Abstract. Early pressurized water reactors were originally designed to operate using stainless steel as cladding material, but during their lifetime this material was replaced by zirconium-based alloys. However, after the Fukushima Daiichi accident, the problems related to the zirconium-based alloys due to the hydrogen production and explosion under severe accident brought the importance to assess different materials. In this sense, initiatives as ATF (Accident Tolerant Fuel) program are considering different material as fuel cladding and, one candidate is iron-based alloy. In order to assess the fuel performance of fuel rods manufactured using iron-based alloy as cladding material, it was necessary to select a specific stainless steel (type 348) and modify properly conventional fuel performance codes developed in the last decades. Then, 348 stainless steel mechanical and physics properties were introduced in the TRANSURANUS code. The aim of this paper is to present the obtained results concerning the verification of the modified TRANSURANUS code version against data collected from the open literature, related to reactors which operated using stainless steel as cladding. Considering that some data were not available, some assumptions had to be made. Important differences related to the conventional fuel rods were taken into account. Obtained results regarding the cladding behavior are in agreement with available information. This constitutes an evidence of the modified TRANSURANUS code capabilities to perform fuel rod investigation of fuel rods manufactured using 348 stainless steel as cladding material.
IntroductionThe available data shows that the steady state performance of steel cladding in the first PWR was considered excellent [1,2]. The material used in the early PWR was mainly AISI 304 (12% cold worked). Nonetheless, some reactors operated using annealed AISI 348, which presents a better corrosion resistance due to the addition of niobium and tantalum in its composition.The substitution of stainless steel by zircaloy as cladding material was due to the lower absorption for thermal neutrons of the zirconium-based alloys which enables to operate with lower enrichment cost. Despite the stainless steel economics penalty, the main advantage of using this material as cladding comes from the reduction of the probability of the violent oxidation reaction that occurs with zirconium-based alloys at high temperatures, as it has occurred in the Fukushima Daiichi accident [3]. As a consequence of this, iron-based alloys once again can be considered as a good option to replace zirconium-based alloys as cladding material improving the safety under accident scenarios [4]. Considering the previous good experience of AISI 348 as cladding, this material could be again applied to replace zirconium-based alloys as PWR fuel cladding.In order to evaluate the fuel performance of fuel rods using AISI 348 as cladding, it is necessary to modify the current fuel performance codes to insert correlations and properties of this materi...