Wednesday, April 18, 2012

Idiots at TEPCO and NHK Can't Figure Out Obvious Fukushima Containment Leak

[Fukushima NukeBlog Index]

TEPCO has this great plan that in order to remove fuel from the damaged reactor, all they have to do is flood the containment bulb, and they'll be able to move everything while it is underwater, just like it's supposed to happen in the reactor pressure vessel when it's not all melted through. So they’ve sent a robot figure out where the damage is that is causing all the water to flow into the basement.  And they can’t find any damage at all.
TEPCO says no water leaks found at No.2 reactor
The operator of the Fukushima Daiichi nuclear plant says inspections using a robot have yet to find serious damage or water leaks at the facility's No. 2 reactor....the robot found no water leaks or traces in manholes on the north and southeast sides of the chamber, where leakage had been suspected..The level of radioactive water accumulated on the plant's premises keeps increasing. The water is believed to have been injected to cool the reactor, which was damaged by last year's earthquake and tsunami.

Any damage to the suppression chamber and the containment vessel will have to be repaired before the vessel is filled with water to retrieve melted fuel rods inside.

Such removal would be a crucial step in decommissioning the reactor.
Wednesday, April 18, 2012 20:56 +0900 (JST)


Ughh. TEPCO, NHK and evidently both the Japanese and American nuclear agencies don’t have any idea either why water would run into the basement leaving only a few meters of water at the bottom as shown in this drawing:

Now at MIT, we have this expression “intuitively obvious”. There is only one path from the upside-down containment bulb to the suppression torus, it is the “downcomers” whose job is to channel hot steam from whatever badness is happening in the containment, and sending into the pool of cool water where it will condense. That’s the key feature of the BWR Mark I containment. You can see in the 3D drawing below the giant pipes running from the bottom of the containment to the big donut.

This shows how workers entered the catwalk on top of the torus, and stairs leading into water

Also notice that the level of the water IS EXACTLY AT THE SAME LEVEL FROM THE TOP OF THE TORUS TO THE EDGE OF THE DOWNCOMERS ABOVE THE BOTTOM OF THE CONTAINMENT. Doesn't take a rocket scientist to figure out THE WATER FALLS DOWN THE DOWNCOMER PIPES. Obviously something open to steam WILL ALSO LET IN WATER. So unless you also waterproofed the turbine basement, where the water ultimately runs, where it is decontaminated and recyled to be sent down the top again, THE CONTAINMENT CANNOT BE FILLED WITH WATER because the fully intact downcomers is going to leak all the water out. Any problem with my logic here folks???

OK, I figured out one problem, if the torus AND the containment didn't have any leaks, the water would fill up the containment, and not the basement. So there are certainly littles somewhere in the system, but they don't have to be big. If they drained out the basement I am sure you would see water leaking out of the containment and / or suppression torus like a ship that sprung a leak or two or dozen.

If they want to fill the containment they will have to seal off the downcomers, which are probably not strong enough to stand the water pressure of 4 floors worth water as they are designed to transport steam, not water. You'd have to drain the basement and torus, and seal off all the downcomers, good luck to that in a high radiation environment. The main problem is that the containment was never engineered to be filled with water, and it is foolish to assume that it can be filled with water if it wasn't designed to take that stress which is the same problem that dam, ship and submarine engineers have to deal with.

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