[ RadSafe ] Fukushima Hot Particles

[Peter Bossew]

Colleagues:

Only now I noticed the 'hot particles' thread. I apologize if I missed
something, and if I am repeating arguments.

The only evidence for hot particles is 

(1) an autoradiography of an airfilter;
(2) an electron microscope picture of an isolated particle.
(3) XRF scan of the particle.
(4) gamma and alpha spcs  of the bare HP. Also easily done (I did it with
Chernobyl HPs.) The r.n. composition is very different from the continuous
phase on the filter.

This is all done quite easily by standard techniques.

Does anybody know about such findings? Please let me know any reference.
(I haven't seen any.)

A gamma spectrum of an air filter is no evidence. A NaI spectrum is just
ridiculous for this purpose.
The argument that Rn progenies attached to aerosols can appear as HPs is
wrong. After a few hours 214Pb,Bi have decayed.  210Pb,Po are usually not
present in enough activity, same for Tn. Btw. it can easily be checked by
investigating BG filters, and if such suspected particle is found, perform
g & a-spc on the isolated particle. Rn and Tn progenies are very easy to
identify (should be a triviality in this forum.)


Generally speaking, the release conditions were such that there is a
chance of HPs. Therefore experimental evidence would be valuable
contribution to understanding the accident.


Thx.

Peter Bossew


(German Federal Radioprotection Authority, Berlin)