Use of field instruments in the operation of environmental surveys around nuclear power plants

An underwater gamma radiation probe was constructed to provide qualitative and quantitative measurements while traveling over bottom sediments. The underwater probe was used at two nuclear power plant sites to determine preoperational levels of radioactivity present in the sediments near the plants. Contour lines of gross gamma activity and the naturally occurring radionuclide potassium-40 were drawn to identify areas of relatively high and low activities. (auth)