2018, Issue 1

Authors & Affiliations

Zyryanova A.A., Meteleva Yu.V., Kozlov A.V., Seleznev E.N., Russkikh I.M.
Institute of Nuclear Materials, Zarechny, Russia

Zyryanova A.A. – Engineer-Physicist on Calculations and Modes, 1 category, Institute of Nuclear Materials.
Meteleva Yu.V. – Engineer-Physicist on Calculations and Modes, 2 category, Institute of Nuclear Materials.
Kozlov A.V. – Physics and Nuclear Safety Team Lead, Institute of Nuclear Materials. Contacts: 624250, Sverdlovsk region, Zarechny, P.O. Box 29. Tel.: +7(34377)3-51-46; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..
Seleznev E.N. – Deputy Chief Engineer for Nuclear and Radiation Safety, Institute of Nuclear Materials.
Russkikh I.M. – Chief Engineer, Institute of Nuclear Materials.

Abstract

One of the problems in the reactor operation process, using beryllium reflector, is beryllium reflector blocks “poisoning” by ⁶Li and ³He nuclei, which have properties of a strong thermal neutron absorber. Beryllium blocks “poisoning” leads to a change of neutronic characteristics of the core – nuclear reactivity degradation, power distribution in the core. As a consequence, uranium-235 fuel feed increases for the reactivity loss compensation during beryllium blocks “poisoning”.
At Institute of Nuclear Materials in IVV-2M reactor metallic beryllium blocks are used as a reflector. Some of them are operated since the start-up in 1996. The rest were installed later. For now many of the blocks lost their neutron reflector properties. They acquired the neutronic characteristics of a high neutron absorber.
It is necessary to keep a number of source data for estimation of beryllium block poisoning degree. The source data is the beryllium blocks movement in active zone cells during its operation, neutron flux density value in active zone cells and its changing during reactor operation. Al this information needs to be keep for each beryllium blocks.
Taking into account service life of reflector blocks and their amount, it is rather difficult to trace the movement of each block, and for some blocks it is impossible. Nevertheless, at IVV-2M reactor a number of activities aimed at experimental determining the degree of beryllium blocks “poisoning” and at saving the neutronic characteristics of “clear” beryllium blocks.

Keywords
nuclear research reactor, beryllium reflector, beryllium blocks, “poisoning”, neutron multiplication factor, nuclei concentration, “weighing process”, reaction rate, neutronic analysis

Article Text (PDF, in Russian)

References

UDC 621.039.51

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2018, issue 1, 1:1