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SSINS No.: 6835
IN 86-95
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
November 10, 1986
Information Notice No. 86-95: LEAK TESTING IODINE-125 SEALED SOURCES IN
LIXI, INC. IMAGING DEVICES AND BONE MIN-
ERAL ANALYZERS
Addressees:
All NRC licensees authorized to use Lixi, Inc. imaging devices or any other
bone mineral analyzer with a sealed source containing iodine-125.
Purpose:
This notice is to alert licensees of a recent incident where the normal
means of testing the sealed source in such devices for leakage was
ineffective and to suggest alternate means of leak testing. It is suggested
that licensees review this information for applicability to their facilities
and consider actions, if appropriate, to preclude similar problems at their
facilities. However, suggestions contained in this information notice do not
constitute NRC requirements; therefore, no specific action or written
response is required.
Description of Circumstances:
Lixi, Inc. imaging devices include a sealed source containing 220 to 450
millicuries of iodine-125 and function much like an X-ray fluoroscope. The
source has to be tested every 6 months to determine if there is any leakage
of iodine-125. Licensees who keep sources longer than 6 months are required
by license to perform this test and send the test samples out for analysis.
This test is now performed by using an alcohol-moistened Q-tip and a dry Q-
tip to wipe certain portions of the source holder as specified in the
instructions. The purpose of the test is to determine if any particulate
iodine-125 is on the sample Q-tips, which would indicate the source was
breached and would have to be replaced to avoid a contamination problem.
However, a recent incident at the Lixi, Inc. facility showed that the
alcohol and dry wipes are not an adequate means of detecting a leaking
source.
During the investigation of the incident, it was found that two sources that
had been returned for exchange were leaking. Alcohol and dry wipes did not
reveal any removable iodine-125 on the various surfaces because the escaping
iodine-125 came out in gaseous form rather than as particulate matter. As a
result, about 15 people inhaled small amounts of iodine-125 which deposited
in their thyroids.
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IN 86-95
November 10, 1986
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The iodine-125 was apparently adsorbed on carbon containing material such as
cardboard, rubber bands, styrofoam, and charcoal that was near the escaping
gas. A survey of these materials revealed elevated radiation levels. Through
these direct surveys and a series of air samples U*sing filter media
containing charcoal, the ruptured sources were located and the airborne
contamination problem was resolved.
Discussion:
Licensees who perform leak tests on their Lixi, Inc. imaging devices should
be aware that the current practice of using alcohol and dry wipes is not an
adequate means of detecting a leaking iodine-125 sealed source. Lixi, Inc.
will be sending a revised leak testing procedure to its customers in the
near future, In the meantime, licensees who are returning source heads for
exchange should include charcoal in the form of granules or a solid piece in
the package with the source head. When Lixi, Inc. receives such packages, it
will survey the charcoal for an indication of leakage. A sodium-iodide
crystal (thin window) detector (or one of similar sensitivity) is required
to detect the low levels of radioactivity that would be encountered in such
surveys.
During the incident investigation, granulated charcoal was placed on a Q-tip
that was then held for several minutes at the window in the source head to
verify leakage. The gaseous iodine-125 that adsorbed onto the charcoal was
easily identified with a crystal detector.
Until the revised procedure arrives from Lixi, Inc., it is suggested that
licensees use the above method for identifying a leaking source. The
granulated charcoal Q-tip may be placed in the plastic envelope that is
included in Lixi's leak test kit and forwarded to a consultant with adequate
instrumentation for analysis.
If you have any questions regarding this matter, please contact the Regional
Administrator of the appropriate NRC Regional Office or this office.
James G. Partlow, Director
Division of Inspection Programs
Office of Inspection and Enforcement
Technical Contact: J. Metzger, IE
(301) 492-4947
Attachment: List of Recently Issued IE Information Notices
Page Last Reviewed/Updated Thursday, March 29, 2012

