| Abstract: | The formation of the institute NII-9 (now the State Science Center of the Russian Federation—A. A. Bochvar All-Russia Scientific-Research Institute of Standardization in Machine Engineering), by a decree of the State Committee on Defense, in 1945 in Moscow and the production at this Institute in 1948 of substantial (milligram) quantities of metallic plutonium from uranium blocks irradiated in the F-1 reactor are recounted. Data on the organization of the work and the creation of special equipment and methods for performing investigations on microsamples of a radioactive, toxic, chemically active material are presented. These investigations led to the discovery of six allotropic modifications of plutonium the temperature ranges of their stability, the melting temperature, the characteristic features of the volume and temperature expansion at phase transitions, and the mechanical properties of the phases. The participation of the Institute staff and of A. A. Bochvar himself in the fabrication of the plutonium warhead in 1949 for the first Soviet atomic bomb is reflected. The directions of the investigations of plutonium performed in subsequent years are indicated. State Science Center of the Russian Federation—A. A. Bochvar All-Russia Scientific-Research Institute of Standardization in Machine Engineering. Translated from Atomnaya énergiya, Vol. 87, No. 3, pp. 170–174, September, 1999. |
