TMLB' sequence (an accident caused by a transient in which core melt occurs because the electric power cannot be restored before the pressure vessel melts through), a number of calculations were performed using the source term code package (STCP) to investigate the influence of several accident management measures on the core/concrete interaction and the containment integrity

  13. Emergency monitoring strategy and radiation measurements. Working document of the NKS project emergency management and radiation monitoring in nuclear and radiological accidents (EMARAD)

    This report is one of the deliverables of the NKS Project Emergency management and radiation monitoring in nuclear and radiological accidents (EMARAD) (20022005). The project and the overall results are briefly described in the NKS publication 'Emergency Management and Radiation Monitoring in Nuclear and Radiological Accidents. Summary Report on the NKS Project EMARAD' (NKS-137, April 2006). In a nuclear or radiological emergency, all radiation measurements must be performed efficiently and the results interpreted correctly in order to provide the decision-makers with adequate data needed in analysing the situation and carrying out countermeasures. Managing measurements in different situations in a proper way requires the existence of pre-prepared emergency monitoring strategies. Preparing a comprehensive yet versatile strategy is not an easy task to perform because there are lots of different factors that have to be taken into account. The primary objective of this study was to discuss the general problematics concerning emergency monitoring strategies and to describe a few important features of an efficient emergency monitoring system as well as factors affecting measurement activities in practise. Some information concerning the current situation in the Nordic countries has also been included. (au)

  14. Emergency monitoring strategy and radiation measurements document of the NKS project emergency management and radiation monitoring in nuclear and radiological accidents (EMARAD)

    Lahtinen, J. [Radiation and Nuclear Safety Authority (STUK) (Finland)

    2006-04-15

    This report is one of the deliverables of the NKS Project Emergency management and radiation monitoring in nuclear and radiological accidents (EMARAD) (20022005). The project and the overall results are briefly described in the NKS publication 'Emergency Management and Radiation Monitoring in Nuclear and Radiological Accidents. Summary Report on the NKS Project EMARAD' (NKS-137, April 2006). In a nuclear or radiological emergency, all radiation measurements must be performed efficiently and the results interpreted correctly in order to provide the decision-makers with adequate data needed in analysing the situation and carrying out countermeasures. Managing measurements in different situations in a proper way requires the existence of pre-prepared emergency monitoring strategies. Preparing a comprehensive yet versatile strategy is not an easy task to perform because there are lots of different factors that have to be taken into account. The primary objective of this study was to discuss the general problematics concerning emergency monitoring strategies and to describe a few important features of an efficient emergency monitoring system as well as factors affecting measurement activities in practise. Some information concerning the current situation in the Nordic countries has also been included. (au)

  15. Development of integrated accident management assessment technology

    This project aims to develop critical technologies for accident management through securing evaluation frameworks and supporting tools, in order to enhance capabilities coping with severe accidents. For the research goal, firstly under the viewpoint of accident prevention, on-line risk monitoring system and the analysis framework for human error have been developed. Secondly, the training/supporting systems including the training simulator and the off-site risk evaluation system have been developed to enhance capabilities coping with severe accidents. Four kinds of research results have been obtained from this project. Firstly, the framework and taxonomy for human error analysis has been developed for accident management. As the second, the supporting system for accident managements has been developed. Using data that are obtained through the evaluation of off-site risk for Younggwang site, the risk database as well as the methodology for optimizing emergency responses has been constructed. As the third, a training support system, SAMAT, has been developed, which can be used as a training simulator for severe accident management. Finally, on-line risk monitoring system, DynaRM, has been developed for Ulchin 3 and 4 unit

  16. Accident knowledge and emergency management

    The report contains an overall frame for transformation of knowledge and experience from risk analysis to emergency education. An accident model has been developed to describe the emergency situation. A key concept of this model is uncontrolled flow of energy (UFOE), essential elements are the state, location and movement of the energy (and mass). A UFOE can be considered as the driving force of an accident, e.g., an explosion, a fire, a release of heavy gases. As long as the energy is confined, i.e. the location and movement of the energy are under control, the situation is safe, but loss of confinement will create a hazardous situation that may develop into an accident. A domain model has been developed for representing accident and emergency scenarios occurring in society. The domain model uses three main categories: status, context and objectives. A domain is a group of activities with allied goals and elements and ten specific domains have been investigated: process plant, storage, nuclear power plant, energy distribution, marine transport of goods, marine transport of people, aviation, transport by road, transport by rail and natural disasters. Totally 25 accident cases were consulted and information was extracted for filling into the schematic representations with two to four cases pr. specific domain. (au) 41 tabs., 8 ills.; 79 refs

  17. Accident knowledge and emergency management

    Rasmussen, B.; Groenberg, C.D.

    1997-03-01

    The report contains an overall frame for transformation of knowledge and experience from risk analysis to emergency education. An accident model has been developed to describe the emergency situation. A key concept of this model is uncontrolled flow of energy (UFOE), essential elements are the state, location and movement of the energy (and mass). A UFOE can be considered as the driving force of an accident, e.g., an explosion, a fire, a release of heavy gases. As long as the energy is confined, i.e. the location and movement of the energy are under control, the situation is safe, but loss of confinement will create a hazardous situation that may develop into an accident. A domain model has been developed for representing accident and emergency scenarios occurring in society. The domain model uses three main categories: status, context and objectives. A domain is a group of activities with allied goals and elements and ten specific domains have been investigated: process plant, storage, nuclear power plant, energy distribution, marine transport of goods, marine transport of people, aviation, transport by road, transport by rail and natural disasters. Totally 25 accident cases were consulted and information was extracted for filling into the schematic representations with two to four cases pr. specific domain. (au) 41 tabs., 8 ills.; 79 refs.

  18. Fundamentals for reviewing accident managements of reprocessing facilities

    The accident at Fukushima Daiichi Nuclear Power Station insisted a necessity of reconsideration of the defence in depth concept against events exceeding design basis. The insistence suggested a need of practical guidance for reviewing accident management measures for such events. Soon after the accident, Japan Nuclear Energy Safety Organization (JNES) started a preliminary study on the points to be considered in reviewing comprehensiveness and consistency of accident management measures for reprocessing facilities. The results of PSA studies which have been pursued at JNES contributed significantly to the preliminary study, because the contents of the PSA studies have a close relation with subjects to be considered in the review. Based on the insight the paper focuses on such relation and discusses fundamentals for the review in terms of the knowledge derived from the PSA and specific features of reprocessing facilities. The result of the study is also described with touching relations to the fundamentals. (author)

  19. Reconstruction of the Chernobyl emergency and accident management

    Full text of publication follows: on April 26, 1986 the most serious civil technological accident in the history of mankind occurred of the Chernobyl Nuclear Power Plant (ChNPP) in the former Soviet Union. As a direct result of the accident, the reactor was severely destroyed and large quantities of radionuclides were released. Some 800000 persons, also called 'liquidators' - including plant operators, fire-fighters, scientists, technicians, construction workers, emergency managers, volunteers, as well as medical and military personnel - were part of emergency measurements and accident management efforts. Activities included measures to prevent the escalation of the accident, mitigation actions, help for victims as well as activities in order to provide a basic infrastructure for this unprecedented and overwhelming task. The overall goal of the 'Project Chernobyl' of the Institute of Risk Research of the University of Vienna was to preserve for mankind the experience and knowledge of the experts among the 'liquidators' before it is lost forever. One method used to reconstruct the emergency measures of Chernobyl was the direct cooperation with liquidators. Simple questionnaires were distributed among liquidators and a database of leading accident managers, engineers, medical experts etc. was established. During an initial struggle with a number of difficulties, the response was sparse. However, after an official permit had been issued, the questionnaires delivered a wealth of data. Furthermore a documentary archive was established, which provided additional information. The multidimensional problem in connection with the severe accident of Chernobyl, the clarification of the causes of the accident, as well as failures and successes and lessons to be learned from the Chernobyl emergency measures and accident management are discussed. (authors)

  20. Medical response and management of radiation accidents

    An overview is provided of educational programs and principles essential to the appropriate medical management of radiation accident victims. Such an education program will provide details of the physical properties of radiation, of the sources of radiation exposure, of radiation protection standards and of biological radiation effects. The medical management of individuals involved in radiation accidents is discussed. Such management includes emergency medical stabilization, locating and quantitating the level and degree of internal and/or external contamination, wound decontamination, medical surveillance and the evaluation and treatment of local radiation injuries

  1. ATHLET validation using accident management experiments

    The computer code ATHLET is being developed as an advanced best-estimate code for the simulation of leaks and transients in PWRs and BWRs including beyond design basis accidents. The code has features that are of special interest for applications to small leaks and transients with accident management, e.g. initialisation by a steady-state calculation, full-range drift-flux model, and dynamic mixture level tracking. The General Control Simulation Module of ATHLET is a flexible tool for the simulation of the balance-of-plant and control systems including the various operator actions in the course of accident sequences with AM measures. The systematic validation of ATHLET is based on a well balanced set of integral and separate effect tests derived from the CSNI proposal emphasising, however, the German combined ECC injection system which was investigated in the UPTF, PKL and LOBI test facilities. PKL-III test B 2.1 simulates a cool-down procedure during an emergency power case with three steam generators isolated. Natural circulation under these conditions was investigated in detail in a pressure range of 4 to 2 MPa. The transient was calculated over 22000 s with complicated boundary conditions including manual control actions. The calculations demonstrations the capability to model the following processes successfully: (1) variation of the natural circulation caused by steam generator isolation, (2) vapour formation in the U-tubes of the isolated steam generators, (3) break-down of circulation in the loop containing the isolated steam generator following controlled cool-down of the secondary side, (4) accumulation of vapour in the pressure vessel dome. One conclusion with respect to the suitability of experiments simulating AM procedures for code validation purposes is that complete documentation of control actions during the experiment must be available. Special attention should be given to the documentation of operator actions in the course of the experiment

  2. US nuclear industry perspective on accident management

    The Nuclear Management and Resources Council (NUMARC) serves as the United States nuclear power industry's principal mechanism for conveying industry views, concerns, and policies regarding industry wide regulatory issues to the Nuclear Regulatory Commission (NRC) and other government agencies as appropriate. NUMARC and the Electric Power Research Institute (EPRI), in support of the NUMARC Severe Accident Working Group's (SAWG's) efforts with regard to accident management, has developed a framework for evaluation of plant-specific accident management capabilities. These capabilities fall into one of three main categories: (1) personnel resources (organization, training, communications); (2) systems and equipment (restoration and repair, instrumentation, use of alternatives); and (3) information resources (procedures and guidance, technical information, process information). The purpose of this paper is to describe this framework, its objectives, the five major steps involved and areas to consider further

  3. Severe accident management. Optimized guidelines and strategies

    The highest priority for mitigating the consequences of a severe accident with core melt lies in securing containment integrity, as this represents the last barrier against fission product release to the environment. Containment integrity is endangered by several physical phenomena, especially highly transient phenomena following high-pressure reactor pressure vessel failure (like direct containment heating or steam explosions which can lead to early containment failure), hydrogen combustion, quasi-static over-pressure, temperature failure of penetrations, and basemat penetration by core melt. Each of these challenges can be counteracted by dedicated severe accident mitigation hardware, like dedicated primary circuit depressurization valves, hydrogen recombiners or igniters, filtered containment venting, containment cooling systems, and core melt stabilization systems (if available). However, besides their main safety function these systems often have also secondary effects that need to be considered. Filtered containment venting causes (though limited) fission product release into the environment, primary circuit depressurization leads to loss of coolant, and an ex-vessel core melt stabilization system as well as hydrogen igniters can generate high pressure and temperature loads on the containment. To ensure that during a severe accident any available systems are used to their full beneficial extent while minimizing their potential negative impact, AREVA has implemented a severe accident management for German nuclear power plants. This concept makes use of extensive numerical simulations of the entire plant, quantifying the impact of system activations (operational systems, safety systems, as well as dedicated severe accident systems) on the accident progression for various scenarios. Based on the knowledge gained, a handbook has been developed, allowing the plant operators to understand the current state of the plant (supported by computational aids), to predict

  4. Management of foodstuffs after nuclear accidents

    A model for the management of foodstuffs after nuclear accidents is presented. The model is a synthesis of traditions and principles taken from both radioactive protection and management of food. It is based on cooperation between the Nordic countries and on practical experience gained from the Chernobyl accident. The aim of the model is to produce a basis for common plans for critical situations based on criteria for decision making. In the case of radioactive accidents it is important that the protection of the public and of the society is handled in a positive way. The model concerns production, marketing and consumption of food and beverage. The overall aim is that the radiation doses should be as low and harmless to health for individual members of the public. (CLS) 35 refs

  5. Development of severe accident management advisory and training simulator (SAMAT)

    The most operator support systems including the training simulator have been developed to assist the operator and they cover from normal operation to emergency operation. For the severe accident, the overall architecture for severe accident management is being developed in some developed countries according to the development of severe accident management guidelines which are the skeleton of severe accident management architecture. In Korea, the severe accident management guideline for KSNP was recently developed and it is expected to be a central axis of logical flow for severe accident management. There are a lot of uncertainties in the severe accident phenomena and scenarios and one of the major issues for developing a operator support system for a severe accident is the reduction of these uncertainties. In this paper, the severe accident management advisory system with training simulator, SAMAT, is developed as all available information for a severe accident are re-organized and provided to the management staff in order to reduce the uncertainties. The developed system includes the graphical display for plant and equipment status, the previous research results by knowledge-base technique, and the expected plant behavior using the severe accident training simulator. The plant model used in this paper is oriented to severe accident phenomena and thus can simulate the plant behavior for a severe accident. Therefore, the developed system may make a central role of the information source for decision-making for a severe accident management, and will be used as the training simulator for severe accident management

  6. Chernobyl reactor accident: medical management

    Chernobyl reactor accident on 26th April, 1986 is by far the worst radiation accident in the history of the nuclear industry. Nearly 500 plant personnel and rescue workers received doses varying from 1-16 Gy. Acute radiation syndrome (ARS) was seen only in the plant personnel. 499 individuals were screened for ARS symptoms like nausea, vomitting, diarrhoea and fever. Complete blood examination was done which showed initial granulocytosis followed by granulocytopenia and lymphocytopenia. Cytogenetic examinations were confirmatory in classifying the patients on the basis of the doses received. Two hundred and thirty seven cases of ARS were hospitalised in the first 24-36 hrs. No member of general public suffered from ARS. There were two immediate deaths and subsequently 28 died in hospital and one of the cases died due to myocardial infarction, making a total of 31 deaths. The majority of fatal cases had whole body doses of about 6 Gy, besides extensive skin burns. Two cases of radiation burns had thermal burns also. Treatment of ARS consisted of isolation, barrier nursing, replacement therapy with fluid electrolytes, platelets and RBC transfusions and antibiotic therapy for bacterial, fungal and viral infections. Bone marrow transplantations were given to 13 cases out of which 11 died due to various causes. Radiation burns due to beta, gamma radiations were seen in 56 cases and treated with dressings, surgical excision, skin grafting and amputation. Oropharangeal syndrome, producing extensive mucous in the oropharynx, was first seen in Chernobyl. The patients were treated with saline wash of the mouth. The patients who had radioactive contamination due to radioactive iodine were given stable iodine, following wash with soap, water and monitored. Fourteen survivors died subsequently due to other causes. Late health effects seen so far include excess of thyroid cancer in the children and psychological disorders due to stress. No excess leukemia has been reported so

  7. Occupational Radiation Protection in Severe Accident Management

    As an early response to the Fukushima Daiichi NPP accident, the Information System on Occupational Exposure (ISOE) Bureau decided to focus on the following issues as an initial response of the joint program after having direct communications with the Japanese official participants in April 2011: - Management of high radiation area worker doses: It has been decided to make available the experience and information from the Chernobyl accident in terms of how emergency worker / responder doses were legally and practically managed, - Personal protective equipment for highly-contaminated areas: It was agreed to collect information about the types of personnel protective equipment and other equipment (e.g. air bottles, respirators, air-hoods or plastic suits, etc.), as well as high-radiation area worker dosimetry use (e.g. type, number and placement of dosimetry) for different types of emergency and high-radiation work situations. Detailed information was collected on dose criteria which are used for emergency workers /responders and their basis, dose management criteria for high dose/dose rate areas, protective equipment which is recommended for emergency workers / responders, recommended individual monitoring procedures, and any special requirement for assessment from the ISOE participating nuclear utilities and regulatory authorities and made available for Japanese utilities. With this positive response of the ISOE official participants and interest in the situation in Fukushima, the Expert Group on Occupational Radiation Protection in Severe Accident Management (EG-SAM) was established by the ISOE Management Board in May 2011. The overall objective of the EG-SAM is to contribute to occupational exposure management (providing a view on management of high radiation area worker doses) within the Fukushima plant boundary with the ISOE participants and to develop a state-of-the-art ISOE report on best radiation protection management practices for proper radiation

  8. Development of emergency response support system for accident management

    Specific measures for the accident management (AM) are proposed to prevent the severe accident and to mitigate their effects in order to upgrade the safety of nuclear power plants even further. To ensure accident management effective, it is essential to grasp the plant status accurately. In consideration of the above mentioned background, the Emergency Response Support System (ERSS) was developed as a computer assisted prototype system by a joint study of Japanese BWR group. This system judges and predicts the plant status at the emergency condition in a nuclear power plant. This system displays the results of judgment and prediction. The effectiveness of the system was verified through the test and good prospects for applying the system to a plant was obtained. 7 refs., 10 figs

  9. PSA use in accident management studies in Japan

    The safety of NPPs in Japan is secured by stringent safety regulations based on the deterministic method, minimizing the possibility a severe accident to a technologically negligible level. PSA is not required in the current regulatory procedures. Accident management based on PSA is a 'knowledge-based' action dependent on utilities' technical knowledge aimed at further reduction of the risk which is kept small enough by existing measures. The paper discusses the following three kinds of PSAs that have been conducted practically and efficiently on NPPs to provide supplemental information about their safety characteristics in addition to the deterministic evaluation used in the regulatory safety review: PSAs on typical NPPs, PSAs on all NPPs to examine candidates for accident management, and PSAs as part of periodic safety review (PSR). 1 fig., 5 tabs

  10. Artificial intelligence applications in accident management

    For nuclear power plant accident management, there are some addition concerns: linking AI systems to live data streams must be mastered; techniques for processing sensor inputs with varying data quality need to be provided; systems responsiveness to changing plant conditions and multiple user requests should, in general, be improved; there is a need for porting applications from specialized AI machines onto conventional computer hardware without incurring unacceptable performance penalties; human factors guidelines are required for new user interfaces in AI applications; methods for verification and validation of AI-based systems must be developed; and, finally, there is a need for proven methods to evaluate use effectiveness and firmly establish the benefits of AI-based accident management systems. (orig./GL)

  11. Severe accident research and management in Nordic Countries - A status report

    The report describes the status of severe accident research and accident management development in Finland, Sweden, Norway and Denmark. The emphasis is on severe accident phenomena and issues of special importance for the severe accident management strategies implemented in Sweden and in Finland. The main objective of the research has been to verify the protection provided by the accident mitigation measures and to reduce the uncertainties in risk dominant accident phenomena. Another objective has been to support validation and improvements of accident management strategies and procedures as well as to contribute to the development of level 2 PSA, computerised operator aids for accident management and certain aspects of emergency preparedness. Severe accident research addresses both the in-vessel and the ex-vessel accident progression phenomena and issues. Even though there are differences between Sweden and Finland as to the scope and content of the research programs, the focus of the research in both countries is on in-vessel coolability, integrity of the reactor vessel lower head and core melt behaviour in the containment, in particular the issues of core debris coolability and steam explosions. Notwithstanding that our understanding of these issues has significantly improved, and that experimental data base has been largely expanded, there are still important uncertainties which motivate continued research. Other important areas are thermal-hydraulic phenomena during reflooding of an overheated partially degraded core, fission product chemistry, in particular formation of organic iodine, and hydrogen transport and combustion phenomena. The development of severe accident management has embraced, among other things, improvements of accident mitigating procedures and strategies, further work at IFE Halden on Computerised Accident Management Support (CAMS) system, as well as plant modifications, including new instrumentation. Recent efforts in Sweden in this area

  12. Severe accident research and management in Nordic Countries - A status report

    Frid, W. [Swedish Nuclear Power Inspectorate, SKI (Sweden)] (ed.)

    2002-01-01

    The report describes the status of severe accident research and accident management development in Finland, Sweden, Norway and Denmark. The emphasis is on severe accident phenomena and issues of special importance for the severe accident management strategies implemented in Sweden and in Finland. The main objective of the research has been to verify the protection provided by the accident mitigation measures and to reduce the uncertainties in risk dominant accident phenomena. Another objective has been to support validation and improvements of accident management strategies and procedures as well as to contribute to the development of level 2 PSA, computerised operator aids for accident management and certain aspects of emergency preparedness. Severe accident research addresses both the in-vessel and the ex-vessel accident progression phenomena and issues. Even though there are differences between Sweden and Finland as to the scope and content of the research programs, the focus of the research in both countries is on in-vessel coolability, integrity of the reactor vessel lower head and core melt behaviour in the containment, in particular the issues of core debris coolability and steam explosions. Notwithstanding that our understanding of these issues has significantly improved, and that experimental data base has been largely expanded, there are still important uncertainties which motivate continued research. Other important areas are thermal-hydraulic phenomena during reflooding of an overheated partially degraded core, fission product chemistry, in particular formation of organic iodine, and hydrogen transport and combustion phenomena. The development of severe accident management has embraced, among other things, improvements of accident mitigating procedures and strategies, further work at IFE Halden on Computerised Accident Management Support (CAMS) system, as well as plant modifications, including new instrumentation. Recent efforts in Sweden in this area

  13. Precept from the management for the accident of Fukushima daiichi

    At 17 hours after the accident of Fukushima Daiichi Nuclear Power Plant due to the Great East Japan Earthquake, National Institute of Radiological Sciences sent the first REMAT (Radiation Emergency Medical Assistance Team) in the 20 km range from the Plant. The team members were confronted by two issues: (1) Medical activities under the infrastructures destructed by a multiple disaster caused by earthquake, tsunami and nuclear accident, which was not presumed. (2) Radiation protection management for dispatched staff. Measures for this situation worked out by activities on the site are presented. (K.Y.)

  14. The expert assistant in accident management

    In the event of a nuclear accident in proximity to an urban area, the consequences resulting from the complex processes of environmental transport of radioactivity would require complex countermeasures. Emphasis has been placed on either modelling the potential effects of such an event on the population, or on attempting to predict the geographical evolution of the release. Less emphasis has been placed on the development of accident management aids with a in-built data acquisition capability. Given the problems of predicting the evolution of an accidental release of activity, more emphasis should be placed on the development of small regional systems specifically engineered to acquire and display environmental data in the most efficaceous form possible. A wealth of information can be obtained from appropriately-sited outstations which can aid those responsible for countermeasures in their decision making processes. The substantial volume of data which would arrive within the duration and during the aftermath of an accident requires skilled interpretation under conditions of considerable stress. It is necessary that a management aid notonly presents these data in a rapidly assimilable form, but is capable of making intelligent decisions of its own, on such matters as information display priority and the polling frequency of outstations. The requirement is for an expert assistant. The XERSES accident management aid has been designed with the foregoing features in mind. Intended for covering regions up to approximately 100 kms square, it links with between 1 and 64 outstations supplying a variety of environmental data. Under quiescent conditions the system will operate unattended, raising alarms remotely only when detecting abnormal conditions. Under emergency conditions, the system automatically adjusts such operating parameters as data acquisition rate

  15. Simulation of severe accident in reactor core for training and accident management

    An Advanced Real-time Severe Accident Simulation (ARTSAS) train reactor operators and accident management teams for scenarios simulating severe accidents in nuclear reactors. The code has been integrated with the real-time tools and the RAINBO graphic package to provide training and analysis tools on workstations as well as on full-scope simulators. (orig.) (4 refs., 1 fig.)

