TOWARD AN INTEGRATED SEISMIC RISK ASSESSMENT FOR NUCLEAR SAFETY IMPROVING CURRENT FRENCH METHODOLOGIES THROUGH THE SINAPS@RESEARCH PROJECT

摘要

The Tohoku earthquake and associated tsunami in March 2011 caused a severe nuclear accident at the Fukushima Daiichi Nuclear Power Plant, where level 7 (International Atomic Energy Agency (IAEA) -INES scale) meltdown at 3 reactors occurred. The underestimation of the seismic and tsunami hazards has been recognized and the seismic margins assessment of the NPPs remains a priority for the whole nuclear community. In this framework an ambitious 5 years research project called SINAPS@ (Earthquake and Nuclear Installations: Ensuring and Sustaining Safety) is currently on-going in France. A reliable estimate of seismic margins is possible only if all uncertainties, epistemic and aleatory, are effectively identified, quantified and integrated in the seismic risk analysis. SINAPS@ brings together a multidisciplinary community of researchers and engineers from the academic and the nuclear world. SINAPS@ aims at exploring the uncertainties associated to databases, physical processes and methods used at each stage of seismic hazard, site effects, soil and structure interaction, structural and nuclear components vulnerability assessments, in a safety approach: the main objective is ultimately to identify the sources of potential seismic margins resulting from assumptions or when selecting the seismic design level or the design strategy. The whole project is built around an "integrating" work package enabling to test state-of-the-art practices and to challenge new methodologies for seismic risk assessment: the real case of Kashiwazaki-Kariwa Japanese nuclear plant, shocked by the severe earthquake in 2007 provided a rich dataset which will be used to compare with the predictions. The present paper mostly illustrates the crucial links and interactions between all actors of the project to reach the objectives.