In the past, stainless steel was utilized as cladding in many PWRs (pressurized water reactors), and its performance under
irradiation was excellent. However, stainless steel was replaced by zirconium-based alloy as cladding material mainly due to its lower
neutron absorption cross section. Now, stainless steel cladding appears as a possible solution for safety problems related to hydrogen
production and explosion as occurred in Fukushima Daiichi accident. The aim of this paper is to discuss the steady-state irradiation
performance using stainless steel as cladding. The results show that stainless steel rods display higher fuel temperatures and wider
pellet-cladding gaps than Zircaloy rods and no gap closure. The thermal performance of the two rods is very similar and the neutron
absorption penalty due to stainless steel use could be compensating by combining small increase in U-235 enrichment and pitch size
changes.