Underwater Gamma Ray Spectrometers for Monitoring Environmental Water at Nuclear Power Stations

An underwater gamma (¿) ray spectrometer has been developed and used to measure the concentration of radioisotopes in water at the following sites: the Columbia and Savannah Rivers, the Ft. Belvoir, Peach Bottom, Indian Point, and Yankee power reactors and the University of Maryland Reactor pool. Concentrations of less than 10 picocuries per liter of reactor-produced isotopes were found at power reactor sites. The experience with this system and similar systems used at sea show that it can be adapted for use on a practical basis for continuous monitoring of environmental water. This paper will describe the detector used in these tests, and then will discuss an environmental monitor system for permanent installation.