ENS 48933
ENS Event | |
|---|---|
05:00 Apr 15, 2013 | |
| Title | Agreement State Report - Contaminated Radiography Camera |
| Event Description | The State of Oklahoma received a report from the licensee, that a new SPEC-150 Radiographer camera was giving an unexpected high radiation reading of 20 mrem. The State responded to the licensee's location to investigate. Contamination was detected on the exterior of the camera, guide tube, and cable. Contamination was also detected on the truck used to transport the camera. The camera had been used at a natural gas plant in Wheeling, Texas. There was no apparent damage to the camera and efforts to decontaminate the camera were unsuccessful. The licensee has placed the camera in a container and stored it in a secure location. It is believed the camera may have a manufacturer defect. The manufacturer has been notified. The truck has been decontaminated.
The State of Texas has been notified and they will determine if any contamination is present at the natural gas plant in Wheeling, Texas. The radiographer and his assistant were checked for contamination and none was found and no internal exposure is expected. The radiographer's dosimeter indicated 10 mrem and the assistant's dosimeter indicated 0 mrem. Both radiographer's film badges have been sent out for processing. The States of Oklahoma and Texas will continue their investigations and provide additional information when it is available.
The following update was received from the State of Oklahoma by email: On Monday afternoon, April 15, 2013, radiographers of Hi-Tech Testing Service, (Oklahoma license OK-32150-01 located in Seiling, OK) were working at a natural gas plant near Wheeler, Texas. After doing their survey following retracting the source, they noted high levels of radiation coming from the right rear truck bed. The camera was not nearby, and there was no obvious source for the radiation. They contacted their RSO [Radiation Safety Officer] and after ensuring that the source was properly retracted and in the camera, and all known sources of radiation were accounted for, they still had the anomalous high reading. The RSO instructed them to return to the office. After some work, the RSO was able to remove the contamination with duct tape. He reported that using an ND-2000 radiation meter in near contact, the duct tape registered approximately 1 R/hour [Rem] (1000 mrem/hour). He reported that the bed was now showing no radiation, and that the radiography camera and associated equipment were showing no radiation. He secured the contaminated tape in his vault, and advised Oklahoma DEQ [Department of Environmental Quality] of this on Monday evening. On Tuesday [4/16/13] morning, DEQ inspectors arrived at the facility to investigate. As a courtesy, we [Oklahoma DEQ] had advised Texas DSHS [Department of State Health Services] radiation control of the report, and possible contamination concerns at the work site in Texas. [Oklahoma] DEQ inspectors checked the area and equipment, including the radiography camera and associated equipment, the radiography truck used during the event, and the shop area where the camera and equipment had been worked on by the RSO. Contamination was found on the bed of the truck in a location where radiographers reportedly assemble and disassemble the camera and associated equipment. Removable contamination was found on the collimator that had been used during the exposures. Radiation was measured from the guide tube and from the crank cable. The radiation in the crank cable extended for several feet from the end of the cable that attaches to the radiography camera, consistent with contamination of the cable from contact with the (presumably contaminated) interior of the guide tube. Other than the bed of the truck, no contamination of the truck was found in this survey. The exterior of the camera was wiped, but no removable contamination was found. Analysis with a portable gamma spec showed that all contamination was Ir-192. Measured radiation levels in near contact on the equipment and truck varied, but were in the hundreds of microR/hour, with the highest being about 800 microR/hour on the collimator. It is important to note that none of this contamination was detectable with the radiography company's instrument, an ND-2000. Separately, we [Oklahoma DEQ] verified the licensee RSO's measurements of the contaminated duct tape that he had used to remove the bulk of the contamination from the truck bed. The tape was under lead shielding in an ammo box that had been used as a transport container, and we did not remove the tape from the container, but got readings in the hundreds of milliR/hour, consistent with the one R in contact figure reported by the company RSO. The radiographers involved live a long distance from the licensee office and were not available to be surveyed or interviewed in person while we were on site. The licensee reports this was the first time that the camera, guide tube, and crank cable had been used (see dates below). We are told that this equipment had been used only together, and had not been used with other equipment, and that it had only been used at the Wheeler, TX. job site. [Oklahoma] DEQ staff worked with the company RSO to remove the remaining contamination from the bed of the pickup truck. Contamination appeared to be in discrete spots on the bed, and removal appeared to be an all or nothing matter Attempts to remove the contamination with duct tape would fail repeatedly, then after another attempt it appeared that all contamination associated with that spot had been removed. Some of the people participating claimed to be able to see a small dark spot on the tape