Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: charli on 29/06/2021 06:39:43

Title: Can you handle old pipe X-ray radiation shielding?
Post by: charli on 29/06/2021 06:39:43
Tim asked:

"Is it dangerous to handle old pipe X-ray radiation shielding?"

Can you help Tim?
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: Bored chemist on 29/06/2021 08:45:08
It is heavy and toxic, but there's no radiation hazard.
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: alancalverd on 29/06/2021 09:46:40
Check that it is lead (soft, grey) and not depleted uranium (hard, yellowish tinge) which is sometimes used because it is denser and maintains its shape, but is radioactive. Tungsten (hard, grey) is safe to handle.
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: evan_au on 29/06/2021 10:44:19
Quote from: OP
Can you handle old pipe X-ray radiation shielding?
X-ray radiation does not induce long-term radioactivity in a material.

Other kinds of radiation (such as exposure to nuclear subatomic particles) does cause transformation of atoms into radioactive isotopes, which poses a long-term radiation hazard
- Eg neutron exposure in a nuclear reactor with 
- Pipes from proton particle accelerators are also likely to have induced radioactive isotopes
- These materials need to be disposed of carefully

Fortunately, lead has a lot of stable isotopes, so often a lead atom will be transformed into another stable lead isotope.
https://en.wikipedia.org/wiki/Isotopes_of_lead

Quote from: alancalverd
depleted uranium (hard, yellowish tinge) which is sometimes used because it is denser and maintains its shape, but is radioactive.
Depleted uranium should be less radioactive than natural uranium.
- Does this cause a problem with exposure in the short or long term?

Quote from: OP
...pipe X-ray radiation shielding?
What puzzles me is why you would use a pipe to carry X-Rays?
- Would it be part of a collimator in an X-Ray machine or X-Ray spectrometer?

Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: chiralSPO on 29/06/2021 14:40:28
If it is shielding, it's probably no more toxic than lead (don't eat it or eat off of it)

But I don't know what you have, and it is possible that it has beryllium in it, which is highly toxic. Beryllium metal is transparent to most x-rays, and is used to build "windows" that let the x-rays out from the source. The metal window itself is toxic, but also, it can corrode and if the pipes were for carrying coolant, it could have very high levels of beryllium in it because the coolant often passes directly over the window repeatedly as it get cycled around.

My advice: leave it alone!
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: alancalverd on 30/06/2021 00:15:29
I think the question relates to shielding materials used during radiographic weld and pipe integrity inspection.  Personnel shielding around the pipe is most likely to be lead, usually sandwiched in plastic or plywood, but the radiation source  is often a radionuclide pellet that is carried in a "torch" with tungsten or uranium filling.

Depleted uranium isn't much less radioactive than the natural stuff, which contains less than 1% of U235, so most of the U235 emission is actually absorbed by the bulk U238. The problem is its reactivity and alpha emission - it can deliver very large doses to e.g.lung tissue if the dust is inhaled.
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: Petrochemicals on 30/06/2021 02:14:01
As a matter of deduction, lead does not become irradiated by xrays as personal protective equipment would become a danger if it where. Lead aprons used to protect radiographers worn for hours a day would soon become a greater danger than a few fractions of seconds of xrays.

Don't play with anything you suspect of being associated with radioactive mateials, one of the worst radiation incedents was caused by abandoned medical equipment in Brazil.
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: alancalverd on 30/06/2021 10:38:09
Nomenclature. It certainly becomes "irradiated" but not "activated".

And the lead coats are not always a Good Thing. Two of Her Majesty's Specialist Inspectors required a client of mine to  wear a lead coat when handling very high energy gamma emitters. This (a) slowed him down so his exposure was extended and (b) increased his skin dose through secondary emission. Thin lead sheets are actually used in industrial radiography as "intensifying" screens to convert a few incoming high energy photons to large numbers of low energy photons and electrons that are absorbed by the x-ray film (or operator's skin).

Not a game for amateurs. But the lead itself is fairly innocuous if undamaged.
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: Bored chemist on 01/07/2021 21:33:55
increased his skin dose through secondary emission
How big was the increase?
(I presume you measured it).
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: alancalverd on 01/07/2021 22:41:31
No need. It's a commonly known fact, well summarised in

https://academic.oup.com/rpd/article-abstract/165/1-4/443/1600900

and various rules-of thumb used by industrial radiographers working at 150 - 300 kV. The joy of lead is its fluorescent edge at around 80 keV,  IIRC.
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: Bored chemist on 01/07/2021 22:53:30
So, what do they use for gamma shielding?



Now, I was aware of the potential for "shielding" making things worse and I'm a chemist.

As you say "
It's a commonly known fact,

So it's quite plausible that the people you referred to knew about it.
But maybe they read the page you cited.


That page you posted says
" 18F, 99mTc, 124I and 131I. 18F results showed a decrease in dose with 0.5-mm Pb shielding "
and
"PET isotope 124I can be adequately shielded using 0.25-mm Pb equivalent aprons".

And maybe they felt that using thin lead shielding is a good thing.

Did you actually take measurements, or are you simply asserting that you know better than them so you must be right?
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: alancalverd on 01/07/2021 23:14:25
Mostly tungsten or depleted uranium for small gadgets, or very thick (centimeters) of lead. If you've ever worn a 0.5 mm lead apron for a day (time was  they were nicknamed "Irish lifejackets" but I guess that's unacceptably non-PC nowadays)  you would realise that it is not a desirable PPE garment, and is pretty ineffective or worse  if your source is Iodine 131 (364 keV) or even Tc99m (141 keV), which constitute the majority of medical radionuclides.

Tungsten alloy aprons are useful at high diagnostic energies (up to say 140 kV x-ray CT systems, ~80 keV peak photon energy) but got a bad name because they are less effective at low energies than lead. Problem is that traditionally PPE is labelled as "0.25 mm lead equivalent at 100 kV" or suchlike and some dumbass physicists complained that they weren't equivalent to 0.25 mm lead at 70 kV (~35 keV peak photon energy). Doesn't anyone stay awake in first-year lectures these days?     

PET isotopes tend to have very short halflives and consequently don't feature much in air cargo.
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: Bored chemist on 02/07/2021 08:31:37
you would realise that it is not a desirable PPE garment
It depends on whether you desire to get zapped.
Unfortunately, very little PPE is comfortable.
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: evan_au on 02/07/2021 23:46:51
Quote from: bored chemist
Unfortunately, very little PPE is comfortable.
I feel quite comfortable in my skin:
- It protects me from microbes in the air
- Stops me from dehydrating
- Provides some UV protection (SPF=1.0)
- Even provides some alpha-particle protection!
- And I feel very uncomfortable if some part of it is removed

I'm quite attached to it, actually...
Title: Re: Can you handle old pipe X-ray radiation shielding?
Post by: Bored chemist on 03/07/2021 00:17:48
I never got round to checking, but I understand that, if you want to find the testing standards for condoms and umbrellas, they are listed under PPE.
That's not the same PPE as far too many of our politicians studied at Uni. Philosophy , Politics and Economics seems.... less current.

There may be suggestions that if some politicians had a better understanding of condoms...