Japan's Kyodo News reported that radioactive water had leaked into the third reactor of the Mihama nuclear plant in Fukui Prefecture, Japan.

"The leak occurred inside the power unit of the third reactor," the agency said. The operating company claims that it will not have an impact on the environment.. the plant is more than 40 years old.”

Southern Japan evacuated after Sakurajima volcano erupts

The station, operated by Kansai Electric Power Corporation, is located in Mihama town of Fukui Prefecture, 320 kilometers west of Tokyo, and covers an area of 520,000 square meters.

Mihama 3 is a pressurized water (hydro-hydro) reactor manufactured by the Westinghouse Corporation with a capacity of 826 megawatts of electricity, and has been in service since 1976.

In June of last year, the reactor, which is over 40 years old, resumed operation, making it the first reactor of this age to be in operation since new safety standards were implemented after the Fukushima disaster in 2011.