The capacity factor of Japan’s commercial nuclear fleet was 30.6% in 2024, the highest level since 2015 when reactor restarts began after a full suspension of nuclear power generation as a result of the March 2011 Fukushima-Daiichi nuclear accident, the Japan Atomic Industry Forum (Jaif) said.

Jaif said total nuclear power generation in 2024 grew by 9.6% to reach 88.8 TWh, also a record level.

A nuclear plant’s capacity factor for a given period is the ratio of the energy produced over that period divided by the energy it would have produced at its reference power capacity over that period.

Jaif said the figure for Japan has been calculated using data gathered from nuclear operating utilities in the country.