Nuclear reactor's roof cracked, two workers reportedly missing at Fukushima plant

[DearAbby]

Nuclear reactor's roof cracked, two workers reportedly missing at Fukushima plant

Thirty-five years ago, Dale G. Bridenbaugh and two of his colleagues at General Electric resigned from their jobs after becoming increasingly convinced that the nuclear reactor design they were reviewing -- the Mark 1 -- was so flawed it could lead to a devastating accident.

Questions persisted for decades about the ability of the Mark 1 to handle the immense pressures that would result if the reactor lost cooling power, and today that design is being put to the ultimate test in Japan. Five of the six reactors at the Fukushima Daiichi plant, which has been wracked since Friday's earthquake with explosions and radiation leaks, are Mark 1s.

Read the full story here. http://huff.to/g3lGpG

[nadinbrzezinski]

1. What I want to know is if the crack is in the primary vessel

[DearAbby]

2. Its confusing

I know there is the main vessel, and then a cement containment vessel which houses the main vessel. I can't figure out which one has been damaged. Both are critical, but the outer shell would be less severe?

[nadinbrzezinski]

3. I guess, but here is a graphic

No, not exactly of this particular reactor

[Statistical]

5. That is a well designed reactor with a independent containment.

Sadly this reactor design looks like this:

?__SQUARESPACE_CACHEVERSION=1299944680212

The MKI has far inferior containment.
It has less open space to absorb increasing pressure.
The reactor is tightly surrounded by containment which makes visual inspect essentially impossible.
The torus below is a "wet containment" (water is unsed to provide a seal rather than a solid "dry containment".
The fuel rods storage tank is positioned above the reactor at the top of the building rather than far away and below the reactor.

Even the shape is bad. A dome is far stronger structure able to handle more stress like in a hydrogen explosion. The dome on cylinder is a good compromise between space and strength. A box just plain sucks.

[TheWraith]

6. There's several, actually.

There's the primary core, which holds the fuel rods and coolant. There's the containment vessel surrounding the primary core, which is the main form of defense. Then there's the outer containment structure, which is more like a thick-skinned steel building, which is used to relieve pressure in the main containment vessel. It was the outer containment structure that was damaged in the previous hydrogen explosions.

[Hannah Bell]

11. maybe you should go to the original source instead of wondering.

reactor BUILDING.

[The_Casual_Observer]

4. They have been slowly working up to this news all day.

[suffragette]

7. Is this the one Reuter's is reporting at #4?

http://af.reuters.com/article/energyOilNews/idAFLJE7ED00A20110315


I wonder how this will impact the spent rods there?

[DearAbby]

8. Is it okay to say

I am getting really anxious about this?

[suffragette]

9. It's ok with me

Feeling anxious myself.

:hug:

[Hannah Bell]

10. Agency official also told a news conference there was a crack in the roof of the reactor BUILDING.

not in the roof of the REACTOR itself.

per the source cited in your report.

http://www.reuters.com/article/2011/03/15/us-japan-quake-roof-idUSTRE72E8H920110315