Monte Carlo Simulation of In-Situ Multi-Scale Damage Detection of AGR Graphite

Abstract The Advanced Gas-Cooled Reactor (AGR) is the most common design of nuclear reactor in the UK. These reactors were commissioned in the 1980s and have now reached the end of their design life. As a type of thermal reactor, it uses graphite as a moderator to control the reaction. The cracking of graphite blocks in the core is an important factor limiting the lifetime of AGR stations. The damage of the AGR graphite will affect the power of the reactor and also become a hidden danger threatening the safety of the reactor. As a thermal reactor, it uses graphite as a moderator. Since graphite bricks cannot be replaced or repaired, in order to ensure the continued operation of the reactor, it is necessary to obtain timely and accurate damage information of graphite bricks. In order to carry out the research on in-situ multi-scale damage detection of AGR graphite, a linear CT imaging detection scheme was designed in combination with the core geometries of the AGR stations. Based on the GEANT4 Monte Carlo simulation software, an experiment is carried out to simulate a series of processes from signal acquisition to image reconstruction. Through the simulation experiment, the detection ability of the linear CT detection system under the interference of strong background radiation field signal in the AGR reactor and the geometric error of the detection system is verified, so as to evaluate the feasibility of the linear CT imaging detection scheme and guide the design of the detection system.