French Post-Fukushima complementary assessments general approach and resulting safety improvements for the high flux reactor located in Grenoble

Following the accident that occurred on the Fukushima Daiichi nuclear power plant on March 11^th 2011, the licensees of French nuclear facilities were asked to engage a safety reassessment of their facilities with the aim of evaluating their capacity to withstand extreme situations beyond design basis assumptions. These specific reassessments, called Complementary Safety Assessments (CSAs), were carried out on the basis of the specifications for the stress tests requested by the European Council. In France, these reassessments included all nuclear power plants in operation but also fuel cycle facilities and research reactors. This paper presents the analysis performed by French licensees in the framework of CSAs and the opinion of the Institute of Radiological Protection and Nuclear Safety (IRSN) which has been largely involved in the review of the CSAs. Then, the paper introduces the concept of "hardened safety core" firstly defined by IRSN and presents a concrete implementation of the "hardened safety core" based on the example of the High Flux Reactor (RHF), which is a research reactor located in Grenoble (France) and operated by the Laue-Langevin Institute (ILL). (author).