Sustainable integration of EU research in severe accident phenomenology and management

Important Severe Accident Research Issues After Accident at Fukushima Daiichi Nuclear Power Station

“…(EURSAFE) has been established and it created the phenomena identification and ranking tables (PIRT) on all aspects of severe accident [8] [9]. Specific severe accident research items have also been reviewed by working group of Atomic Energy Society of Japan (AESJ) in terms of significance of consequences, uncertainties of phenomena and maturity of assessment methodology [10].…”

“…After the Fukushima accident several investigation committees have been established and the following reports have been issued in Japan: (1) Atomic Energy Society of Japan, May 2011 (AESJ) [ Major almost common technical lessons learned from the accident in these reports are as follows: (1) Enhanced measures against extreme external events, such as earthquake and tsunami (2) Ensuring of emergency power supplies in terms of diversity and reliability (3) Enhanced cooling capabilities of reactor core and containment vessel by passive features (4) Improved preventive and mitigative severe accident management measures, including hydrogen control and containment venting (5) Improved preparedness and responses to disaster condition in multiple units site (6) Improved design and operation of spent fuel pool (7) Improved instrumentation system for reactor pressure vessel and containment (8) Revision of safety standards and guidelines, including long-term loss of external power supply against external events (9) Enhanced operators' education and training under beyond design base conditions based on improved accident management measures…”

“…Under EU Program, European expert network for the reduction of uncertainties in severe accident safety issues (EURSAFE) has been established and it created the phenomena identification and ranking tables (PIRT) on all aspects of severe accident [8]. As one of SARNET activities, Severe Accident Research Priority (SARP) Work-Package has identified research priorities by taking as a basis of PIRT carried out in EURSAFE, and the following six issues have been considered to be investigated further with high priority [9]: (1) Core coolability during reflood and debris cooling (2) Ex-vessel melt pool configuration during MCCI and exvessel corium coolability by top flooding (3) Hydrogen mixing and combustion in containment, including the effect of mitigation measures such as recombiner effect on global convection, generation of local stratification by recombiner, ignition by recombiner (4) Melt relocation into water, ex-vessel FCI (5) Oxidizing impact (Ru oxidizing conditions/air ingress for high burn-up and MOX fuel elements) on source term (6) Iodine chemistry in reactor cooling system (RCS) and in containment.…”

The new STRESA tool for preservation of thermalhydraulic experimental data produced in the European Commission

“…At the same time the JRC STRESA-SARNET network (Van Dorsselaere et al, 2011) was initially developed inside the EC FP6 Project Network SARNET-1 and it was actively used in the EC FP6 Project Network SARNET-2. Several individual nodes were connected to JRC STRESA-SARNET portal, containing severe accidents experimental data from several institutions.…”

Combined Analytical and Experimental Investigations for LWR Containment Phenomena

“…THAI I-IV [7]) and international projects (e.g. OECD/NEA SETH-2 [8] and THAI [9], or EU-SARNET [10] and EU-ERCOSAM [11]), an extensive database, including data with high spatial resolution, was established. This data base is well-suited for development and validation of CFD models which are able to describe flow and transport processes, especially the hydrogen distribution, in a containment during an accident.…”