[ RadSafe ] Plutonium found, problems mount at Japan n-plant

[Olsson Mattias :MSO]

About this Pu find. If it is from the Fukushima plant(s) I suppose it's
likely that it is from the fuel stored in the fuel ponds. The extremely
high dose rate that was experienced in the helicopter as water bombing
of a fuel pond was first attempted would indicate that the shielding
effect of the water was gone. If the fuel has been without water to
cover it I suppose it is also possible that some of the fuel elements
have had their cladding degrade. That could allow the release of all
kinds of nasty nuclides to the air, and if spread with the wind the
actinides would contribute very much to the dose (lung dose) for someone
in the path of the release. If that is where the Pu is from they're
lucky it was such small amounts.

I was rather surprised that there wasn't more damage to the ponds and
the fuel stored there after the hydrogen explosions. If the explosions
could shoot debris 200 m up in the air (estimation from the films,
assuming the stacks are 100 m high) I could imagine some dramatic things
happening to a pond in the same part of the building.

All in all, AMAZINGLY sturdy constructions although it seems equally
amazingly stupid to release containment pressure inside the reactor
building instead of either to the atmosphere or a tiosulphate scrubber.
But that's design, I suppose.

All the best,
Mattias Olsson, Sweden