PSI - Issue 60

ScienceDirect Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2023) 000 – 000 Available online at www.sciencedirect.com ScienceDirect StructuralIntegrity Procedia 00 (2023) 000 – 000 Available online at www.sciencedirect.com Procedia Structural Integrity 60 (2024) 324–334

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2452-3216 © 2024 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 the ICONS 2023 Organizers 10.1016/j.prostr.2024.05.053 2452-3216© 2024 T he 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) P eer-review under responsibility of the ICONS 2023 Organizers 2452-3216© 2024 T he 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) P eer-review under responsibility of the ICONS 2023 Organizers © 2024 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 the ICONS 2023 Organizers Abstract The rolled joint between pressure tube and end-fitting in a pressurized heavy water type reactor is critical from integrity and performance point of view as significant magnitudes of residual stresses are generated during the rolling process. The distribution of residual stress in the rolled joint is required for assessment of operational performance and integrity of the same. The 3D FE simulation of the rolling process considering material, geometric and contact nonlinearities are very scarce in literature. Moreover, the discussion regarding development of residual stress in the joint during the rolling process and its subsequent relaxation at higher temperatures and corresponding data are not available in literature. The pull-out strength of the rolled join is an important operational parameter which ensures a leak tightness (due to presence of compressive contact stresses) and other functional requirements of the joint. The strength of the joint also changes significantly with temperature due to change in material properties and release of residual stresses. Especially at the severe accident regime, the strength may reduce to such as extent that the tube may get disassembled from the end-fitting due to joint pull-out. The objective of this work is to evaluate the residual stresses that are present in the joint during the rolling process and also estimate the pull-out strength of the joint at different temperatures using finite element analysis. These results shall be useful to the engineers involved in study of severe accident in Indian pressurized heavy water reactors. Key Words: Rolled joint, Pull-out strength, Zr2.5Nb Pressure tube, end-fitting, PHWRs, FE simulation 1. Introduction Rolled joints are important elements in power generation industries, where the tube are connected to tube-sheets in several types of components such as steam generators, heat exchangers etc. Tube to tube-sheet joints are prepared Abstract The rolled joint between pressure tube and end-fitting in a pressurized heavy water type reactor is critical from integrity and performance point of view as significant magnitudes of residual stresses are generated during the rolling process. The distribution of residual stress in the rolled joint is required for assessment of operational performance and integrity of the same. The 3D FE simulation of the rolling process considering material, geometric and contact nonlinearities are very scarce in literature. Moreover, the discussion regarding development of residual stress in the joint during the rolling process and its subsequent relaxation at higher temperatures and corresponding data are not available in literature. The pull-out strength of the rolled join is an important operational parameter which ensures a leak tightness (due to presence of compressive contact stresses) and other functional requirements of the joint. The strength of the joint also changes significantly with temperature due to change in material properties and release of residual stresses. Especially at the severe accident regime, the strength may reduce to such as extent that the tube may get disassembled from the end-fitting due to joint pull-out. The objective of this work is to evaluate the residual stresses that are present in the joint during the rolling process and also estimate the pull-out strength of the joint at different temperatures using finite element analysis. These results shall be useful to the engineers involved in study of severe accident in Indian pressurized heavy water reactors. Key Words: Rolled joint, Pull-out strength, Zr2.5Nb Pressure tube, end-fitting, PHWRs, FE simulation 1. Introduction Rolled joints are important elements in power generation industries, where the tube are connected to tube-sheets in several types of components such as steam generators, heat exchangers etc. Tube to tube-sheet joints are prepared Third International Conference on Structural Integrity 2023 (ICONS 2023) Estimation of residual stress in the rolled joint and its effect on its pull-out strength at different temperatures R.P. Pandey a , M. K. Samal a,b *, J. Chattopadhyay a,b a Reactor Safety Division, Bhabha Atomic Research centre, Mumbai - 400085, India b Division of Engineering Sciences, Homi Bhabha National Institute, Mumbai - 400094, India. Third International Conference on Structural Integrity 2023 (ICONS 2023) Estimation of residual stress in the rolled joint and its effect on its pull-out strength at different temperatures R.P. Pandey a , M. K. Samal a,b *, J. Chattopadhyay a,b a Reactor Safety Division, Bhabha Atomic Research centre, Mumbai - 400085, India b Division of Engineering Sciences, Homi Bhabha National Institute, Mumbai - 400094, India. * Corresponding author. Tel.: 022-2559-3551; E-mail address: mksamal @barc.gov.in * Corresponding author. Tel.: 022-2559-3551; E-mail address: mksamal @barc.gov.in