Analysis of dose rate experiment: comparison between FENDL, EFF/EAF and JENDL nuclear data libraries

Three different nuclear cross section data packages, largely used in fusion studies, were compared through the analysis of a shut-down dose rate experiment in a mock up of the ITER vacuum vessel. These packages are: the European libraries EFF-3.0 (transport) and EAF-2001 (activation), the Japanese libraries JENDL-FF (transport) and JENDL-3.2 (activation), and the international libraries FENDL-2/MC (transport) and FENDL-2/A (activation). The analysis was carried out using a rigorous two-step method using the MCNP transport code and the FISPACT inventory code, coupled by an automated routing of the MCNP neutron flux spectrum distributions to FISPACT and the FISPACT decay gamma source distributions to MCNP. Analysis was performed from shut down, i.e. immediately after the end of mock-up irradiation with 14 MeV neutrons, up to about three months of decay time. All results were found in good agreement with measurements: within 30% at 1 day, and within the ±12% uncertainty in the comparison in the relevant time interval from a few days up to 1 month after shut down. The differences detected between the data packages, of the order of 20% at maximum in the dose rate, were analysed in terms of neutron flux and spectrum, and of activation cross sections.