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 Orders were issued not to open evaporators without specific authorization of the radsafe section and then only with a monitor present (Reference C.10.3). Experiments showed that the evaporators would not pass radioactivity over into distilled water if they were operated at somewhat reduced rates. Orders to operate at reduced rates were issued, although sources available disagree on whether the approved rate was 75 or 80 percent (Reference C.9.185, p. 19; Reference C.10.6). To remove some of the contaminated scale, ships were to use the "cold-shock" treatment; that is, cold water was run through the hot evaporator tubes that had accumulated radioactive scale. The pipes' rapid contraction caused the scale to flake off and be flushed out (Reference C.10.6). To decrease the formation of new scale, ships were ordered to use a standard scale reduction technique of introducing a mixture of boiler compound and cornstarch continuously into the evaporators (Reference C.10.1). In an effort to reduce contamination on hulls and in evaporators, a number of support ships left the lagoon for one-day trips in the open ocean to flush the sides and interior systems with clear saltwater.

These measures reduced the radiation level inside most ships to 0.1 R/24 hours (gamma) or less. To keep radiation levels down, the ships, where possible, were kept in water indicating 0.001 R/24 hours (gamma) or less. Numerous exceptions to this were necessary, however, to carry out the duties of the task force. Ships used for salvage, radsafe, and survey work sometimes needed to enter waters with higher levels of radioactivity. One source indicated that in some cases a ship's crew was evacuated and the ship was allowed to stand idle, presumably in water with low radioactivity levels, until the readings inside fell below the 0.1 R/24 hours level (Reference C.9.185, p. 20). The source does not indicate the number of ships in this category.

Shift to Kwajalein

On 11 August, CJTF 1 asked the CNO for permission to shift the task force's base to Kwajalein, asserting that the tendency of ships to accumulate radioactivity, especially in their evaporators and in the marine growth on their hulls, mandated leaving Bikini. He emphasized that no hazard to Kwajalein would result and that preparations for CHARLIE (the anticipated third CROSSROADS shot) would not be compromised (Reference C.10.4).

On 19 August the task force was ordered to shift base to Kwajalein. Non-target ships that had reentered the lagoon were monitored before departure and given conditional operational clearances, subject to employing safety procedures to meet each ship's condition. Most were restricted on the amount of time personnel could spend in certain compartments and near certain pieces of equipment (Reference C.9.206, p. V-(D)-4; Reference C-9-185, p. 20).

Commander Joint Task Force 1 Letter of 19 August 1946

Although it was hoped that natural decay and steaming in the open ocean would minimize radioactive exposure of personnel, the Chief of Staff of JTF 1 sent a letter on 19 August to commanding officers of all ships that had been in the lagoon between 25 July and 10 August and hence were radiologically suspect. He wrote that before these ships could be considered completely clear, further monitoring would be needed, especially to ensure the safety of personnel

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