[ RadSafe ] Pipe Cleaners (correction)

[Hansen, Richard]

I would like to correct my previous posting.
Some of the mathematical symbols (micro and plus/minus) were replaced
with "?" symbols.
The corrected text follows:

For more information about NORM in petroleum pipe scales, see the
article in Health Physics:
October 2004 - Volume 87 - Issue 4 - pp 382-397 Radiological Assessment
of Petroleum Pipe Scale
>From Pipe-Rattling Operations
Hamilton, I S.; Arno, M G.; Rock, J C.; Berry, R O.; Poston, J W. Sr;
Cezeaux, J R.; Park, J -M.

The abstract is available at:
http://journals.lww.com/health-physics/Abstract/2004/10000/Radiological_
Assessment_of_Petroleum_Pipe_Scale.5.aspx

Pipes from three oil fields were
rattled to collect as much industry-representative data as possible. The
226Ra specific activity of the pipe scale ranged from 33.6 +- 0.4 to
65.5 +- 0.7 Bq g-1, depending on the formation. A median atmospheric
dust loading of 0.13 mg m-3 was measured in the operator breathing zone.
The respirable fraction was observed to be about 42% to 46%.

Based on cleaning 20 pipes per day,250 d per year on average, annual
committed effective doses for the operator and helper ranged from 0.11
mSv (11 mrem) to 0.45 mSv(45 mrem) for inhalation and from 19 uSv (1.9
mrem) to 97 uSv (9.7 mrem) for incidental ingestion.
Worker annual external dose from thepipe racks ranged from 0 to 0.28 mSv
(28 mrem). In the deposition experiment, more than 99% by weight of the
deposited scale fell within 2 m of the machine centerline, the vast
majority of which was in the downwind direction. The dose from this
deposited material dominated the worker dose estimates. The annual
external dose from dispersed material was estimated to be 2.8 mSv (280
mrem) for the operator and 4.1 mSv (410 mrem) for the helper.

Best regards,
Rick Hansen
Senior Scientist
Counter Terrorism Operations Support Program National Security
Technologies, LLC, for the U.S. Dept of Energy hansenrg at nv.doe.gov
www.ctosnnsa.org