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 CHAPTER 5

POST-BAKER OPERATIONS: BIKINI, KWAJALEIN, AND THE UNITED STATES

In early August it became apparent that while the radiation levels in the water and on the land areas were below tolerance levels, the accumulation of radioactivity in the remaining ships' evaporators, saltwater piping, and marine growth on their hulls presented an increasing problem. Consequently, the base of operation of the task force had to be moved from Bikini. Kwajalein Atoll was selected for the new base (Reference C.0.22, p. 1). On 19 August 1946, movement of all remaining ships to Kwajalein was initiated, and by 26 September 1946 Bikini Atoll was completely evacuated. Subsequently, a large number of them were sunk, others were returned to naval shipyards in the United States for inspection and additional decontamination.

The experience, problems, and solutions associated with ship decontamination at Bikini and in naval shipyards and a discussion of radiological and other problems associated with off-loading ammunition from target ships and securing them at Kwajalein are addressed in this chapter.

REMAINING LIGHTLY CONTAMINATED TARGET SHIPS AT BIKINI

Five target vessels, attack transports USS Bladen (APA-63), USS Cortland (APA-75), USS Fillmore (APA-83), USS Geneva (APA-86), and USS Niagara (APA-87), were on the outer fringes of the target array and were not heavily contaminated by the rainout or the base surge (see Figure 28, Chapter 4). The crews of Bladen, Fillmore, Geneva, and Niagara returned to their ships on 29 July, and Cortland's crew returned on 30 July (Reference A.3, Bladen, Cortland, Fillmore, Geneva, and Niagara).

The ships needed some decontamination work (Reference C.9.185, pp. 4 and 10). Although the radioactivity on these ships' weather surfaces was not sufficient to prevent reboarding and cleanup work, they were found to have radioactivity on the outside of their hulls at the waterline, apparently because marine growth there was taking up radioactive isotopes from the lagoon water. Radioactivity was 0.4 R/24 hours on the inner surface of Niagara's hull, decreasing to 0.1 R/24 hours 5 feet (1.5 meters) toward the center of the ship (Reference C.2.1). After the waterline areas of the five ships were scraped, they steamed in the open ocean for 24 hours in an effort to reduce contamination. Niagara steamed alone on 1 and 2 August and the other four steamed as a group on 4 and 5 August (Reference A.3, Bladen, Cortland, Fillmore, and Geneva). In addition, Geneva's entire bottom was scraped by passing wires under the hull from one side to the other and pulling them toward the stern (Reference C.9.185, p. 18). Upon reaching Pearl Harbor, the small boats of both Cortland and Fillmore were found to be radioactive (References C.2.4 and C.2.5).

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