Effect of surface machining on the environmentally-assisted cracking of Alloy 182 and 316L stainless steel in light water reactor environments: results of the collaborative project MEACTOS

• DOI: 10.1515/corrrev-2022-0121
• Publication Date: 2023-05-12T14:15:53Z
• Authors: Mariia Zimina; Stefan Ritter; Bojan Zajec; Marc Vankeerberghen; Liberato Volpe; Anna Hojná; Rik-Wouter Bosch; Fabio Scenini; Zaiqing Que; Alberto Sáez-Made...; P. Jill Meadows; Michael Grimm; Matthias Herbst; Andraz Legat; Agostino Maurotto; Radek Novotny; Hans-Peter Seifert
• Keywords: environmentally-assisted cracking; crack initiation; avstenitno nerjavno jeklo AISI 304L; lahkovodni reaktor; light water reactor; Stainless steel; AISI 304 stainless steel; Alloy 182; površina obdelave; Initiation; Innovation; ta216; stainless steel; ta116; ta215; pokanje zaradi vplivov okolja; open access; weld metal; Light water reactor; odprti dostop; info:eu-repo/classification/udc/544.5/.6; Stress corrosion cracking; surface treatment; 620; iniciacija razpoke; initiation; stress corrosion cracking; and Infrastructure; zlitina Alloy 182; SDG 9 - Industry; Weld metal

Abstract The main objective of the EU-funded project mitigating environmentally-assisted cracking through optimisation of surface condition (MEACTOS) was to gain knowledge on the ability of different surface machining procedures to mitigate environmentally-assisted cracking (EAC) in typical light water reactor structural materials and environments. Surfaces of cold-worked (CW) type 316L austenitic stainless steel and nickel-based weld metal Alloy 182 flat tapered tensile specimens were machined using different processes. EAC initiation susceptibility of these specimens was evaluated using constant extension rate tensile (CERT) tests under simulated boiling water reactor (BWR) and pressurized water reactor (PWR) conditions and assessed using constant load experiments. More than a hundred tests were performed covering about 10 years of autoclave testing time. Only minor or no measurable improvements in EAC initiation susceptibility as a function of surface treatments (grinding or advanced machining) compared to the standard industrial face milling were demonstrated. In most cases, the stress thresholds for EAC initiation determined in constant load tests confirmed the trend obtained from CERT tests. This paper summarises the most important results and conclusions concerning the EAC initiation behaviour for the CW 316L and Alloy 182 under reducing PWR and oxidizing BWR conditions.