Lead Neutron Data Validation Using Integral Experiments at the VENUS-F and BFS Zero Power Reactors

The Belgian Nuclear Research Centre SCK CEN operates a fast zero-power reactor VENUS-F as a neutronics mock-up of the Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA) and Lead Fast Reactors (LFR). A new experimental campaign at the VENUS-F reactor was performed where fission r ate r atios w ere m easured u sing fi ssion ch ambers wi th de posits of various fissile a nd f ertile m aterials i n t he f uel z one, i n t he l ead r adial a nd l ead a xial reflector. This paper compares the new as well as selected past measurements at VENUS-F with Serpent2 Monte Carlo calculations using JENDL-4.0u2, JEFF-3.3, ENDF/B-VIII.0 and BROND-3.1 lead data evaluations. For collation, the fast lead OECD benchmark MIX-MET-FAST-006 measured at the Russian BFS-1 reactor was also modelled in Serpent2. The calculated benchmark parameters include criticality, spectral indices, radial and axial traverses. Similar calculation-to-experiment discrepancies in threshold spectral indices were encountered at both VENUS-F and BFS-61.