[ RadSafe ] Radium

[Gary Masters]

Good day,

I am at the ANS winter meeting this week. In the Data,
Analysis, and Operations for Nuclear Criticality Safety -
II track yesterday a convincing paper was presented by Doug
Minnema that addresses, I believe, the stories that we've all
heard about those involved in criticality accidents seeing a
focused or reflected blue light as well as the question posed
in this message thread.

The explanation is that the local ionization is so great
that Oxygen and Nitrogen in the air fluoresce along their
characteristic spectral lines. The spectra that is within the
visual range that we do not see seems to be as a result of self
re-absorption. The re-absorption is a function of pressure and
he was able to provide a convincing argument that at ground
level this would result in the color blue.

He drew upon the work done by those in the astronomy field in
explaining auroral affects due to upper atmosphere interactions
with cosmic radiation.

In addition he believes that a sufficiently active alpha
source, such as a large amount of Radium, would produce the
same affect.

In addition, he argued that a significant amount of UV and
IR radiation would be produced in a criticality event due to
this mechanism and stated that this could explain what has
sometimes been perceived as greater than expected surface
tissue damage to the extremities, and the reported sensation
of a heat/shock wave.

The paper should be in the proceeding of the 2007 ANS Winter
Meeting.

Gary Masters

On Mon Nov 12, 2007 at 11:36:04 +0100, Franz Schönhofer wrote:
> Helen, Mike,
> 
> I would not exclude that very high activity samples of radium (I suppose the
> question is certainly about Ra-226) might exhibit a bluish "luminescence" -
> but this might be Cerenkov-light and I would rather expect it in a Ra-226
> solution, especially since radium (the metal) is extremely hygroscopic.
> Please compare it to the Cerenkov-effect in nuclear research reactors like
> the TRIGA-Mark-X-ones. 
>