Castle Yankee

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Castle Yankee was the code name given to one of the tests in the Operation Castle series of American nuclear tests.

1 Jughead
2 Runt II
3 External links
4 References

[edit] Jughead

Yankee was originally intended to be a test of a simplified and lightened bomb version (the TX-16, or "emergency capability" EC-16) of the large and complex cryogenic device (the first successful multi-stage fusion device) tested in Ivy Mike. A small number of EC-16's were produced on an emergency basis to provide a stop-gap thermonuclear weapon capability in response to the Russian nuclear weapons program.

The test device, code-named "Jughead", had been prepared as a backup in case the non-cryogenic "Shrimp" fusion device (first tested in Castle Bravo) failed to work. The test of "Jughead" was cancelled when the Bravo device was successful, and the few EC-16's which were actually built were withdrawn and dismantled.

[edit] Runt II

Jughead was replaced in the Yankee test by the so-called "Runt II" device (the TX-24 bomb, initially the "emergency capability" EC-24), a modified form of the "Runt" device (the TX-17/EC-17) tested in Castle Romeo. Externally identical, the principal difference between them was in the fuel for the fusion stage. While Runt used natural lithium (with 7.5% of the Lithium-6 isotope), Runt II used the same partially enriched lithium (approximately 40% Lithium-6) as the "Shrimp" device tested in Bravo.

It was detonated on May 5, 1954, at Bikini Atoll of the Marshall Islands, on a barge moored in the middle of the crater from the Castle Union test.

Although it has been predicted to produce a yield of 6 to 10 megatons, it actually produced a yield of 13.5 megatons, the second-largest ever yield in a U.S. fusion weapon test. Like the Ivy Mike, Bravo and Romeo tests, a large percentage of the yield was produced by fast fission of the natural uranium "tamper"; 7 megatons of the yield were from this source. The other 6.5 megatons were from fusion reactions; this increase was due to the different fusion fuel. This fusion yield was the largest to date, and set a record that stood for several years.