Information Notice 1990-56, Inadvertent Shipment of a Radioactive Source in a Container Thought to be Empty

Inadvertent Shipment of a Radioactive Source in a Container Thought to be Empty

ML031210458
Person / Time
Issue date:	09/04/1990
Revision:	0
From:	Cunningham R E NRC/NMSS/IMNS
To:
References
IN-90-056, NUDOCS 9008280232
Download: ML031210458 (9)

UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDSWASHINGTON, D.C. 20555September 4, 1990NRC INFORMATION NOTICE NO. 90-56: INADVERTENT SHIPMENT OF A RADIOACTIVE SOURCEIN 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 incidentthat could have resulted In significant radiation exposures to workers ormembers of the public. This notice also serves to remind licensees of theirresponsibilities when importing radioactive materials or when shipping packages.It is expected that licensees will review this information for applicability totheir licensed activities and consider actions, as appropriate, to avoidproblems when importing radioactive materials or shipping packages. However,suggestions contained in this notice do not constitute any new requirements, andno written response is required.

Description of Circumstances

On March 8, 1990, Amersham Corporation (Amersham), Burlington, Massachusetts, anNRC licensee authorized to manufacture and distribute iridium-192 and cobalt-60sealed-sources for use in industrial radiography equipment, received a Model500-SU source changer from its Korean product distributor. In accordance withshipping documents, Amersham expected the source changer to be empty. However,as an Amersham technician approached the source changer, his audible alarmingdosimeter indicated increased radiation levels. Radiation dose rates measuredas high as 10 rem per hour at approximately 18 Inches and 150 rem per hour oncontact. Amersham later discovered that the source changer contained a2.4-curie, iridium-192 source capsule in an unshielded portion of the changer.Because the source changer was transported cross-country by domestic motorcarrier, the potential existed for significant radiation exposure to a varietyof individuals. A more detailed description of the incident is enclosed inAttachment 1.Discussion:NRC shares regulatory responsibility with the U.S. Department of Transportation(DOT) for transportation of radioactive materials. NRC regulations fortransportation of radioactive materials are codified in 10 CFR Part 71,'Packaging and Transportation of Radioactive Material." NRC regulations in10 CFR 71.0(b) state, in part, "The packaging and transport of licensed materialare also subject ... to the regulations of other agencies (e.g., the U.S.Department of Transportation and the U.S. Postal Service) having jurisdiction9008280232 P5 p 9 9-Po-oS9ooc~oq IN 90-56September 4, 1990 over means of transport." DOT's hazardous materials regulations are codified in49 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 carrierfor transport), follow DOT's hazardous materials regulations in Title 49.NRC regulations in 10 CFR 110.27(a)(3), "Export and Import of Nuclear Equipmentand Materials," authorizes any person to import byproduct material if thatperson is authorized to possess the materials under a specific license that hasbeen issued by NRC or an Agreement State. DOT regulations for the import andexport of radioactive materials are specified in 49 CFR 171.12, "Import andexport shipments." 49 CFR 171.12(a) requires, in part, that each personimporting a hazardous material into the United States shall provide the shipper(foreign exporter) and freight forwarder complete information as to therequirements of the DOT hazardous materials regulations that apply to theshipment within the United States.10 CFR 20.205 specifies package receipt and opening requirements for NRClicensees. Pursuant to this section, licensees are required to report to NRCwhen receiving certain packages exhibiting excessive contamination or radiationlevels. In addition, pursuant to 10 CFR 71.95, NRC licensees are required toreport ... any instance in which there is a significant reduction in theeffectiveness of any NRC authorized packaging during use." DOT regulations in49 CFR 171.15 and 171.16 require carriers to immediately report to DOT anyincidents, during transport of hazardous materials, when there are fatalities,injuries involving hospitalization, $50,000 property damage, and, in the caseof radioactive materials, "... fire, breakage, spillage, or suspected radioactivecontamination....Amersham provided an operations manual, with every Model 500-SU source changer,that included instructions to users for returning empty source changers. Theseinstructions described procedures for preparing an empty source changer containingdepleted uranium (DU) shielding as an 'excepted" package, provided the surfaceradiation level was below 0.5 mR/hr. However, NRC determined that the surfaceradiation levels on the source changer involved in this incident exceeded theacceptable level. The Amersham operation manual did not explain how to preparethe 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 thatthere is no source in the container." However, the manual did not list specificprocedures to make this determination. Ordinarily, a visual examination wouldverify the presence (or absence) of a source assembly, as the connector end ofthe assembly would be evident. However, a visual examination would not haverevealed the source in this incident because the source was cut from the sourceassembly. A surface radiation survey could also be used to detect a source in achanger. However, NRC determined that even for a changer containing a 3-curiesource, the surface readings would be indistinguishable from readings obtainedfrom the DU shield of an empty source changer. Amersham estimated that the minimumsource activity detectable through the DU shielding of the Model 500-SU is 4 curies.The incident described in Attachment 1 could have resulted in significantradiation exposures to workers or members of the public. The incident and theforementioned discussion demonstrate the importance of doing the following:

