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Based on the previous background information regarding corrosion in nuclear power plant reactors, here are several typical accident cases related to this issue: 1. The Fukushima Daiichi Nuclear Power Plant accident. Cause of corrosion: Seawater was injected into the reactors after the accident, and the high-salt environment led to severe corrosion of many equipment components, accelerating the aging and deterioration of the facilities. Subsequent impact: The corrosion issue has significantly increased the difficulty of the decommissioning process, and efforts to remove the related fuel fragments continue as of 2025. II. Accidents due to corrosion and damage of fuel cladding. Corrosion mechanism: The zirconium alloy fuel cladding suffers water-side corrosion in the primary water environment; once this corrosion exceeds the design limits, the cladding is damaged and radioactive fission products leak into the coolant. Operational impact: Such accidents are the most common corrosion-related incidents during the operation of nuclear reactors; once they occur, the reactor must be shut down immediately for investigation to prevent further spread of radioactive materials. III. Pipeline failure incidents caused by flow-accelerated corrosion. Corrosion characteristics: In the primary and secondary circuits, the oxide protection layer on the surface of carbon steel pipelines is dissolved under the impact of high-velocity coolant, causing the pipe walls to thin continuously until rupture and leakage occur. Safety consequences: Such incidents can directly lead to coolant loss, and in severe cases, trigger an emergency shutdown of the reactor, posing a threat to the safety of plant operation. IV. Corrosion-related hazards caused by equipment aging – Typical case: In 2026, Unit 1 of the Fukushima Daiichi Nuclear Power Plant experienced corrosion and degradation of components in its cooling system due to equipment aging, which led to pump failures and a disruption in the cooling function. Risk characteristics: In older units that have been in operation for a long time, corrosion risks accumulate rapidly over time, becoming safety issues that cannot be ignored.