Conservative estimations of irradiation embrittlement of reactor pressure vessel steels for WWER-1000 lifetime prediction
Multidiscipline Modeling in Materials and Structures
ISSN: 1573-6105
Article publication date: 17 December 2018
Issue publication date: 7 January 2019
Abstract
Purpose
The purpose of this paper is to consider a procedure of water-water energetic reactor (WWER) reactor pressure vessel (RPV) lifetime prediction at the stages of design and lifetime extension using the standard irradiation embrittlement parameters as defined in regulatory documents. A comparison is made of the brittle fracture resistance (BFR) values evaluated using two criteria: shift in the critical brittleness temperature ΔTc or shift in the brittle-to-ductile transition temperature ΔTp and without shifts (Tc and Tp).
Design/methodology/approach
The radiation resistance was determined using the following three approaches: calculation based on standard values ΔTc and Tc0 or ΔTp and Tp0 (a level of excessive conservatism); calculation based on standard value ΔTc and actual value Tc0 or actual values ΔTp and Tp0 (the level of realistic conservatism); or calculation based on actual values of Tc and Tc0 or Tp and Tp0 (the level of actual conservatism). The BFR was evaluated based on the results of testing the specimens subjected to irradiation in research reactors as well as surveillance specimens subjected to irradiation immediately under operating conditions.
Findings
The excessive conservatism in determining the actual lifetime of nuclear reactor vessel materials can be eliminated by using the immediate values of critical brittleness temperature and ductile-to-brittle transition temperature.
Originality/value
Obtained results can be applied to extend WWER vessel operating time at the stages of designing and operation due to substantiated decrease in conservatism. And it will allow carrying out a statistical substantiated assessment of the resistance to brittle fracture of the RPV steels.
Keywords
Acknowledgements
The work was supported by the Ministry of Education and Science of the Russian Federation in the framework of the Grant Agreement No. 14.579.21.0116 (the unique identifier of the agreement RFMEFI57915X0116).
Citation
Anosov, N.P., Skorobogatykh, V.N., Gordyuk, L.Y., Mikheev, V.A., Pogorelov, E.V. and Shamardin, V.K. (2019), "Conservative estimations of irradiation embrittlement of reactor pressure vessel steels for WWER-1000 lifetime prediction", Multidiscipline Modeling in Materials and Structures, Vol. 15 No. 1, pp. 246-257. https://doi.org/10.1108/MMMS-12-2017-0160
Publisher
:Emerald Publishing Limited
Copyright © 2019, Emerald Publishing Limited