Severe Accident

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K Trambauer - One of the best experts on this subject based on the ideXlab platform.

  • Ranking of Severe Accident Research Priorities
    Progress in Nuclear Energy, 2010
    Co-Authors: B. Schwinges, L Meyer, T Haste, Christophe Journeau, Walter Tromm, K Trambauer
    Abstract:

    Abstract The objectives of the SARNET network are to define common research programmes in the field of Severe Accidents and to develop common computer tools and methodologies for safety assessment in this field. To reach these objectives, one of the work packages, named “Severe Accident Research Priorities” (SARP), aimed at reviewing and reassessing the priorities of research issues as a basis to harmonize and to re-orient research programmes, to define new ones, and to close – if possible – resolved issues on a common basis. The work was performed in close collaboration with 8 participating institutions, led by GRS, representing technical safety organisations, industry and utilities (IRSN, CEA, EDF, FZK, GRS, KTH, TUS, VTT). This action made use notably of (1) the outcomes of the EURSAFE project in the 5th Framework Programme, i.e. the Phenomena Identification and Ranking Tables (PIRT) on Severe Accidents, (2) the results of the validation and benchmarking activities on ASTEC, (3) the results of reactor calculations carried out in the other SARNET tasks, and (4) the outcome of the research performed in the three thematic sub-domains of SARNET (corium, containment and source term). The main outcome of EURSAFE was a list of 21 topics which included recommendations for experimental programmes and code developments. This list formed the basis of the work in SARP. Also the methodology applied in EURSAFE to consider both the risk potential and the Severe Accident issues where large uncertainties still subsist was adopted. The analyses of the progress of research and development activities considered whether (1) any research issue was resolved due to reduction of uncertainties or gain of scientific insights, (2) any new issue had to be added to the list of needed research, (3) any new process or phenomenon had to be included in the general PIRT list taking into account the safety relevance and the lack of knowledge, and (4) any new Accident management program has to be developed to cope with unresolved problems. Furthermore a strategy plan was elaborated to ensure a wide consensus with the end-user requirements and the objectives of SARNET research activities.

  • european expert network for the reduction of uncertainties in Severe Accident safety issues eursafe
    Nuclear Engineering and Design, 2005
    Co-Authors: D Magallon, A Mailliat, J M Seiler, K Atkhen, H Sjovall, S Dickinson, J Jakab, L Meyer, M Buerger, K Trambauer
    Abstract:

    EURSAFE thematic network was a concerted action in the sixth framework programme of the European Commission. It established a large consensus among the main actors in nuclear safety on the Severe Accident issues where large uncertainties still subsist. The conclusions were derived from a first-of-kind phenomena identification and ranking tables (PIRT) on all aspects of Severe Accident also realised in the frame of the project. Starting from a list of all Severe Accident phenomena containing approximately 1000 entries and established by the twenty partner organisations, 106 phenomena were retained eventually as both important for safety and still lacking sufficient knowledge. Ultimately, 21 research areas for addressing these phenomena regrouped according to their similarities were identified. A networking structure for implementing and executing the necessary research was proposed, which promotes integration and harmonisation of the different national programmes. A Severe Accident database structure was proposed to ensure preservation of experimental data and enhanced communication for data exchange and use for Severe Accident codes assessment. The final product, named EURSAFE, is a website network, http://asa2.jrc.it/eursafe, connecting nodes located at partner sites. As the result of an action involving R&D governmental institutions, regulatory bodies, nuclear industry, utilities and universities from six EU Member States (Finland, France, Germany, Spain, Sweden, UK) plus JRC, three European third countries (Czech Republic, Hungary, Switzerland), and USA, EURSAFE represents a significant step towards harmonisation and credibility of the approaches, and resolution of the remaining Severe Accident issues.

Suizheng Qiu - One of the best experts on this subject based on the ideXlab platform.

  • MELCOR Severe Accident analysis for a natural circulation small modular reactor
    Progress in Nuclear Energy, 2017
    Co-Authors: Tae Woon Kim, Wenxi Tian, Yapei Zhang, Shripad T. Revankar, Suizheng Qiu
    Abstract:

