South Korea's Nuclear Safety and Security Commission (NSSC) on 1 February approved the start of the 1350MWe APR1400 reactor at unit 4 of Korea Hydro and Nuclear Power’s (KHNP’s) Shin-Kori nuclear plant.

Construction of the first two APR1400 pressurised water reactors at Shin-Kori 3&4 was authorised in 2006 and a construction licence followed in-April 2008. First concrete for Shin-Kori 3 was poured in October 2008, and for unit 4 in August 2009. Shin-Kori 3 was originally scheduled to begin commercial operation at the end of 2013 followed by unit 4 in September 2014. However, they were postponed because of the need to test safety-related control cabling and then to replace it.

Shin-Kori 3 achieved first criticality in December 2015 and was connected to the grid in January 2016, beginning commercial operation the following  December. Cold hydrostatic testing and hot functional testing was completed at Shin Kori 4 by April 2016. KHNP said in August 2017 that it expected to load fuel in January 2018 for commercial operation in September. The latest delay resulted from the need for design improvements discovered during commissioning work. Additional seismic assessment work was also undertaken following the Gyeongju earthquake in September 2016 and the Pohang earthquake in November 2017. NSSC’s approval followed  an inspection carried out by the Korea Institute of Nuclear Safety.

Construction began in April 2017 and September 2018 of two further APR1400s at Shin Kori 5&6, respectively. Shin-Kori 5 is scheduled to begin commercial operation in March 2022, with unit 6 following one year later. Two further APR1400s are under construction at Shin-Hanul 1&2. Outside South Korea, four APR1400s are under construction at Barakah in the United Arab Emirates, which are scheduled to be in operation by 2020.

NSSC Chairman Uhm Jae-sik told a press conference on 23 January there were "several factors" caused the delay in granting approval but it was not delayed because of the government's nuclear phase-out policy. The same day Korea Bizwire reported that other new nuclear reactors under construction in South Korea are expected to be further delayed as because of the implementation of a revised labour law that limits the maximum weekly working hours to 52.

A statement from Korea's Ministry of Trade, Industry and Energy, said construction of the Shin-Kori 5&6 are not expected to be completed until June 2024. The ministry attributed the delay to the suspension of construction in 2017, along with the changing labour environment, including the new working hour policy. Work was stopped for three months in 2017 to gauge public opinion and was eventually restarted at the recommendation of a civilian panel.

KHNP said workers previously worked for 68 hours a week and that it was unable to increase the number to compensate for the reduced hours  because of space limitations at the Shin-Kori site. The ministry also extended the completion date of Shin-Hanul 1&2 by 11 months to September 2020.

Photo: Turbine building at Shin-Kori 4 (Credit; KHNP)