CISCC Experiment of a Large Plate Sectioned From a Spent Nuclear Fuel Canister

Abstract

As a long-term demonstration of chloride-induced stress corrosion cracking (CISCC) driven by welding residual stress (WRS), a large section (approximately 51 × 46 cm with thickness 16 mm and weight about 30 kg), which contains a circumferential weld, was cut from a full-size mockup canister. Through-wall and part-through-wall (surface) starter cracks, either parallel or perpendicular to the weld, were fabricated with electrical discharge machining (EDM) in the weld region. The stress intensity factors (KI) for each machined starter crack under canister WRS were estimated so as to provide insight into the propensity for crack initiation and growth. Dry salt was applied over these machined cracks on the surface of the large plate and natural deliquescence was allowed to take place at room temperature and 75% RH. This test has been on-going for ten months and the evolution of general corrosion near the starter cracks is monitored and documented; no CISCC has been observed. Two EDM starter cracks have been isolated for five months for a simultaneous experiment with extra salt loading; additional deliquescence and significant corrosion activity have been observed.

Summary of Chloride-induced Stress Corrosion Cracking Experiments with a Spent Fuel Storage Canister Large Plate

“…[10]. The large plate test was initiated May 8, 2019 and completed May 12, 2021 after 2 years exposure.…”