Hokuriku Electric Power Company says it cannot specify when it will be able to fully restore the outside power supply systems to a nuclear plant in central Japan. The Noto Peninsula earthquake on Monday caused a partial failure in the supply. The company says it poses no impact on safety.

At the Shika nuclear plant in Ishikawa Prefecture, the quake damaged piping of two transformers to supply power from outside to the plant's two reactors. Oil for insulation and cooling leaked. As a result, some of the power supply systems became unavailable.

The company initially reported about 3,500 liters of oil leaked from the transformer for the No.2 reactor. But it said on Friday it was actually 19,800 liters.

Company officials said they have also confirmed about 100 liters of oil came out from the piping of another transformer for the No.2 reactor. They added that the transformer is not used for receiving outside power.

The officials said workers had recovered most of the spilled oil by noon on Friday. They said they will start studying a concrete recovery plan for the equipment.

The officials say safety regulations stipulate that one system to gain outside electricity is sufficient as the plant has been offline for a long time.

They say multiple systems currently function, and that the plant has a power source for key safety equipment, such as devices to cool the spent fuel pools.

The officials reported that workers had conducted a visual inspection of all important facilities in the plant by Friday.

The official said the inspection found unevenness and settling of up to 35 centimeters in the concrete-paved ground in at least four areas, including one around the No.1 reactor building. They say there is no safety risk.