    Abstract A natural circulation small modular reactor (NCSMR) is designed and the Severe Accident of the NCSMR was analyzed with MELCOR code in this work. The NCSMR is a 330 MWt light water reactor no reactor coolant pumps and no active safety injection systems similar to the design of NuScale reactor. A MELCOR code model was developed for the reactor. The MELCOR model shows consistent results in steady state operation with the design values. The NCSMR Severe Accident analyzed in this work was induced by the small break loss of coolant Accident in the reactor pressure vessel and a crack in the containment pool wall. The decay heat removal system is assumed to fail for the main steam line break. The results indicated that the RPV pressure decreases quickly while the containment pressure increases followed by the opening of reactor vent valves. The core exposes and heat up with the coolant leakage and finally collapsed to the lower plenum, leading to the lower head breach. High temperature core corium quickly broke the relatively thin containment vessel wall, and was discharged to the containment pool floor, leading to the molten corium concrete interaction. The fission products release during the Accident process was also analyzed. The Severe Accident sequence shows that the NCSMR has much longer time duration for the reactor vessel lower head failure to occur compared to conventional commercial nuclear power plant under Severe Accident conditions. The analysis results help identify appropriate Accident management strategies and countermeasures for the potential extreme natural hazard induced Severe Accidents in NCSMR.

  • Investigation of Severe Accident scenario of PWR response to LOCA along with SBO
    Progress in Nuclear Energy, 2015
    Co-Authors: Hu Liang, Wenxi Tian, Yapei Zhang, Suizheng Qiu
    Abstract:

    Abstract Severe Accident analysis is important for the safety evaluation of a nuclear power plant (NPP). In this paper, analysis has been performed for a Chinese three-loop Pressurized Water Reactor (PWR) Severe Accident induced by loss of coolant Accident (LOCA) along with Station- Block-Out (SBO) using the MIDAC code. The simulation results show the influence of different break sizes in the cold leg on the Severe Accident progression. Important parameters, such as primary coolant system (RCS) pressure, core melting time, pressure vessel rupture time. are analyzed with three different break sizes in the cold leg. With the break size of 0.002 m 2 , the reactor core starts to melt at 1481 s and the lower head fails at 10,317 s after the Accident occurs. With a larger break size of 0.05 m 2 , the reactor core starts to melt at 1066 s and the lower head fails at 2473 s. If the break size is further enlarged to 0.2 m 2 , the reactor core starts to melt at 422 s and the lower head fails at 1757 s. Another case in which a hot leg break is with the size of 0.002 m 2 is performed. The reactor core starts to melt at 3641 s and the lower head fails at 14,744 s. It is less Severe than the cold leg break Accident. The Severe Accident prevention and mitigation measures are summarized based on the computation results. The results are helpful to develop the management strategies and guideline for the Severe Accident of the similar types of PWRs.

  • Severe Accident analysis for a typical pwr using the melcor code
    Progress in Nuclear Energy, 2014
    Co-Authors: Mingjun Wang, Wenxi Tian, Suizheng Qiu
    Abstract:

    Abstract Using the MELCOR code, we simulated and analyzed a Severe Accident at a Chinese pressurized reactor 1000-MW (CPR1000) power plant caused by station blackout (SBO) with failure of the steam generator (SG) safety relief valve (SRV). The CPR1000 response and results for three different scenarios were analyzed: (i) seal leakage and an auxiliary feed water (AFW) supply; (ii) no seal leakage or AFW supply; and (iii) seal leakage but no AFW supply. The results for the three scenarios are compared with those for a simple SBO Accident. According to our calculations, the SG SRV stuck in the open position would greatly accelerate the sequence for a Severe Accident. For an SBO Accident with the SRV stuck open without seal leakage or an AFW supply, the pressure vessel would fail at 9576 s and the containment system would fail at 124,000 s. If AFW is supplied, pressure vessel failure would be delayed nearly 30000 s and containment failure would delay at least 50000 s. When seal leakage exists, pressure vessel failure is delayed about 50 s and containment failure time would delay about 30000 s. The results will be useful in gaining an insight into the detailed processes involved and establishing management guidelines for a CPR1000 Severe Accident.

  • The Severe Accident Analysis of CPR1000 Based on MELCOR Code
    Volume 4: Thermal Hydraulics, 2013
    Co-Authors: Mingjun Wang, Wenxi Tian, Suizheng Qiu
    Abstract:

    The Severe Accident of CPR1000 caused by station blackout with the SG safety valve failure is simulated and analyzed using MELCOR code in this work. The CPR1000 power plant Severe Accident response process and the results with three different assumptions, which are no the seal leakage nor the auxiliary feed water, the seal leakage and auxiliary feed water exist, the seal leakage exist but no auxiliary feed water separately, are analyzed. According to the calculation results, without the seal leakage and auxiliary feed water, pressure vessel would fail at 9576 s. When auxiliary feed water was supplied, pressure vessel’s failure time would delay nearly 30000s. When the seal leakage exists, pressure vessel’s failure time would delay about 50 s. The results are meaningful and significant for comprehending the detailed process of Severe Accident for CPR1000 nuclear power plant, which is the basic standard for establishing the Severe Accident management guideline.

