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Licensed Unlicensed Requires Authentication Published by De Gruyter October 6, 2022

Pressurizer system dynamic model for transient control in PWR

Hala K. Selim ORCID logo EMAIL logo and Neama M. El-Sahlamy
From the journal Kerntechnik


The pressurizer system of pressurized water reactor (PWR) maintains the reactor coolant system pressure during steady-state operation and limits pressure changes during transients. The in/out surge transients will cause pressure variations and they are controlled by either the spray system or the heater system. The spray system is actuated when the pressure exceeds a preset value. The heater system is initiated when the pressure falls below a preset value. The fundamental understanding and a reliable modeling of the pressurizer system behavior under steady state and transient conditions are needed to simulate overall nuclear power plant behavior. In the present study, an algorithm using Python 3.7 is developed to represent the dynamic behavior of the pressurizer system under steady-state and during in/out surge transients. Moreover, RELAP5 code is used to simulate the pressurizer system during the prescribed transients. The analysis and assessment results demonstrate satisfactory control performance during the in/out surge transients that guarantee the safety of PWR during operation. Also, the comparison between Python algorithm and RELAP5 model illustrates the capability and effectiveness of the Python algorithm for dynamic simulation and control.

Corresponding author: Hala K. Selim, Department of Nuclear Safety Engineering, Egyptian Atomic Energy Authority, Cairo, Egypt, E-mail:

  1. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: None declared.

  3. Conflict of interest statement: The authors declare no conflicts of interest regarding this article.


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Received: 2022-04-06
Published Online: 2022-10-06
Published in Print: 2022-12-16

© 2022 Walter de Gruyter GmbH, Berlin/Boston

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