PARIS - (Xinhua) A leak has been discovered in the primary circuit of reactor No. 1 of France's Seifou nuclear power plant, the French electricity company has confirmed.

The leak could delay the restart of the reactor, which is supposed to take place on January 8 in order to help France deal with the energy crisis this winter.

According to the French electricity company, hydraulic testing on the reactor that began on November 2 when the leak was discovered was halted.

The company stated that "the pressure reduction in the primary circuit is not related to a breach in the piping or welding. Rather, it comes from the failure of a specific part used to perform the hydraulic test."

However, no radioactivity has been measured outside the facilities, the company confirmed.