Performance of the High Pressure Xe detector for the Radiation Monitoring System of the Nuclear Power Plants

Abstract

High-pressure Xe (HPXe) ionization chamber is considered as an ideal detector for the Radiation Monitoring System (RMS) in nuclear power plants, since detector response has been shown to be uniform over large temperature ranges up to 170 C. By using the MCNPX simulation code, the energy spectra were calculated with respect to the thickness of the outer shell and the dependence on the incident direction of the radiation sources in the nuclear power plant. A cylindrical HPXe ionization chamber, which was configured with a shielding mesh to improve its energy resolution, was designed and fabricated. With the gas purification and injection system, Xe and 7% 4 He was purified and injected into the chamber and the performances of the chamber were evaluated. The leakage and saturation currents of the chamber were measured with an electrometer, respectively. Linearity against dose rates was also measured with 226 Ra (0.906 mCi) radiation source and the 0.994 of root-mean-square value was estimated. In a future work, energy spectra with the fabricated HPXe ionization chamber will be measured and compared with the simulated energy spectra.