Re: radiation damage in teflon

[Ted de Castro <tdc@xrayted.com>]

I remember a couple a decades ago at a place I worked a fellow was
testing an automated TC 99 generator.  He learned then that teflon valve
seats were susceptible to radiation damage and, as I recall, changed to
metal seated valves.

The point is that this is not a new finding and could probably be found
in the literature somewhere.

"Minnema, Douglas" wrote:
> 
> Dear RADSAFErs,
> 
> As many of you know, there was an event at Los Alamos in March involving a
> release of Pu-238 from a vacuum line associated with a glovebox.  One
> contributing cause was a degraded teflon seat in a valve in the vacuum line.
> As a result, DOE is reviewing the overall application of teflon products in
> our nuclear facilities.
> 
> There are multiple issues involved in this problem, due the particular
> environment that the valve was in.  Therefore, I will need to start sorting
> out the various components that could have led to the degradation.
> Radiation is an obvious one, but there was also the potential for mechanical
> abrasion, thermal damage, and long-term exposure to an oxygen-deficient
> environment.  Any one of these could have been the culprit, or more likely a
> combination.
> 
> I am in the very early stages of beginning to look at the susceptibility of
> teflon products to alpha radiation damage.  As many of us know, teflon is
> very susceptible to damage from radiation in general, but most of the past
> studies that I have found so far only discuss gammas, X-rays, and neutrons.
> However, I need some specific technical information regarding alpha-induced
> damage.  Anybody got any good references or contacts?
> 
> Please contact me directly at the address below.  Any help would be
> appreciated.
> 
> Thanks,
> 
> Doug Minnema, PhD, CHP
> Radiological Control Program Advisor for Defense Programs
> National Nuclear Security Administration, US DOE
> 
> <Douglas.Minnema@ns.doe.gov>
> 
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