Environmental Radiation Monitoring System Development for Atmospheric Plumes from Light Water Reactor Nuclear Power Plants

The environmental monitoring system for radiation exposure due to light water reactor (LWR) nuclear power plant plume is described. This system, employing a NaI(Tl) scintillation detector with an exposure rate conversion circuit, has the capability of highly accurate evaluation of radiation exposure due to an LWR plume with 0.15 million R/yr (39 nC/kg.yr) overevaluation and 0.05 million R/yr (13 nC/kg.yr) underevaluation. Plume exposure is identified by combining the time variation property of the exposure rate with meteorological parameters. Outlines of the present system are described, including monitoring results obtained over a 98-day period by tentative system at an LWR site boundary.