[ RadSafe ] Salsman's uranium trioxide gas proof

[James Salsman]

Dear Dr. Raabe:

A glance at this table in the CRC Handbook shows that gas vapor
particles have substantially different settling and diffusion rates
than the nanometer-scale particles which you reported collecting:
  http://bovik.org/du/scans/crc.jpg

Your refusal to answer any of my questions suggests that:

(1) You did not measure the plutonium dioxide condensation time;

(2) You did not compare the plutonium mass of the recovered combustion
product with the amount of plutonium consumed by the combustion;

(3) You never took into account the excess condensation caused by mass
impactor particle collection devices; and

(4) Your experimental apparatus was incapable of measuring the amount
of plutonium dioxide gas which remained uncondensed.

Am I wrong about any of those points?  If so, which of them and why?

Sincerely,
James Salsman

On 2/1/07, Otto Raabe <ograabe at ucdavis.edu> wrote:
>
>  There was no plutonium dioxide gas because plutonium dioxide has no vapor
> pressure at the experimental temperatures. Even a lonely single molecule of
> plutonium dioxide behaves like a particle rather than a gas at temperatures
> below 2400 degrees Celsius. Such tiny particles are readily collected with
> simple air filters.
>
>  Otto

On 2/1/07, James Salsman <jsalsman at gmail.com> wrote:
> Dear Dr. Raabe,
>
> I read your 1978 Health Physics article on plutonium (cited in full
> below) carefully and with great interest.
>
> I note that you measured condensation in a very small enclosed space.
> How would you compare the condensation rate of metal oxide vapors in
> such a space with the rate in open air?
>
> I was unable to find any mention that you had matched the mass of the
> plutonium in the recovered combustion product with the mass consumed
> by the combustion.  Did you or your colleagues make that comparison?
>
> I note that you, like others from Jofu Mishima through Maryanne
> Parkhurst, have used mass impactors to collect particulate combustion
> product.  Isn't it true that mass impactors force excess condensation,
> and allow gases to escape collection?
>
> Would your apparatus have been able to detect any plutonium oxide gas?  How?
>
> Sincerely,
> James Salsman
>
> On 1/24/07, Otto Raabe <ograabe at ucdavis.edu> wrote:
> >
> >  At 12:59 PM 1/24/2007, you wrote:
> >
> > Are you suggesting that as a gas diffuses and cools below the point at
> >  which it is volatile, more than half of it will condense
> >  "instantaneously?" That is absurd.
> > *******************************************
> >  When the oxide molecule forms by "burning" liquified plutonium or uranium
> > it has different chemical and physical characteristics that the pure metal.
> > Cooling is virtually instantaneous even near the combustion process and
> > results in all (not half) of the vapor being converted to solid oxide
> > particles. These particles rapidly coalesce into chain aggregates as shown
> > in the micrographs in the paper by Carter and Stewart or my own studies
> > referenced below. This is virtually an instantaneous process since the
> > melting and vaporization temperatures of the oxides are much higher than
> > those of the pure metals. Hence, the "vapor" form of the oxides only exists
> > momentarily, if at all,and only if the reaction is hot enough to reach the
> > oxide melting point.
> >
> >  I have conducted these types of experiments and characterized the particles
> > produced by laser vaporization of plutonium. The vapor oxidation and
> > particle formation is virtually instantaneous. The vapor phase exists only
> > in the superheated zone. [Raabe, O.G., S.V. Teague, N.L. Richardson and L.S.
> > Nelson. Aerodynamic and dissolution behavior of fume aerosols produced
> > during the combustion of laser-ignited plutonium droplets in air. Health
> > Physics 35: 663-674 1978.].
> >
> >  Otto
> >
> >  **********************************************
> >  Prof. Otto G. Raabe, Ph.D., CHP
> >  Center for Health & the Environment
> >  University of California
> >  One Shields Avenue
> >  Davis, CA 95616
> >  E-Mail: ograabe at ucdavis.edu
> >  Phone: (530) 752-7754   FAX: (530) 758-6140
> >  ***********************************************