Analysis of Microdosimetric Quantities of Mixed Radiation Fields in the Reactor Building at the Wolsong Nuclear Power Plant

Abstract

A commercially available tissue equivalent proportional counter (TEPC), model FW-AD1, was used as microdosimetric detector to measure the dose equivalent rates at several workplaces in the reactor building of a pressurized heavy water reactor, the Wolsong Nuclear Power Plant unit 3 in Korea. The microdosimetric quantities including the lineal-energy distributions and the dose-mean lineal energy were determined by unfolding the measured data, and then the mean quality factors and the dose equivalent rates were evaluated. The mean quality factors at places where neutron dose rates were significant were in the range of 2.2 to 7.1, while those values were near unity at the places where gamma-ray dose rates dominated. The lineal energy spectra of the reference radiation fields at the Korea Atomic Energy Research Institute (KAERI) were also measured for comparisons. Particularly in the vicinity of the primary heat transport pump, the dose-mean lineal energy and the mean quality factor appeared similar to those values of the D20 moderated 252Cf reference field. The tool and the analysis method can be applied to characterization of other mixed radiation fields.