IN 90-56September 4, 1990 . Licensees who may be importing radioactive materials are advised to reviewDOT's regulations in this area and are reminded of their responsibility toinform foreign exporters of proper packaging, labeling, and other requirementsconcerning transport of radioactive materials in the United States.2. Licensees shipping packages that incorporate DU shields are reminded thatcomplete and accurate radiation surveys must be conducted to verify propershipping requirements, since DU containers may exceed 0.5 mR/hr.3. Licensees returning shielded packages that do not contain radioactivematerial, especially those packages that incorporate DU shields, are cautionedthat complete and accurate radiation surveys must be performed, and that aphysical probe of the package may be necessary to verify that the packagedoes not contain radioactive materials.4. Manufacturers who receive returned packages should ensure that they providecomplete instructions to customers for properly verifying that packagesare empty as well as for meeting restrictions on surface radiation levels.Licensees that return such packages should ensure that these proceduresare strictly followed.5. Licensee are reminded of the need to evaluate incidents for their actualand potential safety consequences. Responsible individuals should revieweven minor incidents for unexpected consequences and to determine if thereare any requirements for reporting the incident to NRC or DOT. Even if theredoes not appear to be an applicable reporting requirement, or if there is someuncertainty about reporting requirements, licensees are encouraged to discussevents with the appropriate regulatory agency. Transportation incidents shouldbe reported to DOT's National Response Center at (800) 424-8802.No written response is required by this information notice. If you have anyquestions about this matter, please contact the appropriate regional office orthis office. Questions concerning DOT requirements should be directed to MichaelWangler, Chief, Radioactive Material Branch, Office of Hazardous MaterialsTransportation, DOT (202) 366-4545.Richard E. Cunningham, DirectorDivision of Industrial andMedical Nuclear SafetyOffice of Nuclear Material Safetyand Safeguards

Technical Contact:

J. Bruce Carrico, NMSS(301) 492-0634

Attachments:

