PARIS, May 11 (Reuters) - Nuclear power generation at EDF's French reactors in April fell by 20.2% year on year to 21.7 terawatt hours (TWh), the energy company said on Wednesday.

Total nuclear generation in France since the start of the year was 113.4 TWh, down 10.3% compared with 126.4 TWh for January-April 2021, EDF said on its website, citing reduced availability of the nuclear fleet that was mainly due to the discovery of stress corrosion at some sites.

In Britain, EDF said its nuclear production last month rose 11.8% compared with April 2021 to 3.8 TWh, while cumulative output since the start of 2022 was up 9.4% versus the same period last year at 15.2 TWh.

(Reporting by Gus Trompiz, editing by Sybille de La Hamaide and Jane Merriman)