Simplified, solid-state, wide-range, stack-gas monitor for nuclear power plants

Government regulations require that radioactive effluent from nuclear power plants be measured and reported and that effluent reporting be based on laboratory analyses. Continuous monitoring during a postulated design-basis accident is also required. Wide-range gas monitors for satisfying regulatory requirements for post-accident radiation monitoring typically have been very complex, and costly to operate and maintain. This paper describes recently developed solid-state detectors that can be mounted directly in the vent stack of a nuclear power plant for monitoring gaseous effluent during normal and postulated accident conditions and also for providing real-time isotopic analysis of the gaseous plant effluent. A proposed stack-gas monitor system using these detectors is described, including anticipated signal levels based on calculations for an actual operating nuclear power plant (a pressurized-water reactor)