scholarly journals Safety assessments and severe accidents, impact of external events on nuclear power plants and on mitigation strategies

2020 ◽  
Vol 6 ◽  
pp. 39
Author(s):  
Jean-Pierre Van Dorsselaere ◽  
Ahmed Bentaib ◽  
Thierry Albiol ◽  
Florian Fichot ◽  
Alexei Miassoedov ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Mitigation Strategies ◽  
Severe Accident ◽  
Severe Accidents ◽  
Accident Management ◽  
External Events ◽  
Safety Assessments ◽  
The University

The Fukushima-Daiichi accidents in 2011 underlined the importance of severe accident management (SAM), including external events, in nuclear power plants (NPP) and the need of implementing efficient mitigation strategies. To this end, the Euratom work programmes for 2012 and 2013 was focused on nuclear safety, in particular on the management of a possible severe accident at the European level. Relying upon the outcomes of the successful Euratom SARNET and SARNET2 projects, new projects were launched addressing the highest priority issues, aimed at reducing the uncertainties still affecting the main phenomena. Among them, PASSAM and IVMR project led by IRSN, ALISA and SAFEST projects led by KIT, CESAM led by GRS and sCO2-HeRO lead by the University of Duisburg-Essen. The aim of the present paper is to give an overview on the main outcomes of these projects.

scholarly journals A decision-support approach to severe accident management in nuclear power plants

2020 ◽  
pp. 1-12
Author(s):  
Marko Bohanec ◽  
Ivan Vrbanić ◽  
Ivica Bašić ◽  
Klemen Debelak ◽  
Luka Štrubelj
Keyword(s):  
Decision Support ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Severe Accident ◽  
Accident Management

Design of Severe Accident Management Systems for Beyond Design Basis External Hazards at Paks NPP

2016 ◽  
Author(s):  
Tamás János Katona ◽  
András Vilimi
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Severe Accident ◽  
Management Systems ◽  
Basic Question ◽  
Severe Accidents ◽  
Design Basis ◽  
Accident Management ◽  
External Events

Paks Nuclear Power Plant identified the post-Fukushima actions for mitigation and management of severe accidents caused by external events that include updating of some hazard assessments, evaluation of capacity / margins of existing severe accident management facilities, and construction of some mew systems and facilities. In all cases, the basic question was, what level of margin has to be ensured above design basis external hazard effects, and what level of or hazard has to be taken for the design. Paks Nuclear Power Plant developed certain an applicable in the practice concept for the qualification of already implemented and design the new post-Fukushima measures that is outlined in the paper. The concept and practice is presented on several examples.

The Formulation of Material Characteristics of Austenitic Stainless Steels at Extremely High Temperature

2017 ◽  
Author(s):  
Kenta Shimomura ◽  
Takashi Onizawa ◽  
Shoichi Kato ◽  
Masanori Ando ◽  
Takashi Wakai
Keyword(s):  
High Temperature ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Structural Integrity ◽  
Austenitic Stainless Steels ◽  
Severe Accident ◽  
Integrity Assessment ◽  
Severe Accidents ◽  
Material Characteristics

This paper describes the formulation of material characteristics of austenitic stainless steels at extremely high temperature which meets in some kinds of severe accidents of nuclear power plants. After the severe accident in Fukushima dai-ichi nuclear power plants, it has been supposed to be very important not only to prevent the occurrence of abnormal conditions, i.e. from the first to the third layer safety, but also to prevent the expansion of the accident conditions, i.e. the fourth layer safety[1] [2]. In order to evaluate the structural integrity under the severe accident condition, material characteristics which can be used in the numerical analyses, such as finite element analysis, were required [3] [4]. However, there were no material characteristics applicable to the structural integrity assessment at extremely high temperature. Therefore, a series of tensile and creep tests was performed for austenitic stainless at extremely high temperature which meets in some kinds of severe accidents of nuclear power plants, namely up to 1000 °C. Based on the acquired data from the tests, monotonic stress-strain equation and creep rupture equation applicable to the structural analysis at extremely high temperature, up to 1000 °C were formulated. As a result, these formulae make it possible to conduct the structural integrity assessment using numerical analysis techniques, such as finite element method.