  16. Early measurements after the Goiania accident

    During the early, intermediate late phase of the Goiania radiological accident different survey methods were applied involving aerial and terrestrial (using a car and directly in the field) inspections. The present work aims to show how and when they were and the obtained results. Furthermore, the 137Cs concentration in soils were determined using a NaI(Tl) spectrometer during the accident, and also in Rio de Janeiro in a high resolution gamma spectrometry system. The concordance among those results and the validity of the 137Cs measurements in soil with NaI(TI) are demonstrated. (author)

  17. A proposal for accident management optimization based on the study of accident sequence analysis for a BWR

    The paper describes a proposal for accident management optimization based on the study of accident sequence and source term analyses for a BWR. In Japan, accident management measures are to be implemented in all LWRs by the year 2000 in accordance with the recommendation of the regulatory organization and based on the PSAs carried out by the utilities. Source terms were evaluated by the Japan Atomic Energy Research Institute (JAERI) with the THALES code for all BWR sequences in which loss of decay heat removal resulted in the largest release. Identification of the priority and importance of accident management measures was carried out for the sequences with larger risk contributions. Considerations for optimizing emergency operation guides are believed to be essential for risk reduction. (author)

  18. OSSA - An optimized approach to severe accident management: EPR application

    There is a recognized need to provide nuclear power plant technical staff with structured guidance for response to a potential severe accident condition involving core damage and potential release of fission products to the environment. Over the past ten years, many plants worldwide have implemented such guidance for their emergency technical support center teams either by following one of the generic approaches, or by developing fully independent approaches. There are many lessons to be learned from the experience of the past decade, in developing, implementing, and validating severe accident management guidance. Also, though numerous basic approaches exist which share common principles, there are differences in the methodology and application of the guidelines. AREVA/Framatome-ANP is developing an optimized approach to severe accident management guidance in a project called OSSA ('Operating Strategies for Severe Accidents'). There are still numerous operating power plants which have yet to implement severe accident management programs. For these, the option to use an updated approach which makes full use of lessons learned and experience, is seen as a major advantage. Very few of the current approaches covers all operating plant states, including shutdown states with the primary system closed and open. Although it is not necessary to develop an entirely new approach in order to add this capability, the opportunity has been taken to develop revised full scope guidance covering all plant states in addition to the fuel in the fuel building. The EPR includes at the design phase systems and measures to minimize the risk of severe accident and to mitigate such potential scenarios. This presents a difference in comparison with existing plant, for which severe accidents where not considered in the design. Thought developed for all type of plants, OSSA will also be applied on the EPR, with adaptations designed to take into account its favourable situation in that field

  19. Severe accident approach - final report. Evaluation of design measures for severe accident prevention and consequence mitigation.

    Tentner, A. M.; Parma, E.; Wei, T.; Wigeland, R.; Nuclear Engineering Division; SNL; INL

    2010-03-01

    An important goal of the US DOE reactor development program is to conceptualize advanced safety design features for a demonstration Sodium Fast Reactor (SFR). The treatment of severe accidents is one of the key safety issues in the design approach for advanced SFR systems. It is necessary to develop an in-depth understanding of the risk of severe accidents for the SFR so that appropriate risk management measures can be implemented early in the design process. This report presents the results of a review of the SFR features and phenomena that directly influence the sequence of events during a postulated severe accident. The report identifies the safety features used or proposed for various SFR designs in the US and worldwide for the prevention and/or mitigation of Core Disruptive Accidents (CDA). The report provides an overview of the current SFR safety approaches and the role of severe accidents. Mutual understanding of these design features and safety approaches is necessary for future collaborations between the US and its international partners as part of the GEN IV program. The report also reviews the basis for an integrated safety approach to severe accidents for the SFR that reflects the safety design knowledge gained in the US during the Advanced Liquid Metal Reactor (ALMR) and Integral Fast Reactor (IFR) programs. This approach relies on inherent reactor and plant safety performance characteristics to provide additional safety margins. The goal of this approach is to prevent development of severe accident conditions, even in the event of initiators with safety system failures previously recognized to lead directly to reactor damage.

  20. Review of current Severe Accident Management (SAM) approaches for Nuclear Power Plants in Europe

    HERMSMEYER Stephan; Iglesias, R.; Herranz, L; REER B.; SONNENKALB M; NOWACK H.; Stefanova, A.; Raimond, E.; CHATELARD P.; FOUCHER Laurent; BARNAK M.; MATEJOVIC P; PASCAL GHISLAIN; VELA GARCIA MONICA; SANGIORGI MARCO

    2014-01-01

    The Fukushima accidents highlighted that both the in-depth understanding of such sequences and the development or improvement of adequate Severe Accident Management (SAM) measures are essential in order to further increase the safety of the nuclear power plants operated in Europe. To support this effort, the CESAM (Code for European Severe Accident Management) R&D project, coordinated by GRS, started in April 2013 for 4 years in the 7th EC Framework Programme of research and development of th...

  1. Severe accident management program at Cofrentes Nuclear Power Plant

    Cofrentes Nuclear Power Plant (GE BWR/6) has implemented its specific Severe Accident Management Program within this year 2000. New organization and guides have been developed to successfully undertake the management of a severe accident. In particular, the Technical Support Center will count on a new ''Severe Accident Management Team'' (SAMT) which will be in charge of the Severe Accident Guides (SAG) when Control Room Crew reaches the Emergency Operation Procedures (EOP) step that requires containment flooding. Specific tools and training have also been developed to help the SAMT to mitigate the accident. (author)

  2. Study on severe accident mitigation measures for the development of PWR SAMG

    2006-01-01

    In the development of the Severe Accident Management Guidelines (SAMG), it is very important to choose the main severe accident sequences and verify their mitigation measures. In this article, Loss-of-Coolant Accident (LOCA), Steam Generator Tube Rupture (SGTR), Station Blackout (SBO), and Anticipated Transients without Scram (ATWS) in PWR with 300 MWe are selected as the main severe accident sequences. The core damage progressions induced by the above-mentioned sequences are analyzed using SCDAP/RELAP5. To arrest the core damage progression and mitigate the consequences of severe accidents, the measures for the severe accident management (SAM) such as feed and bleed, and depressurizations are verified using the calculation. The results suggest that implementing feed and bleed and depressurization could be an effective way to arrest the severe accident sequences in PWR.

  3. Assessment of candidate accident management strategies

    A set of candidate accident management strategies, whose purpose is to prevent or mitigate in-vessel core damage, were identified from various Nuclear Regulatory Commission (NRC) and industry reports. These strategies have been grouped in this report by the challenges they are intended to meet, and assessed to provide information which may be useful to individual licensees for consideration when they perform their Individual Plant Examinations. Each assessment focused on describing and explaining the strategy, considering its relationship to existing requirements and practices as well as identifying possible associated adverse effects. 10 refs

  4. Current state of the technology measures of accident from contamination by the radioactive substance. 2. Overall management of radioactive material contaminated waste in the off-site

    This paper focuses on the disposal standards of the Act on Special Measures Concerning the Handling of Environmental Pollution by Radioactive Materials by the NPS Accident Associated with the Tohoku District - off the Pacific Ocean Earthquake that Occurred on March 11, 2011, which was promulgated on August 30, 2011 as a framework for the management of radioactively contaminated waste and removed soil. It stipulated that the byproducts of water/sewage treatment, major ash, and fly ash up to the radiation of 8,000 Bq/kg can be reclaimed in land. However, fly ash has a limit in landfill conditions, due to very high leaching rate of radioactive cesium. Later, incineration ash with between 8,000 Bq/kg and 100,000 Bq/kg became possible to be buried at disposal sites corresponding to leachate-controlled type. The specified waste with 100,000 Bq/kg or above is reclaimed in land with specified method at a site provided with outer peripheral partition facilities and cut off from the public water and groundwater. In Fukushima Prefecture, the specified waste with 100,000 Bq/kg or above is to be stored in provisional storage facilities, and later sent to final disposal sites outside the prefecture after the volume has been reduced. The decontaminated waste composed of vegetation is covered totally with a breathable waterproof sheet, and stored at a provisional yard. According to the characteristics of each provisional storage yard, there are needs for patrol and management. (A.O.)

  5. Use of probabilistic safety analyses in severe accident management

    An important consideration in the development and assessment of severe accident management strategies is that while the strategies are often built on the knowledge base of Probabilistic Safety Analyses (PSA), they must be interpretable and meaningful in terms of the control room indicators. In the following, the relationships between PSA and severe accident management are explored using ex-vessel accident management at a PWR ice-condenser plant as an example. 2 refs., 1 fig., 3 tabs

  6. Lessons learned from Fukushima accident in relation to emergency management

    The latest accident in Fukushima, Japan, which involved concurrent accidents at multiple nuclear facilities due to the earthquakes and tsunami, as well as station blackouts for an extended period of time, demonstrated the need for an overall review of existing prevention measures. These measures include emergency protection measures for residents beyond the emergency planning zone, the application of radiation protection criteria that consider the release of radioactive materials to the environment over an extended period and the disposal of large-scale radioactive wastes and radiation protection criteria to be applied upon recovery. Accordingly, Japan has taken improvement initiatives in the area of prevention by submitting a government report on the Fukushima accident prior to the IAEA Ministerial Conference on Nuclear Safety in June last year, and the US has devised a regulatory system of its own, including directions for improvement through the NRC, which operated a temporary taskforce specifically for this purpose. This study examined how Japan is responding to the Fukushima accident and investigated directions that countries around the world can take to improve the area of nuclear protection in order to enhance Korea's own radiological emergency management system

  7. Emergency room management of radiation accidents

    Emergency room management of radioactively contaminated patients who have an associated medical injury requiring immediate attention must be handled with care. Radioactive contamination of the skin of a worker is not a medical emergency and is usually dealt with at the plant. Effective preplanning and on-the-scene triage will allow the seriously injured and contaminated patients to get the medical care they need with a minimum of confusion and interference. Immediate medical and surgical priorities always take precedence over radiation injuries and radioactive contamination. Probably the most difficult aspect of emergency management is the rarity of such accidents and hence the unfamiliarity of the medical staff with the appropriate procedures. The authors discuss how the answer to these problems is preplanning, having a simple and workable procedure and finally having 24-h access to experts

  8. A study on the development of framework and supporting tools for severe accident management

    Through the extensive research on severe accidents, knowledge on severe accident phenomenology has constantly increased. Based upon such advance, probabilistic risk studies have been performed for some domestic plants to identify plant-specific vulnerabilities to severe accidents. Severe accident management is a program devised to cover such vulnerabilities, and leads to possible resolution of severe accident issues. This study aims at establishing severe accident management framework for domestic nuclear power plants where severe accident management program is not yet established. Emphasis is given to in-vessel and ex-vessel accident management strategies and instrumentation availability for severe accident management. Among the various strategies investigated, primary system depressurization is found to be the most effective means to prevent high pressure core melt scenarios. During low pressure core melt sequences, cooling of in-vessel molten corium through reactor cavity flooding is found to be effective. To prevent containment failure, containment filtered venting is found to be an effective measure to cope with long-term and gradual overpressurization, together with appropriate hydrogen control measure. Investigation of the availability of Yonggwang 3 and 4 instruments shows that most of instruments essential to severe accident management lose their desired functions during the early phase of severe accident progression, primarily due to the environmental condition exceeded ranges of instruments. To prevent instrument failure, a wider range of instruments are recommended to be used for some severe accident management strategies such as reactor cavity flooding. Severe accidents are generally known to accompany a number of complex phenomena and, therefore, it is very beneficial when severe accident management personnel is aided by appropriately designed supporting systems. In this study, a support system for severe accident management personnel is developed

  9. Assessment of light water reactor accident management programs and experience

    The objective of this report is to provide an assessment of the current light water reactor experience regarding accident management programs and associated technology developments. This assessment for light water reactor (LWR) designs is provided as a resource and reference for the development of accident management capabilities for the production reactors at the Savannah River Site. The specific objectives of this assessment are as follows: 1. Perform a review of the NRC, utility, and industry (NUMARC, EPRI) accident management programs and implementation experience. 2. Provide an assessment of the problems and opportunities in developing an accident management program in conjunction or following the Individual Plant Examination process. 3. Review current NRC, utility, and industry technological developments in the areas of computational tools, severe accident predictive tools, diagnostic aids, and severe accident training and simulation

  10. Assessment of light water reactor accident management programs and experience

    Hammersley, R.J. [Fauske and Associates, Inc., Burr Ridge, IL (United States)

    1992-03-01

    The objective of this report is to provide an assessment of the current light water reactor experience regarding accident management programs and associated technology developments. This assessment for light water reactor (LWR) designs is provided as a resource and reference for the development of accident management capabilities for the production reactors at the Savannah River Site. The specific objectives of this assessment are as follows: 1. Perform a review of the NRC, utility, and industry (NUMARC, EPRI) accident management programs and implementation experience. 2. Provide an assessment of the problems and opportunities in developing an accident management program in conjunction or following the Individual Plant Examination process. 3. Review current NRC, utility, and industry technological developments in the areas of computational tools, severe accident predictive tools, diagnostic aids, and severe accident training and simulation.

  11. A Methodology for Evaluating Severe Accident Management Strategies

    Severe accidents are defined as those which entail at least an initial core damage, in many cases specified as the overcoming of the regulatory fuel. After Fukushima accident, the effectiveness of the severe accident management strategy has been attracted worldwide. There is a typical example of severe accident management strategy like Severe Accident Management and Guideline (SAMG). Unfortunately, suitable method for evaluating the accident management strategy is absence until now. In this study, the evaluation methodology which utilizes the decision tree is developed to evaluate the severe accident management strategies. In addition, we applied the developed methodology to ShinKori nuclear power plant Unit 3, 4 and modeled decision tree for evaluation. In this study, we developed a methodology to evaluate the severe accident management strategy by using decision tree. In addition, the evaluation was carried out by selecting the cavity flooding strategy. Shinkori unit 3, 4 which is APR1400 is selected and analyzed for reference plant. In order to evaluation, decision tree for cavity flooding is modeled. With reliability data, quantification will be conducted. The utility of other severe accident management strategies can be evaluated with proposed methodology in this study. Finally, it is expected that this methodology improves the safety of nuclear power plant

  12. Market-oriented management method of coalmine accident hidden dangers

    LIU Zhao-xia; LI Xing-dong; LU Ying; REN Da-wei

    2007-01-01

    By analyzing the problems which exist currently in the accident hidden dangers management of the coal mine, this paper proposed a new kind of management method-"simulating the market", in which an operation pattern of simulating the market to transact hidden troubles was constructed. This method introduces "Market Mechanism"into safe management, and adopts measurable value to describe the hidden dangers such as" human behavior, technique, environment, equipments etc.". It regards the hidden dangers as "the goods produced by labor" which are found out by the safety managers and the security inspectors, then sells as "commodity". By the process of disposing, counterchecking, re-selling, and redisposing. It forms a set of market-oriented closed-form management pattern of coalmine accident hidden dangers. This kind of management method changes the past traditional methods in which the wageworkers treat safety management passively, but to encourage and restrict them to participate in the check-up and improvement of the hidden dangers.

  13. Assessment of two BWR accident management strategies

    Candidate mitigative strategies for the management of in-vessel events during the late phase (after-core degradation has occurred) of postulated boiling water reactor (BWR) severe accidents were considered at Oak Ridge National Laboratory (ORNL) during 1990. The identification of new strategies was subject to the constraint that they should, to the maximum extent possible, make use of the existing equipment and water resources of the BWR facilities, and not require major equipment modifications or additions. As a result of this effort, two of these candidate strategies were recommended for further assessment. The first was a strategy for containment flooding to maintain the core and structural debris within the reactor vessel in the event that vessel injection cannot be restored to terminate a severe accident sequence. The second strategy pertained to the opposite case, for which vessel injection would be restored after control blade melting had begun; its purpose was to provide an injection source of borated water at the concentration necessary to preclude criticality upon recovering a damaged BWR core. Assessments of these two strategies were performed during 1991 and this paper provides a discussion of the motivation for and purpose of these strategies, and the potential for their success. ((orig.))

  14. Accident Management Issues within the ARTIST Project

    An experimental project to be performed in the ARTIST (AeRosol Trapping In a Steam generaTor ) facility is planned at the Paul Scherrer Institut to address aerosol retention in the various parts of the steam generator (SG) following a steam generator tube rupture (SGTR) event. The project will study phenomena at the separate effect and integral levels, and also address accident management (AM) issues. Seven distinct phases are foreseen: 1) Aerosol retention in the tube under dry secondary side conditions, 2) Aerosol retention in the near field close to break under dry conditions, 3) Aerosol retention in the bundle far field under dry conditions, 4) Aerosol retention in the separator and dryer under dry conditions, 5) Aerosol retention in the bundle section under wet conditions, 6) Droplet retention in separator and dryer sections and 7) Integral tests to examine overall retention. The prescribed values of the controlling parameters (aerosol size, aerosol type, gas flow velocity, residence time, etc) cover the range expected in severe accident scenarios. The ARTIST facility is well suited to study phenomena relating to AM. Refilling of the SG might be adopted as an AM measure during an accident in which the SG has dried out. For instance, water injection will establish a pool where the incoming aerosols can be scrubbed to various degrees depending on the aerosol characteristics, water depth and subcooling and steam content in the carrier gas flow. Aerosols are expected to be removed mainly through inertial impaction and diffusiophoresis (condensation) in the vicinity of the break. Away from the break, the remaining gas breaks up in smaller bubbles which rise in the pool, and periodically squirt out through the narrow constrictions of the support plates. In this latter phase, aerosol removal is mainly due to inertial mechanisms. There are many questions that need to be resolved before deciding on the efficacy of flooding the secondary side of a dry SG. These include

  15. Level 2 PSA methodology and severe accident management

    The objective of the work was to review current Level 2-PSA (Probabilistic Safety Assessment) methodologies and practices and to investigate how Level 2-PSA can support severe accident management programmes, i.e. the development, implementation, training and optimisation of accident management strategies and measures. For the most part, the presented material reflects the state in 1996. Current Level 2 PSA results and methodologies are reviewed and evaluated with respect to plant type specific and generic insights. Approaches and practices for using PSA results in the regulatory context and for supporting severe accident management programmes by input from level 2 PSAs are examined. The work is based on information contained in: PSA procedure guides, PSA review guides and regulatory guides for the use of PSA results in risk informed decision making; plant specific PSAs and PSA related literature exemplifying specific procedures, methods, analytical models, relevant input data and important results, use of computer codes and results of code calculations. The PSAs are evaluated with respect to results and insights. In the conclusion section, the present state of risk informed decision making, in particular in the level 2 domain, is described and substantiated by relevant examples

  16. Health protection measures after the Chernobyl accident

    The article describes the nutritional measures introduced to protect health after the Chernobyl accident, and the associated costs. The toal value of the reindeer meat, mutton, lamb and goat meat saved as a result of such measures in 1987 amounted to approx. NOK 250 million. The measures cost approx. NOK 60 million. The resulting reduction in the radiation dose level to which the population was exposed was 450 manSv. In 1988, mutton/lamb and goat meat valued at approx. NOK 310 million was saved from contamination by similar measures, which cost approx. NOK 50 million. The resulting dose level reduction was approx. 200 manSv. The relationship (cost/benefit ratio) between the overall cost of the measures taken to reduce radioactivity levels in food and the dose level reduction achieved was acceptable. 11 refs

  17. Hygienic measures during accidents at nuclear power plants

    Problems of radiation protection in case of large-scale accidents at nuclear power plants are discussed. Aims and purposes of protective measures are shown. Ways of radiation factor effects at various accident stages are described as well as corresponding protective measures. Attention is paid to the criteria of decision adoption at various accident development phases. Examples from the Chernobyl accident experience are presented. 10 refs.; 3 tabs

  18. Using MARS to assist in managing a severe accident

    During an accident, information about the current and possible future states of the plant provides guidance for accident managers in evaluating which actions should be taken. However, depending upon the nature of the accident and the stress levels imposed on the plant staff responding to the accident the current and future plant assessments may be very difficult or nearly impossible to perform without supplemental training and/or appropriate tools. The MAAP Accident Response System (MARS) has been developed as a calculational aid to assist the responsible accident management individuals. Specifically MARS provides additional insights on the current and possible future states of the plant during an accident including the influence of operator actions. In addition to serving as a calculational aid, the MARS software can be an effective means for providing supplemental training. The MARS software uses engineering calculations to perform an integral assessment of the plant status including a consistency assessment of the available instrumentation. In addition, it uses the Modular Accident Analysis Program (MAAP) to provide near term predictions of the plant response if corrective actions are taken. This paper will discuss the types of information that are beneficial to the accident manager and how MARS addresses each. The MARS calculational functions include: instrumentation, validation and simulation, projected operator response based on the EOPs, as well as estimated timing and magnitude of in-plant and off-site radiation dose releases. Each of these items is influential in the management of a severe accident. (author)

  19. A framework for the assessment of severe accident management strategies

    Severe accident management can be defined as the use of existing and/or altemative resources, systems and actors to prevent or mitigate a core-melt accident. For each accident sequence and each combination of severe accident management strategies, there may be several options available to the operator, and each involves phenomenological and operational considerations regarding uncertainty. Operational uncertainties include operator, system and instrumentation behavior during an accident. A framework based on decision trees and influence diagrams has been developed which incorporates such criteria as feasibility, effectiveness, and adverse effects, for evaluating potential severe accident management strategies. The framework is also capable of propagating both data and model uncertainty. It is applied to several potential strategies including PWR cavity flooding, BWR drywell flooding, PWR depressurization and PWR feed and bleed

  20. A framework for the assessment of severe accident management strategies

    Kastenberg, W.E. [ed.; Apostolakis, G.; Dhir, V.K. [California Univ., Los Angeles, CA (United States). Dept. of Mechanical, Aerospace and Nuclear Engineering] [and others

    1993-09-01

    Severe accident management can be defined as the use of existing and/or altemative resources, systems and actors to prevent or mitigate a core-melt accident. For each accident sequence and each combination of severe accident management strategies, there may be several options available to the operator, and each involves phenomenological and operational considerations regarding uncertainty. Operational uncertainties include operator, system and instrumentation behavior during an accident. A framework based on decision trees and influence diagrams has been developed which incorporates such criteria as feasibility, effectiveness, and adverse effects, for evaluating potential severe accident management strategies. The framework is also capable of propagating both data and model uncertainty. It is applied to several potential strategies including PWR cavity flooding, BWR drywell flooding, PWR depressurization and PWR feed and bleed.

