Establishment and verification of chemical interaction model between fast reactor fuel and cladding under high burnup

Abstract

BackgroundUranium dioxide fuel elements of fast neutron reactor operate under the conditions of high burnup, high neutron fluence rate, high line power and high temperature. Complex physical chemical interactions occur between fuel and the cladding materials. The establishment of fuel element chemical interaction model is very important for the design of high burnup fast reactor fuel element.PurposeThis study aims to establish a chemical interaction model between fast reactor fuel and cladding materials under high burnup.MethodsEmphasis was placed on the chemical interaction phenomenon of the oxide fuel elements of fast neutron reactors. Firstly, the chemical interaction models of uranium dioxide interacted with austenitic stainless steel and ferritic-martensitic steel cladding materials were established by using a dynamic model. Then, special fuel element performance analysis program FIBER-Oxide, developed by China Institute of Atomic Energy (CIAE), was employ to verify these chemical interaction models by experimental data.ResultsThe corrosion model of fast reactor uranium dioxide fuel and austenitic stainless steel can successfully predict the cladding corrosion with maximum burnup of 10.8at% and irradiation damage of 87.5 dpa. The corrosion model of fast reactor uranium dioxide fuel and ferritic-martensitic steel can successfully predict the cladding corrosion with maximum burnup of 9.3at% and irradiation damage of 76.6 dpa.ConclusionsThe results of this study provide important reference value for the design and performance prediction of high burnup uranium dioxide irradiation elements and fuel elements of demonstration fast reactor.

Keywords

• fast reactor fuel element
• pellet cladding interaction
• corrosion cracking
• high burnup