Another question,

I am designing an ETFE seat for a ball valve but I don't know if the ETFE can handle radiation level of 1x10^5Gy/40year. I have a document saying that ETFE can handle 1x10^8 rads but how is it related to 1x10^5Gy/40year?

Many thanks,

The radiation absorbed dose is measured in Gray, rad, rem and Sievert (Sv).
1 rad = 1000 mrad = 10 mGy = 0.01 Gy

so 1X10^5Gy/40year would be a rate  

try http://www.unitconversion.org/radiation-absorbed-dose/gray-to-rads-conversion.html

although technically byrdj is correct - dose per unit time is rate - i think that the 40 year timespan is coming from what a concept similar to committed dose i.e. dose accrued over a life-span.

i'm presuming that the radiation you're talking about is either a gamma or neutron field - 10^5 grays would be 10^7 rads so you could view your 10^8 rads figure in two ways 1)the total dose which exceeds your 10^5 grays over 40 years by a factor of 10. 2) you would need to find out if the 10^8 grays is total or based on some unit of time to make sure you weren't exceeding a dose rate.

regards HM

No more things should be presumed to exist than are absolutely necessary - William of Occam

Radiation effects over time cannot be "assumed" very well: the difference between (very high) energy gamma, (medium energy) gamma, X-ray, thermal and high-energy neutrons, and simple heat stress over time gets very complicated:  Different material react differently to each kind of different radiation damage.

Don't relate "biological equivalent radiation units" to simple metallic damage either: equal (or convertible) biological doses will still have physically different effects in different materials, and a material defect that a cell can "regrow" or "replace" will never go away in a crystal or plastic part.   

If you can't duplicate your requirement in the literature, Run a simple test (at SWRI or someplace equal research institute) of "what radiation" at "what energy" at "what rate" hitting "what material" at "what temperature"?   

Don't assume conditions: Higher temperatures might "repair" interstitial impact damage, or might make it worse.  Higher energies will likely make damage worse, but higher energies might be between resonance points and be less damaging.    

racookpe1978 what is SWRI?

Ultimately i wouldn't expect someone to design a seal (or anything for that matter) for 40 years with no maintenance regime.

Kind regards, HM

No more things should be presumed to exist than are absolutely necessary - William of Occam

Southwest Research Institute - a private (fee-based) facility in San Antonio TX that does long-term fatigue and stress failure (vibration-induced) analysis, along with lots of other areas of practical materials research.    

They're nuclear-licensed - so they can handle and be environmentally safe checking out and disposing of radiation-enhanced test materials, and have tested some nuclear-grade materials and welds for some of the power projects I've worked in the past.   Also aerodynamic and metals testing.

Regrettably, that same license familiarity and proven ability also increases fees.   8<(.

hey cool, just looked at their website - am going to delve a little bit!!

unfortunately add the word nuclear to anything and cost seems to spiral...bit like the word wedding

Cheers, HM

No more things should be presumed to exist than are absolutely necessary - William of Occam

Hello

Looking for radiation effects on valve seats,PTFE,UHMWPE,PEEK,etc

Also materials such as 316 stainless and alloys etc

Anybody got any info or stites etc

Thanks

Charlesan