Aerial radiological survey of the Fort Calhoun Nuclear Power Plant and surrounding area, Fort Calhoun, Nebraska

摘要

An aerial radiological survey was conducted over the Fort Calhoun Nuclear Power Plant in Fort Calhoun, Nebraska, during the period June 19 through June 28, 1993. The survey was conducted at an altitude of 150 feet (46 meters) over a 25-square-mile (65-square-kilometer) area centered on the power station. The purpose of the survey was to document the terrestrial gamma radiation environment of the Fort Calhoun Nuclear Power Plant and surrounding area. The results of the aerial survey are reported as inferred gamma radiation exposure rates at 1 meter above ground level in the form of a contour map. Outside the plant boundary, exposure rates were found to vary between 6 and 12 microroentgens per hour and were attributed to naturally-occurring uranium, thorium, and potassium. The aerial data were compared to ground-based benchmark exposure rate measurements and radionuclide assays of soil samples obtained within the survey boundary. The ground-based measurements were found to be in good agreement with those inferred from the aerial measuring system. A previous survey was conducted on August 9 and 10, 1972, before the plant began operation. Exposure rates measured in both surveys were consistent with normal terrestrial background.