PARIS, Feb. 9 (Xinhua) -- An explosion at a nuclear plant in northwestern France on Thursday injured five people, with no potential risk of a radioactive leak, authorities said.

The blast occurred at 10 a.m. (0900 GMT) at the Flamanville plant outside the nuclear zone, the regional prefecture said.

The explosion was "a significant technical event" which didn't pose "any risk of contamination," local authorities was quoted by French media as saying.

Production at one of the plant's two reactors was halted after the explosion.