See the post below for video of Japanese News announcers talking about the possibility that there could be another hydrogen explosion at the site.
NHK news crawl now confirms efforts will begin to inject nitrogen into one of the containments to head off another explosion.
WSJournal confirms, and adds, that the unit in question is unit one. That is the unit where the mysterious blue flash has been observed, and criticality may still be in progress.
NYTimes has this as of 0502 April 6:
This would be the first time nitrogen is being injected into any of the reactors, Ken Morita, a spokesman for the Nuclear and Industrial Safety Agency said in an interview. The same approach might later be tried for the No. 2 and No. 3 reactors, but the No. 1 unit was chosen first because the pressures and temperatures in that reactor are higher than in the other two.
The Times adds that TEPCO is claiming no immediate risk of an explosion. There is a hair raising discussion of confidential documents from the US Nuclear Regulatory Commission describing ongoing problems at the site.
The inherent dangers and trade offs of this process are discussed in a brief NHK item here:
TEPCO plans to infuse a total of 6,000 cubic meters of nitrogen gas during a 6-day period. The utility company is now checking procedures with the government.
TEPCO says such work requires caution, as an injection of nitrogen gas could cause leaks of radioactive steam and gas from the containment vessel.
Straits Times has the story, see below.
TOKYO – THE operator of a stricken Japanese nuclear power plant on Wednesday said it may inject nitrogen gas into a reactor container to prevent a possible explosion due to a buildup of hydrogen.
Workers at the crippled Fukushima Daiichi plant are concerned that hydrogen gas will build up in the container of reactor number 1 to the level where it will react violently with oxygen, causing an explosion.
‘We are considering injecting nitrogen into the container of reactor number 1 because hydrogen gas has possibly accumulated in the container,’ a Tokyo Electric Power Co (Tepco) official said.
The plan is to inject nitrogen, an inert gas abundant in the atmosphere, to displace the oxygen that could react dangerously with the hydrogen. NTV reported that the nitrogen injection operation could take place ‘as early as today’.
Officials at the Tokyo Electric Power Company, which operates the Fukushima plant, said the latest threat of a hydrogen build-up is taking place at its number-one reactor. Japan’s NHK television quoted officials saying the build-up is occurring inside the containment vessel that keeps radiation from escaping into the atmosphere, and is an indication that the reactor’s core has been damaged.
This is a very, very dangerous development. This is why we’ve been getting the non-specific warnings of “grave” and “serious” problems at the plant.
Russian Prime Minister Vladimir Putin says the situation at Japan’s Fukushima Daiichi nuclear power plant is not improving and has instructed his government to continue closely monitoring radiation levels in areas near Japan.
Putin said this at a meeting on disaster measures with Emergency Ministry officials and meteorological experts on Tuesday.
He said the situation at the nuclear power plant has not improved and that his country must be absolutely sure of the reliability of information concerning Russian territories.