[ RadSafe ] Tritium contamination

Tue Nov 1 10:01:04 CDT 2011

Mattias,

I would think that most of your tritium is in the form of water.  Since water is highly removable from steel, I would tend to think that a method that includes thorough drying would defeat your ability to assume that 3H and 60Co would be in a fixed, or even predictably variable, ratio. 

On the other hand, if your tritium starts the process as hydrogen gas, it will to some degree interact with the surface of the steel and be retained (probably as an hydride) moreso than with water.  However, even in this case, the amount remaining will be a small fraction and will depend on many other factors regarding the circumstances of deposition.  So I too, am not sanguine that a reliable ratio can be discovered.  On the plus side, if you drive off the hydrogen with heat and collect it by trapping at the beginning of the sample prep, you should get a reliable measurement to compare to the dry sample with Co.

Hope this helps,

Brad

Bradly D. Keck, Ph.D., CHP

On Nov 01, 2011, at 07:25 AM, Robert Atkinson <robert8rpi at yahoo.co.uk> wrote:

> A lot will depend on the chemistry too. I know that tritium binding to stainless steels is a big problem with chromatographs and mass spectrometers in bioresearch
>
>
>
> ________________________________
> From: "Brennan, Mike (DOH)" <Mike.Brennan at DOH.WA.GOV>
> To: The International Radiation Protection (Health Physics) MailingList <radsafe at health.phys.iit.edu>
> Sent: Monday, 31 October 2011, 22:04
> Subject: Re: [ RadSafe ] Tritium contamination
>
> Hi, Mattias.
>
> While I am confident there are people here with vastly more experienced
> than I am with tritium, I am going to put my vote in for "general
> statement hopeless".  There are just too many factors to make a
> meaningful generalization.
>
> On the other hand, it tritium is your contaminate of concern, you are in
> pretty good shape, risk-wise. 
>
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Olsson Mattias
> :MSO
> Sent: Monday, October 31, 2011 8:04 AM
> To: The International Radiation Protection (Health Physics) MailingList
> Subject: [ RadSafe ] Tritium contamination
>
> Dear Radsafers,
>
> I am playing around with a nuclide vector that I hope to be able to
> apply for free release measurements. The assumption is that the
> contamination comes from BWR reactor water, and at least Co-60 is
> measurable with a gamma detector. I want to use Co-60 as a key nuclide
> to estimate the amount of a whole array of other nuclides by using the
> known composition of the activity in reactor water.
>
> To set this up is not very difficult, and I also add a function to let
> the nuclide vector "age" for the cases where it is known that the
> contamination occured some time ago.
>
> The thing is that the free release measurements will be done on dry
> materials. That means that the tritium, which is fairly abundant in the
> reactor water, will no longer be there during the measurement. I suppose
> *some* tritium will be retained on the materials, though. Surfaces are
> somewhat prone to exchange protons in an aqueous environment, if nothing
> else. Anyway... What I wonder is if there is any experience on here on
> how much tritium will stay as contamination on a surface if the surface
> is first splashed with tritiated water and then allowed to dry. I
> imagine this would depend on a number of factors (type of surface, ratio
> between available surface and the amount of tritiated water etc) that
> would make a general statement hopeless, but if there are any practical
> examples I would love to hear about them! It could lead me towards a
> conservative reasonable assumption.
>
> All the best,
>
> Mattias Olsson, Sweden
> _______________________________________________
> You are currently subscribed to the RadSafe mailing list
>
> Before posting a message to RadSafe be sure to have read and understood
> the RadSafe rules. These can be found at:
> http://health.phys.iit.edu/radsaferules.html
>
> For information on how to subscribe or unsubscribe and other settings
> visit: http://health.phys.iit.edu
> _______________________________________________
> You are currently subscribed to the RadSafe mailing list
>
> Before posting a message to RadSafe be sure to have read and understood the RadSafe rules. These can be found at: http://health.phys.iit.edu/radsaferules.html
>
> For information on how to subscribe or unsubscribe and other settings visit: http://health.phys.iit.edu
> _______________________________________________
> You are currently subscribed to the RadSafe mailing list
>
> Before posting a message to RadSafe be sure to have read and understood the RadSafe rules. These can be found at: http://health.phys.iit.edu/radsaferules.html
>
> For information on how to subscribe or unsubscribe and other settings visit: http://health.phys.iit.edu