Authors & Affiliations

Kuzina Ju.A., Privezentsev V.V., Sorokin A.P., Rymkevich K.S.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia

Kuzina Ju.A. – Deputy Director General – Director of Thermophysical Department, Cand. Sci. (Tech.), A.I. Leypunsky Institute for Physics and Power Engineering. Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel.: +7(484) 399-86-63, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..
Privezentsev V.V. – Leading researcher, Cand. Sci. (Tech.), A.I. Leypunsky Institute for Physics and Power Engineering.
Sorokin A.P. – Deputy Director of Safety Department, Dr. Sci. (Tech.), A.I. Leypunsky Institute for Physics and Power Engineering.
Rymkevich K.S. – Leading engineer, A.I. Leypunsky Institute for Physics and Power Engineering.

Abstract

The results of experimental studies of heat transfer and temperature fields for fuel assemblies of the peripheral subzone of the reactor core of BREST type with step s/d=1.28 are presented. Four transverse spacers were used for the spacing. The results are compared with the data obtained earlier for a similar model assembly with homogeneous geometry with step s/d=1.33. The modeling coolant was the eutectic Na-K alloy (22%Na+78%K). The experimental data were processed separately for the region between the spacing lattices (smooth sections) and in the region of the spacing lattices. The experimental data are processed in a dimensionless form, and dependences for Nusselt numbers and dimensionless azimuthal temperature irregularities are obtained. In the investigated range of Peclet numbers, the influence of the spacing lattices on the rods is small, the experimental data obtained for the Nusselt number on smooth sections are approximately equal to the corresponding values for lat-tices of smooth fuel elements with steps s/d=1.28 and s/d=1.33. The heat transfer in the pin bundle with 1.28 steps lower than in the pin bundle with 1.33 steps to ~12% for high Peclet numbers and ~5% for laminar flow. Using of spacing lattices lead to a local burst of heat transfer, which is higher than on smooth sections of fuel rod simulators (between lattices). Heat transfer increases as the coolant moves in the bundle. Formulas are obtained for calculating the local Nusselt numbers in the region of the transverse spacing lattices for different zones – directly inside, before and after the lattice. The dimensionless overall maximum temperature non-uniformities along the perimeter of the measuring simulator obtained experimentally demonstrate the absence of a noticeable difference in their values on the smooth sections and in the region of the spacing lattices. Inside the spacing lattices periodic temperature irregularities around the perimeter of the measuring imitator are caused by the touching of the elements of the lattice. The values of periodic non-uniformities are almost independent of the value of the Peclet number.

Keywords
experiment, heat transfer, temperature fields, reactor, heavy coolant, core, pin bundle, transverse displacing lattice, measuring simulator, Nusselt number, Peclet number

Article Text (PDF, in Russian)

References

UDC 536.24:621.039

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2017, issue 4, 4:2