On 8 December 1944, by decree of the
State Defense Committee No. 7102 ss/ov, which accelerated geological exploration work for uranium, Zavenyagin was appointed responsible program manager for the search for uranium in the Soviet Union and in the occupied territories; to carry out the search, the
9th Chief Directorate of the NKVD was deployed. By the same decree, Zavenyagin managed the program to provide logistics concerning the vast mining operations throughout the Soviet Union where his program was to oversee the industrial production of uranium through factories and milling. After the USSR State Defense Order of 20 August 1945 No. 9887ss/ov "On the Special Committee [on the use of atomic energy] under the State Defense Committee," Zavenyagin was responsible for the following areas of work: • He became a member of the special committee and had a voice in resolving all issues within the jurisdiction of the committee. • He became a member of the technical council of a special committee that dealt with issues of scientific research and scientific installations. Another important area of work was the solution of personnel issues: by
Lavrentiy Beria's order,
Mikhail Pervukhin,
Vyacheslav Malyshev,
Boris Vannikov, and Zavenyagin staffed the council sections with scientific and engineering personnel and selected experts to resolve individual issues. In addition, Zavenyagin participated in the selection of construction sites for plants of projects 817 (
Mayak Production Association) and 813 (
Ural Electrochemical Combine). In 1945, Zavenyagin joined the commission under the leadership of member of the
State Defense Committee Anastas Mikoyan: Chairman of the
State Planning Committee Nikolai Voznesensky,
Ivan Kabanov (politician), Head of the PGU
Boris Vannikov, Zavenyagin, and Deputy Chairman of the State Planning Committee . The commission was entrusted with overseeing the provision of
Noginsk plant No. 12 (now
ELEMASH Machine-Building Plant) with equipment for smelting uranium ore. This plant was equipped with Soviet-made vacuum high-frequency electric furnaces, created through war reparations from Germany and import purchases; uranium rods for the
F-1 reactor were smelted in these furnaces. In June and July 1948, Zavenyagin, together with
Igor Kurchatov, supervised the liquidation of two accidents at the first domestic industrial reactor
A-1, having spent a long time in the central reactor hall and being irradiated as a result. On 19 August 1949, Zavenyagin was appointed responsible for the delivery of the
RDS-1 nuclear bomb from
KB-11 (now the
All-Russian Scientific Research Institute of Experimental Physics) to the
Semipalatinsk test site and for the final assembly of the bomb. On the night of 29 August, in his presence, a neutron initiator piston was installed in the central part of the bomb. Soon after the test, he drove a car to the center of the explosion, where the car got stuck in the dust formed after the explosion, and had to return on foot, receiving a large dose of radiation. == Later career ==