Tokyo Electric Power Co. Thursday started injecting nitrogen into one of the reactors at the Fukushima Daiichi nuclear power plant to prevent more hydrogen explosions, Kyodo reported.

Fukushima Daiichi nuclear power plant

The nitrogen was injected into No. 1 reactor containment vessel of the power plant which was paralyzed by the magnitude-9.0 earthquake and subsequent tsunami on March 11.

"It is necessary to inject nitrogen gas into the containment vessel and eliminate the potential for a hydrogen explosion," an official with plant operator Tokyo Electric Power Co told a news briefing.

It is less likely that  hydrogen explosion will hit No. 1 reactor and spread  high levels of radiation into the air, he said.

Hidehiko Nishiyama, a spokesman for the government's Nuclear and Industrial Safety Agency, also confirmed that there is no ''immediate danger'' of explosion and described the injection as ''a preventive measure.''

But TEPCO suspected that the outside casing of the reactor vessel was damaged, said the TEPCO official.

"Under these conditions, if we continue cooling the reactors with water, the hydrogen leaking from the reactor vessel to the containment vessel could accumulate and could reach a point where it could explode," he said.