B. Schwinges - One of the best experts on this subject based on the ideXlab platform.

  • sustainable integration of eu research in Severe Accident phenomenology and management
    Nuclear Engineering and Design, 2011
    Co-Authors: Jeanpierre Van Dorsselaere, L Meyer, B. Schwinges, T Albiol, Bernard Chaumont, T Haste, Christophe Journeau, Bal Raj Sehgal, D Beraha, Alessandro Annunziato
    Abstract:

    In order to optimise the use of the available means and to constitute sustainable research groups in the European Union, the Severe Accident Research NETwork of Excellence (SARNET) has gathered, be ...

  • Ranking of Severe Accident Research Priorities
    Progress in Nuclear Energy, 2010
    Co-Authors: B. Schwinges, L Meyer, T Haste, Christophe Journeau, Walter Tromm, K Trambauer
    Abstract:

    Abstract The objectives of the SARNET network are to define common research programmes in the field of Severe Accidents and to develop common computer tools and methodologies for safety assessment in this field. To reach these objectives, one of the work packages, named “Severe Accident Research Priorities” (SARP), aimed at reviewing and reassessing the priorities of research issues as a basis to harmonize and to re-orient research programmes, to define new ones, and to close – if possible – resolved issues on a common basis. The work was performed in close collaboration with 8 participating institutions, led by GRS, representing technical safety organisations, industry and utilities (IRSN, CEA, EDF, FZK, GRS, KTH, TUS, VTT). This action made use notably of (1) the outcomes of the EURSAFE project in the 5th Framework Programme, i.e. the Phenomena Identification and Ranking Tables (PIRT) on Severe Accidents, (2) the results of the validation and benchmarking activities on ASTEC, (3) the results of reactor calculations carried out in the other SARNET tasks, and (4) the outcome of the research performed in the three thematic sub-domains of SARNET (corium, containment and source term). The main outcome of EURSAFE was a list of 21 topics which included recommendations for experimental programmes and code developments. This list formed the basis of the work in SARP. Also the methodology applied in EURSAFE to consider both the risk potential and the Severe Accident issues where large uncertainties still subsist was adopted. The analyses of the progress of research and development activities considered whether (1) any research issue was resolved due to reduction of uncertainties or gain of scientific insights, (2) any new issue had to be added to the list of needed research, (3) any new process or phenomenon had to be included in the general PIRT list taking into account the safety relevance and the lack of knowledge, and (4) any new Accident management program has to be developed to cope with unresolved problems. Furthermore a strategy plan was elaborated to ensure a wide consensus with the end-user requirements and the objectives of SARNET research activities.

  • The ASTEC integral code for Severe Accident simulation
    Nuclear Technology, 2009
    Co-Authors: J. P. Van Dorsselaere, P. Chatelard, C. Seropian, F. Jacq, J. Fleurot, P. Giordano, N. Reinke, B. Schwinges, H.j. Allelein, W. Luther
    Abstract:

    For several years the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and the German Gesellschaft für Anlagen und Reaktorsicherheit (GRS) mbH have been jointly developing a system of calculation codes - the integral Accident Source Term Evaluation Code (ASTEC) - to simulate the complete scenario of a hypothetical Severe Accident in a nuclear light water reactor, from the initial event until the possible radiological release of fission products out of the containment, i.e., the source term. ASTEC has progressively reached a larger European dimension through projects of the European Commission Framework Programme. In particular, in the frame of the European Severe Accident Research NETwork of Excellence (SARNET), jointly executed research activities were performed with the ultimate objectives of providing physical models for integration into ASTEC and making the code the European reference. This effort will go on in the frame of the SARNET2 next network. The ASTEC models are today at the state of the art, except for reflooding of a degraded core. Many applications have been performed by IRSN for significant safety studies, including the probabilistic safety analysis level 2 on a French pressurized water reactor. The first version V2.0 of the new ASTEC series, released in spring 2009, will allow simulation of the European Pressurized Reactor (EPR) and will include advanced core degradation models. Then, ASTEC will remain the repository of knowledge gained from international research and development. Other long-term objectives are on one hand extension of the scope of application to boiling water reactors and CANada Deuterium Uranium (CANDU) reactors, to Accidents in the ITER Fusion facility, and to Very High Temperature Reactor (VHTR) Generation IV reactors, and on the other hand to the use for emergency response tools and for Severe Accident simulators.

