Background information


World Nuclear Association is grateful to the International Atomic Energy Agency (IAEA) for access to its Power Reactor Information System (PRIS) database, used in the preparation of this report.


At the time of writing, performance data for reactors in Ukraine have not been provided to the IAEA PRIS database.

Estimates for output from Ukraine reactors is based on other data sources, such as overall electricity output from nuclear power plants in Ukraine published by the International Energy Agency, using Ukrainian electricity transmission system operator (UKRENERGO) data, for the period 1 January 2022 to 27 October 2022.

Other data assumptions

Data has not been published for Kakrapar 3, a 630 MWe PHWR-type reactor in India, which has been grid connected, but remains in a trial operation state. Electricity output data provided by the Indian government suggests that the plant produced less than 1 TWh in 2022. For the purposes of this report no electricity production is assigned to the reactor.

Data has not been provided for the Shidao Bay 1 HTGR-type reactor in China. No electricity output has been estimated for this reactor.

Reactor Statuses

The IAEA PRIS reactor database has a status type - Suspended Operation - differentiated from its Operating status. This status has been assigned to 23 reactors in Japan, which have not restarted since their outage after the 2011 accident at Fukushima Daiichi. It has also been assigned to four reactors in India: Madras 1, Rajasthan 1, Tarapur 1 and Tarapur 2. 

World Nuclear Association uses the Operable status for reactors categorised by IAEA as Suspended Operation or Operable., with the exception of Rajasthan 1, which we consider to be in Permanent Shutdown status.

Definition of Capacity Factor

Capacity factors are calculated as the percentage obtained by dividing a reactor’s actual electricity output by the output expected if the reactor operated constantly at 100% of its net capacity. When calculating capacity factors, those reactors that do not generate any electricity during the calendar year are not included. For reactors that start-up or shut down during a calendar year the capacity factor for that year is calculated based on the electricity output that would have been generated were they to operate at 100% output for the fraction of the year in which they were in an operable status.