Hanbit Unit 4 Giant Hole Repair Completed... Countdown to Restart After 5 Years

Fuel Channel Repair on 7th, ILRT Test Completed on 28th
Test Run Started After Loading 177 Fuel Bundles
KHNP "Restart Expected in Mid-Next Month"

The restart of Hanbit Unit 4, which had been halted due to a massive cavity (hole) in the containment building, has entered its final countdown. Repair work to fill the cavity, which measured up to 1.5 meters, was completed earlier this month, and final inspections have begun. It has been five years since operations stopped in 2017.

According to Korea Hydro & Nuclear Power (KHNP) on the 29th, the containment building Integrated Leakage Rate Test (ILRT) for Hanbit Unit 4, located in Yeonggwang, Jeollanam-do, was completed the previous day (28th). The ILRT pressurizes the inside of the containment building to the design basis maximum accident pressure (Pa) of 51.1 psig (pressure unit) to measure the overall leakage rate of the containment building. During this test period, KHNP confirmed that repairs on approximately 140 large and small cavities were properly carried out.

Earlier, KHNP completed repairs on the massive cavity measuring up to 157 cm on the 7th and finished loading 177 fuel assemblies between the 11th and 14th. A KHNP official said, "We successfully completed the ILRT and confirmed that there were no issues with the containment building cavity repairs."

Having confirmed the safety of the containment building, KHNP will begin commissioning by the 5th of next month. This process involves final checks on the appropriate temperature and pressure of the reactor coolant system, which transfers and transports thermal energy. To use a car analogy, it is like starting the engine and verifying the safety of key equipment to ensure actual operation is possible.

[Image source=Yonhap News]

KHNP expects the restart of Hanbit Unit 4 as early as mid-next month. However, this requires review and approval for restart by the Nuclear Safety and Security Commission (NSSC). According to the Nuclear Safety Act, KHNP must obtain permission from the NSSC to restart the nuclear power plant.

KHNP plans to request criticality approval for restart from the NSSC after confirming the final inspection results through the Korea Institute of Nuclear Safety (KINS). There is also a final variable: the NSSC may request additional items for restart based on KINS’s report.

Previously, Hanbit Unit 4 entered planned preventive maintenance in May 2017 after a cavity occurred due to concrete not being poured in part of the containment building that prevents radioactive material leakage. It has remained offline for five years, coinciding with the previous government’s nuclear phase-out policy. After receiving a structural soundness evaluation from regulatory authorities in July, it was confirmed that the repair plan was appropriate, and cavity repair work began in August.

KHNP stated, "We are doing our best with related agencies to complete the final inspection of Hanbit Unit 4 by early next month and to restart it as early as mid-month."

This content was produced with the assistance of AI translation services.