Hanul Unit 6 in South Korea commences its 15th planned preventive overhaul

Korea Hydro & Nuclear Power (KHNP)'s Hanul Nuclear Power Site announced that its Hanul Unit 6 was officially disconnected from the grid at 10:00 a.m. on September 30, fully launching its 15th planned preventive overhaul lasting approximately 72 days.

Hanul Unit 6 is a 1,000-megawatt-class pressurized water reactor (PWR) with a rated electrical power of 1,000 megawatts. During this planned maintenance window, the operations and maintenance team will carry out routine nuclear fuel assembly refueling operations as scheduled, and conduct comprehensive preventive maintenance and performance testing on the reactor primary coolant system, engineered safety features, and conventional island critical electrical equipment.

In addition to routine maintenance items, the Hanul Site will focus on advancing a series of grid-side equipment technical modification projects, including implementing high-voltage circuit breaker capacity expansion modifications, aimed at fundamentally alleviating the transmission section power flow constraints in South Korea's east coast region and enhancing the safety and flexibility of power transmission from the generating units.

In accordance with the compliance requirements of South Korea's Nuclear Safety Act, after completing all statutory inspections, corrective actions, and regulatory conformity on-site reviews, the unit must obtain formal approval for reactor recriticality and restart from the Nuclear Safety and Security Commission (NSSC). The overhaul is expected to be completed and grid-connected power generation restored by mid-December 2026.