Request for 35Cl(n,p) reaction cross-section measurements and re-evaluations from the standpoint of molten chloride salt fast reactor design

A molten chloride salt fast reactor with inherent safety features is being studied in order to utilize spent fuel discharged from light-water reactors effectively and to reduce environmental burdens. A hard neutron spectrum is required to achieve the transmutation of TRU efficiently, which can be realized by using a molten chloride salt. However, it was found that the criticality analysis shows a large difference of 2%Delta k among the effective multiplication factors (k(eff)) obtained using several evaluated nuclear data libraries. A sensitivity analysis was performed to investigate the cause of the difference in k(eff) and it was clarified that the difference of 2%Delta k/k reactivity was due to the difference in cross sections of the Cl-35(n,p)S-35 reaction. Such a large difference in keff makes a reliable core design difficult and strongly affects important core characteristics such as the TRU transmutation rate, conversion ratio, and so on. Therefore, this paper has been prepared to make a strong request for measurements and re-evaluations of the (n,p) cross section of Cl-35.