Development of a Plutonium Air Monitor for Emergency Environmental Monitoring.

We have developed an air monitor which is possible to measure rapidly and sensitively the concentration of plutonium for the environmental monitoring at an accident of a nuclear reprocessing plant. The monitor is designed to collect airborne plutonium by drawing the ambient air through a filter and to detect the activity by alpha spectroscopy. The following two methods are equipped with the monitor: continuous measuremeat at atmospheric pressure and batch measurement at vacuum. The description of the air monitor and the results of performance test are reported.