Analysis of beryllium poisoning effect on liquid metal reactor with U–Be alloy fuel

A liquid metal reactor (LMR) loaded with a fuel compound of uranium and beryllium (U–Be alloy fuel), which was cooled by a lead–bismuth eutectic alloy (PbBi), has been applied in Russian Alfa-class nuclear submarines. Because of the large amount of beryllium in the core, the reaction between the beryllium atoms and neutrons could result in the accumulation of 3He and 6Li, which are called the “poisoned elements” owing to their large thermal neutron capture cross section. The accumulation of neutron absorber can affect the performance of a reactor. In this study, the Super Multi-functional Calculation Program (SuperMC) code, which was developed by Institute of Nuclear Energy Safety Technology of the Chinese Academy of Sciences (INEST, CAS), was adopted to illustrate the influence of beryllium on an LMR.