EDN: GZULTU
Authors & Affiliations
Kuzina Yu.A., Sorokin A.P., Denisova N.A.
A.I. Leipunsky Institute for Physics and Power Engineering, Obninsk, Russia
Kuzina Yu.A. – Director of the Nuclear Power Department, Cand. Sci. (Tech.). Contacts: 1, pl. Bondarenko, Obninsk, Kaluga Region, Russia, 249033. Tel.: +7 (484) 399-70-00 (add. 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.
Abstract
The paper presents the results of experimental studies using an integrated water model of the temperature fields and the flow structure of non-isothermal coolant in the primary circuit of a sodium cooled fast neutron reactor in various regimes: forced circulation, in the course of transition to the decay heat removal regime and emergency cooldown with natural convection of the coolant. It is shown that the lifting forces induced by the movement of a non-isothermal coolant in the upper plenum of the reactor result in formation of an isothermal stable zone of a cold coolant at the periphery of its lower region above the side shields, and its dimensions increase with an increase in the total water flow rate. Significant and stable temperature stratification of the coolant was revealed in the peripheral area of the upper (hot) plenum of the reactor above the side shields, in the pressure- and cold side chambers, in the elevator baffle, in the reactor vessel cooling system, at the outlet of intermediate and autonomous heat exchangers under various operating conditions. At the interfaces of the stratified and recirculation zones, large temperature gradients and fluctuations were recorded. In all the cooldown options investigated, the coolant temperature at the outlet of core fuel assemblies’ heads decreases, and the coolant temperature in the peripheral area of the upper plenum increases in comparison with the forced circulation regime. High efficiency of a passive decay heat removal system of a high-power fast neutron reactor with immersed autonomous heat exchangers was confirmed. Thus, during normal operation, even in the event of failure of three autonomous immersed heat exchangers, the temperature of the equipment inside the reactor remains within the permissible limits, and the decay heat removal from the reactor is ensured without exceeding the limits of safe operation. The results obtained can be used both for verification of computational codes and for the approximate estimation of reactor facility parameters when recalculated based on the similarity criteria.
Keywords
fast reactor, sodium coolant, reactor tank, autonomous heat exchangers, mixing chambers, experiment, forced circulation, emergency cooldown, temperature stratification of coolant, temperature pulsations
Article Text (PDF, in Russian)
References
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UDC 621.039.51
Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2025, no. 1, 1:12.