  1. Application of PCTRAN-3/U to studying accident management during PWR severe accident

    In order to improve the safety of nuclear power plant, operator action should be taken into account during a severe accident. While it takes a long time to simulate the plant transient behavior under a severe accident in comparison with the design based accident, a transient simulator should have both high speed calculation capability and interactive functions to model the operating procedures. PCTRAN has been developing to be a simple simulator by using a personal computer to simulate plant behavior under an accident condition. While currently available means usually take relatively long time to simulate plant behavior, using a current high-powered personal computer (PC), PCTRAN-3/U code is designed to operate at a speed significantly faster than real-time. The author describes some results of PCTRAN application in studying the efficiency of accident management for a pressurized water reactor (PWR) during an severe accident

  2. Emergency medical management of radiation accident. Lessons learned from the JCO criticality accident

    A criticality accident occurred at the JCO nuclear fuel processing plant in Tokai-mura, Japan at 10:35 am on September 30, 1999. Three workers while working nearby were exposed to high doses of radiation, especially rich in neutron. They suffered from the acute radiation syndrome and two of them were still under medical treatment. This criticality accident taught us significant lessons of radiation protection for the personnels, e.g. physicians, nurses and firemen who are expected to rescue radiation-exposed patients in radiation accidents. In this article, medical management of radiation accident, e.g. treatment of patient, with high-dosed radiation-exposure and with internal contamination of radioactive nuclides and estimation of individual radiation dose, were briefly explained. The Japanese Association for Medical Management of Radiation Accident was founded on August 29, 1997, in order to promote the mutual communication of physicians who have to be engaged in treatment of radiation-exposed patients. (author)

  3. Fundamental studies into the process and system performance of nuclear power plant, measuring and automation engineering for accident management. Final report

    The application of pretentious methods of signal handling like Observer, Kalman Filter and Fuzzy-Logic in safety-related systems is still limited. The main aim of the project was the improvement of the quality and reliability of the measured signals as well as the determination of non measurable safety-related process paramters with the help of these methods. The investigations were realized on the example of the determination of the safety-related parameter level in pressure vessels with two-phase mixture considering the static and dynamic behaviour of the hydrostatical measuring system during accidents (loss of coolant accident). At the beginning of the project the emphasis of the research work was on the reactor of VVER 440 (horizontal steam generator). Further investigations were expanded to VVER 1000 and BWR (reactor pressure vessel). The method of treatment included the following components: Experimental analysis of single effects at the test facility Pressurizer Model, modelling and simulation with the help of the simulation code ATHLET, development of model-based measurement methods on the basis of adapted models, verification of the developed models and methods. On the basis of the results of the experiments algorithms were developed, realizing the following tasks: - Diagnosis of the process state of pressure vessel and level measuring system with the help of Fuzzy-Logic, - correction of the level indicated by the measuring system, - calculation of the non measurable variable mixture level by Observer and Kalman Filter on the basis of linear state space models, - ATHLET-modules simulating hydrostatic level measurement system (VVER 440, VVER 1000, BWR). (orig.)

  4. Strategy generator in computerized accident management support system

    An increased interest for research in the field of accident management of nuclear power plants can be noted. Several international programmes have been started in order to be able to understand the basic physical and chemical phenomena in accident conditions. A feasibility study has shown that it would be possible to design and develop a computerized support system for plant staff in accident situations. To achieve this goal the Halden Project has initiated a research programme on Computerized Accident Management Support (CAMS project). The aim is to utilize the capabilities of computerized tools to support the plant staff during the various accident stages. The system will include identification of the accident state, assessment of the future development of the accident and planning of accident mitigation strategies. A prototype is developed to support operators and the Technical Support Centre in decision making during serious accidents in nuclear power plants. A rule based system has been built to take care of the strategy generation. This system assists plant personnel in planning control proposals and mitigation strategies from normal operation to severe accident conditions. The idea of a safety objective tree and knowledge from the emergency procedures have been used. Future prediction requires good state identification of the plant status and some knowledge about the history of some critical variables. The information needs to be validated as well. Accurate calculations in simulators and a large database including all important information from the plant will help the strategy planning. (orig.). (40 refs., 20 figs.)

  5. The management of individuals involved in radiation accidents

    The author defines the objectives and the coverage of two radiation accident courses presented in 1990 by the US Radiation Emergency Assistance Centre and Training Site of the Oak Ridge Associated Universities together with some Australian Medical institutions. It is estimated that the courses, directed towards physicians, radiotherapists and nurses gave plenty practical advices and details on how to go about radiation accident managements. A manual on handling radiation accidents is also to be prepared after the courses

  6. Accidents - Chernobyl accident; Accidents - accident de Tchernobyl

    NONE

    2004-07-01

    This file is devoted to the Chernobyl accident. It is divided in four parts. The first part concerns the accident itself and its technical management. The second part is relative to the radiation doses and the different contaminations. The third part reports the sanitary effects, the determinists ones and the stochastic ones. The fourth and last part relates the consequences for the other European countries with the case of France. Through the different parts a point is tackled with the measures taken after the accident by the other countries to manage an accident, the cooperation between the different countries and the groups of research and studies about the reactors safety, and also with the international medical cooperation, specially for the children, everything in relation with the Chernobyl accident. (N.C.)

  7. Unconventional sources of plant information for accident management

    An essential element to accident management is having as clear a picture as is practical of the plant status and thus of the accident and its progress. Effective, appropriate decisions to control and mitigate an accident are dependent on making this assessment of the accident. The objective of this paper is to stimulate consideration of unconventional plant information sources through discussion of specific examples. A plant's condition during an accident can be characterized by plant parameters such as temperatures and pressures and by plant system operational status. For example, core damage is associated with increasing temperatures, pressures, and radiation levels in many different systems and plant areas. Reg. Guide 1.97 instrumentation exists to provide information to allow operators to take specified manual actions (Type A), to indicate whether plant safety functions are being accomplished (Type B), to indicate the potential for breach of barriers to fission product release (Type C), to indicate operability of individual safety systems (Type D), and to indicate the magnitude of radioactive material releases (Type E). Reg. Guide 1.97 instrument range requirements, with the exception of pressure instruments, address conditions up to design basis conditions. Pressure instrument range requirements exceed design basis conditions. During a severe accident, some instruments may not see conditions beyond their design basis. Effective accident management includes the ability to establish a consistent picture of the accident by accumulating information from as many sources as is practical. Operability of systems and components, and non-safety related temperature, radiation, pressure, and water-level indication can be used to directly indicate, measure, or infer plant parameters which confirm, augment or replace those otherwise available. Innovative uses of information sources thus serve to increase the diversity and flexibility of accident data available. Both the

  8. Systematic Review of Accident Management Programs - Principles, Experiences

    Although all plants have some form of accident management, there is not always a proper review of the accident management program neither of its products, i.e. the various procedures and guidelines. Moreover, such reviews are often limited to Emergency Operating Procedures (EOPs) and Severe Accident Management Guidelines (SAMG). More complex events, which include large damage on the site, require additional tools and procedures / guidelines. The present paper describes a new review method that covers this larger area and is capable to identify problems and shortcomings, and offers solutions for those. It basically exists of a three-tier approach: 1. interviews with the national regulator and/or the plant to evaluate the scope of the accident management as required by the national regulation and in comparison with international regulation; 2. interviews with the plant staff to discuss the technical basis of the accident management program and its implementation; and 3. observation of an exercise to test the capability of the plant staff to execute the accident management procedures and guidelines, as well as the value of the exercise for such test. The method is an extension of the IAEA 'Review of Accident Management Program which is limited to review of EOPs and SAMG. It is based on extensive experience with plant reviews. (authors)

  9. The influence of accident measures on accident scenarios for VVER-1000-Type reactors

    For VVER-1000-type reactors severe accident scenarios and possible mitigation strategies are investigated. The Station blackout sequence is chosen as reference case. At first a comparison between the cases with and without working spray systems is discussed. Afterwards the results of a parametric study investigating the influence of different water volumes on the course of the accident are presented. It can be shown that most of these accident mitigation measures will maintain the containment integrity and reduce the source term. (author)

  10. Preliminary severe accident management strategies for Wolsong nuclear power plants

    Severe accident management strategies for Wolsong 2,3,4 Nuclear Power Plants are presented. The defense in depth concept, which limits release of radioactive materials out of containment building, is applied to develop these strategies. These strategies are actions to prevent or to mitigate core damage, rupture of calandria vessel, rupture of calandria vault, rupture of containment building, and release of radioactive materials. These strategies are deduced from the results of level 2 PSA for Wolsong NPPs. These preliminary results will be assessed further and proved to be effective to Wolsong Plants. Then these severe accident management strategies can be used to develop severe accident management program for Wolsong NPPs

  11. Summary of a workshop on severe accident management for BWRs

    Severe accident management can be defined as the use of existing and/or alternative resources, systems and actions to prevent or mitigate a core-melt accident. For each accident sequence and each combination of strategies there may be several options available to the operator; and each involves phenomenological and operational considerations regarding uncertainty. Operational uncertainties include operator, system and instrument behavior during an accident. During the period September 26--28, 1990, a workshop was held at the University of California, Los Angeles, to address these uncertainties for Boiling Water Reactors (BWRs). This report contains a summary of the workshop proceedings

  12. Implementation of accident management programmes in nuclear power plants

    According to the generally established defence in depth concept in nuclear safety, consideration in plant operation is also given to highly improbable severe plant conditions that were not explicitly addressed in the original design of currently operating nuclear power plants (NPPs). Defence in depth is achieved primarily by means of four successive barriers which prevent the release of radioactive material (fuel matrix, cladding, primary coolant boundary and containment), and these barriers are primarily protected by three levels of design measures: prevention of abnormal operation and failures (level 1), control of abnormal operation and detection of failures (level 2) and control of accidents within the design basis (level 3). If these first three levels fail to ensure the structural integrity of the core, e.g. due to beyond the design basis multiple failures, or due to extremely unlikely initiating events, additional efforts are made at level 4 to further reduce the risks. The objective at the fourth level is to ensure that both the likelihood of an accident entailing significant core damage (severe accident) and the magnitude of radioactive releases following a severe accident are kept as low as reasonably achievable. Finally, level 5 includes off-site emergency response measures, with the objective of mitigating the radiological consequences of significant releases of radioactive material. The implementation of the emergency response is usually dependent upon the type and magnitude of the accident. Good co-ordination between the operator and the responding organizations is needed to ensure the appropriate response. Accident management is one of the key components of effective defence in depth. In accordance with defence in depth, each design level should be protected individually, independently of other levels. This report focuses on the fourth level of defence in depth, including the transitions from the third level and into the fifth level. It describes

  13. Essential severe accident mitigation measures for operating and future PWR's

    material in the containment atmosphere, on the conditions of the core and for effective accident management decisions. These new in-situ sampling technology was developed and implemented to avoid the strong deposition errors of iodine and aerosols in conventional pipe extraction systems. The venting system is introduced for operating plants and can also be used for future plants although it is not required for the EPR. The Sliding Pressure Venting System consists mainly of a venturi scrubber unit with integrated high efficient metal fiber filter followed by means for super sonic throttling and operation under the sliding containment pressure conditions. Due to this special design and operation the system dimensions could be kept small in spite of obtaining high retention rates for aerosols of >99.99% and that for molecular iodide is >99.5%. For the EPR additional measures for maintaining the containment integrity are foreseen: · use of highly reliable dedicated valves for depressurization which supplement normal bleed valves to eliminate high pressure RPV failure · use of a core melt retention device for melt stabilization by means of spreading of the melt within a large compartment adjacent to the reactor pit, followed by flooding, quenching and cooling of the melt from the top and via a bottom cooling structure; · use of a dedicated active two-train containment heat removal system which needs to operate not earlier than 12h after start of the accident

  14. Applying Functional Modeling for Accident Management of Nuclear Power Plant

    Lind, Morten; Zhang, Xinxin

    2014-01-01

    The paper investigate applications of functional modeling for accident management in complex industrial plant with special reference to nuclear power production. Main applications for information sharing among decision makers and decision support are identified. An overview of Multilevel Flow...

  15. Applying Functional Modeling for Accident Management of Nucler Power Plant

    Lind, Morten; Zhang, Xinxin

    2014-01-01

    The paper investigates applications of functional modeling for accident management in complex industrial plant with special reference to nuclear power production. Main applications for information sharing among decision makers and decision support are identified. An overview of Multilevel Flow...

  16. Development of Krsko Severe Accident Management Guidance (SAMG)

    In this lecture development of severe accident management guidances for Krsko NPP are described. Author deals with the history of severe accident management and implementation of issues (validation, review of E-plan and other aspects SAMG implementation guidance). Methods of Westinghouse owners group, of Combustion Engineering owners group, of Babcock and Wilcox owners group, of the BWR owners group, as well as application of US SAMG methodology in Europe and elsewhere are reviewed

  17. Traffic Accident Prediction Model Implementation in Traffic Safety Management

    Wen, Keyao

    2009-01-01

    As one of the highest fatalities causes, traffic accidents and collisions always requires a large amounteffort to be reduced or prevented from occur. Traffic safety management routines therefore always needefficient and effective implementation due to the variations of traffic, especially from trafficengineering point of view apart from driver education.Traffic Accident Prediction Model, considered as one of the handy tool of traffic safety management,has become of well followed with interest...

  18. Severe Accident Management Strategy for EU-APR1400

    In EU-APR1400, the dedicated instrumentation and mitigation features for SAM are being developed to keep the integrity of containment and to prevent the uncontrolled release of fission products. In this paper, SAM strategy for EU-APR1400 was introduced in stages. It is still under development and finally the Severe Accident Management Guidance will be completed based on this SAM Strategy. Severe accidents in a nuclear power plant are defined as certain unlikely event sequences involving significant core damage with the potential to lead to significant releases according to EUR 2.1.4.4. Even though the probability of severe accidents is extremely low, the radiation release may cause serious effect on people as well as environment. Severe Accident Management (SAM) encompasses those actions which could be considered in recovering from a severe accident and preventing or mitigating the release of fission products to the environment. Whether those actions are successful or not, depending on a progression status of a severe accident to mitigate the consequences of severe accident phenomena to limit the release of radioactive materials keeping the leak tightness of the Primary Containment, and finally to restore transient severe accident progression into a controlled and safe states

  19. Regulatory perspective on accident management issues

    Effective response to reactor accidents requires a combination of emergency operations, technical support and emergency response. The NRC and industry have actively pursued programs to assure the adequacy of emergency operations and emergency response. These programs will continue to receive high priority. By contrast, the technical support function has received relatively little attention from NRC and the industry. The results from numerous PRA studies and the severe accident programs of NRC and the industry have yielded a wealth of insights on prevention and mitigation of severe accidents. The NRC intends to work with the industry to make these insights available to the technical support staffs through a combination of guidance, training and periodic drills

  20. Aerosol measurements and nuclear accidents: a reconsideration

    Within its radioactivity environmental monitoring programme, the Commission of the European Communities and in particular its Joint Research Centre wants to encourage the qualitative improvement of radioactivity monitoring. On 3 and 4 December 1987 an experts' meeting has been organized by the Ispra Joint Research Centre in collaboration with the Gesellschaft fuer Aerosolforschung, in order to discuss measuring techniques for radioactive aerosols in the environment in case of a nuclear accident. During the workshop, current practices in routine monitoring programmes in the near and far field of nuclear power plants were confronted with the latest developments in the metrology of aerosols and radioactivity. The need and feasibility of implementing advanced aerosol and radioactivity techniques in routine monitoring networks have been discussed. This publication gives the full text of 12 presentations and a report of the roundtable discussion being held afterwards. It does not intend to give a complete picture of all activities going on in the field of radioactive aerosol metrology; it rather collects a number of common statements of people who approach the problem from quite different directions

  1. Application of simulation techniques for accident management training in nuclear power plants

    Many IAEA Member States operating nuclear power plants (NPPs) are at present developing accident management programmes (AMPs) for the prevention and mitigation of severe accidents. However, the level of implementation varies significantly between NPPs. The exchange of experience and best practices can considerably contribute to the quality, and facilitate the implementation of AMPs at the plants. Various IAEA activities assist countries in the area of accident management. Several publications have been developed which provide guidance and support in establishing accident management at NPPs. The defence in depth concept in nuclear safety requires that, although highly unlikely, beyond design basis and severe accident conditions should also be considered, in spite of the fact that they were not explicitly addressed in the original design of currently operating nuclear power plants (NPPs). Defence in depth is physically achieved by means of four successive barriers (fuel matrix, cladding, primary coolant boundary, and containment) that prevent the release of radioactive material. These barriers are protected by a set of design measures at three levels, including prevention of abnormal operation and failures (level 1), control of abnormal operation and detection of failures (level 2) and control of accidents within the design basis (level 3). Should these first three levels fail to ensure the structural integrity of the core, additional efforts are made at the fourth level of defence in depth in order to further reduce the risks. The objective at level 4 is to ensure that both the likelihood of an accident entailing significant core damage (severe accident) and the magnitude of radioactive releases following a severe accident are kept as low as reasonably achievable. The term 'accident management' refers to the overall range of capabilities of a NPP and its personnel to both prevent and mitigate accident situations that could lead to severe fuel damage in the reactor

  2. Passive depressurization accident management strategy for boiling water reactors

    Highlights: • We proposed two passive depressurization systems for BWR severe accident management. • Sensitivity analysis of the passive depressurization systems with different leakage area. • Passive depressurization strategies can prevent direct containment heating. - Abstract: According to the current severe accident management guidance, operators are required to depressurize the reactor coolant system to prevent or mitigate the effects of direct containment heating using the safety/relief valves. During the course of a severe accident, the pressure boundary might fail prematurely, resulting in a rapid depressurization of the reactor cooling system before the startup of SRV operation. In this study, we demonstrated that a passive depressurization system could be used as a severe accident management tool under the severe accident conditions to depressurize the reactor coolant system and to prevent an additional devastating sequence of events and direct containment heating. The sensitivity analysis performed with SAMPSON code also demonstrated that the passive depressurization system with an optimized leakage area and failure condition is more efficient in managing a severe accident

  3. The computer aided education and training system for accident management

    Under severe accident conditions of a nuclear power plant, plant operators and technical support center (TSC) staffs will be under a amount of stress. Therefore, those individuals responsible for managing the plant should promote their understanding about the accident management and operations. Moreover, it is also important to train in ordinary times, so that they can carry out accident management operations effectively on severe accidents. Therefore, the education and training system which works on personal computers was developed by Japanese BWR group (Tokyo Electric Power Co.,Inc., Tohoku Electric Power Co. ,Inc., Chubu Electric Power Co. ,Inc., Hokuriku Electric Power Co.,Inc., Chugoku Electric Power Co.,Inc., Japan Atomic Power Co.,Inc.), and Hitachi, Ltd. The education and training system is composed of two systems. One is computer aided instruction (CAI) education system and the other is education and training system with a computer simulation. Both systems are designed to execute on MS-Windows(R) platform of personal computers. These systems provide plant operators and technical support center staffs with an effective education and training tool for accident management. TEPCO used the simulation system for the emergency exercise assuming the occurrence of hypothetical severe accident, and have performed an effective exercise in March, 2000. (author)

  4. Emerging framework of safety management after Fukushima accident

    Since the Fukushima accident onset, concerned organizations and experts have tried to identify the causes and effects of the incident. Many have formulated new national regulatory measures to strengthen nuclear safety in an effort to protect the general public to the extent of probabilistic cases of the most severe or extreme accidents. The Japanese government is set to install a regulatory authority, comparable to the US NRC, which is completely independent from the promotion of nuclear energy. An official report of the National Diet (or Senate) of Japan in June of 2012 laments a lack of safety culture and insists the accident could have been prevented if due consideration and attention had been provided. Both France and other European countries have performed stress tests to their operating units, and have identified many areas for improvement including that of their regulatory framework. The US NRC also conducted special inspections of all operating reactors. In addition, the NRC established both near and long term specific goals, and issued a policy statement for streamlining patch worked regulatory framework. It is also applying the Risk informed Defense in Depth Design which includes the extended design basis requirements. The IAEA General Conference adopted a Nuclear Safety Action Plan in September 2011 and organized an International Expert Meeting in March 2012 in order to analyze all relevant technical aspects from the Japanese incident in order to prevent a reoccurrence. Korea is not an exception to this trend. She was swift to conduct a special inspection of operating reactors and is now implementing many scheduled measures. Numerous facts and insights are now available, not only those gained from the Japanese incident, but also those gleaned from experts worldwide concerning a wide array of information. Therefore, this is an opportunistic time to summarize the insights that have been identified with respect to nuclear safety management and to overview

  5. Emerging framework of safety management after Fukushima accident

    Lee, Joo Sang [TUV SUD KOCEN, Yongin (Korea, Republic of); Rawls, Scott [EXCEL, JP (United States)

    2012-10-15

    Since the Fukushima accident onset, concerned organizations and experts have tried to identify the causes and effects of the incident. Many have formulated new national regulatory measures to strengthen nuclear safety in an effort to protect the general public to the extent of probabilistic cases of the most severe or extreme accidents. The Japanese government is set to install a regulatory authority, comparable to the US NRC, which is completely independent from the promotion of nuclear energy. An official report of the National Diet (or Senate) of Japan in June of 2012 laments a lack of safety culture and insists the accident could have been prevented if due consideration and attention had been provided. Both France and other European countries have performed stress tests to their operating units, and have identified many areas for improvement including that of their regulatory framework. The US NRC also conducted special inspections of all operating reactors. In addition, the NRC established both near and long term specific goals, and issued a policy statement for streamlining patch worked regulatory framework. It is also applying the Risk informed Defense in Depth Design which includes the extended design basis requirements. The IAEA General Conference adopted a Nuclear Safety Action Plan in September 2011 and organized an International Expert Meeting in March 2012 in order to analyze all relevant technical aspects from the Japanese incident in order to prevent a reoccurrence. Korea is not an exception to this trend. She was swift to conduct a special inspection of operating reactors and is now implementing many scheduled measures. Numerous facts and insights are now available, not only those gained from the Japanese incident, but also those gleaned from experts worldwide concerning a wide array of information. Therefore, this is an opportunistic time to summarize the insights that have been identified with respect to nuclear safety management and to overview

  6. The DOE technology development programme on severe accident management

    The US Department of Energy (DOE) is sponsoring a programme in technology development aimed at resolving the technical issues in severe accident management strategies for advanced and evolutionary light water reactors (LWRs). The key objective of this effort is to achieve a robust defense-in-depth at the interface between prevention and mitigation of severe accidents. The approach taken towards this goal is based on the Risk Oriented Accident Analysis Methodology (ROAAM). Applications of ROAAM to the severe accident management strategy for the US AP600 advanced LWR have been effective both in enhancing the design and in achieving acceptance of the conclusions and base technology developed in the course of the work. This paper presents an overview of that effort and its key technical elements

  7. Accidents - Chernobyl accident

    This file is devoted to the Chernobyl accident. It is divided in four parts. The first part concerns the accident itself and its technical management. The second part is relative to the radiation doses and the different contaminations. The third part reports the sanitary effects, the determinists ones and the stochastic ones. The fourth and last part relates the consequences for the other European countries with the case of France. Through the different parts a point is tackled with the measures taken after the accident by the other countries to manage an accident, the cooperation between the different countries and the groups of research and studies about the reactors safety, and also with the international medical cooperation, specially for the children, everything in relation with the Chernobyl accident. (N.C.)

