Information Notice No. 90-56: Inadvertent Shipment of a Radioactive Source in a Container Thought to Be Empty
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, D.C. 20555
September 4, 1990
Information Notice No. 90-56: INADVERTENT SHIPMENT OF A RADIOACTIVE
SOURCE IN A CONTAINER THOUGHT TO BE EMPTY
Addressees:
All U.S. Nuclear Regulatory Commission (NRC) licensees.
Purpose:
This notice is provided to inform licensees of a recent transportation
incident that could have resulted in significant radiation exposures to
workers or members of the public. This notice also serves to remind
licensees of their responsibilities when importing radioactive materials or
when shipping packages.
It is expected that licensees will review this information for applicability
to their licensed activities and consider actions, as appropriate, to avoid
problems when importing radioactive materials or shipping packages.
However, suggestions contained in this notice do not constitute any new
requirements, and no written response is required.
Description of Circumstances:
On March 8, 1990, Amersham Corporation (Amersham), Burlington,
Massachusetts, an NRC licensee authorized to manufacture and distribute
iridium-192 and cobalt-60 sealed sources for use in industrial radiography
equipment, received a Model 500-SU source changer from its Korean product
distributor. In accordance with shipping documents, Amersham expected the
source changer to be empty. However, as an Amersham technician approached
the source changer, his audible alarming dosimeter indicated increased
radiation levels. Radiation dose rates measured as high as 10 rem per hour
at approximately 18 inches and 150 rem per hour on contact. Amersham later
discovered that the source changer contained a 2.4-curie, iridium-192 source
capsule in an unshielded portion of the changer. Because the source changer
was transported cross-country by domestic motor carrier, the potential
existed for significant radiation exposure to a variety of individuals. A
more detailed description of the incident is enclosed in Attachment 1.
Discussion:
NRC shares regulatory responsibility with the U.S. Department of
Transportation (DOT) for transportation of radioactive materials. NRC
regulations for transportation of radioactive materials are codified in 10
CFR Part 71, "Packaging and Transportation of Radioactive Material." NRC
regulations in 10 CFR 71.0(b) state, in part, "The packaging and transport
of licensed material are also subject ... to the regulations of other
agencies (e.g., the U.S. Department of Transportation and the U.S. Postal
Service) having jurisdiction
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IN 90-56
September 4, 1990
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over means of transport." DOT's hazardous materials regulations are
codified in 49 CFR Parts 100-180. A provision of NRC regulations in 10 CFR
71.5(a) effectively requires that all licensees (who transport or deliver to
a carrier for transport), follow DOT's hazardous materials regulations in
Title 49.
NRC regulations in 10 CFR 110.27(a)(3), "Export and Import of Nuclear
Equipment and Materials," authorizes any person to import byproduct material
if that person is authorized to possess the materials under a specific
license that has been issued by NRC or an Agreement State. DOT regulations
for the import and export of radioactive materials are specified in 49 CFR
171.12, "Import and export shipments." 49 CFR 171.12(a) requires, in part,
that each person importing a hazardous material into the United States shall
provide the shipper (foreign exporter) and freight forwarder complete
information as to the requirements of the DOT hazardous materials
regulations that apply to the shipment within the United States.
10 CFR 20.205 specifies package receipt and opening requirements for NRC
licensees. Pursuant to this section, licensees are required to report to
NRC when receiving certain packages exhibiting excessive contamination or
radiation levels. In addition, pursuant to 10 CFR 71.95, NRC licensees are
required to report "... any instance in which there is a significant
reduction in the effectiveness of any NRC authorized packaging during use."
DOT regulations in 49 CFR 171.15 and 171.16 require carriers to immediately
report to DOT any incidents, during transport of hazardous materials, when
there are fatalities, injuries involving hospitalization, $50,000 property
damage, and, in the case of radioactive materials, "... fire, breakage,
spillage, or suspected radioactive contamination...."
Amersham provided an operations manual, with every Model 500-SU source
changer, that included instructions to users for returning empty source
changers. These instructions described procedures for preparing an empty
source changer containing depleted uranium (DU) shielding as an "excepted"
package, provided the surface radiation level was below 0.5 mR/hr. However,
NRC determined that the surface radiation levels on the source changer
involved in this incident exceeded the acceptable level. The Amersham
operation manual did not explain how to prepare the package (empty source
changer), when the radiation level exceeds 0.5 mR/hr.
The Model 500-SU operations manual also informed the user to "... assure
that there is no source in the container." However, the manual did not list
specific procedures to make this determination. Ordinarily, a visual
examination would verify the presence (or absence) of a source assembly, as
the connector end of the assembly would be evident. However, a visual
examination would not have revealed the source in this incident because the
source was cut from the source assembly. A surface radiation survey could
also be used to detect a source in a changer. However, NRC determined that
even for a changer containing a 3-curie source, the surface readings would
be indistinguishable from readings obtained from the DU shield of an empty
source changer. Amersham estimated that the minimum source activity
detectable through the DU shielding of the Model 500-SU is 4 curies.
The incident described in Attachment 1 could have resulted in significant
radiation exposures to workers or members of the public. The incident and
the forementioned discussion demonstrate the importance of doing the
following:
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IN 90-56
September 4, 1990
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1. Licensees who may be importing radioactive materials are advised to
review DOT's regulations in this area and are reminded of their
responsibility to inform foreign exporters of proper packaging,
labeling, and other requirements concerning transport of radioactive
materials in the United States.
2. Licensees shipping packages that incorporate DU shields are reminded
that complete and accurate radiation surveys must be conducted to
verify proper shipping requirements, since DU containers may exceed 0.5
mR/hr.
3. Licensees returning shielded packages that do not contain radioactive
material, especially those packages that incorporate DU shields, are
cautioned that complete and accurate radiation surveys must be
performed, and that a physical probe of the package may be necessary to
verify that the package does not contain radioactive materials.
4. Manufacturers who receive returned packages should ensure that they
provide complete instructions to customers for properly verifying that
packages are empty as well as for meeting restrictions on surface
radiation levels. Licensees that return such packages should ensure
that these procedures are strictly followed.
5. Licensee are reminded of the need to evaluate incidents for their
actual and potential safety consequences. Responsible individuals
should review even minor incidents for unexpected consequences and to
determine if there are any requirements for reporting the incident to
NRC or DOT. Even if there does not appear to be an applicable
reporting requirement, or if there is some uncertainty about reporting
requirements, licensees are encouraged to discuss events with the
appropriate regulatory agency. Transportation incidents should be
reported to DOT's National Response Center at (800) 424-8802.
No written response is required by this information notice. If you have any
questions about this matter, please contact the appropriate regional office
or this office. Questions concerning DOT requirements should be directed to
Michael Wangler, Chief, Radioactive Material Branch, Office of Hazardous
Materials Transportation, DOT (202) 366-4545.
Richard E. Cunningham, Director
Division of Industrial and
Medical Nuclear Safety
Office of Nuclear Material Safety
and Safeguards
Technical Contact: J. Bruce Carrico, NMSS
(301) 492-0634
Attachments:
1. Description of Incident
2. Examples of a Source Assembly and
a Model 500-SU Source Changer
3. List of Recently Issued NRC Information Notices
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