L Meyer - One of the best experts on this subject based on the ideXlab platform.

  • sustainable integration of eu research in Severe Accident phenomenology and management
    Nuclear Engineering and Design, 2011
    Co-Authors: Jeanpierre Van Dorsselaere, L Meyer, B. Schwinges, T Albiol, Bernard Chaumont, T Haste, Christophe Journeau, Bal Raj Sehgal, D Beraha, Alessandro Annunziato
    Abstract:

    In order to optimise the use of the available means and to constitute sustainable research groups in the European Union, the Severe Accident Research NETwork of Excellence (SARNET) has gathered, be ...

  • Ranking of Severe Accident Research Priorities
    Progress in Nuclear Energy, 2010
    Co-Authors: B. Schwinges, L Meyer, T Haste, Christophe Journeau, Walter Tromm, K Trambauer
    Abstract:

    Abstract The objectives of the SARNET network are to define common research programmes in the field of Severe Accidents and to develop common computer tools and methodologies for safety assessment in this field. To reach these objectives, one of the work packages, named “Severe Accident Research Priorities” (SARP), aimed at reviewing and reassessing the priorities of research issues as a basis to harmonize and to re-orient research programmes, to define new ones, and to close – if possible – resolved issues on a common basis. The work was performed in close collaboration with 8 participating institutions, led by GRS, representing technical safety organisations, industry and utilities (IRSN, CEA, EDF, FZK, GRS, KTH, TUS, VTT). This action made use notably of (1) the outcomes of the EURSAFE project in the 5th Framework Programme, i.e. the Phenomena Identification and Ranking Tables (PIRT) on Severe Accidents, (2) the results of the validation and benchmarking activities on ASTEC, (3) the results of reactor calculations carried out in the other SARNET tasks, and (4) the outcome of the research performed in the three thematic sub-domains of SARNET (corium, containment and source term). The main outcome of EURSAFE was a list of 21 topics which included recommendations for experimental programmes and code developments. This list formed the basis of the work in SARP. Also the methodology applied in EURSAFE to consider both the risk potential and the Severe Accident issues where large uncertainties still subsist was adopted. The analyses of the progress of research and development activities considered whether (1) any research issue was resolved due to reduction of uncertainties or gain of scientific insights, (2) any new issue had to be added to the list of needed research, (3) any new process or phenomenon had to be included in the general PIRT list taking into account the safety relevance and the lack of knowledge, and (4) any new Accident management program has to be developed to cope with unresolved problems. Furthermore a strategy plan was elaborated to ensure a wide consensus with the end-user requirements and the objectives of SARNET research activities.

  • european expert network for the reduction of uncertainties in Severe Accident safety issues eursafe
    Nuclear Engineering and Design, 2005
    Co-Authors: D Magallon, A Mailliat, J M Seiler, K Atkhen, H Sjovall, S Dickinson, J Jakab, L Meyer, M Buerger, K Trambauer
    Abstract:

    EURSAFE thematic network was a concerted action in the sixth framework programme of the European Commission. It established a large consensus among the main actors in nuclear safety on the Severe Accident issues where large uncertainties still subsist. The conclusions were derived from a first-of-kind phenomena identification and ranking tables (PIRT) on all aspects of Severe Accident also realised in the frame of the project. Starting from a list of all Severe Accident phenomena containing approximately 1000 entries and established by the twenty partner organisations, 106 phenomena were retained eventually as both important for safety and still lacking sufficient knowledge. Ultimately, 21 research areas for addressing these phenomena regrouped according to their similarities were identified. A networking structure for implementing and executing the necessary research was proposed, which promotes integration and harmonisation of the different national programmes. A Severe Accident database structure was proposed to ensure preservation of experimental data and enhanced communication for data exchange and use for Severe Accident codes assessment. The final product, named EURSAFE, is a website network, http://asa2.jrc.it/eursafe, connecting nodes located at partner sites. As the result of an action involving R&D governmental institutions, regulatory bodies, nuclear industry, utilities and universities from six EU Member States (Finland, France, Germany, Spain, Sweden, UK) plus JRC, three European third countries (Czech Republic, Hungary, Switzerland), and USA, EURSAFE represents a significant step towards harmonisation and credibility of the approaches, and resolution of the remaining Severe Accident issues.

T Haste - One of the best experts on this subject based on the ideXlab platform.

