Nuclear output in France

December 2024 December 2025 Change
Output of the month 36.6TWh 39.5TWh 7.9%
Cumulative output 361.7TWh 373.0TWh 3.1%

Nuclear output in December 2025 amounted to 39.5TWh, up by 2.9TWh vs December 2024.

Since the beginning of the year, cumulative annual output was 373.0 TWh, up by 11.3TWh compared to 2024. This is explained by the good availability of the reactors in operation, well managed  outages and still a strong modulation.

Evolution of cumulative nuclear output in France in December 2025 (description bellow)

Nuclear output in the United Kingdom

December 2024 December 2025 Change
Output of the month 3.0TWh 2.6TWh -12.0%
Cumulative output 37.3TWh 32.9TWh -11.7%

Nuclear output in December was 2.6TWh, down 0.4TWh vs December 2024.

Cumulative output was 32.9TWh, 4.4TWh lower than prior year. Steam valve incidents impacted the output at Hartlepool and Heysham 1 in 2024, whereas an important maintenance programme and outages occured in 2025.

Evolution of cumulative nuclear output in UK in December 2025 (description bellow)