  8. Validation of severe accident management guidance for the wolsong plants

    Full text: Full text: The severe accident management(SAM) guidance has been developed for the Wolsong nuclear power plants in Korea. The Wolsong plants are 700MWe CANDU-type reactors with heavy water as the primary coolant, natural uranium-fueled pressurized, horizontal tubes, surrounded by heavy water moderator inside a horizontal calandria vessel. The guidance includes six individual accident management strategies: (1) injection into primary heat transport system (2) injection into calandria vessel (3) injection into calandria vault (4) reduction of fission product release (5) control of reactor building condition (6) reduction of reactor building hydrogen. The paper provides the approaches to validate the SAM guidance. The validation includes the evaluation of:(l) effectiveness of accident management strategies, (2) performance of mitigation systems or components, (3) calculation aids, (4) strategy control diagram, and (5) interface with emergency operation procedure and with radiation emergency plan. Several severe accident sequences with high probability is selected from the plant specific level 2 probabilistic safety analysis results for the validation of SAM guidance. Afterward, thermal hydraulic and severe accident phenomenological analyses is performed using ISAAC(Integrated Severe Accident Analysis Code for CANDU Plant) computer program. Furthermore, the experiences obtained from a table-top-drill is also discussed

  9. The Goiania accident waste management - Reconditioning operation

    As a result of an accidental breakage of a 137Cs radiotherapy source, radioactive waste was generated in Goiania-Brazil. It was collected in different types of packaging and removed to a temporary storage site near Abadia de Goias. After four years in open air storage, corrosion was detected in some packages, especially in the 200 1drums. Measures to ensure a safe interim storage were adopted, until a final disposal plan was to be executed. The objective was to make the waste product suitable for the final disposal requests according to Brazilian standards. These measures were concerned mainly with the waste reconditioning. This paper presents the waste management strategy adopted for this operation

  10. Information processing system and neural network utilization for accident management support

    Tuerkcan, E. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Ciftcioglu, Oe. [Istanbul Technical Univ. (Turkey). Faculty of Electrical and Electronic Engineering; Verhoef, J.P. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Ouden, A.C.B. den [Netherlands Energy Research Foundation (ECN), Petten (Netherlands)

    1996-03-01

    Information processing system with data sensor fusion technology together with potential application of neural network is developed. System is designed for operator in the form of Accident Management Support (AMS) with verification and validation (V and V) for cases of severe accident. To this end, primarily noise analysis techniques are used and their merits are merged for exhaustive information extraction in accident cases where the data from sensors may be obscured by drift, modulation so forth or even incomplete. The information from different methodologies are processed in synergetic form (data sensor fusion) by means of statistical distance measures and neural networks with optimal decisions. (orig.).

  11. Information processing system and neural network utilization for accident management support

    Information processing system with data sensor fusion technology together with potential application of neural network is developed. System is designed for operator in the form of Accident Management Support (AMS) with verification and validation (V and V) for cases of severe accident. To this end, primarily noise analysis techniques are used and their merits are merged for exhaustive information extraction in accident cases where the data from sensors may be obscured by drift, modulation so forth or even incomplete. The information from different methodologies are processed in synergetic form (data sensor fusion) by means of statistical distance measures and neural networks with optimal decisions. (orig.)

  12. Recent Developments in Level 2 PSA and Severe Accident Management

    In 1997, CSNI WGRISK produced a report on the state of the art in Level 2 PSA and severe accident management - NEA/CSNI/R(1997)11. Since then, there have been significant developments in that more Level 2 PSAs have been carried out worldwide for a variety of nuclear power plant designs including some that were not addressed in the original report. In addition, there is now a better understanding of the severe accident phenomena that can occur following core damage and the way that they should be modelled in the PSA. As requested by CSNI in December 2005, the objective of this study was to produce a report that updates the original report and gives an account of the developments that have taken place since 1997. The aim has been to capture the most significant new developments that have occurred rather than to provide a full update of the original report, most of which is still valid. This report is organised using the same structure as the original report as follows: Chapter 2: Summary on state of application, results and insights from recent Level 2 PSAs. Chapter 3: Discussion on key severe accident phenomena and modelling issues, identification of severe accident issues that should be treated in Level 2 PSAs for accident management applications, review of severe accident computer codes and the use of these codes in Level 2 PSAs. Chapter 4: Review of approaches and practices for accident management and SAM, evaluation of actions in Level 2 PSAs. Chapter 5: Review of available Level 2 PSA methodologies, including accident progression event tree / containment event tree development. Chapter 6: Aspects important to quantification, including the use of expert judgement and treatment of uncertainties. Chapter 7: Examples of the use of the results and insights from the Level 2 PSA in the context of an integrated (risk informed) decision making process

  13. Regulatory requirements on accident management and emergency preparedness - concept of nuclear and radiation safety during beyond-design-basis accidents

    Actual practice the and proposals for further activities in the field of Accident Management (AM) in the member countries of the Co-operation Forum of WWER regulators and in Western countries have been assessed. Further the results of the last working group on AM , the overview of interactions of severe accident research and the regulatory positions in various countries, IAEA reports, practice in Switzerland and Finland, were taken into consideration. From this information, the working group derived recommendations on Accident Management. The general proposals correspond to the present state of the art on AM. They do not describe the whole spectra of recommendations on AM for NPPs with WWER reactors. A basis for the implementation of an AM program is given, which could be extended in a follow-up working group. The developments and research concerning AM have to be continued. The positions of various countries with regard to the 'Interactions of severe accident research and the regulatory positions' are given. On the basis of the working group proposals, the WWER regulators could set regulatory requirements and support further developments of AM strategies, making use of the benefits of common features of NPPs with WWER reactors. Concerted actions in the field of AM between the WWER regulators would bundle the development of a unified concept of recommendations and speed up the implementation of AM measures in order to minimise the risks involved in nuclear power generation

  14. Marine Accidents in Northern Nigeria: Causes, Prevention and Management

    Lawal Bello Dogarawa

    2012-01-01

    Boat mishaps tend to be increasing in Nigeria in spite of all regulatory measures which have been taken to prevent and control marine accidents. Boat mishaps could occur anywhere water transportation takes place. However, there is a general impression that water transportation takes place only in the riverine areas located in Southern Nigeria but, this paper reports about marine accident cases in Northern Nigeria. It evaluates the safety measures put in place by operators and other institutio...

  15. Program for accident and incident management support, AIMS

    A prototype of an advisory computer program is presented which could be used in monitoring and analyzing an ongoing incident in a nuclear power plant. The advisory computer program, called the Accident and Incident Management Support (AIMS), focuses on processing a set of data that is to be transmitted from a nuclear power plant to a national or regional emergency center during an incident. The AIMS program will assess the reactor conditions by processing the measured plant parameters. The applied model of the power plant contains a level of complexity that is comparable with the simplified plant model that the power plant operator uses. A standardized decay heat function and a steam water property library is used in the integral balance equations for mass and energy. A simulation of the station blackout accident of the Borssele plant is used to test the program. The program predicts successively: (1) the time of dryout of the steam generators, (2) the time of saturation of the primary system, and (3) the onset of core uncovery. The coolant system with the actual water levels will be displayed on the screen. (orig./HP)

  16. The society's measures against serious accidents

    Methods to obtain better preparedness for accidents leading to release of radioactive material are discussed, and recommendations are made developing a better coordination of the many separate efforts that will be made. More efficient ways for training and education and a modernization of the technology and routines used are also suggested

  17. CATHARE Assessment of PACTEL LOCA Experiments with Accident Management

    Luben Sabotinov

    2010-01-01

    Full Text Available This paper summarizes the analysis results of three PACTEL experiments, carried out with the advanced thermal-hydraulic system computer CATHARE 2 code as a part of the second work package WP2 (analytical work of the EC project “Improved Accident Management of VVER nuclear power plants” (IMPAM-VVER. The three LOCA experiments, conducted on the Finnish test facility PACTEL (VVER-440 model, represent 7.4% cold leg breaks with combination of secondary bleed and primary bleed and feed and different actuation modes of the passive safety injection. The code was used for both defining and analyzing the experiments, and to assess its capabilities in predicting the associated complex VVER-related phenomena. The code results are in reasonable agreement with the measurements, and the important physical phenomena are well predicted, although still further improvement and validation might be necessary.

  18. Severe Accident Management System On-line Network SAMSON

    SAMSON is a computational tool used by accident managers in the Technical Support Centers (TSC) and Emergency Operations Facilities (EOF) in the event of a nuclear power plant accident. SAMSON examines over 150 status points monitored by nuclear power plant process computers during a severe accident and makes predictions about when core damage, support plate failure, and reactor vessel failure will occur. These predictions are based on the current state of the plant assuming that all safety equipment not already operating will fail. SAMSON uses expert systems, as well as neural networks trained with the back propagation learning algorithms to make predictions. Training on data from an accident analysis code (MAAP - Modular Accident Analysis Program) allows SAMSON to associate different states in the plant with different times to critical failures. The accidents currently recognized by SAMSON include steam generator tube ruptures (SGTRs), with breaks ranging from one tube to eight tubes, and loss of coolant accidents (LOCAs), with breaks ranging from 0.0014 square feet (1.30 cm2) in size to breaks 3.0 square feet in size (2800 cm2). (author)

  19. Development of Parameter Network for Accident Management Applications

    When a severe accident happens, it is hard to obtain the necessary information to understand of internal status because of the failure or damage of instrumentation and control systems. We learned the lessons from Fukushima accident that internal instrumentation system should be secured and must have ability to react in serious conditions. While there might be a number of methods to reinforce the integrity of instrumentation systems, we focused on the use of redundant behavior of plant parameters without additional hardware installation. Specifically, the objective of this study is to estimate the replaced value which is able to identify internal status by using set of available signals when it is impossible to use instrumentation information in a severe accident, which is the continuation of the paper which was submitted at the last KNS meeting. The concept of the VPN was suggested to improve the quality of parameters particularly to be logged during severe accidents in NPPs using a software based approach, and quantize the importance of each parameter for further maintenance. In the future, we will continue to perform the same analysis to other accident scenarios and extend the spectrum of initial conditions so that we are able to get more sets of VPNs and ANN models to predict the behavior of accident scenarios. The suggested method has the uncertainty underlain in the analysis code for severe accidents. However, In case of failure to the safety critical instrumentation, the information from the VPN would be available to carry out safety management operation

  20. Development of Parameter Network for Accident Management Applications

    Pak, Sukyoung; Ahemd, Rizwan; Heo, Gyunyoung [Kyung Hee Univ., Yongin (Korea, Republic of); Kim, Jung Taek; Park, Soo Yong; Ahn, Kwang Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    When a severe accident happens, it is hard to obtain the necessary information to understand of internal status because of the failure or damage of instrumentation and control systems. We learned the lessons from Fukushima accident that internal instrumentation system should be secured and must have ability to react in serious conditions. While there might be a number of methods to reinforce the integrity of instrumentation systems, we focused on the use of redundant behavior of plant parameters without additional hardware installation. Specifically, the objective of this study is to estimate the replaced value which is able to identify internal status by using set of available signals when it is impossible to use instrumentation information in a severe accident, which is the continuation of the paper which was submitted at the last KNS meeting. The concept of the VPN was suggested to improve the quality of parameters particularly to be logged during severe accidents in NPPs using a software based approach, and quantize the importance of each parameter for further maintenance. In the future, we will continue to perform the same analysis to other accident scenarios and extend the spectrum of initial conditions so that we are able to get more sets of VPNs and ANN models to predict the behavior of accident scenarios. The suggested method has the uncertainty underlain in the analysis code for severe accidents. However, In case of failure to the safety critical instrumentation, the information from the VPN would be available to carry out safety management operation.

  1. Unconventional sources of plant information for accident management

    Oehlberg, R.; Machiels, A.; Chao, J.; Weiss, J. (Electric Power Research Inst., Palo Alto, CA (United States)); True, D.; James, R. (ERIN Engineering and Research, Walnut Creek, CA (United States))

    1992-01-01

    One phase of accident management covers the actions taken during the course of an accident by the plant operating and technical staff to prevent or minimize off-site radiation releases, gain control, and return the plant to a safe state. Inherent in accomplishing these goals is obtaining a clear picture of the nature of the accident and plant status. Development of a consistent and coherent understanding of the accident and plant status requires plant staff to evaluate and interpret data from a wide range of sources. Plant information during an accident can be obtained from the following sources: (1) plant instrumentation, including Regulatory Guide 1.97 instrumentation; and (2) information sources identified in abnormal operations or emergency operations procedures. Probabilistic risk analyses have shown that events involving the loss of key electrical support systems can be significant contributors to core damage. Such events could jeopardize or degrade instrument availability. Plant-specific accident procedures and interpretation of instruments intended for design-basis events may not be applicable in severe accidents. Information sources such as other nuclear steam supply systems (NSSSs) and balance-of-plant (BOP) instrumentation may be available.

  2. Proceedings of the workshop on operator training for severe accident management and instrumentation capabilities during severe accidents

    This Workshop was organised in collaboration with Electricite de France (Service Etudes et Projets Thermiques et Nucleaires). There were 34 participants, representing thirteen OECD Member countries, the Russian Federation and the OECD/NEA. Almost half the participants represented utilities. The second largest group was regulatory authorities and their technical support organisations. Basically, the Workshop was a follow-up to the 1997 Second Specialist Meeting on Operator Aids for Severe Accident Management (SAMOA-2) [Reports NEA/CSNI/R(97)10 and 27] and to the 1992 Specialist Meeting on Instrumentation to Manage Severe Accidents [Reports NEA/CSNI/R(92)11 and (93)3]. It was aimed at sharing and comparing progress made and experience gained from these two meetings, emphasizing practical lessons learnt during training or incidents as well as feedback from instrumentation capability assessment. The objectives of the Workshop were therefore: - to exchange information on recent and current activities in the area of operator training for SAM, and lessons learnt during the management of real incidents ('operator' is defined hear as all personnel involved in SAM); - to compare capabilities and use of instrumentation available during severe accidents; - to monitor progress made; - to identify and discuss differences between approaches relevant to reactor safety; - and to make recommendations to the Working Group on the Analysis and Management of Accidents and the CSNI (GAMA). The meeting confirmed that only limited information is needed for making required decisions for SAM. In most cases existing instrumentation should be able to provide usable information. Additional instrumentation requirements may arise from particular accident management measures implemented in some plants. In any case, depending on the time frame where the instrumentation should be relied upon, it should be assessed whether it is likely to survive the harsh environmental conditions it will be exposed

  3. A Survey of Implementation of Severe Accident Management in Sweden

    A comprehensive program for severe accident mitigation was completed for all Swedish reactors by the end of 1988. This work included development of new accident management procedures and also training programmes for operators . As a complement to the EOP's, knowledge based handbooks have been written for the reactors in Forsmark and Ringhals. They are intended for the emergency control centre in a late stage of a severe accident, when the procedures in the control room no longer are applicable. In a separate project, the impact from certain actions in a short perspective on the long term scenario has been investigated. Results from that work have been used in the development of knowledge based handbooks as decision support for the emergency control centre. For the PWR's in Ringhals the earlier procedures have been replaced by SAMG from WOG (Westinghouse Owners Group) in a project run by a team in Ringhals with support from Westinghouse. In the ongoing APRI-project (a cooperative effort between the Swedish Nuclear Power Inspectorate, the Swedish power utilities and TVO in Finland), accident management has been addressed in a sub-project with focus on validation of SAM strategies and use of results from the research on severe accidents to improve the SAM strategies. An important part of the program for severe accident mitigation was the development of accident management strategies. This work was documented in EOP's and other documentation to be used by the emergency organisation in case of an accident. Personnel at the utilities took an active part in the work mentioned above and also in later improvements such as the FR1PP project and in the development of handbooks for the emergency control centres in Forsmark and Ringhals. Generally, active participation of the end users in the development of documentation for severe accident management has clear advantages. One is that the staff at the plant will have a better insight in the work. To a certain extent the

  4. Application of probabilistic methods to accident analysis at waste management facilities

    Probabilistic risk assessment is a technique used to systematically analyze complex technical systems, such as nuclear waste management facilities, in order to identify and measure their public health, environmental, and economic risks. Probabilistic techniques have been utilized at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico, to evaluate the probability of a catastrophic waste hoist accident. A probability model was developed to represent the hoisting system, and fault trees were constructed to identify potential sequences of events that could result in a hoist accident. Quantification of the fault trees using statistics compiled by the Mine Safety and Health Administration (MSHA) indicated that the annual probability of a catastrophic hoist accident at WIPP is less than one in 60 million. This result allowed classification of a catastrophic hoist accident as ''not credible'' at WIPP per DOE definition. Potential uses of probabilistic techniques at other waste management facilities are discussed

  5. Seabrook Station Level 2 PRA Update to Include Accident Management

    A ground-breaking study was recently completed as part of the Seabrook Level 2 PRA update. This study updates the post-core damage phenomena to be consistent with the most recent information and includes accident management activities that should be modeled in the Level 2 PRA. Overall, the result is a Level 2 PRA that fully meets the requirements of the ASME PRA Standard with respect to modeling accident management in the LERF assessment and NRC requirements in Regulatory Guide 1.174 for considering late containment failures. This technical paper deals only with the incorporation of operator actions into the Level 2 PRA based on a comprehensive study of the Seabrook Station accident response procedures and guidance. The paper describes the process used to identify the key operator actions that can influence the Level 2 PRA results and the development of success criteria for these key operator actions. This addresses a key requirement of the ASME PRA Standard for considering SAMG. An important benefit of this assessment was the identification of Seabrook specific accident management insights that can be fed back into the Seabrook Station accident management procedures and guidance or the training provided to plant personnel for these procedures and guidance. (authors)

  6. A framework for assessing severe accident management strategies

    Accident management can be defined as the innovative use of existing and or alternative resources, systems and actions to prevent or mitigate a severe accident. Together with risk management (changes in plant operation and/or addition of equipment) and emergency planning (off-site actions), accident management provides an extension of the defense-in-depth safety philosophy for severe accidents. A significant number of probabilistic safety assessments (PSA) have been completed which yield the principal plant vulnerabilities. For each sequence/threat and each combination of strategy there may be several options available to the operator. Each strategy/option involves phenomenological and operational considerations regarding uncertainty. These considerations include uncertainty in key phenomena, uncertainty in operator behavior, uncertainty in system availability and behavior, and uncertainty in available information (i.e., instrumentation). The objective of this project is to develop a methodology for assessing severe accident management strategies given the key uncertainties mentioned above. Based on Decision Trees and Influence Diagrams, the methodology is currently being applied to two case studies: cavity flooding in a PWR to prevent vessel penetration or failure, and drywell flooding in a BWR to prevent containment failure

  7. Managing major chemical accidents in China: Towards effective risk information

    Chemical industries, from their very inception, have been controversial due to the high risks they impose on safety of human beings and the environment. Recent decades have witnessed increasing impacts of the accelerating expansion of chemical industries and chemical accidents have become a major contributor to environmental and health risks in China. This calls for the establishment of an effective chemical risk management system, which requires reliable, accurate and comprehensive data in the first place. However, the current chemical accident-related data system is highly fragmented and incomplete, as different responsible authorities adopt different data collection standards and procedures for different purposes. In building a more comprehensive, integrated and effective information system, this article: (i) reviews and assesses the existing data sources and data management, (ii) analyzes data on 976 recorded major hazardous chemical accidents in China over the last 40 years, and (iii) identifies the improvements required for developing integrated risk management in China.

  8. U.S. nuclear industry perspective on accident management

    The Nuclear Management and Resources Council (NUMARC) serves as the United States nuclear power industry's principal mechanism for conveying industry views, concerns, and policies regarding industry wide regulatory issues to the Nuclear Regulatory Commission (NRC) and other government agencies as appropriate. NUMARC and the Electric Power Research Institute (EPRI), in support of the NUMARC Severe Accident Working Group's (SAWG's) efforts with regard to accident management, has developed a framework for evaluation of plant-specific accident management capabilities. These capabilities fall into one of three main categories: (1) personnel resources (organization, training, communications); (2) systems and equipment (restoration and repair, instrumentation, use of alternatives); and (3) information resources (procedures and guidance, technical information, process information). The purpose of this paper is to describe this framework, its objectives, the five major steps involved and areas to consider further. (orig.)

  9. Applying Functional Modeling for Accident Management of Nuclear Power Plant

    The paper investigate applications of functional modeling for accident management in complex industrial plant with special reference to nuclear power production. Main applications for information sharing among decision makers and decision support are identified. An overview of Multilevel Flow Modeling is given and a detailed presentation of the foundational means-end concepts is presented and the conditions for proper use in modelling accidents are identified. It is shown that Multilevel Flow Modeling can be used for modelling and reasoning about design basis accidents. Its possible role for information sharing and decision support in accidents beyond design basis is also indicated. A modelling example demonstrating the application of Multilevel Flow Modelling and reasoning for a PWR LOCA is presented

  10. Main post-accident management stakes: IRSN's point of view

    Full text of publication follows: Off site management of a radiological crisis covers two phases which need to be clearly distinguished even if there are links between them: emergency phase and recovery phase (also called late or post-accident phase). The presentation will deal with the latter, rather neglected up until recently, but conveying special attention from now on in France and at the international level. It is clear now that the long term management of a radiological or nuclear crisis cannot be reduced to merely site decontamination. Actually, environmental decontamination considerations would be only one amongst other essential economical, social, health, psychological, cultural, and symbolical concerns. This is why off site management of a radiological crisis requires innovative governance, in order to challenge such a complexity. This need for challenge led IRSN to have on the go technical developments and new governance modes reflection. 1) Technical developments: they deal with implementing an organisation, a set of methods, a platform of technical tools which would allow the stakeholders to carry out efficiently their mission during the recovery phase. For example, countermeasures for agricultural and urban rehabilitation are developed within the framework of the 6. PCRDT EURANOS programme. Teams from several countries are involved in common elaboration of rehabilitation strategies based on the best available knowledge. Besides this, simple operational decision aiding tools for the stakeholders (local administration, elected representatives, professional agricultural groups, etc.) are currently developed by IRSN within the framework of the nuclear post-accident exercises. IRSN is also involved in doctrinal reflections about the respective roles of radioactive measurements in the environment and radiological consequences calculation during emergency and recovery phases. Criteria for emergency countermeasures withdrawal are also currently under

  11. Concern on accident management for the Korea next generation reactor

    The Korean Next Generation Reactor (KNGR) is under development to be built after year 2000 in Korea. To enhance its capability of preventing and/or mitigating severe accidents, various safety features are incorporated in its design. Some of them are designed against severe accidents and can be operated based on accident management program (AMP) for the KNGR. In this study, the potential capability of the Safety Depressurization System (SDS) and the Shutdown Cooling System (SCS) to mitigate the consequence of severe accidents was examined by using the MAAP 4.02 code as a preliminary step of the AMP development for the KNGR. The concerned accident sequences are small break loss of coolant accidents (SB LOCAs) with a failure of high pressure safety injection system (HPSIS) and a total loss of feedwater (TLOFW). In the level 1 Probabilistic Safety Assessment (PSA) of the KNGR, the operation of the SDS and SCS was not considered because the failures of the HPSIS and the aggressive secondary side cooling result in core damage based on the success criteria of the level 1 PSA. The analysis results show that the SDS can depressurize the RCS below the shutoff head of the shutdown cooling system (SCS) prior to reactor vessel failure. Although core uncovery and core damage occur early due to the opening of the SDS valves, the MAAP calculation results show that the SCS can reflood the damaged core and that core damage and reactor vessel failure can be mitigated or prevented by the feed-and-bleed operation with those systems. From the analysis results, therefore, it seems that the operation of the SDS and SCS can provide a means of mitigating accident consequences and can be employed as an effective accident management strategy for the KNGR. 5 refs., 6 figs., 4 tabs

  12. The evolution of computerized displays in accident management

    Key regulations implemented by the NRC in 1982, which included requirements such as upgraded emergency operating procedures, detailed control room design reviews, the addition of a safety parameter display system, and the inclusion of a degreed shift technical advisor as part of the operating staff, have enabled the use of computerized displays to evolve as an integral part of accident management within each of the four main vendor groups. Problems, however, remain to be resolved in the area of technical content, information reliability, and rules for use in order to achieve the goal of more reliable accident management in nuclear power plants

  13. The computer aided education and training system for accident management

    The education and training system for Accident Management was developed by the Japanese BWR group and Hitachi Ltd. The education and training system is composed of two systems. One is computer aided instruction (CAI) education system and the education and training system with computer simulations. Both systems are designed to be executed on personal computers. The outlines of the CAI education system and the education and training system with simulator are reported below. These systems provides plant operators and technical support center staff with the effective education and training for accident management. (author)

  14. A systematic process for developing and assessing accident management plans

    This document describes a four-phase approach for developing criteria recommended for use in assessing the adequacy of nuclear power plant accident management plans. Two phases of the approach have been completed and provide a prototype process that could be used to develop an accident management plan. Based on this process, a preliminary set of assessment criteria are derived. These preliminary criteria will be refined and improved when the remaining steps of the approach are completed, that is, after the prototype process is validated through application. 9 refs., 10 figs., 7 tabs

  15. Populations protection and territories management in nuclear emergency and post-accident situation

    This document gathers the slides of the available presentations given during these conference days. Twenty seven presentations out of 29 are assembled in the document and deal with: 1 - radiological and dosimetric consequences in nuclear accident situation: impact on the safety approach and protection stakes (E. Cogez); 2 - organisation of public authorities in case of emergency and in post-event situation (in case of nuclear accident or radiological terror attack in France and abroad), (O. Kayser); 3 - ORSEC plan and 'nuclear' particular intervention plan (PPI), (C. Guenon); 4 - thyroid protection by stable iodine ingestion: European perspective (J.R. Jourdain); 5 - preventive distribution of stable iodine: presentation of the 2009/2010 public information campaign (E. Bouchot); 6 - 2009/2010 iodine campaign: presentation and status (O. Godino); 7 - populations protection in emergency and post-accident situation in Switzerland (C. Murith); 8 - CIPR's recommendations on the management of emergency and post-accident situations (J. Lochard); 9 - nuclear exercises in France - status and perspectives (B. Verhaeghe); 10 - the accidental rejection of uranium at the Socatri plant: lessons learnt from crisis management (D. Champion); 11 - IRE's radiological accident of August 22, 2008 (C. Vandecasteele); 12 - presentation of the CEA's crisis national organisation: coordination centre in case of crisis, technical teams, intervention means (X. Pectorin); 13 - coordination and realisation of environmental radioactivity measurement programs, exploitation and presentation of results: status of IRSN's actions and perspectives (P. Dubiau); 14 - M2IRAGE - measurements management in the framework of geographically-assisted radiological interventions in the environment (O. Gerphagnon and H. Roche); 15 - post-accident management of a nuclear accident - the CODIRPA works (I. Mehl-Auget); 16 - nuclear post-accident: new challenges of crisis expertise (D. Champion); 17 - aid guidebooks

  16. Effect of guidelines on management of head injury on record keeping and decision making in accident and emergency departments.

