Follow up to RE: Tritium Absorption in Materials

[Emil Murat <kerrembaev@yahoo.com>]

Greetings,

I have not seen any replies on this subject for a
while and started wondering if it went into private
emails or else.....

Bharat,

You brought up an interesting in many ways problem.
Personally, I have not done experiments with Tritium
as you've done and my knowledge of this topic is
limited to assumptions which are based on knowledge of
some chemistry and some thermodynamics.

1. I would think that from the beginning Tritium is
behaving as a part of what you have: water, base or
acid and it will be involved in the same basic
chemical organic/inorganic reactions as a H-2, of
course. 
H-3 Polarization does/does not effect
on a organic reaction??... It should...


2. Absorption rate equals to a SUM of chemical
reaction rate and water diffusion rate and it depends
on given conditions; temperature would be the
dominating factor for the chemical reaction.

3. Transfer/Diffusion rate you can find from
Thermodynamics of liquids and gases; H2O will be
penetrating as liquid and as vapor/gas depends on
material structure and temperature, pressure.
If you have some kind of equilibrium: relatively long
exposure time, chemical reactions are balanced balance
It should be "easier" to figure out the constants with
no dynamics. 

4. There may be a/ need to look at "Radiolysis" (Free
Radicals Production)if you had a high Radiation Flux
in your environment. I am not sure how H3 will behave
in that case.

5. The chemical reactions with the absorbing material
will be case-specific and environment-specific.

Inorganic: Metals - Corrosion in the water(no
stainless steel) Acid environment-...

Concrete, plastics, rubber, wood: - stable in the
water.
Graphite - Pretty much chemically inert but H-3
polarization, electrostatics will effect on its
absorption/penetration rate at molecular level.


5. I would suggest you to do, if you have not done it
yet, search literature and perform balk estimates; to
have a some theoretical basis for your experimental
data.

6. As soon as you do that, you may see correlations
with you experimental results.

It is really hard to determine with out some estimates
which will be the major driven mechanism (Chemistry or
Mechanical Transfer) in the process and which will be
neglegable.

Do you know in what chemical form is absorbed H3?
It would interesting to know. 

7. To do only experiments is ......an easier and
softer way in the beginning but later...... it is not
always ENOUGH to solve the problem.
You may get to the point: "To MANY numbers and NOT
ENOUGH explanations".

I am very interested, in ANY info about "Tritium
Problem", specifically "Tracing" it.
I would really appreciate if anybody could bring more
input about Penetration, Tracing, absorption of
Tritium.

Do we need to discover/design the wheel again?

*** Does anybody have an experience with determining
the way to connect "Source Sample" to "Sample Point"
data, other them to do "other isotopes" correlation.

There is a huge experience in Medical Field with
"Labeling" but it has more of microbiology transfer
mechanism as major drive-ter.

Chemical Analysis would be the one, but I am not sure
what to do if there is, basically, something very
close distillate water? How to trace the water if
there is almost no impurities?


Please, keep me in mind if you have received anything
via private emails.
I will keep you updated if I will find out more info.


Emil.


From: Bharat.Patel@jet.uk (Bharat Patel) 
> Does anyone know of any studies done on the
>absorption of tritium in
> various materials, e.g. metals, plastics, rubber,
>wood, graphite, concrete
> etc as a function of the exposure concentration and
>duration of exposure.> 
> I am trying to relate the absorbed level of tritium
>with its exposure
> history. For example from studies we have done, we
>know that for flat
> sheet metal (aluminium), an exposure of 0.3MBq/m3 
>(8uCi/m3) for several
> hundred hours results in an absorption less than
>1Bq/gram in the material,
> whereas an exposure of 80MBq/m3 for a few hours
>results in >500Bq/gram.> 
> Is it reasonable to assume a linear relationship
>between activity in the
> material and its exposure concentration? What other
>factors might
> influence the absorption rate? Incidentally in the
>above examples, we
> found no detectable surface contamination after the
>exposures, whereas the
> volumetric concentrations were detectable. 
> Any insights into this problem would be appreciated.

> 
> Bharat Patel
> Health Physicist> JET Facilities> Abingdon> Oxon>
UK> 








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