Shot YANKEE, which had been detonated on 5 May (Reference 10). At 1330 hours, average topside intensities had reached 20 mR/hr and the ship's washdown system was turned on (Reference 8). With the washdown system still activated, intensities increased to 40 mR/hr by 1730 hours when the fallout apparently ceased. The LST- 975, which did not have a washdown system (Reference 10), reported shipboard intensities approximately twice those on the LST-762 (see Section 2.2.14). The washing down continued on 6 May and, by 0930 hours on 7 May, when decontamination was terminated, intensities had been reduced to 5 mR/hr. On 8 May, a rad-safe survey on the ship indicated average topside intensities were 3 mR/hr. Figure 2-23 depicts the reconstructed radiation environment onboard the LST-762 resulting from Shots BRAVO, ROMEO, and YANKEE, the only three shots in the series resulting in fallout onboard this ship. The LST-762 sortied to Bikini Lagoon only four times during operation CASTLE. The ship contamination model is used to determine the crew exposure due to contaminated lagoon water. Specific periods of time in and out of the lagoon, as well as the corresponding integrated intensities, are given below. Time at Bikini Lagoon Month March In 03/1412-04/1930 07/1410-10/0819 April 13/1206-14/1307 08/1015-11/1242 Integrated Intensity (mR) Out In 04/1930-07/1410 10/0819-13/1206 14/1307-08/1015 11/1242-31/2400 {2.1 84,7 15.0 12.3 Out 42.8 38.3 108.3 60.5 The daily contributions to the free-field integrated intensity on the LST-762 from fallout (topside) and ship contamination (below) are shown in Table 2-12. 89