Optimization of the Test Frequency of Pressurizer Safety Valves in VVER Reactors

V. I. Skalozubov

Interagency Center for Fundamental Scientific Research in Energy and Ecology Sector of the National Academy of Sciences of Ukraine, Odesa Polytechnic and Ministry of Ecology and Natural Resources of Ukraine, 1, Shevchenko Ave, Odesa, 65044

https://orcid.org/0000-0003-2361-223X

Yu. O. Komarov

https://orcid.org/0000-0002-4696-6551

Yu. S. Katsarskyi

https://orcid.org/0009-0001-9932-2880

V. Yu. Kochnieva

https://orcid.org/0000-0001-7397-3573

V. V. Hrybanov

https://orcid.org/0009-0005-7315-2667

DOI: doi.org/10.31717/2311-8253.26.1.5

Abstract

A methodology has been developed to optimize the frequency of functional tests of the pressurizer safety valve system during the power unit maintenance period under loads corresponding to the conditions of accidents/emergency, taking into account the required reliability of operability monitoring and regulatory requirements for strength conditions under cyclic thermodynamic and mechanical loads. Based on the developed methodology, an optimal strategy for testing the pressurizer safety valve system is proposed as a deviation from the Annexes to the Technological Regulations for the Safe Operation of the Unit 3 of the Rivne NPP: The test frequency related to checking the operation of the pilot operated safety valve of the pressurizer with a real increase in primary circuit pressure is once every 8 years; The test frequency related to checking the tightness of the locks of the pilot operated safety valve of the pressurizer, adjustment of the springs and activation of the main valve using a pneumatic test stand and a measuring lever is once every 4 years; Tests of the safety valve system of the pressurizer, related to monitoring automation and control schemes, correspond to the frequency established in the Technological Regulations for the Safe Operation of the Unit 3 of the Rivne NPP; After 8 years of operation or the accidents, emergency situations, violations of normal operating conditions, a full technical inspection of the pressurizer safety valve system is performed and, if necessary, the test strategy is adjusted during the maintenance campaigns.

Keywords: test, accident, safety valve, pressurizer, frequency, methodology, power unit.

References

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Published

2025-13-03

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