Aerial radiological survey of the Washington. Date of survey: July 1982 Public Power Supply System (WPPSS) Nuclear Project and surrounding area, Richland, Washington

An aerial radiological survey was performed from 14 to 20 July 1982 over a 270-square-kilometer area centered on the Washington Public Power Supply System (WPPSS) Nuclear Project located near Richland, Washington. All gamma ray data were collected by flying parallel lines spaed 152 meters (500 feet) apart at an altitude of 91 meters (300 feet) above ground level. Count rates obtained from the aerial platform were converted to total external exposure rates at 1 meter above the ground and are presented in the form of an isoradiation contour map. The observed exposure rates ranged from 5 to 15 microroentgens per hour (μR/h) with the average background ranging from 9 to 12μR/h. These values include an estimated cosmic ray contribution of 3.7 μR/h. The exposure rates obtained from ground-based measurements taken in background locations within the survey area displayed positive agreement the aerial data