Performance Analysis of an Enhanced Cr-Coated Fuel Cladding System

This work investigates the effectiveness of Cr coatings on fuel cladding systems to improve accident tolerance in pressurized water reactors. This study is focused on evaluating the neutronics performance of zirconium alloy claddings coated with Cr (Zr alloy-Cr) and comparing them with the current Zr-U system. The critical parameters related to the performance of such a reactor design, like multiplication factor, neutron spectrum, and radial neutron flux, are assessed by the simulation performed with the Monte Carlo code Serpent 2.1.31. Chromium coatings can significantly enhance the corrosion resistance and thermal conductivity for increased reactor safety. Furthermore, an adhesive layer, such as molybdenum, would further stabilize the coating and solve any problem of interdiffusion occurring at a high temperature. Optimal designs identified are comprised of a 10-µm-thick Cr overlay with 2.20-µm-thick molybdenum as the adhesive layer to provide optimal performance while minimizing the negative influence of the neutron economy. This study proves the potential of the Cr-coated cladding system for short- to medium-term solutions in improved safety and efficiency in nuclear reactors, mainly under severe accident conditions.