1. Description of Incident2. Examples of a Source Assembly anda Model 500-SU Source Changer3. List of Recently Issued NRC Information Notices ATTACHMENT 1IN 90-56September 4, 1990 DESCRIPTION OF INCIDENTOn March 8, 1990, Amersham Corporation (Amersham), Burlington, Massachusetts, aU.S. Nuclear Regulatory Conmission (NRC) licensee authorized to manufacture anddistribute iridium-192 and cobalt-60 sealed sources for use in Industrialradiography equipment, received a shipment of 14 source changers from its Seoul,Korea product distributor, NDI Corporation (NDI). The source changers (shieldeddevices routinely used by manufacturers to ship new, high-activity sources toradiography licensees, and by the radiography licensees to return "depleted,"lower-activity sources) were expected to be empty by Amersham and were,according to shipping documentation.When the source changers arrived at Amersham, the wooden shipping crate hadbroken apart, leaving the devices scattered over the floor of the truck trailer.The truck driver proceeded to remove pieces of the broken crate and to rearrangethe changers to ease their removal. As an Amersham technician approached thetrailer, his audible alarming dosimeter indicated increased radiation levels inthe area. Using a survey instrument, he measured radiation dose rates ofbetween 60 and 100 millirems per hour at an estimated 15 feet from the back ofthe trailer. The technician advised the truck driver to stay out of the areaand then informed Amersham's Radiation Safety Officer (RSO) of the situation.The RSO was able to identify and isolate the source changer that was emittingthe radiation. Performing surveys with a survey probe at the end of a longextension, the RSO measured radiation dose rates as high as 10 rems per hour atapproximately 18 inches and 150 remis per hour at contact with an unshieldedportion of the source changer. Amersham's employees later discovered that thesource changer contained a small sealed source capsule in the unshielded portionof the housing. Amersham employees were able to safely remove the capsule andsecure it in a hot cell for evaluation and analysis. Anersham's RSO thenadvised NRC's Region I office of the incident.Two inspectors were dispatched from Region I to perform a preliminary review ofthe event and to ensure that the materials and documents were preserved forlater investigation. The shipment of source changers originated in Seoul,Korea. It was transported to Los Angeles by ship, and subsequently carriedacross the United States by a domestic motor carrier. Therefore, the potentialexisted for significant radiation exposure to a variety of individuals,depending on proximity to the source and duration of exposure. Consequently,NRC dispatched an Incident Investigation Team (1IT) to perform a comprehensivereview of the event and to determine the potential for exposure to those whohandled the source changer and to members of the general public who came inclose proximity to it.The source had no manufacturer's identification markings or serial number.Amersham was able to determine that the capsule was a 2.4-curie, iridium-192Model 8 sealed source manufactured by Industrial Nuclear Company (INC) of SanLeandro, California. Through communications with INC; INC's Korean productdistributor, Boo Kyung Sa Ltd.; and the Korean authorities, the IIT identified ATTACHMENT 1IN 90-56September 4, 1990 Korea Industrial Testing Company (KIT) Seoul, Korea as the last user of thesource. The source had an initial activity of 56 curies on its date ofmanufacture, April 13, 1989. Amersham's Korean product distributor, NDI, alsoidentified KIT as the last user of the Amersham Model 500-SU source changer, inwhich the capsule was discovered.Most radiographic operations involve projecting a radioactive source out of itsshielded position within a radiography device into a pre-positioned tube. Inorder to facilitate handling, the source capsules are attached to one end of ashort piece of cable with a connector attached to the other end. This piece ofequipment is described as a 'source assembly.' An example of a typical sourceassembly is shown in Attachment 2. A drawing of Amersham's Model 500-SU sourcechanger is also shown.Apparently, Korean users were using source changers as storage devices fordecaying depleted sources, before disposal. To store a source in a Model 500-SUsource changer, the source capsule would be cut from the assembly, dropped intothe source tube, and would fall to the shielded position. After the sourcedecayed sufficiently, the source changer would be used to move the source to adisposal area. The IIT was able to verify that KIT used the source changerinvolved in this incident in such a manner, and that KIT failed to remove thesource before returning the source changer. Amersham reported that it hadreceived source changers containing severed source capsules (the source remainedin the shielded area) on two previous occasions, and that from 1985 to 1989, atleast nine source changers were returned from Korea with contaminated sourcetubes.Through document review and personnel interviews, the IIT was able to determinehow the source changer was returned to Amersham. In January 1990, KIT returnedthe Amersham source changer to NDI. Neither NDI nor KIT surveyed the sourcechanger, because both believed it to be empty; however, NDI did survey thestorage area where it stored the source changer and found only low radiationlevels. The KIT source changer and 13 others were then shipped to a packingcompany in Seoul and placed in a wooden transportation crate. The crate wastrucked to Pusan, Korea and delivered to a container freight station, where itwas loaded into a transoceanic shipping container and then onto a South Koreancontainer cargo ship. Except for identifying its destination and the shipper(NDI), the crate was unlabeled. A bill of lading identified the crate as M1 BOXRADIOISOTOPES," and