    Thomson, R.; Gray, J; Madhok, R; Mordue, A.; Mendelow, A D

    1994-01-01

    OBJECTIVE--To compare record keeping and decision making in accident and emergency departments before and after distribution of guidelines on head injury management as indices of implementation. DESIGN--Before (1987) and after (1990) study of accident and emergency medical records. SETTING--Two accident and emergency departments in England. PATIENTS--1144 adult patients with head injury in department 1 (533 in 1987, 613 in 1990) and 734 in department 2 (370, 364 respectively). MAIN MEASURES--...

  17. Plant specific severe accident management - the implementation phase

    Many plants are in the process of developing on-site guidance for technical staff to respond to a severe accident situation severe accident management guidance (SAMG). Once the guidance is developed, the SAMG must be implemented at the plant site, and this involves addressing a number of additional aspects. In this paper, approaches to this implementation phase are reviewed, including review and verification of plant specific SAMG, organizational aspects and integration with the emergency plan, training of SAMG users, validation and self-assessment and SAMG maintenance. Examples draw on experience from assisting numerous plants to implement symptom based severe accident management guidelines based on the Westinghouse Owners Group approach, in Westinghouse, non-Westinghouse and VVER plant types. It is hoped that it will be of use to those plant operators about to perform these activities.(author)

  18. Proceedings of the specialist meeting on selected containment severe accident management strategies

    Twenty papers were presented at the first specialist meeting on Selected Containment Severe Accident management Strategies, held in Stockholm, Sweden, in 1994, half of them dealing with accident management strategies implementation status, half of them with research aspects. The four sessions were: general aspects of containment accident management strategies, hydrogen management techniques, other containment accident management strategies (spray cooling, core catcher...), surveillance and protection of containment function

  19. The circumstances of severe accident measure implementation and 'the residual risk'

    Time-series sequence and direct and root causes of Fukushima Daiichi accident were up to validation of Hatamura's investigation committee on the accident but it would be clear that measure against tsunamis was not good enough. Based on this unprecedented accident, revision of safety design review guide and regulatory requirements of severe accident (SA) measure were under consideration while SA measure had been implemented as public self-safety management by administrative guidance. History of SA measure preparation including the introduction of 'the residual risk' for expansion and upgrade of SA measure in new review guide of seismic design of nuclear power reactor facilities was looked back to learn lessons for better safety operation of nuclear facilities. Nuclear operators established accident management (AM) incorporating appropriate SA measure extracted from probabilistic safety assessment (PSA) in 2002, which had been expanded and reinforced by periodic safety review (PSR). At the revision of regulation in 2003, PSA became requirement of operational safety program but not mandatory as before and lost the chance of regulatory review at the PSR. Extent of SA measure had not been expanded based on latest knowledge of SA research and PSA technology. Evaluation of 'the residual risk' obtained by seismic PSA could not be reported at seismic back check so far because seismic evaluation against ground motion was obliged to be preferred. Safety regulation system based on safety culture of both nuclear operators and regulators should be established for implementation of advanced AM for a certainty. (T. Tanaka)

  20. Development of Integrated Evaluation System for Severe Accident Management

    Kim, Dong Ha; Kim, K. R.; Park, S. H.; Park, S. Y.; Park, J. H.; Song, Y. M.; Ahn, K. I.; Choi, Y

    2007-06-15

    The objective of the project is twofold. One is to develop a severe accident database (DB) for the Korean Standard Nuclear Power plant (OPR-1000) and a DB management system, and the other to develop a localized computer code, MIDAS (Multi-purpose IntegrateD Assessment code for Severe accidents). The MELCOR DB has been constructed for the typical representative sequences to support the previous MAAP DB in the previous phase. The MAAP DB has been updated using the recent version of MAAP 4.0.6. The DB management system, SARD, has been upgraded to manage the MELCOR DB in addition to the MAAP DB and the network environment has been constructed for many users to access the SARD simultaneously. The integrated MIDAS 1.0 has been validated after completion of package-wise validation. As the current version of MIDAS cannot simulate the anticipated transient without scram (ATWS) sequence, point-kinetics model has been implemented. Also the gap cooling phenomena after corium relocation into the RPV can be modeled by the user as an input parameter. In addition, the subsystems of the severe accident graphic simulator are complemented for the efficient severe accident management and the engine of the graphic simulator was replaced by the MIDAS instead of the MELCOR code. For the user's convenience, MIDAS input and output processors are upgraded by enhancing the interfacial programs.

  1. Development of Integrated Evaluation System for Severe Accident Management

    The objective of the project is twofold. One is to develop a severe accident database (DB) for the Korean Standard Nuclear Power plant (OPR-1000) and a DB management system, and the other to develop a localized computer code, MIDAS (Multi-purpose IntegrateD Assessment code for Severe accidents). The MELCOR DB has been constructed for the typical representative sequences to support the previous MAAP DB in the previous phase. The MAAP DB has been updated using the recent version of MAAP 4.0.6. The DB management system, SARD, has been upgraded to manage the MELCOR DB in addition to the MAAP DB and the network environment has been constructed for many users to access the SARD simultaneously. The integrated MIDAS 1.0 has been validated after completion of package-wise validation. As the current version of MIDAS cannot simulate the anticipated transient without scram (ATWS) sequence, point-kinetics model has been implemented. Also the gap cooling phenomena after corium relocation into the RPV can be modeled by the user as an input parameter. In addition, the subsystems of the severe accident graphic simulator are complemented for the efficient severe accident management and the engine of the graphic simulator was replaced by the MIDAS instead of the MELCOR code. For the user's convenience, MIDAS input and output processors are upgraded by enhancing the interfacial programs

  2. Handbook for medical management of persons exposed in radiation accidents

    The document is intended as a rapid reference handbook for the use of physicians who may be called upon to handle the cases of radiation emergency. It deals mainly with the diagnosis and treatment procedures which should be followed by medical officers. The handbook has following sections : basic radiobiology, classification of radiation accidents and preparedness for medical intervention, management of external radiation exposure, management of radioactive contamination, and action plan for handling radiation facilities. It is advisable to have a separate medical unit for proper management of persons exposed in radiation accidents. Infrastructure and facilities required in such a set-up are described. Names and addresses of : (1) physicians in India who have specialized in medical management of radiation injuries, and (2)medical doctors trained in radiation protection and occupational health in different states of India are listed in an appendix. (M.G.B.). 10 refs., figs., tabs

  3. Recommendations on accident management for NPP with WWER

    The work deals with the analysis of practices in the field of beyond design basis accidents (BDBA) management in countries operating WWER type reactors. The recommendations of the working group are presented. The aim is to cooperate the actions of the regulatory bodies for the development of an unified concept for recommendations and to speed up the DBDA management realization for the decreasing of the risk from the nuclear power plant operation

  4. Nuclear emergency preparedness in Germany - an introduction. Pt. 1. Accident management in NPPs

    For the realization of all safety-relevant requirements of the Atomic Energy Act (Atomgesetz, AtG) and their attached legal and sublegal nuclear regulations the design and operation of nuclear power plants in Germany is based on the 'Multi-Level Defense-in-Depth Safety Concept'. Experiences derived from severe accidents and continuously conducted safety research led to development and implementation of strategies and measures of severe accident management step by step in order to recognize plant states beyond the design basis in good time, to control their course and to limit their on-site and off-site consequences effectively. An overview is provided of the integration of severe accident management into the defense-in-depth concept and the on-site technical, organizational and administrative precautionary measures are described. (orig.)

  5. Neural network-based expert system for severe accident management

    This paper presents the results of the second phase of a three-phase Severe Accident Management expert system program underway. The primary objectives of the second phase were to develop and demonstrate four capabilities of neural networks with respect to nuclear power plant severe accident monitoring and prediction. A second objective of the program was to develop an interactive graphical user interface which presented the system's information in an easily accessible and straightforward manner to the user. This paper describes the technical and regulatory foundation upon which the expert system is based and provides a background on the development of a new severe accident management tool. This tool provides data to assist in; (1) planning and developing priorities for recovery actions, (2) evaluating recovery action feasibility, (3) identifying recovery action options, and (4) assessing the timing and possible effects of potential recovery strategies. These performance characteristics represent the goals identified for the Severe Accident Management Strategies Online Network (SAMSON) which is currently under development. 4 refs, 1 fig., 1 tab

  6. Decision-making guide for management of agriculture in the case of a nuclear accident

    For several years, agricultural and nuclear professionals in France have been working on how to manage the agricultural situation in the event of a nuclear accident. This work resulted in measures at both the national (Aube nuclear safety exercises in 2003, INEX3 in 2005) and international levels (EURATOM Programmes). Following on from the European FARMING (FP5) and EURANOS (FP6) works, ACTA', IRSN and six agricultural technical institutes which are specialized in agricultural production and processing network (arable crop [especially cereals, maize, pulses, potatoes and forage crops], fruits and vegetables, vine and wine, livestock farming [cattle, sheep, goats, pigs, poultry]), created a resource adapted to the French context: the Decision-aiding Tool for the Management of Agriculture in case of a Nuclear Accident. Devised for the Ministry of Agriculture services supporting state officials in a radiation emergency, this manual focuses on the early phase following the accident when the state of emergency would make discussion on countermeasures with a large stakeholder panel impossible. Supported by the Ministry of Agriculture and Fisheries and the French Nuclear Safety Authority, this project increased knowledge of post-accident management strategies and made an important contribution to the national think tank set up within the framework of the French Steering Committee for managing the post-event phase of a nuclear accident (CODIRPA). This article describes how the manual evolved throughout the project and the development of new resources. (authors)

  7. Decision-making guide for management of agriculture in the case of a nuclear accident

    For several years, agricultural and nuclear professionals in France have been working on how to manage the agricultural situation in the event of a nuclear accident. This work resulted in measures at both the national (Aube nuclear safety exercises in 2003, INEX3 in 2005) and international levels (EURATOM Programmes). Following on from the European FARMING (FP5) and EURANOS (FP6) works, ACTA', IRSN and six agricultural technical institutes which are specialized in agricultural production and processing network (arable crop [especially cereals, maize, pulses, potatoes and forage crops], fruits and vegetables, vine and wine, livestock farming [cattle, sheep, goats, pigs, poultry]), created a resource adapted to the French context: the Decision-aiding Tool for the Management of Agriculture in case of a Nuclear Accident. Devised for the Ministry of Agriculture services supporting state officials in a radiation emergency, this manual focuses on the early phase following the accident when the state of emergency would make discussion on countermeasures with a large stakeholder panel impossible. Supported by the Ministry of Agriculture and Fisheries and the French Nuclear Safety Authority, this project increased knowledge of post-accident management strategies and made an important contribution to the national think tank set up within the framework of the French Steering Committee for managing the post-event phase of a nuclear accident (CODIRPA). This article describes how the manual evolved throughout the project and the development of new resources

  8. Beyond Design Basis Severe Accident Management as an Element of DiD Concept Strengthening

    The 4th Level of DiD is ensured by management of beyond design basis accidents which is achieved by implementation of the Beyond Design Basis Accidents Management Guidance (BDBAMG) and, if necessary, by additional technical devices and organizational measures at NPP Unit. BDBAMG is located between Levels 3 and 5 in DiD and is related to them. It is connected with Level 3 by means of conditions generated at this Level and according to which BDBAM should be initiated (Level 4). It is associated with Level 5 by conditions which necessitate implementation of Emergency planning. Both types of conditions should be identified in BDBAMG. BDBAs including the phase of severe damage of fuel and protective barriers (severe accidents) in accordance with Russian regulatory framework are a subset of all BDBAs set. In this connection, such accident scenarios meet the representativeness criterion for further analysis and development of Guidance for their management. BDBAMG availability, as it provides robustness of DiD as a whole, is an obligatory condition for obtaining a NPP operational license. In the process of BDBAMG development and implementation a feedback with technical and organizational measures, comprising Level 1 and, to a less extent, Level 2, comes up. BDBAMG verification is an important final stage of its development. Addressing severe accidents, it is a challenging issue for a full scope simulator and may require its software modernization to make it responsive to severe accident phenomena. The existing BDBAMGs should be updated due to NPP Unit modernizations and in conjunction with the latest knowledge on severe accident phenomenology and lessons learnt from known events (e.g. NPP Fukushima). Thus, improvements incorporated in BDBAMG, enhance the strength of DiD. (author)

  9. Evaluation of RCS injection strategy by normal residual heat removal system in severe accident management

    Highlights: • Integrated severe accident analysis model of ALWR RCS, ESF and containment is built. • Large-break loss of coolant accident and loss of feed water accident are analyzed. • Effectiveness of RNS injection strategy and plant system response are investigated. • Impact of RNS injection on hydrogen generation and distribution is evaluated. • Negative impact induced by different RCS depressurization measures is investigated. - Abstract: Severe Accident Management Guidelines (SAMGs) suggests mitigating the consequence of severe accident scenarios by using the non-safety systems if the safety systems are unavailable. For 1000 MWe advanced passive pressurized water reactor (PWR), the normal residual heat removal system (RNS) is proposed to implement the Reactor Coolant System (RCS) injection strategy during severe accidents if safety systems fail. Therefore, evaluation of the effectiveness and negative impact of RNS injection strategy is performed, in which two typical severe accident sequences are selected, which are the typical low-pressure core melt accident sequence induced by Large-break Loss of Coolant Accident (LLOCA) with double-ended guillotine break at cold leg and the typical high-pressure core melt accident induced by Loss of Feed Water (LOFW), to analyze RCS response using the integrated severe accident analysis code. The plant model, including RCS, Engineering Safety Features (ESF), containment and RNS, is built to evaluate the effectiveness of RNS injection by comparing the sequences with and without RCS injection, which shows that RNS injection can terminate core melt progression and maintain core cooling in these accident sequences. However, hydrogen generated during the core reflooding is investigated for the negative impact, which shows that RNS may increase the hydrogen concentration in the containment. For the sequence induced by LOFW, two different RCS depressurization measurements are compared, which shows that opening ADS

  10. Severe accident analysis to verify the effectiveness of severe accident management guidelines for large pressurized heavy water reactor

    Highlights: • The progression of severe accident initiated from high pressure scenario of station black out has been analyzed using RELAP5/SCDAP. • The effectiveness of SAMG actions prescribed has been established through analysis. • The time margin available to invoke the SAMG action has been specified. - Abstract: The pressurized heavy water reactor (PHWR) contains both inherent and engineered safety features that help the reactor become resistant to severe accident and its consequences. However in case of a low frequency severe accident, despite the safety features, procedural action should be in place to mitigate the accident progression. Severe accident analysis of such low frequency event provides insight into the accident progression and basis to develop the severe accident management guidelines (SAMG). Since the order of uncertainty in the progression path of severe accident is very high, it is necessary to study the consequences of the SAMG actions prescribed. The paper discusses severe accident analysis for large PHWRs for multiple failure transients involving a high pressure scenario (initiation event like SBO with loss of emergency core cooling system and loss of moderator cooling). SAMG actions prescribed for such a scenario include water injection into steam generator, calandria vessel or calandria vault at different stages of accident. The effectiveness of SAMG actions prescribed has been investigated. It is found that there is sufficient time margin available to the operator to execute these SAMG actions and the progression of severe accident is arrested in all the three cases

  11. Severe accident analysis to verify the effectiveness of severe accident management guidelines for large pressurized heavy water reactor

    Gokhale, O.S., E-mail: onkarsg@barc.gov.in; Mukhopadhyay, D., E-mail: dmukho@barc.gov.in; Lele, H.G., E-mail: hglele@barc.gov.in; Singh, R.K., E-mail: rksingh@barc.gov.in

    2014-10-15

    Highlights: • The progression of severe accident initiated from high pressure scenario of station black out has been analyzed using RELAP5/SCDAP. • The effectiveness of SAMG actions prescribed has been established through analysis. • The time margin available to invoke the SAMG action has been specified. - Abstract: The pressurized heavy water reactor (PHWR) contains both inherent and engineered safety features that help the reactor become resistant to severe accident and its consequences. However in case of a low frequency severe accident, despite the safety features, procedural action should be in place to mitigate the accident progression. Severe accident analysis of such low frequency event provides insight into the accident progression and basis to develop the severe accident management guidelines (SAMG). Since the order of uncertainty in the progression path of severe accident is very high, it is necessary to study the consequences of the SAMG actions prescribed. The paper discusses severe accident analysis for large PHWRs for multiple failure transients involving a high pressure scenario (initiation event like SBO with loss of emergency core cooling system and loss of moderator cooling). SAMG actions prescribed for such a scenario include water injection into steam generator, calandria vessel or calandria vault at different stages of accident. The effectiveness of SAMG actions prescribed has been investigated. It is found that there is sufficient time margin available to the operator to execute these SAMG actions and the progression of severe accident is arrested in all the three cases.

  12. Implementation of Severe Accident Management Strategy at the Loviisa NPP

    A comprehensive severe accident management (SAM) strategy has been developed by Fortum for the Loviisa NPP in Finland. The strategy ensures reliable prevention and mitigation of containment - threatening phenomena, and it is built around a set of SAM safety functions. This paper focusses on the implementation status of the new SAM approach. We describe how and to what extent the modifications with regards to containment isolation, primary system depressurization, hydrogen mitigation, in-vessel retention of corium, and long-term containment cooling have been carried out. When implementing SAM, it was also necessary to modify the emergency response organisation to include a SAM support team. SAM guidelines, procedures and a SAM Handbook have been written. The automatic containment isolation function has been studied carefully within the SAM project. A successful isolation function is of paramount importance, when radioactive releases from the core can be expected to occur soon. Certain modifications have been carried out so that it is now possible to manually actuate missing isolation signals and to lock isolation status. New local control centres have been built to enable manual closure of certain isolation valves. Several new containment leak-tightness measurements have been installed. New depressurization valves, manually operated relief valves, were installed in 1996 for primary system depressurization purposes. The modifications to the ice condenser doors have been carried out in the years 2000 and 2001. Passive auto-catalytic recombiners have been successfully field-tested in the Loviisa containment atmosphere. We aim for installation in the year 2002. The locations of the glow plugs are being updated in a currently ongoing project. In-vessel retention of molten corium through external cooling of the reactor pressure vessel required certain plant modifications e.g. in order to guarantee access of water to the RPV wall. Most significantly, the support structures

  13. Management of a radiological emergency. Experience feedback and post-accident management

    In France, the organization of crisis situations and the management of radiological emergency situations are regularly tested through simulation exercises for a continuous improvement. Past severe accidents represent experience feedback resources of prime importance which have led to deep changes in crisis organizations. However, the management of the post-accident phase is still the object of considerations and reflections between the public authorities and the intervening parties. This document presents, first, the nuclear crisis exercises organized in France, then, the experience feedback of past accidents and exercises, and finally, the main aspects to consider for the post-accident management of such events: 1 - Crisis exercises: objectives, types (local, national and international exercises), principles and progress, limits; 2 - Experience feedback: real crises (major accidents, other recent accidental situations or incidents), crisis exercises (experience feedback organization, improvements); 3 - post-accident management: environmental contamination and people exposure, management of contaminated territories, management of populations (additional protection, living conditions, medical-psychological follow up), indemnification, organization during the post-accident phase; 4 - conclusion and perspectives. (J.S.)

