Wolsong 1 cleared for continued operation

South Korea's nuclear safety regulator has approved a seven-year licence extension for the refurbished and uprated Wolsong 1 pressurized heavy water reactor. The unit has been offline for two years while discussions continued on renewing its licence.

South Korea's nuclear safety regulator has approved a seven-year licence extension for the refurbished and uprated Wolsong 1 pressurized heavy water reactor. The unit has been offline for two years while discussions continued on renewing its licence.

The four Candu units at Wolsong (Image: Konicof)

The Nuclear Safety and Security Commission (NSSC) announced today that it had voted in favour of the 32-year-old Candu 6 reactor operating until 2022. Following a 14-hour meeting, seven government-appointed members of the commission voted in favour of the licence extension, while two members abstained.

Wolsong 1 - the country's second-oldest power reactor - began generating power in 1983 but was taken out of operation in April 2009 for an extended maintenance outage that included replacement of all its pressure tubes and calandria tubes. Candu reactors are designed to undergo refurbishment after approximately 25 years of operation, requiring a major outage but allowing reactor life to be extended by up to 30 years. For all Candu reactors, this involves complete retubing. The reactor came back into operation in July 2011 with its performance raised from 629 MWe to 657 MWe. However, Wolsong 1's operating licence expired around the end of 2012.

The NSSC began a process of stress tests, checks and discussions which culminated last October with a conclusion by the Korea Institute of Nuclear Safety that the unit is suitable for operation until November 2022 given certain engineering improvements over the long term.

Plant owner Korea Hydro and Nuclear Power (KHNP) welcomed the commission's decision and said it aims to return the unit to operation in April.

In December 2007, Korea's Ministry of Science and Technology (MOST) gave approval for Kori 1 - the country's oldest reactor - to continue operating for a further ten years. The 576 MWe pressurized water reactor started up in 1977.

Researched and written
by World Nuclear News