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

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 the European Commission. It gathers 18 partners from 12 countries: IRSN, AREVA NP SAS and EDF (France), GRS, KIT, USTUTT and RUB (Germany), CIEMAT (Spain), ENEA (Italy), VUJE and IVS (Slovakia), LEI (Lithuania), NUBIKI (Hungary), INRNE (Bulgaria), JSI (Slovenia), VTT (Finland), PSI (Switzerland), BARC (India) plus the European Commission Joint Research Center (JRC). The CESAM project focuses on the improvement of the ASTEC (Accident Source Term Evaluation Code) computer code. ASTEC,, jointly developed by IRSN and GRS, is considered as the European reference code since it capitalizes knowledge from the European R&D on the domain. The project aims at its enhancement and extension for use in severe accident management (SAM) analysis of the nuclear power plants (NPP) of Generation II-III presently under operation or foreseen in near future in Europe, spent fuel pools included. In the frame of the CESAM project one of the tasks consisted in the preparation of a report providing an overview of the Severe Accident Management (SAM) approaches in European Nuclear Power Plants to serve as a basis for further ASTEC improvements. This report draws on the experience in several countries from introducing SAMGs and on substantial information that has become available within the EU “stress test”. To disseminate this information to a broader audience, the initial CESAM report has been revised to include only public available information. This work has been done with the agreement and in collaboration with all the CESAM project partners. The result of this work is presented here.JRC.F.5-Nuclear Reactor Safety Assessmen

HYDROGEN MANAGEMENT STRATEGIES AND ANALYSIS CODES IMPLEMENTED BY THE OECD/NEA MEMBER COUNTRIES

In the follow-up to the Fukushima accident, the OECD/NEA CSNI initiated an activity within its member countries to review and assess their hydrogen management strategies under severe accident conditions and the associated computer codes used for the hydrogen safety analysis. A CSNI report, titled Hydrogen Management and Related Computer Codes, was thereafter published by OECD/NEA in 2014 June, consisting of information contributed by 15 OECD/NEA member countries. This paper summarizes the major findings obtained in the activity. The state of knowledge on hydrogen generation, distribution, combustion and mitigation is presented. The corresponding computer codes that are used by the member countries for hydrogen safety analysis are discussed, including code capabilities and validation status assessed against the hydrogen behavior associated with generation, distribution, combustion and mitigation. The hydrogen management strategies are presented based on the literature findings. The status of hydrogen management systems implemented by the member countries are discussed, including national requirements, mitigation measures and their implementation status, and considerations on the interaction of engineering safety systems with hydrogen behavior during severe accidents. The CSNI report has provided a basis for assessing severe accident management strategies and identifying gaps in code capabilities and validations, and providing insights for model enhancement and application. It is expected to be a useful handbook for nuclear safety authorities, research institutions, and utilities.JRC.F.5-Nuclear Reactor Safety Assessmen

CSNI Post-Fukushima Activity on Hydrogen - Part II: Computer Codes and Validations

This paper provides an overview of the status report on Hydrogen Management and Related Computer Codes published by CSNI in 2014 June with a focus on part II of the report on computer codes. An assessment of the capabilities and validation status of eleven computer codes used by the member countries for hydrogen analysis was assessed against a list of phenomena defined for hydrogen generation, distribution, combustion and mitigation. The general approaches employed by these codes to model hydrogen behavior and the code performance in recent international benchmarks are discussed. The purpose of this paper is to identify gaps in model capabilities and validations, and to provide insights for model enhancement and application.JRC.G.I.4-Nuclear Reactor Safety and Emergency Preparednes

Proceedings of the 1. OECD (NEA) CSNI-specialist meeting on instrumentation to manage severe accidents

The meeting was structured in the following sessions: I. Information Needs for Managing Severe Accidents (6 papers). II. Capabilities and Limitations of Existing Instrumentation (5 papers). III. Unconventional Use and Further Development of Instrumentation. (6 papers). IV. Operational Aids and Artificial Intelligence (5 papers). The presentations are separately indexed in the database. (orig.)Available from TIB Hannover: RN 6050(93) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

CFD and LP Code Benchmark on the Onset of PAR Operation in Case of Extremely Low Oxygen Concentration

Proceedings in Conferenc

Management and Uncertainties of Severe Accidents (MUSA): An H2020-Euratom Project

In the current state of maturity of severe accident codes, application of BEPU (Best Estimate Plus Uncertainties) methodology in severe accident analysis, including Accident Management (AM), might provide key insights in terms of predictability and research needs. The EC project on “Management and Uncertainties of Severe Accident (MUSA)”, funded by Horizon 2020 Framework Programme, is aimed to assess the capability of severe accident codes when modeling reactor and SFP (Spent Fuel Pool) accident scenarios of Gen II and Gen III reactor designs, AM included. To do so, UQ (Uncertainty Quantification) methodologies are to be used, with a focus on Source Term (ST). The overall budget of the project is € 5,768,452.50, which means around 630 person-months