Sunday, April 17, 2011

#Fukushima I Nuke Plant: Reactor 4 Spent Fuel Pool Needs Support

I'm reading the "roadmap" (in Japanese; English version is not up yet) that TEPCO released yesterday on how and when the Fukushima I Nuke Plant accident winds down. As far as I can tell, TEPCO will continue to do what it's been doing for over a month now: muddling along, and hoping something may finally work.

What is interesting to me is not their "roadmap" (because it is no such thing) but the assessment of the current condition and plans to address the problems in the next few months.

I've already mentioned their assessment that the Containment Vessels of the Reactors 1 through 3 are highly likely to have a crack/gap/opening through which the radioactive steam is escaping.

Here's another one that's very curious:

The Spent Fuel Pool of the Reactor 4 may need a support structure from underneath.

That would mean, I assume, that without such a structure, the Reactor 4's Spent Fuel Pool is in danger of collapsing and falling.

Uh oh.

The building walls were blown out by powerful explosions in the Reactors 3 and 4, but TEPCO seems particularly worried about the Reactor 4 building walls. In the current assessment section regarding the Spent Fuel Pools,

Damage to the Reactor building walls that support the Spent Fuel Pools:
In particular, the Reactor 4 building's structural integrity needs to be checked.
(Action No.20) The Reactor 4 building's structural integrity to withstand earthquakes checked. [It doesn't say how it was checked.]
(Action No.21) Continue to monitor, and come up with a remedy as needed.

And that remedy is Action No.26, to be done in the next three months:

Put a structural support from beneath the Reactor 4 Spent Fuel Pool.

What do they mean by putting a structural support from beneath? Here's a diagram at the end of the "roadmap" (see the red circle I added):

Again, no information on how they could even enter the reactor building to do the work. It's just to make Prime Minister Kan and other Ministers happy that they have a "plan". Never mind that it's not really a plan but a wish list.


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