Like most I’ve been watching US television for news on the reactor disasters at Fukushima.
The one source, outstanding above all, has been ol’ Frank von Hippel, director of the Program for Science and Global Security at Princeton.
I remember von Hippel from a time, many years ago, when I subscribed to the Bulletin of the Atomic Scientists.
Von Hippel has been on Rachel Maddow and for tonight’s show he gave the clearest-for-the-layman explanation of what one of the primary threats is at Daichi.
Any mistakes in this interpretation are mine.
It centers on the spent fuel rods pool at, I think, Daichi 4. They need constant circulative cooling and no longer have it so their radioactive decay heat, which is no longer dissipated, boils off or splits what water covering remains or that which is added in insufficient volume in an emergency.
As it happens (or when it happens), the temperature of the rods rises even more intensely, destroying their cladding, blistering and blowing it off. Explosions occur because of the generation of quantities of hydrogen gas, leftover from the oxidation of the hot zirconium metal fuel cladding.
According to von Hippel there is now no easy way to determine the state of the infrastructure and the rods because intense gamma radiation — which means some large quantity of radioactive metal has actually been uncovered — and the destruction of sensors and cameras at the site.
When the rods are uncovered by the water mediator/shield and the cladding perforated or destroyed, the heat also drives off the spent fuel’s volatile radioisotopes. And that process is the spraying of radioactive waste into the prevailing winds. Unless it’s contained by intact walls.
Each Daichi reactor contains between 60 and 80 tons of fuel rod assemblies.
Spent fuel rod pools concentrate exhausted fuel rod assemblies.
Von Hippel said he had heard estimates of anywhere between 2 and 8 reactor cores being present in the spent fuel rod pool in question.
And so the problem of catastrophe, in terms of raw numbers, is rendered quite clearly.
It’s incomprehensible to me (well, cynically, no it’s not) that a significant number of Americans would think this disaster is about them and commence a hoarding rush on potassium iodide and Geiger counters.
“Ask a GE Technician” reads one of the evil AdSense ads on one of my posts at SITREP GlobalSec. Sometimes it disappears, so you have to get quick and lucky.
The catastrophically failed reactors at Daichi are all GE’s.