DPA Calculation in Japanese Spallation Neutron Source

Harada, Masahide   ; Watanabe, Noboru; Konno, Chikara  ; Meigo, Shinichiro   ; Ikeda, Yujiro; Niita, Koji*

For a construction of maintenance and storage scenarios for JSNS, lives of structure material need to be estimated. DPA (Displacement per Atom) was a major index of radiation damage. So we evaluated DPA value of each component. Function of the DPA calculation was equipped to the PHITS code, which was particle and heavy ion transport code. For DPA calculation, displacement cross section was necessary. Displacement cross sections of neutron below 150 MeV were processed by the NJOY code from LA150 library and those of neutron above 150MeV and proton in the all energy region were obtained from energies of fragments calculated in the PHITS. By using the PHITS, we calculated DPA values and DPA mapping. We obtained that the peak DPA values at end of 5000MWh operation were 4.1 for target vessel, 2.8 for reflector and moderator vessels, and 0.4 for proton beam windows, respectively. We estimated the target life at 1 year and the moderator life at 6 year.