[ RadSafe ] Fwd: Which welding rods are hot?

[Dan McCarn]

Hi Chris:

I'm going to take a wild guess here, since my "reference" is the behavior
of the progeny of U-238 in a mineral lattice.

That's what I thought about radon being emitted from mineral grains, that
it would be minimal. But I was wrong. For natural thorium, there are three
alpha decays with an energy in excess of 4 MeV in the decay chain to
Rn-220.  If these alphas behave in a similar way to U-238 decay, then the
recoil energy, perhaps 50-100 KeV, should have dislocated the
progeny significantly by the time that it becomes Rn-220, allowing more to
escape.

But then, the thorium is part of a metal and may behave differently.

See Figure 6 in the following hyperlink:
Fig. 6. Recoil range vs α- recoil energy of radionuclides of U–Th
radioactive series in water (*ρ*=1) and calcite (*ρ*=2.7).

http://www.sciencedirect.com/science/article/pii/S0883292700000779


-- 
Dan ii

Dan W McCarn, Geologist
108 Sherwood Blvd
Los Alamos, NM 87544-3425
+1-505-672-2014 (Home – New Mexico)
+1-505-670-8123 (Mobile - New Mexico)
HotGreenChile at gmail.com (Private email) HotGreenChile at gmail dot com


On Tue, Nov 6, 2012 at 6:15 AM, <franz.schoenhofer at chello.at> wrote:

> Chris,
>
> You forget that thorium is also radioactive.
>
> Franz
>
>
>
>
> ---- Chris Alston <achris1999 at gmail.com> schrieb:
> > Hi Stewart
> >
> > Thing is, thoron (radon-220) has a 55-second half-life.  So, probably
> > only the tiniest quantities can escape the rod, from its very surface.
> >
> > Cheers
> > cja
> >
> >
> > ---------- Forwarded message ----------
> > From: Stewart Farber <safarber at optonline.net>
> > Date: Mon, Nov 5, 2012 at 4:27 PM
> > Subject: Re: [ RadSafe ] Which welding rods are hot?
> > To: "The International Radiation Protection (Health Physics)
> > Mailing       List" <radsafe at health.phys.iit.edu>
> >
> >
> > TIG welding rods. Labeled 3% thoria by weight. Quite a source. I've
> > been to some welding supply houses to get LN2 which have thousands of
> > lbs of these TIG rods on shelves behind the counter.  Think of the
> > employees Rn-220 inhalation !
> >
> >
> > Stewart Farber, MS Public Health
> > Farber Medical Solutions, LLC
> >
> > [203] 441-8433 [o]
> > [203] 522-2817 [m]
> > [203] 367-0791 [fax]
> >
> >
> > -----Original Message----- From: Ted de Castro
> > Sent: Monday, November 05, 2012 3:05 PM
> > To: The International Radiation Protection (Health Physics) Mailing List
> > Subject: [ RadSafe ] Which welding rods are hot?
> >
> > I know I've encountered some considerably hot welding rods - but didn't
> > notice the type designation.
> >
> > I just checked my own supply - so 60's, 70's and 78's - I was SURE at
> > least my 6010 would be hot --- but NO - they none were.
> >
> > So - asked of anyone who has some hot ones --- what type?
> >
> > thanks
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> --
> Franz Schoenhofer, PhD, MinRat
> Habicherg. 31/7
> A-1160 Vienna
> Austria
> mobile: ++43 699 1706 1227
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