Re: Radiation effects on PVC

[daleboyce@charter.net]

Hi Eric,



I don't have any info on PVC, but some experience.  I did get some info on

Teflon and other plastics from Los Alamos a few years ago. Teflon PTFE is

about the worst known resistance to radiation damage as far as plastics go.

The fluorines get knocked off and react with whatever is around. Serious

damage to the Teflon occur at sub 10^5 rad exposure.  Kel-f another

fluorinated plastic PCTFE is much more resistant. It takes more than 10^6

rad to get the same degradation.



Other non-fluorinated plastics withstand 10^7-10^8 rad.  Those with aromatic

rings or conjugated double bonds that can disperse energy more easily can

take the most.  If I had to WAG it, I would put PVC into the 10^6-10^7

range. Since you are talking about 10^6 rad/year, you might want to try the

folks at Los Alamos.  I can't lay my hands on their contact info at the

moment, but will look for it.



However, I have worked with hotcells with PVC liners with dose rates in that

range, and they seemed to stand up okay.  We did have a seam crack though

that caused a spill to escape containment. So it is possible that

embrittlement from radiation played a part.



Dale





----- Original Message ----- 

From: "Hill, Eric D" <Eric.Hill@TycoHealthcare.com>

To: <radsafe@list.Vanderbilt.Edu>

Sent: Friday, April 16, 2004 9:30 AM

Subject: Radiation effects on PVC





>

> Does anyone have information on the radiation effects on PVC?  We plan on

> using PVC welding rods in a hotcell where gamma rad. levels will be on

order

> of 100r/hr.  Thanks in advance.

>

> Eric Hill

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