Authors & Affiliations

Shlepkin A.S., Morozov A.V.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia

Shlepkin A.S. – postgraduate student, A.I. Leypunsky Institute for Physics and Power Engineering. Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel.: +7((985)272-37-95; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..
Morozov A.V. – Leading Researcher, Dr. Sci. (Tech.), A.I. Leypunsky Institute for Physics and Power Engineering.

Abstract

This article concludes with a series of papers devoted to the effects of non-condensible gases on the condensation processes of steam occurring in the VVER-1200 steam generator operating in the condensation mode in the event of an accident with a rupture of the main circulation pipeline.
These issues are of great practical importance, related to the justification of the capacity of the passive heat removal system – in spite of the use of air heat exchangers in SPOT that allow the system to divert practically unlimited heat, the time of the passive heat removal system is not infinite and is limited a decrease in the capacity of the steam generator in the condensation mode caused by the accumulation in the PG tube bundle of non-condensing gases coming from the reactor and covessels of the system of hydraulic capacitances of the first level.
The article presents the results of processing data obtained in the course of experimental studies at the stand "GE2M-PG", built in IPPE.
To study the processes of heat transfer in experiments, the temperature difference between the first and second contours was studied. During the analysis of experimental data it was found out that the value of the temperature head between the contours is affected not only by the mass of the gases accumulated in the tube of the steam generator, but also by the rate of their accumulation.
Also, it turned out that the "positive feedback" between the steam generator and the heat exchanger of the passive heat removal system (SPOT) has a significant positive effect on the efficiency of steam condensation, consisting in the following. As a result of the accumulation of non-condensable gases in the tube bundle, the heat transfer coefficient decreases, thereby causing a reduction in steam flow into the steam generator tube, which leads to a decrease in the heat flux from the first to the second circuit. For this reason, the temperature of the second circuit is reduced (due to the operation of the SPOT), thereby increasing the temperature difference between the media of the first and second circuits of the reactor installation. This leads to an increase in the flow rate of steam entering the steam generator from the reactor.
In addition, three semi-empirical formulas were obtained, which allow calculating the changes in power, the temperature difference between the circuits and the heat transfer coefficient for the steam generator model in the investigated range of concentrations of non-condensible gases in the vapor. The maximum deviation of the values obtained by the calculated and experimental method does not exceed 20%.

Keywords
VVER, steam generator, condensing modes, non-condensing gases, gas-vapor mixture

Article Text (PDF, in Russian)

References

UDC 621.039.58:536.423.4

Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants", 2018, issue 3, 3:14