Hydrogen accumulates in pipes at Fukushima’s No. 1 reactor, Asahi, September 24, 2011:
Hydrogen has accumulated to a level higher than previously thought in pipes connected to the No. 1 reactor containment vessel [...]
The nitrogen injections are believed to have lowered the hydrogen concentration considerably, but some hydrogen, being lighter than nitrogen, may be accumulating near the top of the containment vessel without being driven out. [...]
Nor could TEPCO measure how much hydrogen may have been generated in the containment vessel. [...]
TEPCO said it is investigating the possibility that hydrogen has also accumulated in a similar manner at the plant’s No. 2 and No. 3 reactors. [...]
Where does TEPCO think the hydrogen is coming from?
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.
Published: September 25th, 2011 at 7:54 pm ET
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