South Korea’s nuclear power output this month should register its best performance ever, coming in at 22,215 average MWs (aMWs). December output was +17.2% above the prior month’s level, and +15.2% higher than that for December of 2020 (see Figure 1).
Figure 1. South Korea Nuclear Power Output: Dec 2021 vs. Prior Month & Prior Year

Source: CapraView
The last time we saw a level exceeding 20,000 aMWs was in April of 2016, and this is the 4th consecutive month that output has hovered above the 5-year envelope (see Figure 2).
Figure 2. South Korea Nuclear Output (Jan 2016 to Dec 2021)

Source: CapraView
December’s performance benefited from the return of 3 units in late November (Kori 3, Kori 4 and Shin-Kori 1), which were able to make full-month contributions. Shin-Kori 3’s return at the start of December also added to this month’s total.
With the return of these 4 units, all but 2 of South Korea’s 24 nuclear power units are now in operation. And with Shin-Hanul #1 (1,400 MW) on track to start up in mid-2022, South Korea is poised to ratchet up its nuclear output to even higher levels next year.