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B.P. Konstantinov St. Petersburg Nuclear Physics Institute (IPPN or PNPI)

  • Location
    Gatchina, Leningrad Oblast
  • Type
    Nuclear-Research and Development
  • Facility Status

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Founded in 1956 as a branch of the Ioffe Physico-Technical Institute, PNPI became an independent entity in 1971. 1 The Institute, which is a part of the Russian Academy of Sciences, is a state research center, and is one of the four organizations comprising the pilot cooperation project at the National Research Center Kurchatov Institute, established in 2009. 2

PNPI conducts research on neutron physics, high energy physics, theoretical physics, and molecular and radiation biophysics. Its primary activities in the area of nuclear physics include proton and small-angle diffraction scattering. It also conducts applied research in engineering, medicine, and ecology. 3

The institute is home to a critical assembly and two research reactors, all of which are HEU-powered. The VVR-M reactor, commissioned in 1959, is one of the oldest in Russia. In turn, the PIK high-flux research reactor is Russia’s newest research reactor. 4 The startup of the PIK has been repeatedly delayed. 5 For an overview of Russia’s HEU policy and the full list of Russia’s facilities using HEU, see the Russia Civilian HEU profile.


Radiation (Ionizing)
Radiation that has sufficient energy to remove electrons from substances that it passes through, forming ions. May include alpha particles, beta particles, gamma rays, x-rays, neutrons, high-speed electrons, high-speed protons, and other particles capable of producing ions.
Critical Assembly
A critical assembly is an assembly of sufficient fissionable material and moderator to sustain a fission chain reaction at a very low power level. This permits study of the behavior of the components of the assembly for various fissionable materials in different geometrical arrangements.
Research reactor
Research reactor: Small fission reactors designed to produce neutrons for a variety of purposes, including scientific research, training, and medical isotope production. Unlike commercial power reactors, they are not designed to generate power.
Highly enriched uranium (HEU)
Highly enriched uranium (HEU): Refers to uranium with a concentration of more than 20% of the isotope U-235. Achieved via the process of enrichment. See entry for enriched uranium.


  1. “‘История института’ History of the Institute, Петербургский институт ядерной физики” Petersburg Institute of Nuclear Physics, www.pnpi.spb.ru.
  2. “Петербургский институт ядерной физики им. Б.П. Константинова” B.P. Konstantinov St. Petersburg Nuclear Physics Institute, Национальный исследовательский центр “Курчатовский институт” National Research Centre “Kurchatov Institute,” www.nrcki.ru.
  3. “‘Об институте’ [About the Institute], Петербургский институт ядерной физики” [Petersburg Institute of Nuclear Physics], www.pnpi.spb.ru.
  4. J. E. Matos, "Technical Challenges for Conversion of Civilian Research Reactors in Russia," Presentation at the National Academy of Sciences, 29 November 2010, Washington, D.C.
  5. Pavel Podvig, "More Delays for PIK Reactor," International Panel on Fissile Materials Blog, 9 August 2011, www.fissilematerials.org.


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