....also known as NORM, for Naturally Occurring Radioactive Materials :
RADIOLOGICAL ASSESSMENT OF PETROLEUM PIPE SCALE FROM PIPE-RATTLING OPERATIONS Health Phys. 87(4): pages 382-396; October 2004
L.S. Hamilton, M.G. Arno, J.C. Rock, R.O. Berry, J.W. Poston, J.R. Cezeaux, and J - M. Park
Abstract Petroleumpipe scale, consisting of concentrated inorganic solids such as barium sulfate, can deposit in the inside of down-hole pipes during the normal course of oil field pumping operations. (comes from subterranean water moving upwards with petroleum) A portion of this scale has been shown to contain naturally occurring radioactive materials (NORM), predominantly compounds of radium.
When these pipes are removed from the well, there is a potential for radiation doses to the oil field workers handling the pipes, especially as the pipes are cleaned for reuse.
A thorough sampling and measurement protocol was applied under a variety of weather conditions in an outdoor laboratory to obtain an accurate indication of the radiological and aerodynamic characteristics of scale release and dust dispersion during petroleum pipe scale removal from out-of-service pipes with a restored, historically relevant outdoor pipe-cleaning machine. Exposure rate data were also obtained for both the pre-cleaned pipes, and the general area inhabited by workers during the descaling operation.
Four radiation exposure pathways were investigated: 1) inhalation of pipe scale dust generated during pipe rattling, 2) incidental ingestion of the pipe scale dust, 3) external exposure from uncleaned pipes, and 4) external exposure from pipe scale dispersed on the ground.
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, depending on the formation. A median atmospheric dust loading of 0.13 mg /m3 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 microSV (1.9 mrem) to 97 microSV (9.7 mrem) for incidental ingestion.
Worker annual external dose from the pipe 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.
Wow, it never occured to me that petroleum well casing might become contaminated with radioactive materials. The data suggests the pipes are surprisingly 'hot' with it. I wonder if switching to a wet blasting method could reduce the dust load (although high pressure sprays will produce aerosols.)
Body Scans are all the rage, but how many do we need?
1,300 Radiation dose in millirems (mrems) from a single full-body computed tomography (CT) scan
1.5 miles Distance you'd need to have been from the Hiroshima atomic explosion to receive an equivalent dose
29 Radiation dose in millirems from smoking a pack of cigarettes
0.08% Increase in risk of death from cancer after full-body scan
3.75% increase in risk of death from cancer if you receive a full-body CT scan anually starting at age 25
300 Average annual radiation dose from natural sources, in mrem, per person in the U.S.
1 average annual dose, in mrem, from eating one or two bananas a week
57 Million Number of full-body CT scans performed in 2003
$16 Billion Estimated annual cost of unnecesary diagnostic imaging
7 Percentage of patients informed of the risks of their CT scans
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SOURCES:
American College of Radiology, David J. Brenner/Columbia University Medical Center, U.S. Food and Drug Administration, David C. Levin/Thomas Jefferson University Hospital, National Institute of Health, Nuclear Energy Institute, Yale University School of Medicine.
