Second unit of South Korea’s Shin Hanul power plant reaches criticality for the first time

South Korea’s Shin Hanul 2 nuclear unit has reached another important milestone on its way to commercial operation. It achieved criticality for the first time this week, a key prerequisite for its operation. The APR-1400 unit will now undergo operational tests at various power levels. Once commissioned, it will become South Korea’s 28th nuclear reactor generating electricity. 

South Korean utility Korea Hydro & Nuclear Power (KHNP) announced that its Shin Hanul 2 nuclear unit achieved criticality for the first time at 7:00 on December 6. In a nuclear reactor, this refers to a state in which a fission chain reaction is sustained at a constant power level.

Construction of the 1350 MWe APR-1400 pressurized water reactor at Shin Hanul 2 began in June 2013.  After construction was completed and the unit passed cold and hot functional tests, it received an operating licence in early September.  A total of 241 fuel assemblies were then loaded into the reactor core between September 11 and 18.

Before officially entering service, the unit will now undergo a series of tests at different power levels. KHNP says it will contribute electricity to help meet peak winter demand as early as December. The company is currently planning to officially start operations in the first half of 2024.

More APR-1400 reactors enter service

Shin Hanul 2 will be the fourth unit of its type to enter service in South Korea and the seventh or eighth worldwide (Barakah 4 in the United Arab Emirates is also at a similar stage of commissioning .).

“Shin Hanul 1, the same type of unit as Shin Hanul 2, began commercial operation in December last year and has been operating for 365 days without a fault,” KHNP said in a press release.

The first two APR-1400 units were built and commissioned at the Saeul 1 and 2 power plant (formerly Shin Kori 3 and 4). They were followed by Shin Hanul 1 and three more units at the Barakah power plant. South Korea is currently building more APR-1400 units at Saeul 3 and 4 and Shin Hanul 3 and 4, with KHNP selecting their supplier at the end of November.