a rider to the bill of lading-described the freight as.1 Box, 371 KGS, .23 CBM, Said to contain: 14 ea of transportation emptycontainer of radioisotopes' and Identified the source changers' model number(all were Amersham 500-SUs) and serial numbers.Eleven days after leaving Pusan, the ship docked at a Port of Los Anglesterminal, where the ocean container was removed and taken to a U.S. containerfreight station. Here the cargo was unloaded from the ocean container anddamage to the crate containing the 14 source changers first documented. Thecrate and other freight destined for the East Coast-were then loaded aboard anenclosed 48-foot trailer. Because the crate was to be the last item delivered, ATTACHMENT 1IN gO-56September 4, 1990 the crate was positioned in the front-right corner of the trailer, close to thetractor cab. The tractor-trailer, driven by a senior driver and a drivertrainee, arrived at its final destination, a trucking company warehouse nearLogan Airport in Boston, Massachusetts, after a seven-day cross-country trip.The drivers made 14 stops, during the trip, to weigh the truck, obtain food andfuel, and to unload other freight. When the crate was unloaded at the Bostonwarehouse, the workers noted that the crate was severely damaged and thatseveral of the source changers had fallen from the crate. The senior driverreturned the source changers to the crate, and warehouse workers later attemptedto repair the crate. The crate then remained in storage at the warehouse for 14days, waiting release by the U.S. Customs Service, after which it was trucked toAmersham's facility.In estimating whole-body doses for all persons who were postulated to have beenexposed to radiation during the transportation and storage of a possiblyunshielded source, the IIT found that it was unable to determine exactly whenthe source capsule may have been dislodged from the source changer tube orexactly where the source changer was positioned in the array of 14 changers.However, damage to the crate was observed when it was removed from the oceancontainer. Therefore, the IIT and the Korean authorities theorized that thecrate was damaged when it was loaded into the ocean container, and that theimpact may have been substantial enough to knock the source out of its shieldedposition. Estimates of radiation exposure were based on a worst-case analysis,which assumed that the source was located in the crate nearest any occupiedareas, and that the source was unshielded by the depleted uranium shields in thesame or adjacent source changers.IIT estimates of exposure ranged from no significant exposure for a U.S.Department of Agriculture Plant Protection Quarantine Officer who boarded thecargo ship to inspect its food provisions, to more than 27 and 34 rem for thedriver trainee and senior driver, respectively, who transported the cratecross-country. NRC also made arrangements with Oak Ridge AssociatedUniversities (ORAU), Medical Sciences Division, for cytogenetic evaluation ofthe five persons identified as having the highest potential for exposure. Thecytogenetic evaluation involved the examination of a randomly selected set oflymphocytes (a white blood cell) to determine how many in the set exhibitradiation-induced chromosome aberrations among 500 first-division metaphases.ORAU reported that four persons exhibited between 0 and 1 aberrations per 500metaphases scored, indicating that they were in the range for non-irradiatedpersons. The only person known to have been actually exposed to the source, thedriver who delivered the source changers to Amersham's facility (IIT estimatedexposure was 500 millirem) exhibited 2 aberrations per 500 metaphases scored,which is consistent with the estimated radiation exposure, but not an indicationof significant exposure. Korean authorities reported that no personnelexposures were identified for individuals who may have been exposed to theradioactive source in that countr ATTACHMENT 1IN 90-56September 4, 1990 The IIT has detailed its description of the incident, the methodology used inits investigation, and presented its findings and conclusions in NUREG-1405.Individuals who may be interested in obtaining more information about theincident may purchase copies of NUREG-1405 from:The Superintendent of DocumentsU.S. Government Printing OfficeP.O. Box 37082Washington, DC 20013-7082(202) 275-2060 or -2171orThe National Technical Information ServiceSpringfield, VA 22161 ATTACHMENT 2IN 90-56September 4, 1990 IR-192SOURCECABLELOCK BALLORIVE CABLECONNECTIONTypical Source Holder AmsamblyPADLOCK ANDSEAL WIREEW View of M0de1 Soo-Su Source Chan Attachment 3IN 90-56September 4, 1990 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to90-5583-44Supp. 190-5489-18Supp. 190-5390-5290-5190-50Recent Operating Experi-ence on Loss of ReactorCoolant Inventory WhileIn A Shutdown ConditionPotential Damage toRedundant Safety Equip-ment As A Result ofBackflow Through theEquipment and Floor DrainSystemSummary of RequalificationProgram DeficienciesCriminal Prosecution ofWrongdoing Committed bySuppliers of NuclearProducts or ServicesPotential Failures ofAuxiliary Steam Piping andthe Possible Effects on theOperability of Vital Equip-mentRetention of BrokenCharpy Specimens8/31/908/30/908/28/908/24/908/16/908/14/90All holders of OLsor CPs for nuclearpower reactors.All holders of OLsor CPs for nuclearpower reactors.All holders of OLsor Cps for nuclearpower reactors.All holders of OLsor CPs for nuclearpower reactors.All holders of OLsor CPs for nuclearpower reactors.All holders of OLsor CPs for nuclearpower reactors.All holders of OLsor CPs for nuclearpower reactors.All holders of OLsor CPs for nuclearpower reactors.Failures of Voltage-Dropping 8/8/90Resistors in the PowerSupply Circuitry of ElectricGovernor SystemsMinimization of MethaneGas in Plant Systems andRadwaste Shipping Containers8/8/90OL -Operating LicenseCP -Construction Permit