Power generation automatically halted at Korea’s Hanbit 2 nuclear reactor

Korea Hydro & Nuclear Power (KHNP) headquarters [Courtesy of KHNP]

The Hanbit 2 nuclear reactor in Yeonggwang County experienced an automatic halt in operations due to an unexpected cooling water supply malfunction, raising concerns about potential power supply disruptions, especially as South Korea is anticipating a scorching heatwave after the rainy season.

According to Korea Hydro & Nuclear Power (KHNP), the 950,000-kilowatt reactor ceased power generation at around 11:57 a.m. The shutdown occurred when a turbine stopped functioning upon detecting an abnormal signal during the testing of the special protection scheme (SPS). The SPS is a device designed to prevent overloads in the transmission lines connected to the Korea Electric Power Corp.

A KHNP official explained that the water level in the steam generator suddenly decreased, triggering a low-level water warning and consequently leading to the plant‘s suspension.

KHNP plans to initiate follow-up measures, including component replacement, as soon as the cause of the malfunction is identified. The investigation will be carried out by the Korea Institute of Nuclear Safety (KINS) under the Nuclear Safety and Security Commission. KINS confirmed that there were no abnormal incidents, including radiation leaks, and the plant was in a stable condition.

Hanbit 2, which began operation in 1987, is set to reach its design lifespan in 2026. During the previous Moon Jae-in administration, the plant was scheduled for decommissioning in line with the nuclear phase-down policy. However, under President Yoon Suk Yeol’s government, a policy to continue operating aged nuclear reactors was pursued, leading Hanbit 2 to submit periodic safety assessment reports to KINS for ongoing operation at the end of last month.

The sudden halt of the reactor just before the full-fledged heatwave is raising concerns about potential electricity supply issues. Nonetheless, KEPCO officials said that the impact of the suspension on power supply is minimal, as other power generators can sufficiently compensate. South Korea’s total power generation capacity is about 140GW, and Hanbit 2 accounts for less than 1 percent of this capacity.

Earlier, the Ministry of Trade, Industry, and Energy projected a peak power demand of 92.7GW for this summer, with a maximum projection of 97.8GW, accounting for exceptional weather conditions. The country’s maximum power supply capability was estimated to be a record 106.4GW.