Gamma heating rate evaluation for material irradiation test in the Joyo experimental fast reactor

Maeda, Shigetaka   ; Naito, Hiroyuki; Soga, Tomonori ; Aoyama, Takafumi 

The evaluation of the spatial distribution of heating in fast reactors requires consideration of all the intensity components. However, the delayed ray yield data of all actinides are not prepared in evaluated nuclear data files such as ENDF or JEDNL. In this study, new neutron/ cross section constants based on JENDL-3.2 and -4 were developed. The delayed yields were added to JENDL-3.2 and JENDL-4. Based on these modified JENDL-3.2 and -4, MATXSLIB-type library for conventional discrete ordinate multi-group transport code were generated. Neutron and ray coupling calculations for the experimental fast reactor Joyo core, based on transport theory as a fixed source problem, revealed that the flux increased by approximately 40% when the delayed intensity in both JENDL-3.2 and -4 were considered. The calculated heat rates were verified by comparison with the measured data obtained by on-line irradiation rigs. It was confirmed that the calculated heat rates agreed with the measurements within 3-12%.