Evaluation for self-powered neutron detector used in sodium-cooled fast reactor

Abstract

Due to the advantages of high-temperature tolerance, strong radiation resistance, tiny size, and self-powered feature, Self-Powered Neutron Detectors (SPNDs) have been widely used in the 2^nd and 3^rd generation reactors. The typical 4^th generation reactors have higher temperature, higher neutron flux, stronger irradiation, harder neutron energy spectrum and more ununiform neutron/gamma distribution than the 3^rd generation reactors. These features may affect SPND’s response performance when SPND is utilized in the 4^th generation reactors. Due to its advantages in the sustainable development of nuclear fission energy, Sodium-cooled fast reactor (SFR) is chosen for this study. It is found in the study that resonant absorption plays an important role due to the harder energy spectrum in the fast reactors. In the meanwhile, current amplitude, current components, and emitter burn-up have been compared for common emitter materials, suggesting Hf is more suitable for long-term use in SFR. Finally, Hf-SPND’s response dependence on deployment position has been studied and it’s found that the current amplitude and component vary considerably with positions, indicating that position correction is required.