PSI - Issue 60

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect

Structural Integrity Procedia 00 (2023) 000 – 000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 60 (2024) 390–401

© 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 Leak-Before-Break (LBB) of high enthalpy piping of Indian NPPs require fracture stability demonstration of pipelines with postulated cracks under design basis earthquake loads. Earlier large number of cyclic fracture and corresponding monotonic fracture tests on large sized pipe components were conducted at room temperature. In current program, monotonic/cyclic fracture experiments are extended to reactor operating temperature (300 o C). The aim of this study is to demonstrate the structural integrity of SA333Gr6 piping and Stainless Steel (SS) 304LN welds under monotonic/cyclic loading which simulates extreme earthquake events and operating temperatures. Total six pipes/pipe welds of carbon steel (8 - inch NB ~219 mm outer diameter and 19 mm thick) and SS304LN (12 - inch NB~324 mm and outer diameter ~25 mm thick) with through-wall cracks have been tested under four-point bending. Two monotonic fracture tests have been conducted at 300 o C under monotonic loadings. Different experimental results like LLD (Load Line Displacement), Total Load, CMOD (crack mouth opening displacement), Crack Growth values have been obtained. Based on this data the load carrying capacity are obtained for both 8-inch and 12-inch cracked pipes. The cyclic fracture tests have also been conducted at 300 o C under fully reversing cyclic loading on four pipes. Three 8-inch SA333Gr6 pipes have been tested under different magnitude of peak load values. Similarly, one 12-inch SS pipe is also tested under cyclic loading. For carbon steel pipes, the reduction in load capacity is slightly higher under cyclic loadings at 300 o C compared to that at room temperature. However, for stainless steel pipes the load reduction factor at 300 o C is in good agreement with that at room temperature. © 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 Third International Conference on Structural Integrity 2023 (ICONS 2023) Fracture investigation at 300 o C on carbon-steel and austenitic stainless-steel pipes of NPPs under cyclic loads M. K. Sahu a *, S. K. Gupta a , Suranjit Kumar a , P. K. Singh a , M. Saravanan b , S. Vishnuvardhan b , A. Ramachandra Murthy b and S. Parivallal b a Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai 400085, India b Fatigue & Fracture Laboratory, CSIR - Structural Engineering Research Centre, Chennai - 600 113, India

* Corresponding author. Tel.: +91-22-25593557. E-mail address: mksahu@barc.gov.in

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

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.2024.05.060