Analysis of degassing time of pressurized water reactor pressurizer

The thermal degassing characteristics especially the degassing time of the pressurizer is essential for the design and operation of the nuclear reactor. However, the related studies are rarely published publically. This paper studies the pressurizer thermal degassing characteristics and presents its application to a pressurizer of a typical pressurized water Small and Medium sized Reactor (SMR). Firstly, the steady-state thermal degassing process of the pressurizer is analyzed. A theoretical pressurizer degassing model is developed and verified by comparing with the experiment, which supports the reliability of the model. Secondly, the index of the degassing time is defined and the influencing factors of the degassing time are analyzed theoretically. Thirdly, based on the thermal-hydraulic restrictions of the degassing process of the SMR pressurizer, a degassing time optimization scheme is proposed to optimize the pressurizer degassing time. Through the application of the optimization algorithm, the degassing hydrogen time of the SMR pressurizer is reduced by 10.3% in contrast with the degassing hydrogen time of the SMR pressurizer at its preliminary design value.