Mechanical-structural analysis of a stainless steel fuel rod under burst test conditions

Abstract

After the Fukushima nuclear accident in 2011, the nuclear research community has initiated research into the development of fuels that are resistant to accidents. In this context, iron-based alloys have emerged as a good alternative to zirconium alloys. In order to make possible the cladding material replacement, studies related to their mechanical properties are necessary. Thus, the present study carried out a mechanical-structural evaluation from the available data collection regarding the mechanical properties of stainless steel 348, specifically in the conditions of the burst test. Burst tests were performed at various temperatures ranging from 32°C up to 450 °C. Then, a computational model was created based on the specimen of the burst test. Numerical simulation was performed considering the tensile tests of stainless steel at various temperatures. The numerical results were compared with the results of the burst test. Test and simulations were comparable leading to computational model validation. As austenitic stainless steels have structural stability for low and high temperatures, the results could be extrapolated to temperatures higher than those in the burst test. After the validation of the computational model, simulations were performed for temperatures higher than 450ºC, thus obtaining a burst pressure curve as a function of the temperature for stainless steel ANSI 348. The correlation of burst data as function of temperature could be implemented in the FRAPTRAN code, in order to make possible the evaluation of the behavior of a fuel rod with stainless steel ANSI 348 under postulated accident conditions (LOCA).