Hydrogen has accumulated to a level higher than previously thought in pipes connected to the No. 1 reactor containment vessel at the Fukushima No. 1 nuclear power plant, the plant‘s operator said Sept.
However, the company acknowledged there was no way to tell whether the hydrogen in the pipes had been generated immediately after the onset of the crisis on March 11 or in later stages. Nor could TEPCO measure how much hydrogen may have been generated in the containment vessel.
The company has been injecting nitrogen into the reactor so that the level of oxygen inside becomes low enough to prevent blasts.
But a TEPCO spokesman said workers at the Fukushima Daiichi nuclear plant measured a 100 percent flammable gas in a pipe connected to the power station’s reactor number one.
The discovery of the hydrogen accumulation came when TEPCO was analyzing gas in the pipes connected to the interior of the No. 1 reactor containment vessel while installing a device to reduce the amount of radioactive substances leaking from the vessel.
9/23/2011,Tepco announced they detected 1% of hydrogen in the pipes of Reactor 1.
9/24/2011,Tepco announced the detection limit was only 1% in the last test.
By the additional measurement conducted in the afternoon of 9/23 ,they detected nearly 100% of the gas in the pipe is hydrogen and other varieties of the flammable gas.
“It is not clear exactly where and how this gas was created,” the spokesman said. “We are considering ways to deal with it.”
He added, “It is likely that we will continue to survey the gas to identify it and use nitrogen to bring its level low enough [to avoid explosions].”
TEPCO said most of the accumulated hydrogen was generated by a reaction under high temperatures between water vapor and the surface of nuclear fuel rods that were exposed after water was lost following the March 11 earthquake and tsunami.
Even now, the damaged reactors may be generating small amounts of hydrogen as water decomposes through irradiation from the melted fuel rods.
- Unit 1 containment, detection of more than 10,000ppm of hydrogen (enformable.com)
- TEPCO Earthquake Information Update as of March 14, 2300(JST) – Fukushima Daini Unit 1 in Cold Shutdown – All Fuel Became Uncovered AGAIN (enformable.com)
- March 11th, 2011 – Fukushima Daini Information (enformable.com)
- March 12th, 2011 UPDATE on Fukushima Daiichi – 15:30 telecon – NRC unsuccessful so far in lead role (enformable.com)