PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY
Series: Nuclear and Reactor Constants

since 1971

Русский (РФ)

ISSN 2414-1038 (online)

Authors & Affiliations

Kuzina Yu.A., Sorokin A.P., Denisova N.A.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia

Kuzina Yu.A. – Director of Nuclear Energetic Department, Cand. Sci. (Tech.). Contacts: 1, Bondarenko sq., Obninsk, Kaluga region, 249033. Tel.: +7 (484) 399-86-63; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..
Sorokin A.P. – Chief Researcher, Dr. Sci. (Tech.).
Denisova N.A. – Lead Engineer, A.I. Leypunsky Institute for Physics and Power Engineering.

Abstract

The results of experimental studies on an integral water model of the temperature fields and the flow structure of a non-isothermal primary coolant in the sodium-cooled fast neutron reactor in various regimes: forced circulation, during the transition to the decay heat removal and decay heat removal with natural convection of the coolant are presented in the article. It is shown, that under the influence of lift forces on the non-isothermal coolant flow in the upper chamber of the reactor at the periphery of its bottom region over the side shields, a stable cold coolant isothermal zone is formed, whose dimensions increase with increase of total water flow rate. An essential and stable coolant temperature stratification was detected in the peripheral area of the upper (hot) chamber over the side shields, in the cold and pressure chambers, in the elevator baffle, in the cooling system of the reactor vessel, and in the outlet of intermediate and autonomous heat exchangers in different operating regimes. Large gradients and temperature fluctuations are registered at the interface of stratified and recycling formations. In all studied cool down versions, the coolant temperature at the outlet from the heads of the core fuel assembly is decreased and the coolant temperature in the peripheral zone of the upper chamber is increased as compared to the forced circulation. High efficiency of a passive decay heat removal system of high-power fast reactor with submersible autonomous heat exchangers is confirmed. Thus, in a normal operation regime, even in case of malfunction of three submersible autonomous heat exchangers, the temperature of the equipment inside the reactor remains within acceptable limits and decay heat removal from the reactor does not exceed safe operation limits. The obtained results can be used for computer code verification and for approximate estimate of the reactor plant parameters on the similarity criteria basis.

Keywords
fast reactor, reactor tank, integral layout, submersible heat exchangers, experiment, thermal hydraulics, temperature stratification of the coolant, forced convection, natural convection, decay heat removal

Article Text (PDF, in Russian)

References

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2022, issue 1, 1:15