The operator of the Shika nuclear power plant in quake-hit Ishikawa Prefecture says systems to supply electricity to the facility from outside sources remain partially unusable.

But the utility says electricity continues to be supplied to the plant through other means and that sources of power for important safety equipment are secure.

Hokuriku Electric Power Company held a news conference on Tuesday, one day after a magnitude 7.6 earthquake struck the prefecture.

Both of the No.1 and No.2 reactors at the plant, which are located in the town of Shika, had been taken offline long before the earthquake.

The operator said a tremor that was equivalent to an intensity of upper 5 on the Japanese scale of 0 to 7 was observed in the second basement floor of the No.1 reactor building when the massive quake occurred at around 4:10 p.m.

The reactor observed a seismic movement of 336.4 gals in a horizontal direction and 329.9 gals in a vertical direction. These were both lower than the maximum projected figures before the 2011 accident at the Fukushima Daiichi nuclear power plant of 600 gals in a horizontal direction and 405 gals in a vertical direction.

Hokuriku Electric officials said the pipes of two transformers used for the two reactors to receive electricity from outside have been damaged due to the earthquake, with oil for insulation and cooling leaking out.

The officials said the oil leakage amounts to 3,600 liters at the No.1 reactor and 3,500 liters at the No.2 reactor. They said systems using the two transformers remain unable to receive electricity.

They also said both reactors are receiving electricity from other means, adding that emergency diesel generators have enough fuel to last seven days.

The officials say there are no problems with the systems for cooling spent nuclear fuel.