Friday, September 23, 2011

More than 10,000 ppm Hydrogen Detected Inside the Pipe That Leads to Containment Vessel of Reactor 1

Speaking of hydrogen, TEPCO just announced it detected hydrogen at 2 locations inside the pipe that leads to the Containment Vessel of Reactor 1.

TEPCO's handout for the press on September 23 says (not their exact words):

  • TEPCO was planning to cut the pipe for the spray system to install a gas management system for the Reactor 1 Containment Vessel;
  • Before cutting, they measured hydrogen inside the pipe to be safe. More than 10,000 ppm hydrogen was detected;
  • They won't cut the pipe until the safety is assured.

10,000 ppm is equivalent to 1%. As we know from the previous post, if the hydrogen density is more than 4% in the air, a hydrogen explosion could happen.

The company assures us, according to Yomiuri Shinbun, that the existence of hydrogen in the pipe had been expected, although the density was higher than expected, and that there would be no danger of an explosion.

So if TEPCO says "more than 10,000 ppm", it either means they didn't bring the instrument that could measure higher than 10,000 ppm, or they don't want you to know how high.

I wouldn't be surprised at either. We haven't heard anything more about the location near the exhaust stack for Reactors 1 and 2 that measured "more than 10 sieverts/hour". Was it 11 sieverts? 20 sieverts? 50 sieverts?

It could be the same here in the pipe. "More than 10,000 ppm" could be 11,000 ppm, 20,000 ppm, or 40,000 ppm.

Yomiuri also mentions the reassuring word from TEPCO:


TEPCO has been injecting nitrogen into the Containment Vessel since April, and it is considered there is hardly any oxygen that would be required for an explosion, according to the company. TEPCO says there is no immediate danger of explosion.

Here we go again, "no immediate" danger. (Calling Mr. Edano...) That word makes me nervous.

Besides, the very fact that the water being injected into the Reactor Pressure Vessel somehow ends up in the basement means the Containment Vessel is leaking badly. Nitrogen that's been injected since April is leaking, as the pressure doesn't go up at all. How would they know that there is hardly any hydrogen left? It could easily leak in from outside, couldn't it?


Anonymous said...

This is very interesting.

If you combine this info with the previous post (only boiling water is producing sufficient amounts of hydrogen) it means, TEPCO kind of confirmed (unintentionally) that the corium is still way hot and actually not completely covered with water (if at all).

Another point is, if you consider one of Arnies excellent videos. He pointed out, once the tent around number 1 is closed, he expects TEPCO to stop nitrogen injection, since the aim of the tent is to reduce the radiation for the workers on site and allow work closer to the reactors. But if they keep injecting nitrogen, the nitrogen will go into the air of the tent and reduce the oxygen level too much for the workers. Now, TEPCO can stop the nitrogen injection, but they can not stop the hydrogen production by the intense radiation of the still hot corium. Will this mean, there is a chance the tent will fill with hydrogen? Not a nice thought if you want to do some construction work there (lost of sparks..).

Anyway, it seems to me that TEPCO is also quite worried about that hydrogen and therefore wants to install the 'gas management system' (probably a simple pipe to a chimney or the venting stack outside the building). I really hope they will not use their standard plastic pipes, since hydrogen can easily pass through plastic walls over time....

Anonymous said...

You make some good points, 1:39.

The corium can be expected to continue boiling water. It's composed of material far outside your normal experience. Out of control reactors bring up all kinds of unusual effects, disassociation of water into hydrogen is one of them. A video of the corium would be quite interesting. Then you'd see just how energetic this sh*t is, and that it doesn't belong in blob form. On a rapid time scale it may have moments when it's not in contact with water even though 'submerged'.

TEPCO is also telling us it could tell us all gaseous components near the vessels, and chooses not to.
The 'gas management system' is needed, and you can bet it's not just for hydrogen.

Anonymous said...

Kind of a phallic Powerpoint there...

Anonymous said...

Previous comment is so stupid.

Anonymous said...

They cut a core spray line because they want to vent gasses through it? Does this mean that they will not be cooling #1 from above, as they are doing with #2? Why would that be, I wonder?

Anonymous said...

I absolutely not understand how the hydrogen problem is not to solve. as i read at the blog of a German former scientist ( it is international standard to have catalytic recombiners that work passively, that means without external power.

Taro said...

Check out subliminal message of that TEPCO drawing at:

Anonymous said...


that is a good point on the recombiners, yet another indicator of reluctance because everything near these reactors is hot radiation emitters.

This disaster is the nuke industry laid bare. Overpowering radiation, unwillingness to spend the money to do it right.

An Iced Cake.

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