  14. Proceedings of the first OECD (NEA) CSNI-Specialist Meeting on Instrumentation to Manage Severe Accidents

    OECD member countries have adopted various accident management measures and procedures. To initiate these measures and control their effectiveness, information on the status of the plant and on accident symptoms is necessary. This information includes physical data (pressure, temperatures, hydrogen concentrations, etc.) but also data on the condition of components such as pumps, valves, power supplies, etc. In response to proposals made by the CSNI - PWG 4 Task Group on Containment Aspects of Severe Accident Management (CAM) and endorsed by PWG 4, CSNI has decided to sponsor a Specialist Meeting on Instrumentation to Manage Severe Accidents. The knowledge-basis for the Specialist Meeting was the paper on 'Instrumentation for Accident Management in Containment'. This technical document (NEA/CSNI/R(92)4) was prepared by the CSNI - Principle Working Group Number 4 of experts on January 1992. The Specialist Meeting was structured in the following sessions: I. Information Needs for Managing Severe Accidents, II. Capabilities and Limitations of Existing Instrumentation, III. Unconventional Use and Further Development of Instrumentation, IV. Operational Aids and Artificial Intelligence. The Specialist Meeting concentrated on existing instrumentation and its possible use under severe accident conditions; it also examined developments underway and planed. Desirable new instrumentation was discussed briefly. The interactions and discussions during the sessions were helpful to bring different perspectives to bear, thus sharpening the thinking of all. Questions were raised concerning the long-term viability of current (or added) instrumentation. It must be realized that the subject of instrumentation to manage severe accidents is very new, and that no international meeting on this topic was held previously. One of the objectives was to bring this important issue to the attention of both safety authorities and experts. It could be seen from several of the presentations and from

  15. Accident management advisor system (AMAS): A Decision Aid for Interpreting Instrument Information and Managing Accident Conditions in Nuclear Power Plants

    Accident management can be characterized as the optimized use of all available plant resources to stop or mitigate the progression of a nuclear power plant accident sequence which may otherwise result i n reactor vessel and containment failure. It becomes important under conditions that have low probability of occurring. However, given that these conditions may lead to extremely severe financial consequences and public health effects, it is now recognized that it is important for the plant owners to develop realistic strategies and guidelines. Recent studies have classified accident management strategies as: - the use of alternative resources (i.e., air, water, power), - the use of alternative equipment (i.e., pumps, water lines, generators), the use of alternative actions (i.e., manual depressurization and injection, 'feed and bleed', etc.) The matching of these alternative actions and resources to an actual plant condition represents a decision process affected by a high degree of uncertainty in several of its fundamental inputs. This uncertainty includes the expected accident progression phenomenology (e.g., the issue of high pressure core ejection from the vessel in a PWR plant with possible 'direct containment heating'), as well as the expected availability and behavior of plant systems and of plant instrumentation. To support the accident management decision process with computer-based decision aids, one needs to develop accident progression models that can be stored in a computer knowledge based and retrieved at will for comparison with actual plant conditions, so that these conditions can be recognized and dealt with accordingly. Recent Probabilistic Safety Assessments (PSAs) [1] show the progression of a severe accident through and beyond the core melt stages via multi-branch accident progression trees. Although these 'accident tree models' were originally intended for accident probability assessment purposes, they do provide a basis of initial information

  16. The role of SKI in the severe accident management programme in Sweden

    The Swedish Nuclear Power Inspectorate (SKI) has responsibilities in all regulatory aspects of the licensing and operation of nuclear reactors. The twelve Swedish reactors have all implemented technical as well as procedural features for the avoidance and mitigation of the consequences of severe accidents. Work is presently in progress to further develop accident management as well as to further reinforce the basis of knowledge in order to verify measures taken. In the event of an accident, SKI has a specific duty to provide an independent assessment of the potential course of the accident in order to assist regional authorities in making decisions on emergency actions. This paper accounts for SKI's past and present efforts in the severe accident management programme. In all parts of reactor operation human factor aspects are essential, and so indeed in severe accident management. The paper brings forward these aspects in the SKI programme. In conclusion: In war it is common sense that you can only trust proven equipment and trained organizations. The same applies to Severe Accident Management. Technical equipment must be adequate and operable. Tools must be logical, clean cut, easy to find, easy to use and if possible easy to learn. The organization should be clear with regard to distribution of authority and responsibility, have short links of communication, be easy to mobilize and be staffed with competent and dedicated people who are well trained to their tasks. Preparedness against nuclear accidents must always be a consideration in daily operational work. Ensuring that good conditions exist for accident management is one important objective of SKI's assessment. Another is the analysis of organizational behaviour in emergency situations. A frequent conclusion of accident analysis is the major role played by the human factor. It is not hard to find examples where accident management decisions have been taken too soon, on the basis of insufficient information

  17. Accident Precursor Analysis and Management: Reducing Technological Risk Through Diligence

    Phimister, James R. (Editor); Bier, Vicki M. (Editor); Kunreuther, Howard C. (Editor)

    2004-01-01

    Almost every year there is at least one technological disaster that highlights the challenge of managing technological risk. On February 1, 2003, the space shuttle Columbia and her crew were lost during reentry into the atmosphere. In the summer of 2003, there was a blackout that left millions of people in the northeast United States without electricity. Forensic analyses, congressional hearings, investigations by scientific boards and panels, and journalistic and academic research have yielded a wealth of information about the events that led up to each disaster, and questions have arisen. Why were the events that led to the accident not recognized as harbingers? Why were risk-reducing steps not taken? This line of questioning is based on the assumption that signals before an accident can and should be recognized. To examine the validity of this assumption, the National Academy of Engineering (NAE) undertook the Accident Precursors Project in February 2003. The project was overseen by a committee of experts from the safety and risk-sciences communities. Rather than examining a single accident or incident, the committee decided to investigate how different organizations anticipate and assess the likelihood of accidents from accident precursors. The project culminated in a workshop held in Washington, D.C., in July 2003. This report includes the papers presented at the workshop, as well as findings and recommendations based on the workshop results and committee discussions. The papers describe precursor strategies in aviation, the chemical industry, health care, nuclear power and security operations. In addition to current practices, they also address some areas for future research.

  18. The Assesment Of Radioactive Accident Management On The RSG-GAS

    In the operational reactor facilities include RSG-GAS, safety factor for radioactive accident very important to be prioritized. Till now the anticipate happening radioactive accident on the RSG-GAS threat only by the RSG-GAS Operation Manual. For increasing the working function need to create radioactive accident management by facility level. From studying result which source IAEA guidebook, can be composed the assessment accident management of radioactive the RSG-GAS.The sketching this accident management of radioactive to be hoped can helping P2TRR organization by handling radioactive accident if this moment happen on the RSG-GAS

  19. Development of the french accident management and procedures - role of operators in accident and incident management

    This paper gives a brief overview of the set of emergency operating procedures for French NPPs and the method used to built and validate these procedures. Particular emphasis is put on the role and organisation of the operating team during an incident or accident. (orig.)

  20. A structured approach to individual plant evaluation and accident management

    The need for long term development of accident management programs is acknowledged and the key tool for that development is identified as the IPE Program. The Edison commitment to build an integrated program is cited and the effect on the IPE effort is considered. Edison's integrated program is discussed in detail. The key benefits, realism and long term savings, are discussed. Some of the highly visible products such as neural network artificial intelligence systems are cited

  1. Role of accident analysis in development of severe accident management guidance for multi-unit CANDU nuclear power plants

    This paper discusses the role of accident analysis in support of the development of Severe Accident Management Guidance for domestic CANDU reactors. In general, analysis can identify what types of challenges can be expected during accident progression but it cannot specify when and to what degree accident phenomena will occur. SAMG overcomes these limitations by monitoring the actual values of key plant indicators that can be used directly or indirectly to infer the condition of the plant and by establishing setpoints beyond which corrective action is required. Analysis can provide a means to correlate observed post-accident plant behavior against predicted behaviour to improve the confidence in and quality of accident mitigation decisions. (author)

  2. Development and validation of Maanshan severe accident management guidelines

    Maanshan is a Westinghouse pressurized water reactor Nuclear Power Plant (NPP) located in south Taiwan. The Severe Accident Management Guideline (SAMG) of Maanshan NPP is developed based on the Westinghouse Owners Group (WOG) SAMG. The Maanshan SAMG is developed at the end of 2002. MAAP4 code is used as tool to validate the SAMG strategies. The development process and characteristics of Maanshan SAMG is described. A Station BlackOut (SBO) accident for Maanshan NPP which occurred in March 2001 is cited as a reference case for SAMG validation. A SBO accident is simulated first. The severe accident progression is simulated and the entry condition of SAMG is described. Mitigation actions are then applied to demonstrate the effect of SAMG. A RCS depressurization, RCS injection, and containment hydrogen reduction strategies are used to restore the system to a stable condition as power is recovered. Hot leg creep rupture is occurs during the mitigation action that is not considered in WOG SAMG. The effect of the RCS depressurization, RCS injection, and containment hydrogen reduction strategies are analyzed with MAAP4 code

  3. Measuring patients' experiences in the Accident and Emergency department

    Bos, N.

    2013-01-01

    Two questionnaires were used to measure patients’ experiences in the Accident and Emergency department (A&E). First, the English A&E department questionnaire used in the English National Survey Programme, and after translation in Dutch used in the Netherlands. The second questionnaire concerned the

  4. Irradiation Accidents in Radiotherapy Analyze, Manage, Prevent

    Why do errors occur? How to minimize them? In a context of widely publicized major incidents, of accelerated technological advances in radiotherapy planning and delivery, and of global communication and information resources, this critical issue had to be addressed by the professionals of the field, and so did most national and international organizations. The ISMP, aware of its responsibility, decided as well to put an emphasis on the topic at the occasion of its annual meeting. In this frame, potential errors in terms of scenarios, pathways of occurrence, and dosimetry, will first be examined. The goal being to prioritize error prevention according to likelihood of events and their dosimetric impact. Then, case study of three incidents will be detailed: Epinal, Glasgow and Detroit. For each one, a description of the incident and the way it was reported, its investigation, and the lessons that can be learnt will be presented. Finally, the implementation of practical measures at different levels, intra- and inter institutions, like teaching, QA procedures enforcement or voluntary incident reporting, will be discussed

  5. The technical requirements concerning severe accident management in nuclear power plants

    The Great East Japan Earthquake with a magnitude of 9.0 (The 2011 off the Pacific coast of Tohoku Earthquake) occurred on March 11, 2011, and the beyond design-basis tsunami descended on the Fukushima Daiichi Nuclear Power Plant by the earthquake. Eventually, the core cooling systems of the units 1, 2 and 3 could not operate stably, they all suffered severe accident, and hydrogen explosions were triggered in the reactor buildings of units 1, 3 and 4. In the light of these circumstances, Atomic Energy Society of Japan (AESJ) decided to establish a standard that consolidates the concept of maintaining and improving severe accident management. In the SAM standard, the combination of hardware and software measures based on the risk assessment enables a scientific and rational approach to apply to scenarios of various severe accidents including low-frequency, high-impact events, and assures safety with functionality and flexibility. The SAM standard is already established in March, 2014. After publication of the SAM standard, with regard to effectiveness assessment for accident management and treatment of the uncertainty of severe accident analysis code, for example, the detailed guideline will be prepared as appendices of the standard. (author)

  6. Strategy adopted for the safe management of the waste arising from the Goiania accident

    The radiological accident in Goiania brought on an unexpected radioactive decontamination problem which generated a large volume of waste. The key to a straightforward management of this waste was the definition of a successful strategy to deal with it. To achieve this, several fundamental aspects were taken into account. Among the most important, one can mention the properties of the waste, the infrastructure available for its collection, the decontamination logistics, the motivation and commitment of the workers of different organizations involved in the cleanup tasks, the politically sensitive definition of handling a different kind of waste and the administrative procedures to set up reliable records on the waste collected. In the aftermath of the accident, management of the waste became complex because of the delay in agreeing on and setting up a disposal facility. Four years after the accident, corrosion was detected in some packages and measures were taken to ensure safe interim storage until final disposal. These measures focused on waste reconditioning, the development and implementation of a database containing a detailed inventory of the waste and the development of a national safety evaluation procedure for the final disposal facility. An overview is presented of the management of the waste derived from the Goiania accident, as well as the solutions adopted for final disposal. (author)

  7. Severe accident management (SAM), operator training and instrumentation capabilities - Summary and conclusions

    for SAM. In most cases existing instrumentation should be able to provide usable information. Additional instrumentation requirements may arise from particular accident management measures implemented in some plants. In any case, depending on the time frame where the instrumentation should be relied upon, it should be assessed whether it is likely to survive the harsh environmental conditions it will be exposed to. Though uncertainties still remain in the understanding of some severe accident phenomena, this should not be considered as a de-facto impediment against using simplified models both as operator aids in the course of an accident and as an option of a simulator severe accident mathematical model. These tools, however, should be based on state-of-the-art physics and calibrated using more sophisticated codes. Having the capability for periodic assessment of trends and predictions against real plant parameter evolution, and subsequent correction, is also advised for such tools. Being prepared for the unexpected is the major objective pursued in training, especially when capabilities extend into severe accident situations. When training for severe accidents is contemplated, skill-oriented sessions should be emphasized as they allow evaluating operator reactions in highly perturbed situations. However, it is also advised to increase operator awareness in case of severe accident situations through tailored sessions stressing knowledge of basic phenomena involved in degraded situations. Though computer-based training could well prevail in the long run, table-top exercises as currently implemented by many utilities also bring extremely valuable results

  8. Westinghouse severe accident management guidance overview and current status

    The Westinghouse Owners Group has completed a major development program in Severe Accident Management. This program draws on all presently available sources of information in the field, including in the field, including NRC, NUMARC and EPRI programs, plant specific Individual Plant Examinations and Probabilistic Safety Assessments, and other international activities. The program has developed a full set of Severe Accident Management Guidance (SAMG) applicable to Westinghouse and Westinghouse licensee PWR plant. The SAMG enhances the capabilities of the plant emergency response team for accident sequences that progress to fuel damage, and therefore beyond the range of applicability of present guidance in the form of Emergency Operating Procedures. Since the first draft of SAMG was transmitted officially to the WOG members and the NRC in July 1993, many activities have been carried out by the different organizations involved, and although no significant changes to the SAMG structure have resulted from these activities, several enhancement have been included, mainly from the comments recorded during the generic SAMG validation exercise at the Point Beach plant. With the issue in June 1994 of the revision 0 SAMG, some plants in the U.S. and abroad are already implementing plant specific guidelines. This paper provides an overview of the SAMG package, and also describe the most important comments and feedback from the validation and review efforts. (author)

  9. Proceedings of the specialist meeting on severe accident management implementation

    The Niantic Specialist meeting was structured around three main themes, one for each session. During the first session, papers from regulators, research groups, designers/owners groups and some utilities discussed the critical decisions in Severe Accident Management (SAM), how these decisions were addressed and implemented in generic SAM guidelines, what equipment and instrumentation was used, what are the differences in national approaches, etc. During the second session, papers were presented by utility specialists that described approaches chosen to specific implementation of the generic guidelines, the difficulties encountered in the implementation process and the perceived likelihood of success of their SAM program in dealing with severe accidents. The third session was dedicated to discussing what are the remaining uncertainties and open questions in SAM. Experts from several OECD countries presented significant perspectives on remaining open issues

  10. PWR accident management realated tests: some Bethsy results

    The BETHSY integral test facility which is a scaled down model of a 3 loop FRAMATOME PWR and is currently operated at the Nuclear Center of Grenoble, forms an important part of the French strategy for PWR Accident Management. In this paper the features of both the facility and the experimental program are presented. Two accident transients: a total loss of feedwater and a 2'' cold leg break in case of High Pressure Safety Injection System failure, involving either Event Oriented - or State Oriented-Emergency Operating Procedures (EO-EOP or SO-EOP) are described and the system response analyzed. CATHARE calculation results are also presented which illustrate the ability of this code to adequately predict the key phenomena of these transients. (authors). 13 figs., 11 refs., 2 tabs

  11. Summary and conclusions: Specialist Meeting on Severe Accident Management Implementation

    During the first session of this meeting, regulators, research groups, designers/owners' groups and some utilities discussed the critical decisions in SAM (Severe Accident Management), how these decisions were addressed and implemented in generic SAM guidelines, what equipment and instrumentation was used, what are the differences in national approaches, etc. During the second session, papers were presented by utility specialists that described approaches chosen for specific implementation of the generic guidelines, the difficulties encountered in the implementation process and the perceived likelihood of success of their SAM programme in dealing with severe accidents. The third and final sessions was dedicated to discussing what are the remaining uncertainties and open questions in SAM. Experts from several OECD countries presented significant perspectives on remaining open issues

  12. RASPLAV, Refine accident management strategies during a reactor core meltdown

    Description: OECD RASPLAV Project. The RASPLAV project aimed to refine accident management strategies during a reactor core meltdown; it was completed in June 2000. Little is known about the complex interactions that take place during a core meltdown, so one of the RASPLAV project's primary goals was to develop an understanding of this process. The information gathered during tests at the Kurchatov Institute have allowed scientists to develop models of a core meltdown. These models can be used in the design of new reactors and in refining the accident procedures for existing ones. Two aspects of the issue were considered. First, for existing reactors, where external cooling may not be practicable, the process and time sequence before melt-through were studied. This was to help develop management strategies for severe accidents. Secondly, for future and some existing reactor designs, the project aimed to determine the heat transfer conditions under which cavity flooding can be a viable accident management option. The project was run in two successive phases. The RASPLAV Phase-2 project investigated the progression of a severe accident and in particular the thermal loading imposed by a corium pool on the lower head of a Light Water Reactor (LWR) vessel. It followed an earlier Phase-1 project dedicated mainly to the build-up of the experimental and analytical infrastructure. The project objectives were to obtain relevant data on the physical and thermal behavior of the corium in large-scale tests, to derive thermal-physical property data for various molten core materials, and to investigate the effects of stratification of molten materials. The programme of work involved the use of the large facilities available at the Kurchatov Institute in Russia. Four large-scale tests were carried out and were complemented by a series of smaller-scale experiments, all involving the use of materials representative of power reactor cores. Experiments with these test materials in

  13. Utilization technique of 'radiation management manual in medical field (2012).' What should be learnt from the Fukushima nuclear accident

    From the abstract of contents of the 'Radiation management manual in medical field (2012),' the utilization technique of the manual is introduced. Introduced items are as follows: (1) Exposure management; exposure management for radiation medical workers, patients, and citizens in the medical field, and exposure management for radiation workers and citizens involved in the emergency work related to the Fukushima nuclear accident, (2) Health management; health management for radiation medical workers, (3) Radiation education: Education/training for radiation medical workers, and radiation education for health care workers, (4) Accident and emergency measures; emergency actions involved in the radiation accidents and radiation medicine at medical facilities

  14. Impact of short-term severe accident management actions in a long-term perspective. Final Report

    The present systems for severe accident management are focused on mitigating the consequences of special severe accident phenomena and to reach a safe plant state. However, in the development of strategies and procedures for severe accident management, it is also important to consider the long-term perspective of accident management and especially to secure the safe state of the plant. The main reason for this is that certain short-term actions have an impact on the long-term scenario. Both positive and negative effects from short-term actions on the accident management in the long-term perspective have been included in this paper. Short-term actions are accident management measures taken within about 24 hours after the initiating event. The purpose of short-term actions is to reach a stable status of the plant. The main goal in the long-term perspective is to maintain the reactor in a stable state and prevent uncontrolled releases of activity. The purpose of this short Technical Note, deliberately limited in scope, is to draw attention to potential long-term problems, important to utilities and regulatory authorities, arising from the way a severe accident would be managed during the first hours. Its objective is to encourage discussions on the safest - and maybe also most economical - way to manage a severe accident in the long term by not making the situation worse through inappropriate short-term actions, and on the identification of short-term actions likely to make long-term management easier and safer. The Note is intended as a contribution to the knowledge base put at the disposal of Member countries through international collaboration. The scope of the work has been limited to a literature search. Useful further activities have been identified. However, there is no proposal, at this stage, for more detailed work to be undertaken under the auspices of the CSNI. Plant-specific applications would need to be developed by utilities

  15. Fundamental study on serious accidents and their management in fuel fabrication/enrichment facilities and reprocessing facilities

    The 'Act for the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors' was amended and issued in June 2012 taking into account the lessons derived from the accident of TEPCO Fukushima Daiichi Nuclear Power Plant occurred in March 2011. The main amendments were as follows; Preparation for the management of serious accidents, Introduction of evaluation system for safety improvement, Application of new standards to existing nuclear facility (back-fitting). Japan Nuclear Energy Safety organization (JNES) started this fundamental study on serious accidents and their management, as a safety studying in fuel fabrication/enrichment facilities and reprocessing facilities, for the purpose to contribute to the implementation of new Rules by Nuclear Regulation Authority. From the technical view to be concerned such as fundamental concept of the Rules and applicability of risk-informed regulation, the following 7 subjects were studied: 1) Application concept of the defense in depth to these facilities. 2) Positioning of serious accidents and their management in the defense in depth. 3) Definition of the serious accidents in these facilities. 4) Postulated external events for the study of the serious accidents and their management. 5) Objectives and requirements of the accident management (assurance of reliability). 6) Confirmation logic flow on sequence of the serious accidents and the accident management measures. 7) Applicability of risk information. During the study on these subjects, features of the facilities were clarified at first. Based on concept of the defense in depth, which is the basic principle in safety, and referring to information related to domestic/foreign serious accidents, JNES conducted the fundamental study and made the following suggestions: 1) Definition of the serious accidents of the facilities. The definition is expected to contribute the discussion on new Rules by Nuclear Regulation Authority. 2) Methodology to examine the

  16. The EPR concept for serious accident management, and accompanying research

    An accident, even if the probability of occurrence is so low that it can practically be excluded, must not require any serious external emergency measures, such as evacuation of human populations outside the immediate neighbourhood of the plant. This demand, which in the meantime has also become part of the German article law, creates a new situation for future light water reactors. In addition to the measures which are to reduce the probability of occurrence of serious accidents, a level is introduced which is designed to control the consequences of serious accidents with postulated core meltdown. The introduction of specific measures and design characteristics is a new challenge which cannot be met by industry alone. It is necessary to resort, to a large extent, to present and future research and development work which has been and will be carried out in this area by large-scale research institutions and universities. As regards the EPR, research and development cooperation in this field has been intensified recently. The CEA research centres and the FZKA signed an agreement on information exchange. (orig./HP)

  17. Specific features of RBMK severe accidents progression and approach to the accident management

    Fundamental construction features of the LWGR facilities (absence of common external containment shell, disintegrated circulation circuit and multichannel reactor core, positive vapor reactivity coefficient, high mass of thermally capacious graphite moderator) predetermining development of assumed heavy non-projected accidents and handling them are treated. Rating the categories of the reactor core damages for non-projected accidents and accident types producing specific grope of damages is given. Passing standard non-projected accidents, possible methods of attack accident consequences, as well as methods of calculated analysis of non-projected accidents are demonstrated

  18. The Role Of Industrial Safety Measures In Combating Occupational Hazards And Accidents In India

    Sharmistha Bhattacharjee

    2012-10-01

    Full Text Available The presence of occupational hazards and industrial accidents de-motivates the worker to contribute their best to the organization. The participation of workers in the workplace which promises safety and security fosters teamwork, quality of product high productivity and a good communication between management and the industrial workers. For combating occupational hazards and accidents in an industrial site, safety is necessary and a challenging issue in an industrial environment. Serious technological accidents happens everyday somewhere in the world, causing deaths, injuries and damages to the environment and to the employees Most accidents are caused by people. People are not aware of how to use protective equipments nor are they aware of industrial hygiene and security measures. This paper provides an overview from the secondary sources of data on occupational hazards and accidents, and focuses on the safety and security services and measures provided by the institutions and government to combat the problems to provide an understanding of the situation in Indian context

  19. Specialist meeting on selected containment severe accident management strategies. Summary and conclusions

    The CSNI Specialist Meeting on Selected Containment Severe Accident Management Strategies held in Stockholm, Sweden in June 1994 was organised by the Task Group on Containment Aspects of Severe Accident Management (CAM) of CSNI's Principal Working Group on the Confinement of Accidental Radioactive Releases (PWG4) in collaboration with the Swedish Nuclear Power Inspectorate (SKI). Conclusions and recommendations are given for each of the sessions of the workshops: Containment accident management strategies (general aspects); hydrogen management techniques and other containment accident management techniques; surveillance and protection of containment function

  20. Nuclear Malaysia Disaster Management-Japan Nuclear Accident

    Japan worst Nuclear Accident tragedy due to the earthquake and tsunami, were shocking the world. Malaysia also feels the impact from this disaster. Nuclear Malaysia personnel was mobilize to perform the radiation and contamination monitoring at Malaysian Airport (KLIA and KKIA), environmental monitoring and sampling at Kudat, Sabah, contamination screening centre at Block 13 and also at National Radiology Emergency Centre at AELB. This paper will discuss how this disaster management being performs and its challenge and also the number or personnel and man-hours involved within 1st month after the tragedy. (author)

  1. Improvement of Severe Accident Analysis Computer Code and Development of Accident Management Guidance for Heavy Water Reactor

    Park, Soo Yong; Kim, Ko Ryu; Kim, Dong Ha; Kim, See Darl; Song, Yong Mann; Choi, Young; Jin, Young Ho

    2005-03-15

    The objective of the project is to develop a generic severe accident management guidance(SAMG) applicable to Korean PHWR and the objective of this 3 year continued phase is to construct a base of the generic SAMG. Another objective is to improve a domestic computer code, ISAAC (Integrated Severe Accident Analysis code for CANDU), which still has many deficiencies to be improved in order to apply for the SAMG development. The scope and contents performed in this Phase-2 are as follows: The characteristics of major design and operation for the domestic Wolsong NPP are analyzed from the severe accident aspects. On the basis, preliminary strategies for SAM of PHWR are selected. The information needed for SAM and the methods to get that information are analyzed. Both the individual strategies applicable for accident mitigation under PHWR severe accident conditions and the technical background for those strategies are developed. A new version of ISAAC 2.0 has been developed after analyzing and modifying the existing models of ISAAC 1.0. The general SAMG applicable for PHWRs confirms severe accident management techniques for emergencies, provides the base technique to develop the plant specific SAMG by utility company and finally contributes to the public safety enhancement as a NPP safety assuring step. The ISAAC code will be used inevitably for the PSA, living PSA, severe accident analysis, SAM program development and operator training in PHWR.

