South Korean nuclear restarts to help meet peak demand

Returning nuclear capacity in South Korea is expected to help the country cope with a spike in seasonal temperatures and peak power demand.

Three nuclear units are expected to resume operations in the near term, according to a notice published by energy and trade ministry Motie today.

These are the 1.4GW Shin Kori 4 reactor, which has been off line because of an unplanned outage since 29 May, and the 700MW Wolsong 3 and 1GW Shin Wolsong 1 units.

Shin Wolsong 1 was expected to return from maintenance on 27 July, but instead started up yesterday and will reach full capacity by 21 July, the government said. Wolsong 3 is due to return on 23 July, as scheduled.

The Shin Kori 4 reactor is awaiting approval to restart following its outage and the completion of an inspection on 15 July and could resume operations on 21 July, the ministry said.

If these units return as planned, nuclear availability would average 16.6GW this week, from 15.5GW last week. Average July availability would be 16.2GW, down from actual generation of 18.4GW in July 2020.

The boost to nuclear availability should help to balance peak demand, but is unlikely to drastically slow the expected rise in generation from fossil fuel compared with a year earlier as power demand surges.

Daily peak power demand has averaged 77.9GW so far this month, up from 67.6GW a year earlier. Daily mean Seoul temperatures are forecast to average 28.2°C this month, which would be only the second time in 10 years that July temperatures have surpassed 28°C and higher than the 26.3°C 10-year average for the month.

Argus analysis shows that combined coal and gas-fired generation may need to rise by 6.4GW on the year to 45.6GW this month.

By Jake Horslen

South Korean nuclear generation GW

Seven-day avg peak South Korean power demand GW