Operation Castle

Operation Castle
Bravo had the highest yield of all US nuclear weapon tests.
Information
Country	United States
Test site	Ebiriru (Ruby), Enewetak Atoll Elugelab (Flora), Enewetak Atoll Eninmen (Tare), Bikini Atoll Namu (Charlie), Bikini Atoll Yurochi aka Irioj (Dog), Bikini Atoll
Period	1954
Number of tests	6
Test type	barge, dry surface
Max. yield	15 megatonnes of TNT (63 PJ)
Test series chronology
← Operation Upshot–Knothole Operation Teapot →

Operation Castle was a United States series of high-yield (high-energy) nuclear tests by Joint Task Force 7 (JTF-7) at Bikini Atoll beginning in March 1954. It followed Operation Upshot–Knothole and preceded Operation Teapot.

Conducted as a joint venture between the Atomic Energy Commission (AEC) and the Department of Defense (DoD), the ultimate objective of the operation was to test designs for an aircraft-deliverable thermonuclear weapon. All the devices tested, which ranged in weight from 6,520 to 39,600 pounds (2,960 to 17,960 kg), were built to be dropped from aircraft. However, ballistic casings, fins and fusing systems would have to be attached.^[1]

Operation Castle was considered by government officials to be a success as it proved the feasibility of deployable "dry" fuel designs for thermonuclear weapons. There were technical difficulties with some of the tests: one device had a yield much lower than predicted (a "fizzle"), while two other bombs detonated with over twice their predicted yields. One test in particular, Castle Bravo, resulted in extensive radiological contamination. The fallout affected nearby islands, including inhabitants and U.S. soldiers stationed there, as well as a nearby Japanese fishing boat (the Daigo Fukuryū Maru), resulting in one direct fatality and continued health problems for many of those exposed. Public reaction to the tests and an awareness of the long-range effects of nuclear fallout has been attributed as being part of the motivation for the Partial Test Ban Treaty of 1963.