キャッスル作戦
In March 1954, "Cocopa" was one of the ships tasked to support Operation Castle, a series of high-energy (high-yield) nuclear tests by Joint Task Force SEVEN (JTF-7) at Bikini Atoll. Official reports indicated that crewmembers suffered the highest doses (2.2 rem) of radiation endured by any of the navy ships present at this operation.