Expansion of Wolsong Used Fuel StoreApproved

South Korea's Nuclear Safety and Security Commission (NSSC) today approved Korea Hydro & Nuclear Power's (KHNP) application to construct additional capacity for the interim storage of used fuel at the Wolsong nuclear power plant. Current storage at the existing used fuel facility is nearing full capacity.

An on-site dry storage facility has been in operation for the four Candu pressurised heavy water reactors at the Wolsong plant. Dry storage in MACSTOR/KN-400 (Modular Air-Cooled Storage 400) modules is used for the fuel after six years of cooling in pools. Seven modules of MACSTOR-400 with a total capacity of 168,000 bundles were constructed in 2010. KHNP applied in April 2016 to add a further seven MACSTOR-400 modules at Wolsong.

KHNP said that, as of September last year, more than 93% of the used fuel storage capacity at Wolsong had been used. It estimates that the current storage facility would be full by November 2021 and warned that it may have to take some reactors offline if additional storage was not added by then.

The NSSC's approval today follows Korea Institute of Nuclear Safety's assessment that the existing storage facility and its proposed expansion meet all regulatory requirements and do not pose a risk to the environment.

KHNP expects construction of the seven additional MACSTOR-400 modules to take at least 19 months to complete, The Electronic Times reported last August. This would mean that construction of the new modules would need to start by April this year if the new capacity is to be available by November 2021.

The Wolsong site in Gyeongju, North Gyeongsang Province, houses four 700 MWe Candu 6 reactors, which began commercial operation between 1983 and 1999. KHNP announced in June 2018 that Wolsong 1 will be retired prior to the expiration of its operating licence in 2022 due to the "uncertain economic viability" of its continued operation. The unit was declared as having been shut down on 24 December last year.