One of TEOTWAWKI's hair triggers is about to get squeezed.
The spent fuel rods at Fukushima Reactor 4 soak in a pool about 100ft above the ground. The pool is "cantilevered" and supported by a framework of posts that were weakened in the 2011quake / tsunami.
Ground under the structure has been settling, which is... ah... UNsettling!
Another quake, further settling or an explosion (several possibilities on site) can collapse the whole shebang, spilling their contents - rods and the water covering and cooling them.
Should the spent fuel rods remain uncovered by water for any length of time, their cladding oxidizes, producing hydrogen and heat. Very soon, this combustible mixture begins to burn (possibly explosively), along with the various metals and metallic oxides comprising the rods.
In this not-even-the-worst case, radioactive materials enter the atmosphere as smoke and debris, and blow with the wind. Our way, among others.
In other words, this is a pretty good candidate for a SHTF event.
In the face of this grave risk action is about to be taken. TEPCO is preparing to begin evacuation of the endangered storage pool with transfer to less at-risk storage.
Problem is, this is one delicate operation. The pool was badly shaken, and rods are out of their proper positions. Debris is still present in the pool. Did we mention the ground under it is soft? Or that the whole area is outrageously radioactive??
The extraction process involves untested techniques, large masses, a physically unstable, dangerous and convoluted environment whose condition is not entirely known. Extraction will be manual (vs. standard, precise computer control). It will take at best a year to complete. And, rather than assemble the collective expertise and enterprise of world experts, face is being preserved by going it alone.
In other words, TEPCO - the same ones who've bungled and lied to the Japanese people and the world at large - are 'handling it'.
I quote Plant Chief Akira Ono:
I personally believe this kind of thing is very close to being impossible. It’s not the first time for us to do this operation. At any ordinary nuclear power plant, workers remove spent fuel.But, of course, this is a pacifier for the public. No one has done this before. The plant is no longer 'ordinary', if it ever was.
Oh, I could go on, but these guys do a better summary.
So let's say it does go... what might happen?
Well, the effects of radiation range from long-term heightened cancer rates to acute radiation poisoning / sickness. Problem is, it's hard to say where along that spectrum it'll lie before it's arrived and, preferably, gone.
Meanwhile, the mere news that a plume is blowing toward population centers, I would guess, will bring out widespread reactions of a panicky nature.
I won't try to predict what the... ah... fallout will be. But my guess is that it's a powerful, potential domino, aside from the physical impact of any radioactive exposure.
So, I repeat, a SHTF trigger is about to be squeezed in the global game of russian roulette. We hope for CLICK, but many experts are laying long odds on BANG.
Got your affairs in order?