PSI - Issue 68

M. Zarazovskii et al. / Procedia Structural Integrity 68 (2025) 391–397 M. Zarazovskii et al./ Structural Integrity Procedia 00 (2025) 000–000

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4. Conclusions 1. Experimental procedures for determining the Fracture Toughness of metal at cryogenic temperatures using pre cracked half-size SE(B) and C(T)0.16T specimens with a crack have been worked out. 2. New experimental data of the on Fracture Toughness of WWER-1000 RPV base material (15Kh2NMFAA steel) in the initial state was obtained. 3. Comparison the determined Master-Curves for WWER-1000 RPV material with the corresponding curves specified in the WWER nucreal standards PNAE G-7-002-86, VERLIFE and SOU NAEK 177:2023 shows that the standard curves are too conservative. Acknowledgements The presented work has been performed as a part of the STRUMAT-LTO (Structural Materials Research on Parameters Influencing the Material Properties of RPV Steels for Safe Long-Term Operation of LWR NPPs) project which was approved by NUGENIA. STRUMAT-LTO has received funding from the Euratom research and training programme 2019 - 2020 under grant agreement No 945272. References Report on tests of 10GN2MFA steel, its welded joints and anticorrosive claddings on experience of fabrication and operation of hull equipment of W-1000 plant., 2000 (in Russian). ASTM E1921-17a, "Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range," West Conshohocken, PA, 2017. Wallin, K. Fracture toughness transition curve shape for ferritic structural steels. In "Proceedings of the Joint FEFG/ICF International Conference on Fracture of Engineering Materials and Structures", Eds. S.H. Teoh and K.H. Lee, Elsevier, London, pp. 83-88, (1991a). Wallin, K., Planman, T., Valo, M., and Rintamaa, R., “Applicability of Miniature Size Bend Specimens to Determine the Master-Curve Reference Temperature To,” Engineering Fracture Mechanics, Vol 68, 2001, pp. 1265-1296. Wallin, K. (1989). Master-Curve Analysis of Ductile to Brittle Transition Region Fracture Toughness Round Robin Data (The Euro Fracture Toughness Curve). VTT Technical Research Centre of Finland. Unified Procedure for Lifetime Assessment of Components and Piping in WWER NPPs, «VERLIFE» Version 2008 – 275 р. STRUMAT-LTO Deliverable 1.1. Influence of high fluence irradiation on tensile properties of PWR and VVER-1000 RPV model steels and effectiveness of annealing, Research and Innovation Action, 2023. TU 108.765-78: Billets of steel grades 15Kh2NMFA, 15Kh2NMFA-A and 15Kh2NMFA class 1 for hulls, covers and other reactor components, Moscow: Soviet Standards, 1978. Samsonov G.V., Kitz A.I., Kyuzdeni O.A. et al. Sensors for temperature measurement in industry. - Kiev: Naukova Dumka, 1972. — 224 p. (in Russian). PNAE G-7-002-86. Code for Strength Calculations of Components and Piping in Nuclear Power Plants, Moscow: Energoatomizdat, 1987. (in Russian). SOU NNEGC 177:2023. Standard of organization of Ukraine, National Nuclear Energy Generating Company. Methodology for brittle fracture assessment of reactor pressure vessel (Kyiv, State enterprise NNEGC “Energoatom”, 2019) 49 p. (in Ukrainian). RD EO 0606-2005. Methodology for Brittle Fracture Resistance Calculation of WWER Reactor Pressure Vessels (MRCR-SCR-2004). - SPb.- Moscow, 2004. – 65 p. International Atomic Energy Agency, "Master-Curve approach to monitor fracture toughness of reactor pressure vessels in nuclear power plants," IAEA-TECDOC-1631, Vienna, 2009. FRACTESUS Deliverable D6.9. Fracture mechanics testing of irradiated RPV steels by means of sub-sized specimens. Testing protocols and reporting formats. 2021. ASTM E647-22, "Standard Test Method for Measurement of Fatigue Crack Growth Rates," West Conshohocken, 2022. ASTM E399-22, "Test Method for Linear-Elastic Plane-Strain Fracture Toughness of Metallic Materials" West Conshohocken, 2022.