The Nuclear Safety And Security Commission said on the 19th that it had launched an investigation after heavy water leaked at Wolsong Nuclear Power Plant Unit 2 in Gyeongju, North Gyeongsang.
The Nuclear Safety And Security Commission received a report from Korea Hydro & Nuclear Power around 4:30 a.m. that heavy water had leaked from the moderator purification system at Wolsong Unit 2. The moderator purification system removes impurities that arise in the heavy water used as a reactor moderator and manages its quality. Heavy water refers to an artificial form of water produced by combining deuterium, an isotope of hydrogen, with an oxygen molecule.
KHNP reported to the Nuclear Safety And Security Commission's Wolsong Nuclear Power Plant Regional Office at 5:16 a.m. the same day, and the regional office arrived on site at 5:50 a.m. and began an inspection. After confirming the heavy-water leak, KHNP carried out leak isolation by stopping the relevant pump. The leaked heavy water was collected in the reactor auxiliary building compartment and the internal sump and was reported not to have escaped outside.
As of 12 p.m., the leak volume was about 265 kg, and KHNP said it would later calculate the exact amount and report again. Wolsong Unit 2 has been shut down since entering planned preventive maintenance on the 1st.
The Nuclear Safety And Security Commission said it confirmed there were no notable radiation-related issues outside the plant. "The regional office is checking on-site safety, and an investigation team made up of experts from the Korea Institute of Nuclear Safety (KINS) will be dispatched to the site," it said.