A Comparison of Hazard Prediction and Assessment Capability Software Dose-Rate Contour Plots to a Sample of Local Fallout Data from Test Detonations

A comparison of Hazard Prediction and Assessment Capability (HPAC) software dose-rate contour plots to a sample of local nuclear fallout data from test detonations in the continental United States, 1945 - 1962, is performed. Fallout data from test detonations is obtained from "Compilation of Local Fallout Data from Test Detonations 1945- 1962 Extracted from DASA 1251, Volume I - Continental U.S. Tests." This report contains fallout plots and radiation contours for each test in the atmospheric nuclear test program conducted by the United States prior to 1963. These plots are compared with the plots resulting from Defense Threat Reduction Agency's (DTRA) HPAC software using test day wind data and additional wind data for up to seven days following each test. The results from HPAC were extrapolated to H+1 hour using the t-1.2 decay approximation. A visual comparison of the plots revealed mismatches between observed and predicted data. A numerical comparison using Warner, et al, Rowland and Thompson, dose-rate contour area comparisons and grounded unit time reference dose rate corroborated the results of the visual comparisons.