AtomicWombat said:
I've been with this discussion pretty much since the start and the possibility of the No.3 explosion originating in the primary containment and blowing off the containment plug has NOT been debunked; it has been debated with no clear consensus so far.
The mechanism of the building 3 explosion remains open, but any explanation MUST explain why it is clearly different from the explosion in builkding 1.
Yes, what the Wombat said above, but with a few added comments:
1) it was not a single explosion at unit 3 -- there were multiple explosions, probably 3 discrete explosive events.
2) it appears that there may have been simultaneous or near simultaneous explosions involving:
a) the "containment" - exact nature and extent of damage unknown,
b) the spent fuel pool - with partial ejection of the contents of the SFP, extent unknown, and
c) an explosion of accumulated hydrogen with destruction of the building (secondary containment)
. . . and with a bunch of added questions:
As for the definition of "cold" in regards to the residual core temperatures, how cold is cold enough to add boron (or some other material?) to prevent re-criticality and to consider entombing the residual core contents in concrete without ongoing cooling? It it a matter of weeks, months or years that might be anticipated to achieve this?
It is in the realm of possibility to consider entombment combined with a closed loop cooling system? I can't see how.
Would spent fuel be entombed as well (seems doubtful)? If not, then would not some sort of clean up of the spent fuel would have to precede permanent entombment?
What of the "giant elephant" in this disaster scenario, the little mentioned large SFP7 out back? The spent fuel stored there will have to be permanently maintained somehow. This will either have to occur in place or all of that spent fuel is going to have to be removed and stored at an alternate facility that is not highly contaminated and dangerous on a long term to maintain.
What does the "big picture" TO DO LIST look like for Fukushima? Perhaps:
1) cool the cores of U1, 2, 3,
2) contain, entomb the cores of U1, 2, 3,
3) clean up SFP1, 2, 3, 4,
4) clean up external contamination near and far from the Fukushima site as best possible,
5) safely operate or permanently shut down U5,6, and
6) safely operate or permanently shut down SFP7,
So far, it seems to me that TEPCO is still struggling with item #1, and perhaps starting on item #4.
Am I missing any of the "BIG" items on the to do list?
Addendum:
Here's one I may have missed:
7) build a giant new facility for the long-term storage, reprocessing, and disposal of high-level radioactive wastes. Somewhere within a 20K radius of the Fukushima plant might seem an obvious location, given real estate prices.
