The radiochemist who led the Radium Institute and laid the institutional foundations of Soviet nuclear physics
On 1 December 1921, in his Petrograd laboratory, Khlopin personally obtained the Soviet Union's first high-activity radium preparation.
One of the founders of Soviet radiochemistry, he produced the country's first domestic radium in 1921 and formulated the law of microcomponent distribution between phases (Khlopin's law) in 1924. Succeeding Vernadsky as director of the Radium Institute, he installed Europe's first cyclotron there in 1937, creating the experimental basis for fission research. In June 1940 he and Vernadsky submitted a memorandum on the uranium problem that led to the creation of the Uranium Committee on 30 July, with Khlopin as its first chairman, placing him at the center of pre-war nuclear research coordination. After the war his institute developed the plutonium separation technology that made the 1949 test possible.
Activities and affiliations
Career Timeline
- 1915Began research at the Academy of Sciences Radiological Laboratory at Vernadsky's invitation
- 1921Obtained the first Soviet high-activity radium preparation
- 1922–1935Deputy director and head of the chemical department, Radium Institute
- 1936–1950Director of the Radium Institute
- 1940Chairman of the Academy of Sciences Committee on the Uranium Problem
- 1943, 1946, 1949Three-time Stalin Prize laureate
- 1945Founded the USSR's first radiochemistry chair at Leningrad University
Related historical events
The cyclotron and postwar plutonium technology
As the Radium Institute’s scientific and administrative leader, Khlopin helped build an institutional base combining accelerator research with radiochemistry. In 1932, Georgy Gamow and the head of the institute’s physics department, Lev Mysovsky, proposed building a one-metre cyclotron there; Vladimir Vernadsky and Khlopin supported the project. Khlopin secured funding, arranged contracts with Leningrad factories to manufacture equipment, and organized a team that included Mysovsky, the young Igor Kurchatov, Veniamin Rukavishnikov and Abram Alikhanov. Construction began in 1933 and the cyclotron became operational in 1937. Researchers used it to irradiate uranium and study fission products and transuranium elements; they also obtained small quantities of plutonium.
After the institute was evacuated to Kazan during the war, Khlopin remained its director. In 1943 the institute was tasked with developing a chemical process to separate plutonium from irradiated uranium. Researchers compared ion exchange, solvent extraction and precipitation, then chose a simple, low-cost acetate-fluoride process. They completed the process development in April 1946. Plant B in the Urals was built on its basis and began operation on 1 March 1949. Radium Institute personnel also took part in the Soviet Union’s first nuclear test in August that year. This work connected the institute’s radiochemical capacity, developed under Khlopin’s leadership, to an industrial process for the state nuclear program.