  • sustainable integration of eu research in Severe Accident phenomenology and management
    Nuclear Engineering and Design, 2011
    Co-Authors: Jeanpierre Van Dorsselaere, L Meyer, B. Schwinges, T Albiol, Bernard Chaumont, T Haste, Christophe Journeau, Bal Raj Sehgal, D Beraha, Alessandro Annunziato
    Abstract:

    In order to optimise the use of the available means and to constitute sustainable research groups in the European Union, the Severe Accident Research NETwork of Excellence (SARNET) has gathered, be ...

  • Ranking of Severe Accident Research Priorities
    Progress in Nuclear Energy, 2010
    Co-Authors: B. Schwinges, L Meyer, T Haste, Christophe Journeau, Walter Tromm, K Trambauer
    Abstract:

    Abstract The objectives of the SARNET network are to define common research programmes in the field of Severe Accidents and to develop common computer tools and methodologies for safety assessment in this field. To reach these objectives, one of the work packages, named “Severe Accident Research Priorities” (SARP), aimed at reviewing and reassessing the priorities of research issues as a basis to harmonize and to re-orient research programmes, to define new ones, and to close – if possible – resolved issues on a common basis. The work was performed in close collaboration with 8 participating institutions, led by GRS, representing technical safety organisations, industry and utilities (IRSN, CEA, EDF, FZK, GRS, KTH, TUS, VTT). This action made use notably of (1) the outcomes of the EURSAFE project in the 5th Framework Programme, i.e. the Phenomena Identification and Ranking Tables (PIRT) on Severe Accidents, (2) the results of the validation and benchmarking activities on ASTEC, (3) the results of reactor calculations carried out in the other SARNET tasks, and (4) the outcome of the research performed in the three thematic sub-domains of SARNET (corium, containment and source term). The main outcome of EURSAFE was a list of 21 topics which included recommendations for experimental programmes and code developments. This list formed the basis of the work in SARP. Also the methodology applied in EURSAFE to consider both the risk potential and the Severe Accident issues where large uncertainties still subsist was adopted. The analyses of the progress of research and development activities considered whether (1) any research issue was resolved due to reduction of uncertainties or gain of scientific insights, (2) any new issue had to be added to the list of needed research, (3) any new process or phenomenon had to be included in the general PIRT list taking into account the safety relevance and the lack of knowledge, and (4) any new Accident management program has to be developed to cope with unresolved problems. Furthermore a strategy plan was elaborated to ensure a wide consensus with the end-user requirements and the objectives of SARNET research activities.

  • SARNET integrated European Severe Accident Research-Conclusions in the source term area
    Nuclear Engineering and Design, 2009
    Co-Authors: T Haste, D. Bottomley, P. Giordano, L. Cantrel, L. Herranz, N. Girault, R. Dubourg, J.-c. Sabroux, F. Parozzi, A. Auvinen
    Abstract:

    The overall aim of the SARNET (Severe Accident Research NETwork), in the EU 6th Framework programme was to integrate in a sustainable manner the research capabilities of fifty-one European organisations from eighteen member states of the European Union (EU) plus the Joint Research Centres, with one Canadian company, to resolve important remaining uncertainties and safety issues concerning existing and future nuclear plant, especially water-cooled reactors, under hypothetical Severe Accident conditions. It emphasised integrating activities, spreading of excellence (including knowledge transfer) and jointly executed research, with the knowledge gained being encapsulated in the European Severe Accident modelling code ASTEC. This paper summarises the achievements over the whole project in the Source Term Topic, which dealt with potential radioactive release to the environment, covering release of fission products and structural materials from the core, their transport in the primary circuit, and their behaviour in the containment. The main technical areas covered, as emphasised by the earlier EURSAFE project, were the effect of oxidative conditions on fission product release and transport (especially the behaviour of the highly radiotoxic ruthenium under air ingress conditions), iodine volatility in the primary circuit, control rod aerosol release (Ag-In-Cd) that affects iodine transport, containment by-pass in the case of steam generator tube rupture, aerosol retention in containment cracks, aerosol remobilisation in the circuit, and iodine/ruthenium behaviour in the containment especially concerning the volatile fraction in the atmosphere. The studies also covered performance of new experiments, analysis of existing data, and formulation and improvement of theoretical models. Significant progress was made in each area. Looking to the future, the 7th Framework successor project SARNET2 covers the remaining issues concerning iodine and ruthenium, including practical application of the results. The results outlined here will make a good basis for this continued endeavour. © 2009 Elsevier B.V. All rights reserved.