Numerical Study of the Gas-Steam Transient Behavior in the Integrated Pressurizer Available to Purchase

The integrated gas-steam pressurizer stabilizes the pressure by compressing the gas and steam mixture. It has attracted much attention because of its simple structure, eliminating heating and spraying of equipment, and preventing the liquid boiling. The NHR series developed by Institute of Nuclear and New Energy Technology in Tsinghua University uses the integrated gas-steam pressurizer. The major loop thermal parameters in NHR series increased progressively, which made it suitable for heating, industrial steam supply and seawater desalinization. In order to ensure the safety of the NHR series major loop system and guarantee the natural circulation capability of the system under high temperature and pressure, the researches on the gas-steam transient characteristics of the integrated gas-steam pressurizer is needed. This paper is mainly about study on transient characteristics of the gas-steam typed pressurizer using the Relap5 code. The classic experiment on the pressure behavior of gas-steam pressurizer during the in-surge performed at MIT is considered as reference objects, and the analysis model is established by using Relap5 code. By comparing the computing results with the MIT experiment data about pressure-time, the applicability of Relap5 code for forecasting the transient behavior of the gas-steam (nitrogen) pressurizer has been verified. The results show that Relap5 code can effectively track the transient behavior of the pressure in the gas-steam pressurizer. In addition, the transient characteristics of the integrated gas-steam pressurizer in the NHR series have been studied. It is founded that the pressure and the liquid temperature adjoining to the pressurizer lag behind the power change in natural circulation loop with integrated gas-steam pressurizer, and the liquid temperature adjoining to the pressurizer and the liquid volume under the pressurizer are the main factors determining the pressure change.