  2. Campfire-2000: Comprehensive Accident Management Program Featuring Innovative Research and Engineering for the Year 2000 and Beyond

    The CAMPFIRE-2000 accident management program is being developed at the Korea Atomic Energy Research Institute symphonizing the proven state-of-the-art technologies and newly proposed innovative research and engineering. The ultimate goal of the program is to resolve the plant-specific accident management issues utilizing a coherent, consistent, pragmatic, methodical approach. The program focuses on the preventive measures to maintain reactor core geometry and the mitigative measures to secure containment integrity, should a severe accident take place in a nuclear power plant. CAMPFIRE-2000 consists of strategy assessment methods, guidance and procedures, instrumentation and information, calculational aids and tools, human and organization factors, handbook of accident management, and technical expert system. In particular, the one most immediate issue involves the simulation of the rather rapid cooling of the core debris and the reactor vessel lower head of be Three Mile Island Unit 2 nuclear plant as has recently been identified from post-accident metallurgical testing of the sample specimens. As a top-notch companion experiment for CAMPFIRE-2000, a large-scale, real-material, high pressure system test SONATA-IV is proposed as a multi-lateral, multi-disciplinary project calling for international collaboration to investigate the potentially inherent, naturally-occurring in-vessel cooling mechanism from the very relevant severe accident management perspective

  3. Contributions to elaboration of concept and measures for optimized management of beyond-design-basis accidents in German LWR power plants

    In the present Project SR 2227 ordered by the Federal Office for Radiation Protection (BfS) within the framework of the Nuclear Regulatory Investigation Program of the Federal Ministry for Environment, Nature Conservation and Nuclear Safety (BMU), major contributions were worked out with regard to the concept and measures for an optimum influencing control of event sequences beyond the design basis of nuclear power plants with light water reactors. The studies dealt with extremely unlikely conditions under which core damage is to be expected due to the boundary conditions postulated or already has occurred. A total of 7 different basic scenarios were analysed with the MELCOR integral code for the PWR reference plant. These concerned LOCAs with small and large leaks in the reactor cooling system (RCS) and transients at low and high RCS pressure. The earliest moment of core destruction was calculated to occur after about half an hour, the latest one after 5.5 hours. The highest rate of H2 formation was determined for cases involving a rather slow progression of core destruction. The retention of released fission products in the RCS strongly depends on the release path into the containment. (orig./GL)

  4. WWER Technical Support Center and Training of its Staff for Severe Accident Management

    The Russian Utility organization Concern Rosenergoatom (REA) has well developed multi-level system of prevention and liquidation of emergency situations at nuclear power plants. This system covers all aspects related to beyond design accidents - from the technical support of the plant personnel to the measures for protection of the population and environment. In case a radiation dangerous situation or accident at a NPP occurred, the urgent help is being performed by the OPAS group, which coordinates the activities of forces and means participating in localization and liquidation of accident. Technical and information needs of the OPAS group is assured by Crisis center of REA (CC) with its Expert group. The task of CC is the development of the technical recommendations for the plant personnel on the accident management measures aimed to prevent the severe accident or to restrict its consequences. This task is being solved by Expert group (EG) of Crisis center in interaction with the Technical support centers (TSC) established in different design and scientific organizations (NSSS General designer, NPP General designer, Scientific leader of NPP design, institutes of Academy of Sciences, etc). Each TSC is being considered as a constituent of Rosenergoatom CC. Such Technical support center for WWER nuclear power plants (WWER TCS) has been established in OKB Gidropress some years ago. Three modes of WWER TSC operation (and, accordingly, its interaction with REA CC) are defined: normal operation, increased readiness and emergency situation. In case of beyond design accident on a plant, WWER TSC under request of REA CC will develop the recommendations for CC Expert group aimed to prevent the accident progression to the severe phase or to restrict the severe accident consequences, if it nevertheless has occurred. In chapter 2 of the present paper, place and role of WWER TSC in general system of emergency response of Rosenergoatom is highlighted. TSC structure, functions of

  5. Construction safety: Can management prevent all accidents or are workers responsible for their own actions?

    The construction industry has struggled for many years with the answer to the question posed in the title: Can Management Prevent All Accidents or Are Workers Responsible for Their Own Actions? In the litigious society that we live, it has become more important to find someone open-quotes at faultclose quotes for an accident than it is to find out how we can prevent it from ever happening again. Most successful companies subscribe to the theme that open-quotes all accidents can be prevented.close quotes They institute training and qualification programs, safe performance incentives, and culture-change-driven directorates such as the Voluntary Protection Program (VPP); yet we still see construction accidents that result in lost time, and occasionally death, which is extremely costly in the shortsighted measure of money and, in real terms, impact to the worker''s family. Workers need to be properly trained in safety and health protection before they are assigned to a job that may expose them to safety and health hazards. A management committed to improving worker safety and health will bring about significant results in terms of financial savings, improved employee morale, enhanced communities, and increased production. But how can this happen, you say? Reduction in injury and lost workdays are the rewards. A decline in reduction of injuries and lost workdays results in lower workers'' compensation premiums and insurance rates. In 1991, United States workplace injuries and illnesses cost public and private sector employers an estimated $62 billion in workers'' compensation expenditures

  6. Generalities on nuclear accidents and their short-dated and middle-dated management

    All the nuclear activities present a radiation risk. The radiation exposure of the employees or the public, may occur during normal activity or during an accident. The IRSN realized a document on this radiation risk and the actions of protection. The sanitary and medical aspects of a radiation accident are detailed. The actions of the population protection during an accident and the post accident management are also discussed. (A.L.B.)

  7. Identification and evaluation of PWR in-vessel severe accident management strategies

    This reports documents work performed the NRC/RES Accident Management Guidance Program to evaluate possible strategies for mitigating the consequences of PWR severe accidents. The selection and evaluation of strategies was limited to the in-vessel phase of the severe accident, i.e., after the initiation of core degradation and prior to RPV failure. A parallel project at BNL has been considering strategies applicable to the ex-vessel phase of PWR severe accidents

  8. Developement of integrated evaluation system for severe accident management

    Kim, Dong Ha; Kim, H. D.; Park, S. Y.; Kim, K. R.; Park, S. H.; Choi, Y.; Song, Y. M.; Ahn, K. I.; Park, J. H

    2005-04-01

    The scope of the project includes four activities such as construction of DB, development of data base management tool, development of severe accident analysis code system and FP studies. In the construction of DB, level-1,2 PSA results and plant damage states event trees were mainly used to select the following target initiators based on frequencies: LLOCA, MLOCA, SLOCA, station black out, LOOP, LOFW and SGTR. These scenarios occupy more than 95% of the total frequencies of the core damage sequences at KSNP. In the development of data base management tool, SARD 2.0 was developed under the PC microsoft windows environment using the visual basic 6.0 language. In the development of severe accident analysis code system, MIDAS 1.0 was developed with new features of FORTRAN-90 which makes it possible to allocate the storage dynamically and to use the user-defined data type, leading to an efficient memory treatment and an easy understanding. Also for user's convenience, the input (IEDIT) and output (IPLOT) processors were developed and implemented into the MIDAS code. For the model development of MIDAS concerning the FP behavior, the one dimensional thermophoresis model was developed and it gave much improvement to predict the amount of FP deposited on the SG U-tube. Also the source term analysis methodology was set up and applied to the KSNP and APR1400.

  9. Development of the severe accident risk information database management system SARD

    The main purpose of this report is to introduce essential features and functions of a severe accident risk information management system, SARD (Severe Accident Risk Database Management System) version 1.0, which has been developed in Korea Atomic Energy Research Institute, and database management and data retrieval procedures through the system. The present database management system has powerful capabilities that can store automatically and manage systematically the plant-specific severe accident analysis results for core damage sequences leading to severe accidents, and search intelligently the related severe accident risk information. For that purpose, the present database system mainly takes into account the plant-specific severe accident sequences obtained from the Level 2 Probabilistic Safety Assessments (PSAs), base case analysis results for various severe accident sequences (such as code responses and summary for key-event timings), and related sensitivity analysis results for key input parameters/models employed in the severe accident codes. Accordingly, the present database system can be effectively applied in supporting the Level 2 PSA of similar plants, for fast prediction and intelligent retrieval of the required severe accident risk information for the specific plant whose information was previously stored in the database system, and development of plant-specific severe accident management strategies

  10. Development of the severe accident risk information database management system SARD

    Ahn, Kwang Il; Kim, Dong Ha

    2003-01-01

    The main purpose of this report is to introduce essential features and functions of a severe accident risk information management system, SARD (Severe Accident Risk Database Management System) version 1.0, which has been developed in Korea Atomic Energy Research Institute, and database management and data retrieval procedures through the system. The present database management system has powerful capabilities that can store automatically and manage systematically the plant-specific severe accident analysis results for core damage sequences leading to severe accidents, and search intelligently the related severe accident risk information. For that purpose, the present database system mainly takes into account the plant-specific severe accident sequences obtained from the Level 2 Probabilistic Safety Assessments (PSAs), base case analysis results for various severe accident sequences (such as code responses and summary for key-event timings), and related sensitivity analysis results for key input parameters/models employed in the severe accident codes. Accordingly, the present database system can be effectively applied in supporting the Level 2 PSA of similar plants, for fast prediction and intelligent retrieval of the required severe accident risk information for the specific plant whose information was previously stored in the database system, and development of plant-specific severe accident management strategies.

  11. Summary and conclusions of the specialist meeting on severe accident management programme development

    The CSNI Specialist meeting on severe accident management programme development was held in Rome and about seventy experts from thirteen countries attended the meeting. A total of 27 papers were presented in four sessions, covering specific aspects of accident management programme development. It purposely focused on the programmatic aspects of accident management rather than on some of the more complex technical issues associated with accident management strategies. Some of the major observations and conclusions from the meeting are that severe accident management is the ultimate part of the defense in depth concept within the plant. It is function and success oriented, not event oriented, as the aim is to prevent or minimize consequences of severe accidents. There is no guarantee it will always be successful but experts agree that it can reduce the risks significantly. It has to be exercised and the importance of emergency drills has been underlined. The basic structure and major elements of accident management programmes appear to be similar among OECD member countries. Dealing with significant phenomenological uncertainties in establishing accident management programmes continues to be an important issue, especially in confirming the appropriateness of specific accident management strategies

  12. Environmental radioactivity measurements at BNL following the Chernobyl accident

    Measurements are reported of the concentrations at Berkeley in Gloucestershire of radioactivity in the air, rainwater, tap water, soil, herbage and fresh vegetables for the period 29 April 1986 to 15 May 1986, following the Chernobyl Power Station accident. Data for up to 18 gamma emitting isotopes are reported, together with some limited actinide-in-air measurements. Deposition velocities are calculated and an assessment is presented of the sensitivity of the techniques employed. Some data are also included on the gaseous composition of the cloud and the isotope dependent dose rate from deposition. (author)

  13. Accident evolution and barrier function and accident evolution management modeling of nuclear power plant incidents

    Every analysis of an accident or an incident is founded on a more or less explicit model of what an accident is. On a general level, the current approach models an incident or accident in a nuclear power plant as a failure to maintain a stable state with all variables within their ranges of stability. There are two main sets of subsystems in continuous interaction making up the analyzed system, namely the human-organizational and the technical subsystems. Several different but related approaches can be chosen to model an accident. However, two important difficulties accompany such modeling: the high level of system complexity and the very infrequent occurrence of accidents. The current approach acknowledges these problems and focuses on modeling reported incidents/accidents or scenarios selected in probabilistic risk assessment analyses to be of critical importance for the safety of a plant

  14. Role of the man-machine interface in accident management strategies

    First, this paper gives a short general review on important safety issues in the field of man-machine interaction as expressed by important nuclear safety organisations. Then follows a summary discussion on what constitutes a modern Man-Machine Interface (MMI) and what is normally meant with accident management and accident management strategies. Furthermore, the paper focuses on three major issues in the context of accident management. First, the need for reliable information in accidents and how this can be obtained by additional computer technology. Second, the use of procedures is discussed, and basic MMI aspects of computer support for procedure presentation are identified followed by a presentation of a new approach on how to computerise procedures. Third, typical information needs for characteristic end-users in accidents, such as the control room operators, technical support staff and plant emergency teams, is discussed. Some ideas on how to apply virtual reality technology in accident management is also presented

  15. Development Process of Plant-specific Severe Accident Management Guidelines for Wolsong Nuclear Power Plants

    A severe accident, which occurred at the TMI in 1979 and Chernobyl in 1986, is an accident that exceeds design basis accidents and leads to significant core damage. The severe accident is the low possibility of occurrence but the high severity. To mitigate the consequences of the severe accidents, Korean Nuclear Safety Committee declared the Severe Accident Policy in 2001, which requested the development of Severe Accident Management Guidelines (SAMGs) for operating plants. SAMG is a symptom-based guidance that takes a set of actions to alleviate the outcomes of severe accidents and to get into the safe stable plant condition. The purpose of this paper is to presents the strategic development process of the PHWR SAMG. The guidelines consist of 5 categories: an emergency guide for the main control room (MCR) operators, a strategy implementing guide for the technical support center (TSC), six mitigation guides, a monitoring guide, and a termination guide

  16. Development of the MIDAS GUI environment for severe accident management and analyses

    MIDAS is being developed at KAERI as an integrated severe accident analysis code with existing model modification and new model addition. Also restructuring of the data transfer scheme is going on to improve user's convenience. In this paper, various MIDAS GUI systems which are input management system IEDIT, variable plotting system IPLOT, severe accident training simulator SATS, and online guidance module HyperKAMG, are introduced. In addition, detail functions and usage of these systems for severe accident management and analyses are described

  17. Radiation accidents and their management: emphasis on the role of nuclear medicine professionals

    Bomanji, Jamshed B.; NOVRUZOV, Fuad; Vinjamuri, Sobhan

    2014-01-01

    Large-scale radiation accidents are few in number, but those that have occurred have subsequently led to strict regulation in most countries. Here, different accident scenarios involving exposure to radiation have been reviewed. A triage of injured persons has been summarized and guidance on management has been provided in accordance with the early symptoms. Types of casualty to be expected in atomic blasts have been discussed. Management at the scene of an accident has been described, with e...

  18. The management of risk to society from potential accidents

    The main report of the United Kingdom Atomic Energy Authority (UKAEA) Working Group on Risks to Society from Potential Major Accidents is presented. It is the outcome of a study by AEA Technology, the trading name of the UKAEA, in support of its own decision-making on risk management of the nuclear plants and laboratories it controls. The principles underlying decisions on social risk are of much broader applicability, however. The report is prefaced by an Executive Summary which is intended to be a stand-alone summary of the results of the study. The topics covered include: an examination of the nature of risk; the distinction to be drawn between individual and societal risk; existing risks; risk estimation; goals and targets as defined in terms of acceptance, tolerability and comparison between risks; regulations relating to risk targets; risk management decisions in theory and practice; societal risk management. A final chapter brings together the conclusions and recommendations from the preceding nine with respect to risk estimation, evaluation, management and overall approach. Two appendices deal with cost benefit analysis and provide a glossary and acronyms. (UK)

  19. Comprehensive Health Risk Management after the Fukushima Nuclear Power Plant Accident.

    Yamashita, S

    2016-04-01

    Five years have passed since the Great East Japan Earthquake and the subsequent Fukushima Daiichi Nuclear Power Plant accident on 11 March 2011. Countermeasures aimed at human protection during the emergency period, including evacuation, sheltering and control of the food chain were implemented in a timely manner by the Japanese Government. However, there is an apparent need for improvement, especially in the areas of nuclear safety and protection, and also in the management of radiation health risk during and even after the accident. Continuous monitoring and characterisation of the levels of radioactivity in the environment and foods in Fukushima are now essential for obtaining informed consent to the decisions on living in the radio-contaminated areas and also on returning back to the evacuated areas once re-entry is allowed; it is also important to carry out a realistic assessment of the radiation doses on the basis of measurements. Until now, various types of radiation health risk management projects and research have been implemented in Fukushima, among which the Fukushima Health Management Survey is the largest health monitoring project. It includes the Basic Survey for the estimation of external radiation doses received during the first 4 months after the accident and four detailed surveys: thyroid ultrasound examination, comprehensive health check-up, mental health and lifestyle survey, and survey on pregnant women and nursing mothers, with the aim to prospectively take care of the health of all the residents of Fukushima Prefecture for a long time. In particular, among evacuees of the Fukushima Nuclear Power Plant accident, concern about radiation risk is associated with psychological stresses. Here, ongoing health risk management will be reviewed, focusing on the difficult challenge of post-disaster recovery and resilience in Fukushima. PMID:26817782

  20. Measures for reduction of severe accident consequences: Comprehensive evaluation of the results sponsored by the BMI

    A number of analytical studies were initial in the past by the Federal Ministry of Interior (BMI) of FRG, to investigate the potential of additional constructive measures for risk reduction. Those measures were proposed especially against uncontrolled overpressurization of the containment due to continuous gas/steam generation, penetration of the foundation of the reactor building by melt-concrete interaction, and failure of the containment due to violent hydrogen combustion. This report gives an overview about those studies and summarizes their results. Concerning uncontrolled overpressurization, only filtered venting may be a reasonable measure, while it seems to make not much sense, to look at measures against penetration of the foundation like 'core-catcher' in further detail. To prevent hydrogen combustion with severe consequences, several potential possibilities exist, but none of them can be considered as a safe measure. Additional analysis concerning hydrogen distribution and combustion in a multi-compartment containment are necessary. All studies mentioned in this report, deal with additional constructive measures to mitigate the consequences of severe accidents. Up to day in FRG, the potential of accident prevention and mitigation of its consequences by still or again operable and already existing systems of a plant have not been investigated in detail. As indicated by first results, the use of those systems in the frame of an appropriate accident management may have a large potential for risk reduction. (orig.)

  1. Influence diagrams and decision trees for severe accident management

    A review of relevant methodologies based on Influence Diagrams (IDs), Decision Trees (DTs), and Containment Event Trees (CETs) was conducted to assess the practicality of these methods for the selection of effective strategies for Severe Accident Management (SAM). The review included an evaluation of some software packages for these methods. The emphasis was on possible pitfalls of using IDs and on practical aspects, the latter by performance of a case study that was based on an existing Level 2 Probabilistic Safety Assessment (PSA). The study showed that the use of a combined ID/DT model has advantages over CET models, in particular when conservatisms in the Level 2 PSA have been identified and replaced by fair assessments of the uncertainties involved. It is recommended to use ID/DT models complementary to CET models. (orig.)

  2. A database system for the management of severe accident risk information, SARD

    Ahn, K. I.; Kim, D. H. [KAERI, Taejon (Korea, Republic of)

    2003-10-01

    The purpose of this paper is to introduce main features and functions of a PC Windows-based database management system, SARD, which has been developed at Korea Atomic Energy Research Institute for automatic management and search of the severe accident risk information. Main functions of the present database system are implemented by three closely related, but distinctive modules: (1) fixing of an initial environment for data storage and retrieval, (2) automatic loading and management of accident information, and (3) automatic search and retrieval of accident information. For this, the present database system manipulates various form of the plant-specific severe accident risk information, such as dominant severe accident sequences identified from the plant-specific Level 2 Probabilistic Safety Assessment (PSA) and accident sequence-specific information obtained from the representative severe accident codes (e.g., base case and sensitivity analysis results, and summary for key plant responses). The present database system makes it possible to implement fast prediction and intelligent retrieval of the required severe accident risk information for various accident sequences, and in turn it can be used for the support of the Level 2 PSA of similar plants and for the development of plant-specific severe accident management strategies.

  3. Waste management facility accident analysis (WASTE ACC) system: software for analysis of waste management alternatives

    This paper describes the Waste Management Facility Accident Analysis (WASTEunderscoreACC) software, which was developed at Argonne National Laboratory (ANL) to support the US Department of Energy's (DOE's) Waste Management (WM) Programmatic Environmental Impact Statement (PEIS). WASTEunderscoreACC is a decision support and database system that is compatible with Microsoft reg-sign Windows trademark. It assesses potential atmospheric releases from accidents at waste management facilities. The software provides the user with an easy-to-use tool to determine the risk-dominant accident sequences for the many possible combinations of process technologies, waste and facility types, and alternative cases described in the WM PEIS. In addition, its structure will allow additional alternative cases and assumptions to be tested as part of the future DOE programmatic decision-making process. The WASTEunderscoreACC system demonstrates one approach to performing a generic, systemwide evaluation of accident risks at waste management facilities. The advantages of WASTEunderscoreACC are threefold. First, the software gets waste volume and radiological profile data that were used to perform other WM PEIS-related analyses directly from the WASTEunderscoreMGMT system. Second, the system allows for a consistent analysis across all sites and waste streams, which enables decision makers to understand more fully the trade-offs among various policy options and scenarios. Third, the system is easy to operate; even complex scenario runs are completed within minutes

  4. Analytical support for SAMG development as a part of accident management

    The decision to built up and implement a comprehensive Accident Management Program applying best world-wide knowledge made during last year at Temelin. A small group of engineers dedicated to Accident Management was formed at Temelin NPP as a part of the plant organisation scheme. A short summary of these activities performed by this group is presented. (author)

  5. Procedures for field measurements in the case of nuclear accident

    Very simplified, reduced and shorted procedures for main objectives of emergency field monitoring in case of nuclear accident are given only. They could be implemented in Croatia using resources nowadays available. Procedures for gamma/beta dose rates in plume and ground deposition survey and unknown situation evaluation, procedures for alpha and gamma/beta surface contamination measurement, field personnel/equipment contamination and decontamination measurement as well as for in-situ gamma spectrometry measurements are presented. Purpose, short discussion, general precautions and limitations as well as basic equipment and supplies needed are given for all of procedures discussed also. Only measuring steps are given with more details in form of short and clear instructions. (author)

  6. Nuclear Measurement Technologies and Solutions Implemented during Nuclear Accident at Fukushima

    Fukushima accident imposed a stretch to nuclear measurement operational approach requiring in such emergency situation: fast concept development, fast system integration, deployment and start-up in a very short time frame. This paper is describing the Nuclear Measurement that AREVA-BUNM (CANBERRA) has realized and foresight at Fukushima accident site describing the technical solution conceived developed and deployed at Fukushima NPP for the process control of the treatment system of contaminated water. A detailed description of all levels design choices, from detection technologies to system architecture is offer in the paper as well as the read-out and global data management system. This paper describes also the technical choices executed and put in place to overcome the challenges related to the high radiological contamination on site. (authors)

  7. A preliminary study for the implementation of general accident management strategies

    Yang, Soo Hyung; Kim, Soo Hyung; Jeong, Young Hoon; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-12-31

    To enhance the safety of nuclear power plants, implementation of accident management has been suggested as one of most important programs. Specially, accident management strategies are suggested as one of key elements considered in development of the accident management program. In this study, generally applicable accident management strategies to domestic nuclear power plants are identified through reviewing several accident management programs for the other countries and considering domestic conditions. Identified strategies are as follows; 1) Injection into the Reactor Coolant System, 2) Depressurize the Reactor Coolant System, 3) Depressurize the Steam Generator, 4) Injection into the Steam Generator, 5) Injection into the Containment, 6) Spray into the Containment, 7) Control Hydrogen in the Containment. In addition, the systems and instrumentation necessary for the implementation of each strategy are also investigated. 11 refs., 3 figs., 3 tabs. (Author)

  8. Unconventional sources of plant information for accident management

    Oehlberg, R. (Electric Power Research Inst., Palo Alto, CA (United States). Nuclear Power Div.); Machiels, A. (Electric Power Research Inst., Palo Alto, CA (United States). Nuclear Power Div.); Chao, J. (Electric Power Research Inst., Palo Alto, CA (United States). Nuclear Power Div.); Weiss, J. (Electric Power Research Inst., Palo Alto, CA (United States). Nuclear Power Div.); True, D. (ERIN Engineering and Research, Inc., Walnut Creek, CA (United States)); James, R. (ERIN Engineering and Research, Inc., Walnut Creek, CA (United States))

    1992-07-01

    The paper highlighted that other information sources can help to augment and confirm data available from dedicated accident instrumentation such as Reg. Guide 1.97 Instrumentation: inferences of plant status are possible from measurements and measurement trends obtained from instruments not expected to function, observations of system or component operability/inoperability, and observations of locally harsh environmental conditions. Detailed plant-specific examples are given, e.g. regarding the reactor pressure and level indication in BWRs, or the reactor cavity temperature indication on WE-type PWRs which the authors speculate may yield information related to vessel and core temperature. The authors advocate that others look at their information sources in a creative way. (orig.)

