Authors & Affiliations

Gordeev S.S.1, Sorokin A.P.2
1 National Research Nuclear University "MEPHI", Moscow, Russia
2 A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia

Gordeev S.S. – graduate student, National Research Nuclear University "MEPHI". Contacts: 31, Kashirskoe shosse, Moscow, Russia, 115409. Tel.: (967) 179 20 80, 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.), A.I. Leypunsky Institute for Physics and Power Engineering.

Abstract

During the campaign the temperature field in the fast reactors core with sodium coolant exposed to the combined effect of various factors. The results of the analysis of various factors that determine the formation of the temperature regime of fuel subassemblies of fast reactors core during the campaign and their effects on temperature. The main factors are the distribution of the geometric parameters, the energy release of the fuel elements, the coolant flow rate and the intensity of interchannel and interpackage exchange, stochastic deviations in the values of these parameters and their changes during reactor operation. A significant influence on the temperature regime of the core can provide the forming of the core which is complex and can occur in a significant range of parameters. Nonuniformity of the energy release of the fuel elements in the cross section of the fuel subassembly leads generally to the increase in the maximum temperature of the fuel elements and the maximum azimuthal nonuniformity of the temperature of the fuel element. Interpackage leaking coolant and interpackage heat transfer determine the temperature changes are mainly peripheral fuel elements. The influence of all factors indicates a possible overheating of the cladding of fuel elements on 10-20% of the average heating of the coolant in fuel subassemblies for nominal conditions and 50-100% from the average heating of the coolant in fuel subassemblies with significant distortion of fuel subassemblies during the campaign. A significant factor in the formation of temperature fields in fuel subassemblies is interchannel exchange, effectively leveling the local nonuniformity of temperature in the fuel subassembly. The generalized relations for the distribution of the velocity and temperature of the coolant in the cross section of the fuel subassembly, the maximum azimuthal non-uniformity of the temperature of the peripheral fuel elements of the displacement of the fuel elements in the central and peripheral regions of fuel subassemblies are obtained. Thermophysical substantiation of regimes of the fuel subassemblies of fast reactors core with sodium coolant need to be carried out taking into account the influence of various factors, including the forming of fuel subassemblies during the campaign.

Keywords
fast reactor, campaign, sodium, core, fuel subassembly, cover, fuel element, cladding, temperature, flow rate, factor, geometrical parameters, energy release, deformation, stochastic variations of the parameters, interchannel mixing, interpackage exchange, the maximum temperature, nonuniformity of temperature

Article Text (PDF, in Russian)

References

UDC 621.039:532.54

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants", 2018, issue 2, 2:22