Comparison of fuel performance codes using stainless steel as cladding material

The cladding material in the firsts PWRs (pressurized water reactors) was stainless steel which was later replaced by zirconium-based alloys mainly due to their lower neutron absorption cross section which impacts on the operational cost of the reactor. However, after Fukushima Daiichi Accident, stainless steel cladding appears as an alternative to zirconium-based alloys to overcome the safety problems related to hydrogen production and explosion in nuclear power plants under severe accident conditions. In order to assess the fuel performance of fuel rods manufactured using stainless steel as cladding material, it is necessary to modify conventional fuel performance codes developed in the last decades. The aim of this paper is to discuss the results obtained under steady-state irradiation for fuel rods manufactured using stainless steel as cladding applying two new versions of fuel performance codes, one based on FRAPCON (named IPEN-CNEN/SS) and TRANSURANUS. These fuel performance codes were modified with the inclusion of the mechanical and physical properties of the stainless steel 348. The performance under the same power history was investigated and compared considering the stainless steel expected behavior. The results obtained from IPEN-CNEN/SS and TRANSURANUS simulations have presented the same trends and global performance under steady-state irradiation. (author)