Tepco to Inject Unit 3 with Nitrogen

Tuesday, July 12, 2011 @ 04:07 PM gHale


In a move to prevent a hydrogen explosion, Tokyo Electric Power Co. (Tepco) will soon begin injecting nitrogen into reactor 3 at the Fukushima No. 1 power plant.

The injection of nitrogen into the No. 3 reactor will occur as soon as Tepco gets the go ahead from the Nuclear and Industrial Safety Agency (NISA) and local governments. Tepco has started injecting nitrogen into reactors 1 and 2.

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The injection of nitrogen into the No. 3 unit is part of “step one,” which could happen by July 17. Tepco began injecting nitrogen in the No. 1 unit in April. This wasn’t possible for unit 3 because excessively high radiation prevented workers from laying the necessary groundwork.

The utility said it can start the injection after connecting hoses to the necessary pipes at the reactor. It found out Friday pipes and hoses will be easy to connect and the work should take only a few days.

Tepco also said NISA instructed it to submit a report concerning the nitrogen injection.

The utility plans to achieve a cold shutdown of the reactors after stable cooling occurs.

Still, high levels of radiation at the No. 3 reactor building could prevent workers from carrying out the nitrogen injection, Tepco official Junichi Matsumoto said at a news conference Friday.

He said Tepco will consider increasing the number of radiation-blocking mats at the building to reduce workers’ exposure to radiation.

The ratio of the nation’s 54 commercial nuclear reactors that are actually operating came to 36.8 percent in June, according to the Japan Atomic Industrial Forum.

The ratio should remain low in the face of possible delays in restarting those reactors suspended for regular checkups, after the government suddenly ordered additional safety assessments called “stress tests.”

The government had said earlier that sufficient steps occurred to restart and safely operate two reactors suspended for checks at the Genkai power plant in Saga Prefecture.

But on Wednesday, it said additional safety assessments would occur at all nuclear power plants to check the reactors’ capacity to withstand extreme natural events, causing prefectural and local government leaders to retract or postpone their decisions to approve rebooting the two Genkai reactors in the near future.

According to NISA, the operation ratio of commercial reactors stood at 67.3 percent in fiscal 2010 and 65.7 percent the year before. The rate should drop significantly this fiscal year.



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