2 -% SECTION 1 INTRODUCTION AND SUMMARY During the period 1-2 March 1954, twenty-eight Army and Air Force personnel stationed at Rongerik Atoll in the Marshall Islands were exposed to radioactive fallout from Shot Bravoof Operation CASTLE. The purpose of this report is to determine the whole body gamma radiation dose received by these personnel prior to their evacuation from the atoll, plus their organ dose commitments from internal emitters. rete LA tO on Tors o The gamma radiation dose, is reconstructed as follows. we bie = The radiological —_ environment resulting from Shot Bravd fallout is determined from time-of-arrival data on Rongerik, modeled deposition, “measured decay rates, and a later reading on Rongerik. Personnel activity scenarios are considered in conjunction with radiation shielding factors to arrive at film badge doses on an individual basis. Although film | badge readings are available, they relate inadequately to personnel dose. Readings” that reflect well-specified exposures indicate good agreement with corresponding A small, but systematic, difference indicates srrailiveimemndaltie 4 . wae calculated personne!doses, which are in the vicinity of 40 rem. 4 calculated doses. ~ 4 iol eee iodine-131 is determined from“the body metabolism of iodine that led to a measured activity of I-131 in a pooled urine sample taken 17 days after ‘Bravo. The radionuclide inventory for the time of intake is normalized to the level of I-13] activity, thereby indicating the full intake of radioactivity. =tenpespeeaimie BRse conversion factors for each radionuclide, are developed for calculation of internal dose commitments was ieleRT chs