Greenpeace pointed out that a substandard material is used in some nuclear power stations in Korea. The Korea Hydro & Nuclear Power Corporation, in response, said that the same material is used around the world.
According to Greenpeace, the alloy material Inconel 600, which has been considered to be dangerous since the 1970s, is used in 14 power plants located in Korea, whereas the United States and France have replaced it with Inconel 690 since around 1989. “Hanbit 3 and 4 and four more units, all of which were built after 1989, are using Inconel 600,” a Greenpeace representative said, adding, “The accident at Hanbit 3 in October this year was because of the heat pipe coolant leakage in the steam generator using this material, and 12 more accidents attributable to the material have occurred since 1986.”
Regarding this issue, the Korea Hydro & Nuclear Power Corporation explained that Hanbit 3 was impaired not because of the material but foreign matter, and Hanbit Units 3 and 4 used the same material used in American power stations when it was designed in 1987. “The Inconel 690 was still being tested when Hanul Units 3 and 4 were designed in 1991, and we have already replaced it with the Inconel 690 in the steam generators of five out of the 14 power plants using the 600, with the replacement process scheduled for 2018 and 2019 for Hanbit 3 and 4,” a corporate representative added.
Greenpeace also maintained that a large-scale disaster comparable to Chernobyl and Fukushima, in which nuclear fuel rods melt, could occur if multiple heat pipes were broken at the same time. The corporation denied the possibility though. The environmental organization also criticized that the corporation and the Nuclear Safety and Security Commission, while well aware of current problems, are unwilling to address them with the sacrifice of economic efficiency.
In the meantime, the commission confirmed on Dec. 4 that the earthquake-proof performance of the power supply devices of Hanul 1 and 2 fell short of the minimum standards and told the facilities to be reinforced. “We have found out during the regular inspection that the cabinet fixing unit housing a 220V power supplier for monitoring, control, and measuring systems was not produced as designed,” it said.