Overview of Revised Level 2 PRA Standard in Japan

2016 ◽  
Author(s):  
Koichi Nakamura ◽  
Yoshiyuki Narumiya ◽  
Yutaka Abe
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Technical Committee ◽  
Lessons Learned ◽  
Severe Accident ◽  
Severe Accidents ◽  
New Findings ◽  
Accident Research ◽  
Level 2

In this paper, we introduce the overview of the standard for Procedure of Level 2 Probabilistic Risk Assessment (PRA) for nuclear power plants established and issued by the Atomic Energy Society of Japan (AESJ). The first edition of the standard was published in 2008 through the discussions at the Level 2 Subcommittee under the Risk Technical Committee of the Standards Committee. As an enforcement standard based on the PRA procedure, the standard specifies the requirements which should have the PRA dealing with incidents resulting from internal events at nuclear power plants during power operation, and the concrete methods of meeting it. This new version standard is regular revision. In revising the 2008 version standard, we updated various requirements to reflect advancements in Level 2 PRA techniques based on new technological findings after the publication of the previous standard and to improve the quality and transparency of this standard. In particular, the lessons learned and new findings from the severe accidents of Fukushima Dai-ichi nuclear power plants, which occurred on March 11 of 2011, were significant. The reason was that three cores were melted down and large amounts of FP were released in the accidents. We investigated the latest documents relevant to severe accident research, and the measure against a severe accident established after the severe accidents of Fukushima Dai-ichi nuclear power plants. Furthermore, we extracted the matter, which should be reflected by comparison with international standard for PRA, ASME/ANS standard and IAEA SSG-4. Here, we introduce the outline and the feature of the AESJ standard for level 2 PRA. We also introduce the future renewal plan of the standard including the extension of the scope for external event, such as an earthquake and tsunami.

Development of severe accident management guidance (SAMG) for the Canadian CANDU 6 nuclear power plants

2008 ◽  
Vol 238 (4) ◽  
pp. 1093-1099 ◽  
Author(s):  
Thinh Nguyen ◽  
Raj Jaitly ◽  
Keith Dinnie ◽  
Ron Henry ◽  
Don Sinclair ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Severe Accident ◽  
Accident Management ◽  
Management Guidance

Discussing the Modification of Dedicated Lines Used for Severe Accident Depressurization

2013 ◽  
Author(s):  
Bo Zhang ◽  
Jing Liu ◽  
Xichao Liu ◽  
Yafu Gao ◽  
Aicheng Gong
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Second Generation ◽  
Numerical Results ◽  
Severe Accident ◽  
Excessive Heat ◽  
Severe Accidents ◽  
Present Structure

A barrier that limits the development of the nuclear power plants is the problem of the depressurization for severe accidents. The present work addresses this issue by adding the dedicated severe accident depressurization system that is placed on the top of the pressurizer. This design enables the excessive heat to be directly pumped into the atmosphere to lower the pressure in the containment. The theoretical and numerical results indicated that the addition of the dedicated severe accident depressurization system does not affect the performance of the second generation of PWRs. More importantly, this design not only significantly reduces the LERF value but also facilitates the modification of the present structure.

scholarly journals The European Research on Severe Accidents in Generation-II and -III Nuclear Power Plants

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jean-Pierre Van Dorsselaere ◽  
Ari Auvinen ◽  
David Beraha ◽  
Patrick Chatelard ◽  
Christophe Journeau ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Computer Code ◽  
Severe Accident ◽  
Research Network ◽  
Combustion Source ◽  
Joint Research ◽  
Severe Accidents ◽  
Young Researchers

Forty-three organisations from 22 countries network their capacities of research in SARNET (Severe Accident Research NETwork of excellence) to resolve the most important remaining uncertainties and safety issues on severe accidents in existing and future water-cooled nuclear power plants (NPP). After a first project in the 6th Framework Programme (FP6) of the European Commission, the SARNET2 project, coordinated by IRSN, started in April 2009 for 4 years in the FP7 frame. After 2,5 years, some main outcomes of joint research (modelling and experiments) by the network members on the highest priority issues are presented: in-vessel degraded core coolability, molten-corium-concrete-interaction, containment phenomena (water spray, hydrogen combustion…), source term issues (mainly iodine behaviour). The ASTEC integral computer code, jointly developed by IRSN and GRS to predict the NPP SA behaviour, capitalizes in terms of models the knowledge produced in the network: a few validation results are presented. For dissemination of knowledge, an educational 1-week course was organized for young researchers or students in January 2011, and a two-day course is planned mid-2012 for senior staff. Mobility of young researchers or students between the European partners is being promoted. The ERMSAR conference is becoming the major worldwide conference on SA research.

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