RE: Degradation of plastic from radiation levels

["Christoph Hofmeyr" <chofmeyr@nnr.co.za>]

Radsafers,

The susceptibility to radiation damage varies enormously, depending on

the type of plastic.  I recall that three decades ago our design office

had some literature in the form of a table that indicated at what kind

of exposure various types were considered degraded, i.e. had undergone

significant physical change.  Off the top of my head I remember that

teflon was one of the least resistant types at 1e+6 rad, whereas

(poly?)styrene was good up to 1e+12 rad, and poly-ethylene might have

been around 1e+9 rad.  This type of information must be available, but

unfortunately I have no ready reference.  My guess would be that the

relevant tests would have been done with X-rays or electrons, or close

to spent nuclear fuel elements.  Alphas have such a short range that

they would have a superficial effect.

Chris Hofmeyr

chofmeyr@nnr.co.za <mailto:chofmeyr@nnr.co.za> 



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

From: Kai Kaletsch [mailto:info@eic.nu]

Sent: 13 February 2002 00:04

To: radsafe@list.vanderbilt.edu

Subject: Re: Degradation of plastic from radiation levels





Coax cables around a linear accelerator will typically have the black

outside sleeve unaffected, while you can shake out the white insulation.

 

I don't know if beta and alphas have the same effect on plastic as

gammas. Plastic bags that hold uranium ore seem to degrade rather

quickly even though the dose rate is quite low. This could be chemical

thing too.

 

Some plastic bags are especially made to degrade easily. Don't use

those.

 

Kai



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

From: John White <mailto:radjcw@HOTMAIL.COM>  

To: radsafe@list.vanderbilt.edu <mailto:radsafe@list.vanderbilt.edu>  

Sent: Tuesday, February 12, 2002 2:17 PM

Subject: Re: Degradation of plastic from radiation levels





In a former life, I worked 13 years in Nuclear Effects engineering for a

defense firm and vulnerability of plastics to various levels of

radiation was a major effort, including degradation as well as

enhancement of thermal and physical stability due to ionizing radiation.

The Nuclear and Space Radiation Effects branch of the IEEE has a

substantial library of papers on this topic.  You will probably be able

to do a minimal web search to find the specific info you seek.  I

believe Sandia (Phillips lab, etc.) has done some research on plastics

and radiation.    The effects depend on the type of plastic.  



Examples of info:  A few megarads crosslinks molecules of polyethlyene,

making it stronger.  The same few megarads turn teflon into powder.



*****************************



John C. White 

Assistant Director 

  Radiation Safety Officer 

Environmental Health and Safety 

The University of Texas Southwestern Medical Center at Dallas 

************************************* 



The above communication represents views of the author only. No

representation of The University of Texas is intended or implied.



*************************************



>From: "Guinn, Charles D" 



>Reply-To: "Guinn, Charles D" 

>To: "RADSAFE ListServe (E-mail)" 

>Subject: Degradation of plastic from radiation levels 

>Date: Tue, 12 Feb 2002 12:06:29 -0700 

> 

>Radsafers, 

>Is there anyone out there who might know an approximate radiation level

that 

>would cause the degradation of plastic (i.e., plastic bags)? 

> 

>Charlie 

> 

>Charles D. Guinn, CHP, RRPT 

>Sandia National Laboratories 

>PO Box 5800 MS0651 

>Albuquerque, NM 87185-0651 

>(505) 284-4027 FAX: (505) 844-8313 

> 

> 



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