wee eee EXPOSURE TO FALLOUT: ATOLLS le, TT. Lessard, IR, THE RADIATION DOSE Pp. Miltenberger, EXPERIENCE ls, H. AT Cohn, RONGELAP Is. iv. AND UTIRIK Musolino, | IR. A. Conard and 2T. McCraw lBrookhaven National Laboratory, Upton, New York 11973, U.S.A. and 2Department of Energy, Office of Operational Safety, Washington, DC 20545, U.S.A. From June 1946 to August 1958, the U.S. Department of Defense and the Atonic Energy Commission conducted nuclear weapons tests in the Northern Marshall Islands. On March 1, 1954, BRAVO, an aboveground test in the Castle series, produced a large amount of radioactive debris, some of which subsequently fell on Rongelap and Utirik Atolls due to an wumexpected wind shift. In order to avoid external and internal dose from the deposited radioactivity, the inhabitants of these atolls were relocated out of the affected area. They returned to Utirik in June 1954 and to Rongelap in June 1957. Environmental and personnel radiological monitoring programs were initiated in the mid 1950's by Brookhaven National Laboratory. The objective was to maintain a comprehensive radiological safety progran. Post-return body-burden histories and activity-ingestion rate patterns were determined as were estimates of internal committed effective dose equivalent. External exposure rate and living pattern data were also collected. Relationships between body burden or urine activity concentration and a declining continuous intake scenario were developed in order to model retrospective and prospective 2 ae a ew cease remains Nadaarnttioeneh Ot tas eB riencudsebine: | “Apannaertasinlher dose equivalent (See Figure 1). The dosimetric conclusions for the protracted exposure are summarized in Table l. Figure 1: atoll. Body burden history for Rongelap adults post return to their hone ee