Fri Mar 25 10:16:54 CDT 2011

```How about waders (trout fishing type) and air fed hoods to mitigate heat
fatigue if that's a problem.

LA

-----Original Message-----
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Strickert, Rick
Sent: Friday, March 25, 2011 10:09 AM
To: The International Radiation Protection (Health Physics) Mailing List

According to an India Today news report: "The contaminated water seeped over
the top of their boots as the workers were working to get the damaged
plant's cooling system"

The internet article
(http://indiatoday.intoday.in/site/Story/133330/world/japan-two-fukushima-n-
picture of what at least some of the workers were wearing.

starting @ 29 seconds) showing the workers in protective outfits.

Rick Strickert
Austin, TX

-----Original Message-----
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Lachapelle, Edward
B
Sent: Friday, March 25, 2011 8:38 AM
To: 'The International Radiation Protection (Health Physics) Mailing List'

Good point about the Sr-90/Y-90 equilibrium.  (Sometimes you miss the
obvious.)

Given the same assumptions, I got a dose to curie factor of 1.6E-6 Gy/hr per
Bq/sq. cm.

That resulted in a Y-90 concentration of 0.08 Ci/L.

And for a 600/hr rads of beta dose, I got .01 mCi/sq. cm.  You're within the

Ed Lachapelle

-----Original Message-----
[mailto:radsafe-bounces at agni.phys.iit.edu] On Behalf Of Glenn R. Marshall
Sent: Friday, March 25, 2011 6:18 AM
To: The International Radiation Protection (Health Physics) Mailing List

Assuming Sr-90 is the culprit, the beta dose is from Y-90 with a 0.934 MeV
average energy.  A "very quick" calculation shows a dose of about 600
rad/hour from skin contamination of 1 mCi/cm2.  Disclaimer: I only had a
minute to do this and don't have time to check my math.....

But if that's true, they have a problem.

Glenn Marshall, CHP

-----Original Message-----
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Lachapelle, Edward
B
Sent: Thursday, March 24, 2011 5:24 PM
To: 'The International Radiation Protection (Health Physics) Mailing List'

Here are my thoughts:

If you assume that the dose was on the order of 500 Rads, and they were
exposed for 10 hours, that would be 50 Rads/hr, or 0.5 Gy/hr.

If you also assume that the dose was from beta radiation from Sr-90,
(average beta energy of 0.196 MeV), and using a skin dose calculation from
Cember's "Introduction to Health Physics," you get a conversion of 4.9E-7
Gy/hr per Bq/sq. cm.

If you assume that there was about 0.1 cm of thickness of water over the
area, that would result in a Sr-90 concentration of 0.3 Ci/L.

Ed Lachapelle, M.S., CHP

-----Original Message-----
[mailto:radsafe-bounces at agni.phys.iit.edu] On Behalf Of Strickert, Rick
Sent: Thursday, March 24, 2011 1:51 PM
To: The International Radiation Protection (Health Physics) Mailing List

Below are a couple of links on reports that three workers at the Fukushima
No. 3 reactor got beta-radiation burns on their feet when they were laying
electrical cables while standing in radioactively-contaminated water.  One
report stated: "TEPCO said radioactive water may have seeped through the
water to stick to their skin."

The workers also received radiation doses of 17 to 18 rem while working from
10 AM to 12:10 PM (suggesting a 1.2 - 1.3 rem/h average dose rate).  It's
not clear whether the workers were standing in water the entire 14 hours.

Can one estimate (or WAG) the solution concentrations of beta-emitters
(Ci/L) that would have to be in the water for the workers to get radiation
burns from the water that seeped through the workers' radiation protective
gear (e.g. Tyvex booties over work shoes?)?

http://e.nikkei.com/e/fr/tnks/Nni20110324D24JF855.htm
ater-110324/20110324/?hub=CalgaryHome

Rick Strickert
Austin, TX
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