A Monte Carlo method for quantitatively calculating the neutron sensitivity of rhodium self-powered neutron detectors in reactors

Purpose Self-powered neutron detectors (SPNDs) with rhodium emitters exhibit high thermal neutron sensitivity and extensively equipped in nuclear reactors for core monitoring. The neutron sensitivity of SPND is the most significant criterion that directly determines the measured neutron flux and power and thereby needs to be accurately calibrated.
Methods In this presented paper, the physical characteristics of rhodium SPND and its reaction mechanism with in-core neutrons were described thoroughly. Based on the inherent space electric field of concentric cylindrical SPND, three formulas with different approaches were proposed to quantitatively calculate the effective signal of SPND. The neutron sensitivity of rhodium SPND was then calculated quantitatively using the Monte Carlo (MC) methods. In order to expand the application scope of rhodium SPND, its sensitivity performance in four different types of pressurized water reactors (PWRs) was also been simulated and compared.
Results and improvements The effectiveness and correctness of the model have been verified through experiments and comparisons with previous studies. The methods proposed in this paper have been successfully applied to industrial applications of reactor monitoring, and have demonstrated considerable reliability and accuracy.