Thanks, John.
That Wikipedia article essentially says the same thing as the quote (and
link) that I provided. It does give a bit of a hint as to the origins of
that wacky unit, WL. And of course it lays out the radon decay scheme
for those not familiar with it. (This is one of the four major decay
schemes in the isotope kingdom.)
You probably would not be surprised that we had a working concern about
radon and its daughter products in the nuclear powered submarines that I
served on. Radon is a common fission product in uranium fission. I don't
think I'm spilling any secrets to say that we monitored continuously for
such like.
Interestingly, in Groton CT I've seen a few days in port when we had to
seal the submarine to prevent the outside air from setting off our
monitoring alarms. We also, at times, had to monitor and occasionally
decontaminate personnel when they came on board. Thermal inversions and
a nearby commercial plant apparently conspired ....
Jim
John M. Steele wrote:
Jim,
You might find the discussion in Wikipedia useful:
http://en.wikipedia.org/wiki/Radon
Look about 1/3 down the page in concentration units. It discusses the
issue of measuring just the radon or radon and progeny.
The WL units are disguised measurements of total radioactivity energy
(rather than number) per liter.
While this helps, I'm still a little confused, so no tough questions,
OK. :)
------------------------------------------------------------------------
*From:* James R. Frysinger <[email protected]>
*To:* U.S. Metric Association <[email protected]>
*Sent:* Fri, February 12, 2010 3:15:50 PM
*Subject:* [USMA:46611] Can it get any harder?
I've been investigating the problem of radon buildup in homes in our
area. We live in a karstic limestone region in the Eastern Highland Rim
of the Nashville basin, just at the western edge of the Cumberland
Plateau. Our county seat, Spencer, is on the plateau and located 7 km SE
of our home. We have a basement, so this is more than idle curiosity.
The State of Tennessee provides free testing (as does the National
Safety Council. The stated level of radon activity at or above which
action is recommended is 4 pCi/L or 0.02 WL.
Now, I understand curies and the radioactivity of radon. It's too bad
that the EPA and other federal and state agencies haven't shifted to
using becquerels yet, but that's another matter. But what about "0.02 WL"?
I found it at
http://www.nsc.org/safety_home/BringSafetyHome/Documents/Radon%20FAQ.doc
and it says:
[quote]
What is a "working level" (WL)?
Some devices measure radiation from radon decay products, rather than
radiation coming directly from radon. Measurements from these devices
are often expressed as WL. As noted above, conversions from WL to pCi/L
are usually approximate. A level of 0.02 WL is usually equal to about 4
pCi/L in a typical home.
If a working level (WL) value is converted to a radon level (pCi/L), the
conversion is usually approximate and is based on a 50 percent
equilibrium ratio. If the actual equilibrium ratio is determined (which
is rare), it should be stated. The 50 percent ratio is typical of the
home environment, but any indoor environment may have a different and
varying relationship between radon and its decay products. Technically
speaking, 1 WL represents any combination of short-lived radon decay
products in one liter of air that will result in the ultimate emission
of 1.3 x 105 MeV of potential alpha energy.
[end quote]
That latter figure is obviously 1.3 × 10^5 MeV.
Working level? Couldn't the National Safety Center and Environmental
Protection Agency come up with a more "hoo-doo" unit of measurement? So,
what is 1 WL? 200 pCi/L? Who would want to work in THAT environment?
I've sent off for a free test kit from the State of Tennessee's
Department of Environment & Conservation. In the meantime, I intend to
keep on working in my basement level (BL), which is the location of my
workshop.
I do encourage everyone to check the maps to see if they shouldn't get a
free test done. Face it, your tax dollars have already paid for everyone
else's.
Jim
-- James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
