UPDATE (Apr 7) -TEPCO Completes Nitrogen Injection At Unit 1
An operation to reduce the risk of a hydrogen explosion at the crisis-hit Fukushima Daiichi atomic power station’s No. 1 reactor by injecting it with nitrogen has gone smoothly, the plant’s operator Tokyo Electric Power Co. said Thursday. Pressure in the reactor’s containment vessel has risen as expected, indicating the success of the operation.
In its operation to prevent a hydrogen explosion at the No. 1 reactor, TEPCO plans to insert nearly 6,000 cubic meters of nitrogen, an inert gas, into the reactor over six days and estimates that about 200 cubic meters were injected between 1:30 a.m. and 9:50 a.m. Thursday.
The firm and the government’s Nuclear and Industrial Safety Agency said they believe chances are slim that another hydrogen explosion will occur immediately or that high volumes of radioactive substances will be emitted following the nitrogen injection operation. – Kyodo News (April 7)
UPDATE – Nuclear and Industrial Safety Agency – Seismic Damage Information (the 74th Release)
The Nuclear and Industrial Safety Agency stated that at Units 1 through 4 at Fukushima Daiichi NPS , “White smoke was confirmed to generate continuously.” Reported on April 6.
TEPCO Press Release (Apr 6) – Measures Taken To Prevent Explosion
Injection of Nitrogen to Reactor Containment Vessel of Fukushima Daiichi Nuclear Power Station Unit 1
“Regarding Fukushima Daiichi Nuclear Power Station Unit 1, taking into account the possibility of hydrogen accumulating inside, we have been considering encapsulation of hydrogen by injecting nitrogen to the reactor containment vessel.
Today, we received an order from minister of economy, trade and industry to report on matter such as necessity of encapsulating nitrogen, method for implementation, and impact assessment of safety.
Accordingly, we have compiled related matters and reported to minister of economy, trade and industry today. The report was approved after the deliberation in the Ministry of Economy, Trade and Industry.
Based on the report, we will begin injecting nitrogen to the reactor containment vessel of Unit 1 today, around 10:30pm”. END
Update [Apr.9] - TEPCO announced 0n 4_9 that they would perform an additional operation to inject nitrogen gas into the containment vessel of the Number 1 reactor to prevent a possible hydrogen explosion, TEPCO plans to increase the purity of nitrogen gas from 98 percent to 99.98 percent.