Study of neutron sensitivity for vanadium self-powered neutron detector in nuclear reactors

Vanadium self-powered neutron detectors (SPNDs) are widely used as in-core unmovable detectors in nuclear power plants to continuously carry out data monitoring of neutron flux and nuclear power. In this study, a theoretical calculation model is presented for determining the signal current and thermal neutron sensitivity of vanadium SPNDs. First, the physical characteristics and reaction mechanisms in vanadium SPNDs irradiated with neutrons were discussed thoroughly. Then, a computational approach to determine the neutron sensitivity of the vanadium SPND based on a Monte Carlo method without assumptions and approximations was introduced. Finally, in order to verify the performance of the vanadium SPND and our methodology, the calculated values were compared with experimental measurements and the previous literature. It can be found that all the results agree well with the experimental measurements and that the maximum differences do not exceed 3%, which demonstrates the reliability and effectiveness of the method and further improves the calculation accuracy.