Первый тесты fusion bomb:

США - 1952, Teller–Ulam design
СССР - 1953, "Слойка", слабое подобие fusion bomb, от которой пришлось отказаться из-за бесперспективности и перейти к украденнму Teller–Ulam design, первый тест в 1955 году


Joe Four

The first Soviet test of a hydrogen bomb was on August 12, 1953 and was nicknamed Joe 4 by the Americans; it was not a "true" fusion bomb (it was more like a "boosted" fission bomb than a staged thermonuclear device, and had a yield comparable to large fission weapons; around 90% of its yield was directly or indirectly from fission).