"George" Shot Is Pivotal
In 1951, U.S. scientists performed the first test-site explosion experiments involving thermonuclear reactions. The "Item" boosted atomic bomb was one such test. Another was the testing of a classical Super model with a binary initiator operating on the radiation-implosion principle patented by Klaus Fuchs and John von Neumann in 1946. The test was code-named "George," and the device was called the "Cylinder." This was the final major change to the bomb design before the "George" shot, which was successfully performed on May 9, 1951, and was the "largest fission explosion to date" that "succeeded in igniting the first small thermonuclear flame ever to burn on earth." The test was roughly the 40th in a series of nuclear tests performed up to that time in the U.S.
Despite the negative results obtained in 1950 from theoretical studies of the classical Super's performance, the inclusion of "George" in the 1951 test plan was pivotal to the American thermonuclear program. "George" stood out as a device that confined and utilized radiant energy from a primary atomic bomb to compress and ignite a secondary, physically isolated core containing thermonuclear fuel. Teller used results of the boosted-fission "George" test to confirm the fusion of heavy hydrogen elements before preparing for their first true multi-stage Teller-Ulam hydrogen-bomb test. Many scientists initially against the weapons, such as J. Robert Oppenheimer and Hans Bethe, changed their previous opinions, seeing the development as being unstoppable.
In June 1951, Edward Teller and De Hoffman issued a report on the effectiveness of using lithium-6 deuteride in the new superbomb configuration. The problem was creating enough lithium-6 in the U.S., and research was delayed while yet another concept was explored: using a more sophisticated chemical implosion technique to build a uranium-235 atomic bomb with a TNT equivalent of several hundred kilotons. Work began on the construction of such a bomb in the U.S. in 1950, and it was tested successfully on November 16, 1952, in a test called the "King" shot. The plan was to develop an "Alarm Clock" that would release energy well in excess of 1 megaton, but it was difficult to create such a large bomb using that design. The solution: return to the development of thermonuclear devices.