# Operation CASTLE Commander's Report

Operation CASTLE was a six-detonation test series held at the Atomic Energy Commission's (AEC) Pacific Proving Ground in the Spring of 1954. This test series, principally conducted at the Enewetak and Bikini Atolls in the northwestern Marshall Islands, provided proof tests of large-yield thermonuclear, or hydrogen, devices. CASTLE represented the end of a drive for a workable thermonuclear weapon and the beginning of the refinement of large-H-bombs into smaller and more efficient weapons. After CASTLE, the U.S. could choose in a range of small tactical weapons to large strategic weapons. From this point, weapons development programs concentrated on producing bombs of specific nuclear weapons effects -- heat, blast, and radiation. The Bravo event of the CASTLE series yielded 15 megatons, unexpectedly the most ever exploded in atmospheric testing by the U.S.. A scientific miscalculation based on a then-unknown "tritium fusion bonus" of highly enriched lithium-6 contributing the the detonation yield caused the yield to be about two and a half times of that what was expected. Reports indicate that Bravo was the single worst incident of fallout exposure in all of the U.S. atmospheric testing program. Despite winds in an acceptable flow zone, the greatly unexpected yield caused a much larger mushroom than originally calculated, causing a much wider and massive accumulation path of fallout danger. Fallout was scattered over more than 5,000 square miles of ocean and islands,…

- Kind: Short
- Year: 1954
- Runtime: 13 min
- By: Joint Task Force 7
- Genres: War
- Archive: [Internet Archive](https://archive.org/details/CastleCommandersReport1954)
- Licence or status: [CC BY-NC-ND 2.5](http://creativecommons.org/licenses/by-nc-nd/2.5/) (as the archive states it)
- Who can watch: Teens profiles and older (the archive gives no rating; placed by Invisible Network from its collection and subjects)

[Watch now](https://invisiblenetwork.ai/watch/archive/ia/CastleCommandersReport1954?play=1)