Last changed 20 December 2000
|Operation Castle was a series of high yield thermonuclear
weapon design tests. Following the initial experimental demonstration
of the Teller-Ulam principles in Operation Ivy (the Sausage device
detonated in the Ivy Mike test) both weapon labs rushed to develop a
number of deliverable weaponized designs. The original schedule
included a weaponized version of the cryogenic fuel system used in
Sausage (designated the EC-16, the test device being named JUGHEAD);
plus a variety of other extensions and new concepts. One of these new
approaches - the use of non-cryogenic "dry" (lithium deuteride) fuel -
was a spectacular (and disastrous) success with a yield far exceeding
expectations. Some of the other tests were also much larger than
expected - in fact the three largest tests ever carried out by the U.S.
were all part of Operation Castle.
Not all new concepts were successful, for example the first UCRL thermonuclear device fizzled. Included in the test series were experimental systems not intended for immediate deployment, weapon designs soon deployed on an emergency basis, and two designs that had already reached emergency deployment status despite never having been tested. One of these was the cryogenic TX-16, which was deleted from the test schedule (and removed from service) when solid fuel proved highly effective.
An important factor in planning Castle was the availability of lithium enriched in Li-6. The U.S. thermonuclear weapon program had been stuck in the doldrums prior to the breakthroughs of Ulam and Teller in early 1951, and no plans had been made for producing this fusion fuel. Once a workable design for a high yield fusion weapon had been conceived though, it became a race to get a large lithium enrichment plant into production. The Soviets in contrast had decided to pursue a thermonuclear design of limited potential (the Sloika/Alarm Clock), and had begun constructing lithium enrichment facilities before the United States. The Soviet Union exploded a "dry" device of this type the August preceding Castle - at the time that the first U.S. lithium enrichment plant was just starting up. Due to the current lithium-6 shortage, several weapon designs tested in Castle therefore used only partially enriched, or even unenriched lithium.
CASTLE HISTORY OF TASK GROUP 7.4, PROVISIONAL FOR THE MONTH OF APRIL,
Author: POLAKOF M, SAUNDERS D, HOBBS F, LUCAS G E