Rapid Monitoring of Gaseous Fission Products Released from Nuclear Power Stations

Abstract

Quantitative monitoring of gaseous fission products by rapid, in situ measurements was conducted around nuclear power stations in Taiwan. A portable high-resolution germanium detector with portable a multichannel analyzer was used in the field monitoring work. The detecting unit was calibrated using activated Ar, Kr, and Xe isotopes dispersed in a large chamber to obtain absolute efficiency curve in terms of counts per gamma per m3 versus gamma-ray energy. The calibrated detecting unit was brought to the nuclear power plants for in situ monitoring for both normal operation and nuclear accidental drill. In a typical four-hour measurement, the detection limits for most Kr and Xe fission product isotopes are only 0.0028% ~ 0.98% of the derived air concentration imposed by the local authority. The dose rate caused by gaseous radioisotopes released from nuclear power stations and dispersed to the surroundings can be quantitatively monitored in a short period using this portable unit.