after the successful removal, consistent with a small chip of Ir-192 remaining on the tape. When we concluded our work, all levels we could find on the truck bed were 10 microR/hour or less in near contact. The contaminated guide tube, crank cable, collimator, and all wastes associated with the decontamination efforts were placed in plastic bags where possible, placed in a large trash can, and secured in the licensee's vault for removal. The work bay where all surveys had taken place was surveyed and found to be uncontaminated. [Oklahoma] DEQ staff and the licensee RSO called SPEC, manufacturer and distributor of the equipment, and advised them of the situation. DEQ requested that SPEC arrange for packaging and shipment of all contaminated material back to SPEC. SPEC representatives were at the licensee facility on Wednesday, April 17, 2013 and packaged all contaminated material and equipment for shipment to SPEC. To our knowledge, the actual shipment has not occurred yet. We were advised verbally that the SPEC staff found very low (no further information is available at this time) contamination on the truck, and that they surveyed the two radiographers and the clothes they had worn during the incident, and found low (no further information available at this time) contamination on one radiographer's shirt sleeve. The radiographer estimates he wore the shirt for about 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br /> on the day of the incident, and had not worn it since. SPEC has taken custody of the contaminated shirt. We were told that SPEC personnel surveyed the homes and privately-owned vehicles of the radiographers last night and found no contamination. We are expecting a written report from SPEC. The tentative opinion of the [Oklahoma] DEQ inspectors and the licensee RSO is that our findings are consistent with the presence of a limited number of particles of Ir-192 that had been present on the outside of the source. How the contamination came to be there is unclear. However present, it seems likely that the contamination was deposited inside the guide tube during the initial exposures, and some contamination fell out of the guide tube during assembly and disassembly of the camera. The 'all-or-nothing' removal of contamination from each area suggests that the contamination was in the form of relatively sizable chips, not in the form of a very fine particulate. [Oklahoma] DEQ will continue to investigate. We have cooperated with Texas [DSHS] staff as described above, and have informed the state of Louisiana. We were told that Texas staff visited the job site in Texas, and were guided to a single location of use by facility staff, where Texas staff found no contamination. In interviews with the radiographers, Oklahoma DEQ staff were told by the radiographers that radiography had been conducted at several sites in the plant over several days. We informed Texas of this discrepancy and the possibility of additional sites that might need to be checked for contamination. We understand that Texas staff are meeting at the job site this afternoon with the licensee RSO, one of the radiographers, and SPEC staff to check for contamination at all sites where radiography was performed. This is an interim report based on initial investigations and phone conversations with many of the actors, and has not undergone substantial review. More information will be provided later of further actions, or of any corrections or clarifications needed. Camera was used for shooting at the job site from April 8-12, 2013 and on April 15, 2013. Areas of interest that appear to [Oklahoma] DEQ at this time include: 1) The licensee RSO was not able to detect contamination remaining on the truck bed, and had never identified any contamination on the associated equipment. [Oklahoma] DEQ found contamination at levels of definite concern present on both of these. The RSO was using an NDS-2000, a very common industrial radiography survey meter that is optimized for measuring high levels of radiation. Based on this experience, this model (and possibly similar instruments optimized for radiographer use) may not be sensitive enough to reliably detect contamination of this sort. [Oklahoma] DEQ was readily able to detect the contamination with a MicroR meter, portable gamma spec, and with a pancake probe. 2) How the source came to be contaminated with Iridium is of interest, especially how the source was shipped with external contamination present, if that was indeed the case.
The following update was received from the State of Oklahoma via email: On Thursday afternoon, Texas radiation control and SPEC personnel met with the licensee RSO and one of the radiographers involved in the incident at the Wheeler, TX job site. We are told they did surveys of all locations where radiography had been performed, and no contamination was detected. Notified R4DO (Drake) and FSME Event Resource via email. |
| Where | |
|---|---|
| Hi-Tech Testing Service Seiling, Oklahoma (NRC Region 4) | |
| License number: | OK-32150-01 |
| Organization: | Ok Deq Rad Management |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+36.75 h1.531 days <br />0.219 weeks <br />0.0503 months <br />) | |
| Opened: | Mike Broderick 17:45 Apr 16, 2013 |
| NRC Officer: | John Shoemaker |
| Last Updated: | Apr 19, 2013 |
| 48933 - NRC Website | |
Hi-Tech Testing Service with Agreement State | |
WEEKMONTHYEARENS 505992014-11-05T06:00:0005 November 2014 06:00:00
[Table view]Agreement State Agreement State Report - Lost and Recovered Radiography Camera ENS 489332013-04-15T05:00:00015 April 2013 05:00:00 Agreement State Agreement State Report - Contaminated Radiography Camera 2014-11-05T06:00:00 | |