Tokyo Electric Power Co. (TEPCO began pumping nitrogen gas into a stricken reactor at the troubled Fukushima Daiichi nuclear power plant on Thursday to prevent the risk of a hydrogen explosion.
Workers injected nitrogen gas into the containment vessel of the plant's No. 1 reactor in process that could take several days, according to the embattled utility firm.
But following the firm managing to stem the flow of radioactive water from flowing freely into the Pacific Ocean yesterday, the latest move was described by Japan's nuclear safety agency as " preventative."
"It is necessary to inject nitrogen gas into the containment vessel and eliminate the potential for a hydrogen explosion," Hidehiko Nishiyama, Deputy-General of Japan's Nuclear and Industrial Safety Agency told a press briefing.
Nishiyama added that the risk of further hydrogen explosions that previously blew apart reactor buildings No. 1 and No. 3, causing dangerous levels of radioactive substances to be released into the atmosphere, was "extremely low."
That said, due to fears that the outside casing of the reactor vessel has been damaged, while an explosion remains unlikely, the scenario has not been completely ruled out, the nuclear safety agency said.
"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," a TEPCO official was quoted as saying Thursday.