Background spectrometric measurements in the vicinity of the Calvert Cliffs nuclear power plant

High-resolution gamma-ray spectrometric background measurements have been performed at over 100 locations in the vicinity of the Calvert Cliffs nuclear power plant as part of a background radiation characterization program sponsored by the Baltimore Gas and Electric Company. These measurements consisted of field and laboratory analyses similar to those undertaken by Yankee Atomic Environmental Laboratory. Field measurements were undertaken using a portable HPGe detector system. Soil samples collected in the field were measured and analyzed at the University of Maryland Nuclear Engineering Laboratory (UMNEL). In addition, exposure rates were measured using sensitive survey instruments. In general, radioactivity from the uranium and thorium decay chains is higher in the piedmont than the coastal plain areas. This has also been seen in separate radon surveys carried out in the state of Maryland. Fission product background levels (mainly from 137Cs) were observed at many locations where the soil has not been disturbed since the end of atmospheric weapons testing. Cesium-137 levels around Calvert Cliffs nuclear power plant are about the same as those in the surrounding counties