Radiological assessment of the limits and potential of reduced activation ferritic/martensitic steel F82H

Tanigawa, Hiroyasu; Someya, Yoji; Sakasegawa, Hideo   ; Hirose, Takanori; Ochiai, Kentaro

The practical implementation of F82H pertaining to the element control and mechanical properties was reviewed, and the reduced activation level was discussed based on the data. It is found that Ni is the element that should be removed to reduce the activation levels, while preventing contamination during the melting process is essential for reducing Ni concentrations. Another element discussed is N. The amount of C transmuted from N must be reduced to achieve the shallow land burial limit. However, N plays an important role in the realization of high-temperature properties. Furthermore, at least 100 ppm of N will remain in the steel when large-scale melting by electric arc furnace is employed. Using Al for deoxidation of the RAFM steel has no significant impact on the activation levels, and the impact of the minor elements such as Ag is negligible compared to that of Ni and N. There is no way to reduce the decay heat by an order of magnitude because the main source elements of the decay heat are the key elements of RAFM, which cannot be reduced.