Benchmark experiments in venus: a nuclear data package for LWR Pu-recycle

The Venus International Programme (VIP) has validated the reactor codes DORT, GOG and TWOTRAN for reactivity and fission rate distribution calculations in PWR and BWR MOX configurations. The VIP programme aimed at validating reactor codes in order to meet safety requirements enforced by licensing authorities. The VIPO programme has been set up in order to cope with future developments of the nuclear fuel cycle. The tendency of going to higher burn-ups causes the need to investigate a possible positive void coefficient at high plutonium enrichments. The programme has validated the DORT, TORT, WIMS and KENO reactor codes for criticality calculations and KENO for fission rate distribution calculations in voided and non-voided MOX configurations. The VIPEX-PWR programme aims at measuring parameters for 17 by 17 MOX PWR fuel assemblies, mainly of interest for reactor operation, e.g. βeff, Am effect, control rod worth, etc... One of the most important parameters measured in the VENUS are the fission rate distributions and the spectrum index at specific positions in the reactor. The measurement of these parameters requires several gamma scanning techniques that will be described. (author)