PSI - Issue 68

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2025) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2025) 000–000

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ScienceDirect

Procedia Structural Integrity 68 (2025) 391–397

European Conference on Fracture 2024 Reference temperature determination of RPV steel using small-sized fracture toughness specimens M. Zarazovskii a , S. Shukayev b , K. Lukianenko a,b, * a IPP-CENTRE LLC, Budindustrii Street 5B, 01013 Kyiv, Ukraine b Igor Sikorsky Kyiv Polytechnic Institute, Prospect Beresteiskyi 37, 03056 Kyiv, Ukraine Abstract The efficiency of the Master-Curve reference temperature (MCRT) determination for Reactor Pressure Vessel (RPV) material using three-point bending half-thick SE(B) and compact tension C(T)0.16T specimens is analysed. The designed and manufactured experimental equipment for fracture toughness (FT) testing at cryogenic temperatures is described. For specimen cooling the liquid nitrogen and its vapours were used. Specimen pre-cracking was performed according to ASTM E647 standard, FT testing, and data treatment – in accordance with ASTM E399 and ASTM E1921. The experiments were carried-out on the specimens produced from two WWER-1000 RPV forgings made of 15Kh2NMFAA steel in initial (unirradiated) state. The experimental data were processed using the Master Curve methodology. It is shown that the as old USSR’s PNAE G-7-002-86 design FT curve as well as modern Ukrainian SOU NAEK 177:2023 and EU’s VERLIFE curves, are too conservative relatively to the obtained Master Curves. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers Keywords: Master-Curve; reference temperature; fracture toughness; half-thick SE(B); compact tension. 1. Introduction To ensure the safety of nuclear power plants (NPPs), it is important to demonstrate the integrity of the RPV in all operating conditions. The RPV service life is defined based on the fracture mechanics calculations. In accordance with the regulatory requirements of countries with developed nuclear industries the RPV integrity criterion is expessed as: European Conference on Fracture 2024 Reference temperature determination of RPV steel using small-sized fracture toughness specimens M. Zarazovskii a , S. Shukayev b , K. Lukianenko a,b, * a IPP-CENTRE LLC, Budindustrii Street 5B, 01013 Kyiv, Ukraine b Igor Sikorsky Kyiv Polytechnic Institute, Prospect Beresteiskyi 37, 03056 Kyiv, Ukraine Abstract The efficiency of the Master-Curve reference temperature (MCRT) determination for Reactor Pressure Vessel (RPV) material using three-point bending half-thick SE(B) and compact tension C(T)0.16T specimens is analysed. The designed and manufactured experimental equipment for fracture toughness (FT) testing at cryogenic temperatures is described. For specimen cooling the liquid nitrogen and its vapours were used. Specimen pre-cracking was performed according to ASTM E647 standard, FT testing, and data treatment – in accordance with ASTM E399 and ASTM E1921. The experiments were carried-out on the specimens produced from two WWER-1000 RPV forgings made of 15Kh2NMFAA steel in initial (unirradiated) state. The experimental data were processed using the Master Curve methodology. It is shown that the as old USSR’s PNAE G-7-002-86 design FT curve as well as modern Ukrainian SOU NAEK 177:2023 and EU’s VERLIFE curves, are too conservative relatively to the obtained Master Curves. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers Keywords: Master-Curve; reference temperature; fracture toughness; half-thick SE(B); compact tension. 1. Introduction To ensure the safety of nuclear power plants (NPPs), it is important to demonstrate the integrity of the RPV in all operating conditions. The RPV service life is defined based on the fracture mechanics calculations. In accordance with the regulatory requirements of countries with developed nuclear industries the RPV integrity criterion is expessed as: © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers

* Corresponding author. Tel.: +380-73-403-65-94 E-mail address: Lukianenko-km@ipp-centre.com.ua * Corresponding author. Tel.: +380-73-403-65-94 E-mail address: Lukianenko-km@ipp-centre.com.ua

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers 2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers 10.1016/j.prostr.2025.06.071