In May 1948, Kurchatov's group, together with a number of other scientists, was directed to the All-Russian Scientific Research Institute of Experimental Physics or KB-11 in the closed city of Sarov, Nizhny Novgorod Oblast, as part of the Soviet nuclear weapons program.

While there, he witnessed a deception during an unexpected visit by Lavrentiy Beria, the feared head of Soviet security and the politician in charge of the nuclear program under Stalin.

[citation needed] Kurchatov put Davidenko in charge of one of three teams working simultaneously on neutron primers for nuclear bombs.

Starting that year, he had repeatedly and strongly encouraged the theoretical physicists Andrei Sakharov and Zeldovich to pursue the route of atomic implosion to compress thermonuclear fuel for a hydrogen bomb in a two-stage device.

While there, they collected newly-fallen snow to concentrate and analyse for radionuclides from the U.S.'s Operation Ivy test earlier that month at Enewetak Atoll.

[1][4][5][6] Davidenko was already amongst several employees of the Installation who were considered too important to risk flying; for example, in 1953 he returned from preparations at the Semipalatinsk Test Site in Kazakhstan for the RDS-6 device – the first Soviet hydrogen bomb – in chief nuclear weapons designer Yulii Khariton's train carriage with other scientists.

The introduction to the final report by Sakharov and Zeldovich on 25 June stated, "The participation of V. A. Davidenko was extremely profitable in the discussion of the problem during its early stage (1952)."