Main outcomes from the JASMIN project: development and validation of ASTEC-Na for severe accident simulation in Na-cooled fast reactors

The 4 ½ year JASMIN Project, ended in May 2016, was launched in the frame of the 7^th Research Framework Programme of the European Commission. It was inspired by the renewed interest in SFR technology and the Gen-IV challenging targets developed through the GIF initiative [1] of designing innovative reactors with higher safety standards than for the original Gen-III reactors that intrinsically prevent severe accidents or mitigate their consequences. The generic aim was the enhancement of the current capability of the ASTEC-Na code in analyzing severe accidents in Na-cooled reactors and, more especially, to develop its capacities to evaluate the consequences of unprotected accidents with fuel pin failure on material relocation and primary system loads and to predict fission product and aerosol behavior once released. To that extent, the JASMIN project represented a unique opportunity to bring together different actors of nuclear safety in Europe around the ASTEC-Na code. This enabled the achievement of a lot of work to validate and qualify the developed models in ASTEC-Na by comparison with other severe accidents codes (SAS-SFR, SIMMER…) and with dedicated past experimental results (i.e. CABRI tests..). The development and validation work performed during the project explored different technical areas (Na thermal-hydraulics, fuel pin thermos-mechanics, source term and neutronics). In that sense, ASTEC-Na has a big opportunity to cover many aspects of the SFR safety analysis. As a consequence, JASMIN perfectly fits what stated in the ESNII (European Sustainable Nuclear Industrial Initiative) roadmap by developing and benchmarking European computer codes for ESNII Fast Neutron Reactors, in particular relating to safety performance, leading to establish a common platform for modelling and simulation. (author)