  9. Proceedings of the Specialist Meeting on Severe Accident Management Programme Development

    Effective Accident Management planning can produce both a reduction in the frequency of severe accidents at nuclear power plants as well as the ability to mitigate a severe accident. The purpose of an accident management programme is to provide to the responsible plant staff the capability to cope with the complete range of credible severe accidents. This requires that appropriate instrumentation and equipment are available within the plant to enable plant staff to diagnose the faults and to implement appropriate strategies. The programme must also provide the necessary guidance, procedures, and training to assure that appropriate corrective actions will be implemented. One of the key issues to be discussed is the transition from control room operations and the associated emergency operating procedures to a technical support team approach (and the associated severe accident management strategies). Following a proposal made by the Senior Group of Experts on Severe Accident Management (SESAM), the Committee on the Safety of Nuclear Installations decided to sponsor a Specialist Meeting on Severe Accident Management Programme Development. The general objectives of the Specialist Meeting were to exchange experience, views, and information among the participants and to discuss the status of severe accident management programmes. The meeting brought together utilities, accident management programme developers, personnel training programme developers, regulators, and researchers. In general, the tone of the Specialist Meeting - designed to promote progress, as contrasted with conferences or symposia where the state-of-the-art is presented - was to be rather practical, and focus on accident management programme development, applications, results, difficulties and improvements. As shown by the conclusions of the meeting, there is no doubt that this objective was widely attained

  10. Measuring and Managing Knowledge

    Housel, Thomas; Bell, Arthur H.

    2001-01-01

    Managing and measuring knowledge teaches through the case method, with extended discussion and investigation of high-interest business scenarios from areas of health management, investment, the Internet, telecommunications, computer technologies, food industry management, heavy industry, and a variety of service industries. In each case, readers learn how new tools of knowledge management can positively impact bottom-line profits and overall business strategy. Readers conclude the businesse...

  11. Design measures for prevention and mitigation of severe accidents at advanced water cooled reactors. Proceedings of a technical committee meeting

    Over 8500 reactor-years of operating experience have been accumulated with the current nuclear energy systems. New generations of nuclear power plants are being developed, building upon this background of experience. During the last decade, requirements for equipment specifically intended to minimize releases of radioactive material to the environment in the event of a core melt accident have been introduced, and designs for new plants include measures for preventing and mitigating a range of severe accident scenarios. The IAEA Technical Committee Meeting on Impact of Severe Accidents on Plant Design and Layout of Advanced Water Cooled Reactors was jointly organized by the Department of Nuclear Energy and the Department of Nuclear Safety to review measures which are being incorporated into advanced water cooled reactor designs for preventing and mitigating severe accidents, the status of experimental and analytical investigations of severe accident phenomena and challenges which support design decisions and accident management procedures, and to understand the impact of explicitly addressing severe accidents on the cost of nuclear power plants. This publication is intended to provide an objective source of information on this topic. It includes 14 papers presented at the Technical Committee meeting held in Vienna between 21-25 October 1996. It also includes a Summary and Findings of the Working Groups. The papers were grouped in three sections. A separate abstract was prepared for each paper

  12. Policy elements for post-accident management in the event of nuclear accident. Document drawn up by the Steering Committee for the Management of the Post-Accident Phase of a Nuclear Accident (CODIRPA). Final version - 5 October 2012

    Pursuant to the Inter-ministerial Directive on the Action of the Public Authorities, dated 7 April 2005, in the face of an event triggering a radiological emergency, the National directorate on nuclear safety and radiation protection (DGSNR), which became the Nuclear safety authority (ASN) in 2006, was tasked with working the relevant Ministerial offices in order to set out the framework and outline, prepare and implement the provisions needed to address post-accident situations arising from a nuclear accident. In June 2005, the ASN set up a Steering committee for the management of the post-accident phase in the event of nuclear accident or a radiological emergency situation (CODIRPA), put in charge of drafting the related policy elements. To carry out its work, CODIRPA set up a number of thematic working groups from 2005 on, involving in total several hundred experts from different backgrounds (local information commissions, associations, elected officials, health agencies, expertise agencies, authorities, etc.). The working groups reports have been published by the ASN. Experiments on the policy elements under construction were carried out at the local level in 2010 across three nuclear sites and several of the neighbouring municipalities, as well as during national crisis drills conducted since 2008. These works gave rise to two international conferences organised by ASN in 2007 and 2011. The policy elements prepared by CODIRPA were drafted in regard to nuclear accidents of medium scale causing short-term radioactive release (less than 24 hours) that might occur at French nuclear facilities equipped with a special intervention plan (PPI). They also apply to actions to be carried out in the event of accidents during the transport of radioactive materials. Following definitions of each stage of a nuclear accident, this document lists the principles selected by CODIRPA to support management efforts subsequent to a nuclear accident. Then, it presents the main

  13. Overview of training methodology for accident management at nuclear power plants

    Many IAEA Member States operating nuclear power plants (NPPs) are at present developing accident management programmes (AMPs) for the prevention and mitigation of severe accidents. However, the level of implementation varies significantly between NPPs. The exchange of experience and best practices can considerably contribute to the quality and facilitate the implementation of AMPs at the plants. The main objective of this publication is to describe available material and technical support tools that can be used to support training of the personnel involved in the accident management (AM), and to highlight the current status of their application. The focus is on those operator aids that can help the plant personnel to take correct actions during an emergency to prevent and mitigate consequences of a severe accident. The second objective is to describe the available material for the training courses of those people who are responsible of the AMP development and implementation of an individual plant. The third objective is to collect a compact set of information on various aspects of AM training into a single publication. In this context, the AM personnel includes both the plant staff responsible for taking the decision and actions concerning preventive and mitigative AM and the persons involved in the management of off-site releases. Thus, the scope of this publication is on the training of personnel directly involved in the decisions and execution of the SAM actions during progression of an accident. The integration of training into the AMP development and implementation is summarized. The technical AM support tools and material are defined as operator aids involving severe accident guidelines, various computational aids and computerized tools. The operator aids make also an essential part of the training tools. The simulators to be applied for the AM training have been developed or are under development by various organizations in order to support the training on

  14. Knowledge data base for severe accident management of nuclear power plants

    For the reinforcement of the safety of NPPs, the continuous efforts are very important to take in the up-to-date scientific and technical knowledge positively and to reflect them into the safety regulation. The purpose of this present study is to gather effectively the scientific and technical knowledge about the severe accident (SA) phenomena and the accident management (AM) for prevention and mitigation of severe accident, and to take in the experimental data by participating in the international cooperative experiments regarding the important SA phenomena and the effectiveness of accident management. Based on those data and knowledge, JNES is developing and improving severe accident analysis models to maintain the severe accident analysis codes and the accident management knowledge base for assessment of the NPPs in Japan. The activities in fiscal year 2010 are as follows; Experimental study on OECD/NEA projects such as MCCI, SERENA, SFP and international cooperative PSI-ARTIST project, and analytical study on accident management review of new plant and making regulation for severe accident. (author)

  15. Knowledge data base for severe accident management of nuclear power plants

    For the reinforcement of the safety of NPPs, the continuous efforts are very important to take in the up-to-date scientific and technical knowledge positively and to reflect them into the safety regulation. The purpose of this present study is to gather effectively the scientific and technical knowledge about the severe accident (SA) phenomena and the accident management (AM) for prevention and mitigation of severe accident, and to take in the experimental data by participating in the international cooperative experiments regarding the important SA phenomena and the effectiveness of accident management. Based on those data and knowledge, JNES is developing and improving severe accident analysis models to maintain the severe accident analysis codes and the accident management knowledge base for assessment of the NPPs in Japan. The activities in fiscal year 2011 are as follows; Experimental study on OECD/NEA projects such as MCCI, SERENA, SFP and international cooperative PSI-ARTIST project, and analytical study on accident management review of new plant and making regulation for severe accident. (author)

  16. Best practice guide for radioactivity measurement laboratories in a post-accident situation

    Published for laboratories likely to be asked to perform radioactivity measurements at the time of or after a radiological or nuclear accident in France or abroad, this guide aims at defining the best practices in terms of laboratory organisation (sample flow management, personnel radioprotection, sample identification and recording, sample cross-contamination risks, result transmission, archiving of data, results and samples, waste dismissal), and in terms of metrology (adaptation to needs in terms of detection limit and measurement uncertainty, preferred use of gamma spectrometry, analysis strategies)

  17. Accident management to ensure containment integrity at Seabrook Station

    This paper reports that PSA results for Seabrook Station have shown capability and strength of the large dry primary containment to withstand early pressure loads that could result from a potential severe core damage event. To build upon a high degree of confidence that containment integrity would be maintained in light of issues such as direct containment heating (DCH) and induced steam generator tube rupture (ISGTR), select accident management strategies have been evaluated for the plant. These strategies include emergency response technical support center procedures and hardware modifications to eliminate the potential for DCH and ISGTR for high pressure core melt scenarios. Operator actions that would result from these strategies include primary system depressurization using the pressurizer power-operated relief valves (PORV) and use of fire water pumps to prevent overheating and thermal creep rupture of the steam generator tubes. The risk management effectiveness of these strategies was quantified with the use of a full-scope Level 3 PSA model of Seabrook Station. A byproduct of this evaluation is a current assessment of the risk significance of DCH and ISGTR for this paper

  18. Developing and validating severe accident management guidelines using SAMPSON-RELAP/SCDAPSIM.MOD3.4

    The development and validation of Severe Accident Management Guidelines (SAMGs) must consider complex thermal-hydraulic and severe accident phenomena. Yet, many of the simplified integral Severe Accident codes, that have been used widely to develop SAMGs in Europe, Asia, and the United States, cannot accurately predict many of these complex interactions. By contrast, detailed codes such as SAMPSON-RELAP/SCDAPSIM have shown, through comparison with the TMI-2 accident and experiments, that they can predict such complex behavior. This paper describes the merger of SAMPSON with RELAP/SCDAPSIM/MOD3.4, reviews the severe accident phenomena important for Severe Accident Management, and then describes the potential impact of using SAMPSON-RELAP/SCDAPSIM on the development and validation of SAMGs. A companion paper, being presented at this conference provides an example of the application of SAMPSON-RELAP/SCDAPSIM for the development and validation of a SAMG for a Nuclear Power Plant. (authors)

  19. Marine Accidents in Northern Nigeria: Causes, Prevention and Management

    Lawal Bello Dogarawa

    2012-11-01

    Full Text Available Boat mishaps tend to be increasing in Nigeria in spite of all regulatory measures which have been taken to prevent and control marine accidents. Boat mishaps could occur anywhere water transportation takes place. However, there is a general impression that water transportation takes place only in the riverine areas located in Southern Nigeria but, this paper reports about marine accident cases in Northern Nigeria. It evaluates the safety measures put in place by operators and other institutional bodies in the areas and assesses the level of infrastructure in terms of quantity, quality and accessibility to boat operators, boat users and institutional staff. Questionnaires were administered through individual and group interviews with boat owners, boat drivers, boat users, boat builders, boat engine mechanics, local government officials, maritime workers union, the marine police, traditional regulators and staff of the federal government agencies for maritime affairs. The paper found that marine transportation is neglected in Northern Nigeria with dilapidated jetties, ill-equipped marine police, non-functional ferries and boast meant to be used by federal officials and wrecks in water channels without removal. Maritime safety is therefore compromised with cases of overloading carrying people, animals, grains and petroleum products in one boat without fire extinguisher and no lifejackets. The paper concludes that there are considerable water transportation activities in Northern Nigeria without a corresponding government attention. It is therefore recommend that government should intervene by providing lifejackets, fire extinguishers, training of surveyors, refurbishing ferries for enforcement as well as creating safety awareness in the region.

  20. EFFICIENCY OF REPEATED AND UNSCHEDULED TRAINING AS THE MEASURES TO PREVENT ACCIDENTS AT SUPPLY DEPOTS AND WAREHOUSES

    Bocharova Irina Nikolaevna

    2013-05-01

    Full Text Available This paper presents the results of the analysis of the state of occupational safety at supply depots and warehouses. It is revealed that most accidents involve the employees who have less than one year’s service. Experience has proven that the preventive activities to avoid occupational traumatism are efficient when a complex of workplace safety measures is implemented. The experts consider the repeated and unscheduled training to be very important events. This is supported by the fact that among the employees of the commercial establishments who underwent repeated and unscheduled training, the number of individuals who suffered an accident is small. The efficient functioning of the occupational safety training system is infeasible without ensuring the motivation for assimilating the knowledge and forming the complete foundation for safe labor. In order to reduce the number of accidents, one should proceed from the principle of responding to accidents to the system for professional risk management.

  1. Management of a severe accident on a pressurised water reactor in France

    This brief document defines what a severe accident is on a nuclear reactor, indicates the different failure modes which have been defined (vapour explosion in the reactor vessel, hydrogen explosion, and so on). It describes the management of a core fusion accident for pressurized water reactors, for which a guide has been designed, the GIAG (intervention guide for a severe accident situation). The principles of such an intervention are described, and then the approach for an EPR reactor

  2. Radiological protection from radioactive waste management in existing exposure situations resulting from a nuclear accident

    Sugiyama, Daisuke; Hattori, Takatoshi

    2012-01-01

    In environmental remediation after nuclear accidents, radioactive wastes have to be appropriately managed in existing exposure situations with contamination resulting from the emission of radionuclides by such accidents. In this paper, a framework of radiation protection from radioactive waste management in existing exposure situations for application to the practical and reasonable waste management in contaminated areas, referring to related ICRP recommendations was proposed. In the proposed...

  3. Measurement of the Portsmouth Gaseous Diffusion Plant criticality accident alarm

    Measurements of the Portsmouth Gaseous Diffusion Plant's nuclear criticality accident radiation alarm signal response time, sound wave frequency, and sound volume levels were made to demonstrate compliance with ANSI/ANS-8.3-1986. A steady-state alarm signal is produced within one-half second of obtaining a two-out-of-three detector trip. The fundamental alarm sound wave frequency is 440 hertz. The sound volume levels are greater than 10 decibels above background and ranged from 100 to 125 A-weighted decibels. The requirements of the standard were met; however the recommended maximum sound volume level of 115 dBA was exceeded. Emergency procedures require immediate evacuation upon initiation of a facility's radiation alarm. Comparison with standards for allowable time of exposure at different noise levels indicate that the elevated noise level at this location does not represent an occupational injury hazard. 8 refs., 5 figs

  4. Measurement of steam condensation on aerosols und LWR accident conditions

    The report summarizes the results of experiments on steam condensation onto aerosol particles. A facility was constructed which allows the direct measurement of the condensation processes. The thermodynamic boundary conditions were typical for a core melt accident. Different aerosol species were used, especially uranium dioxide which constitutes a large fraction of the core melt aerosol. As a general result the condensation process in supersaturated atmospheres causes a drastic change in the shape of the aerosol particles. Originally fluffy chain-like aggregates are compressed to nearly spherical dense particles. A significant simplification of the NAUA-model can be used because the commonly encountered shape factor problems become non-existent. This also leads to a greater reliability of computed results. (orig./HP)

  5. Severe accident instrumentation systems for BWR water level and temperature in primary containment vessel measurements

    The severe accident at TEPCO's Fukushima Daiichi nuclear power station (TF1 accident) in March 2011 brought the lost of the functions of many instrumentation systems. In order to enable the measurements of the important parameters such as reactor water level, temperature and so on even in a case such as the TF1 accident occurs, severe accident instrumentation systems are being developed. In this paper, new system configurations of BWR water level measurement and temperature measurement in primary containment vessels are proposed. Then performance tests for prototype sensors of these measurement systems under high temperature conditions are described. (author)

  6. A Study on Reinforcement of the Accident Management System in Korea

    The aim of this study is to present the status of post-Fukushima actions with respect to accident management and also provides the current status of developing EDMGs and applicability of a FLEX strategy in Korea. As part of the post-Fukushima actions in Korea, SAMGs will be revised to improve the effectiveness of accident management. For this purpose, it is recommended to revise the EOPs and SAMGs and establish the EDMGs with consideration of prolonged SBO, spent fuel pool cooling, using mobile equipment for accident control, feedback of the implementation of the action items of the special safety inspection, multiple severe accidents for all reactors at a site. It is considered that the FLEX strategy may be useful to mitigate the accidents like Fukushima. Therefore, it is recommended to adopt this strategy including provision of the equipment with protection from external events. The Fukushima accident revealed that EOPs and SAMGs were not effectively coping with and mitigating the severe accident caused by extreme natural hazards such as earthquake and tsunami. The accident indicated needs for strengthening the existing accident management procedures such as emergency operating procedures (EOPs) and severe accident management guidelines (SAMGs). In particular, these procedures should address the possibility of extreme natural hazards causing a prolonged SBO condition, which affects multiple-units and Spent Fuel Pools (SFPs) (NTTF Recommendation 9). In addition, in order to prevent and mitigate the potential damage in an extensive scale at a multi-unit site due to external events, fire, various kinds of countermeasures are required by the Regulatory Body. These are the follow-up actions to the special safety inspection carried out just after the Fukushima accident and the stress tests for old plants. Especially, the Extensive Damage Mitigation Guidelines (EDMGs) are being provided by the utility in conjunction with adoption of the FLEX strategy (diverse and

  7. EC Research Contribution to Decision-making Processes Relevant to Severe Accident Management

    As a result of the two well-known civil nuclear accidents and of the consequent increase in safety requirements, the need to properly assess severe accident (SA) scenarios for present and future nuclear power plants (going beyond the traditional three-level defence-in-depth strategy) became evident. In this line, various research activities were launched and are performed within the Euratom Framework Programmes, in particular the completed Fourth one (F P-4, 1994-1998) and the present Fifth one (FP-5, 1998-2002). The initial orientation of the EC research activities was mainly focused on improving the understanding of the phenomena and mechanisms involved in such accidents, in order to contribute to prevent possible final radioactivity releases. A consensus on how to model those SA phenomena in accident safety analyses by means of specific tools (SA codes developed, verified and validated through experimental results provided) is reasonably advanced. Currently, the EC research activities related to severe accidents are balanced between a twofold approach aimed at assessing the risks related with severe accident scenarios and to support the development of severe accident management (SAM) strategies, together with the optimisation of backfitting measures for existing reactors or specific designs for future nuclear power plants. This new orientation is confronting difficulties, inherent to the phenomenological character of several research activities, which make a direct application of the results into SAM measures premature in some cases. In this regard, this paper presents a series of ten selected FP-5 projects with emphasis placed on the applicability of research results towards SAM strategies to be used by decision-makers amongst utilities, the nuclear industry in particular designers, and regulators. The majority of them also contain -further to the SAM approach- supporting elements focused on risk assessment. The revised programme of the key action 'Nuclear

  8. Development of a reactor vessel failure diagnosis system for accident management

    Diagnosis of vessel failure provides for operators and TSC personnel very important information to manage the severe accident in nuclear power plant. However, operators can not diagnose the reactor vessel failure by watching the temporal trends of some parameters because they never have experienced the severe accident. Therefore, this study proposes a method on the diagnosis of the PWR vessel failure using a Spatiotemporal Neural Network (STN). STNs can deal directly with both the spatial and the temporal aspects of input signals and can well identify a time-varying problem. The target patterns are generated from MAAP code. Vessel failure diagnosis has been performed for 8 accidents and the developed STNs have been verified for untrained three severe accidents. STNs identifies the vessel failure time and the initiating events. For example, when large break LOCA (break size = 0.16 m2) is used for input accident scenario, only the output value for the target pattern of LBLOCA is activated greater than the threshold value near the real vessel failure. To validate vessel failure diagnosis system and to train severe accident to operators, extensive severe accident simulator is to be an absolute necessity. Therefore, a simplified severe accident simulator, SIMAAP (severe accident Simulator based on MAAP), has been developed. SIMAAP simulates the various severe accident progress through on-line communication with MAAP

  9. Management of severe pelvic injury following road traffic accident in a resource-limited setting

    A 34 year old woman involved in road traffic accident with severe anterior and posterior pelvic fractures with associated soft tissue injury was referred from Wa Regional Hospital 18 hours after the accident to Tania Specialist Hospital in Tamale. Emergency resuscitative measures such as catheterization and management of pain with analgesics were initiated. Computed tomography (CT scan) or Magnetic resonance imaging has been recommended as the appropriate tools for risk assessment in such cases however none of this was available at the time of the accident. The only assessment tool available was the C-arm machine which was used to X-ray the pelvis in the following plane; anterio - posterior pelvic - inlet and pelvic - outlet. Early internal reduction and stabilization of pelvis was immediately carried out using the procedure of open reduction and internal fixation (ORIF). Approximately 2 weeks after the operation, radiographs showed signs of healing and the patient was discharged on partial body weight bearing. Upon second review 12 weeks post operatively, complete recovery was accomplished.

  10. Severe human factor accidents and their management in a in-service nuclear Power plant

    Human Reliability Analysis (HRA) is an important part of Probabilistic Safety Assessment (PSA) in a nuclear power plant (NPP). It can be used to evaluate and quantify the behaviors of the operators in a post-accident response. The paper picks up the serious human factor event sequences that contribute more than 5% to the overall Core Damage Frequency (CDF) involved in PSA through a HRA analysis on a domestic PWR. The basic human error probabilities (BHEPs) of these human factor event sequences are resulted, on the basis of which the actions of the operators within the main control room (MCR) after the accidents are analyzed and their criticalities are arranged in order. The paper, from the point of engineering management,puts forward the measures to improve the corresponding emergency operating procedures (EOPs) and the MCR surroundings through analyzing serious human factor event sequence arrangement and the actions of operators in the post-accident interferences. With regard to the operator's interferences of high criticality the NPP should enforce training and improve its ability of interferences. (authors)