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Combined with the previously discussed background related to corrosion and damage of zirconium alloy cladding, the following are typical specific cases that have been disclosed: Three Mile Island Nuclear Accident in the United States (1979) A core meltdown occurred in Unit 2. 90% of the fuel rod zirconium alloy cladding in the core was completely damaged, and 47% of the nuclear fuel melted. It was a landmark and severe cladding damage event in the history of nuclear power. Fukushima Nuclear Accident in Japan (2011) After the cooling system of Unit 1 failed, the temperature of the zirconium alloy cladding rose to 2800°C, and a violent zirconium-water reaction occurred with water vapor, producing more than 800kg of hydrogen and triggering an explosion. A large number of zirconium alloy claddings were completely damaged, eventually leading to a meltdown of the reactor core. Vogtle Unit 1 Incident in the United States (2018) The unit returned to full power operation after refueling and overhaul. An abnormal increase in the krypton, xenon, and iodine isotope content in the primary circuit was detected. After investigation, it was confirmed that there was a zirconium alloy cladding damage incident. The power plant continued to monitor its scope of impact during the remaining fuel cycle. China's Taishan Nuclear Power Plant Unit 1 Incident (2021) A slight increase in the radioactivity level in the primary circuit was detected during operation, and it was confirmed that about 5 fuel rods' zirconium alloy claddings were damaged. The damage ratio was less than 0.01%, which was far lower than the maximum damage ratio allowed by the design of 0.25%. The incident was assessed as Level 0 of the International Nuclear Event Classification, which is an operational deviation with no important safety significance.