PNO-IV-96-065, on 961206,industrial Radiography Overexposure Occurred.Tulsa Gamma Ray Inc Radiographer Unlocked Vault Door & Retrieved Survey Instrument,Left Inside by Connell Partnership,Ltd Radiographer
| ML20135D131 | |
| Person / Time | |
|---|---|
| Site: | 03012319 |
| Issue date: | 12/09/1996 |
| From: | Linda Howell, Mark Shaffer NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| References | |
| PNO-IV-96-065, PNO-IV-96-65, NUDOCS 9612090259 | |
| Download: ML20135D131 (2) | |
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Decembnr 9,1996 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-IV-96-065 l This preliminary notification constitutes EAh'.Y notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is 7
known by Region IV staff in Arlington, Texas on this date.
j Facility Licensee Emeroency Classificalign Tulsa Gamma Ray, Inc. Notification of Unusual Event Tulsa Gamma Ray, Inc. Alert 1127 South Lewis Site Area Emergency Tulsa, Oklahoma 74104 General Emergency Dockets: 03012319 License No: 35-17178-01 X Not Applicable
Subject:
INDUSTRIAL RADIOGRAPHY OVEREXPOSURE On December 6,1996, a representative of Tulsa Gamma Ray, Inc. (TGR) notified Region IV j staff of an incident that occurred on November 20,1996, at Yuba Heat Transfer (YHT), a pressure vessel fabrication facility in Tulsa, Oklahorra. TGR radiographers perform radiography at YHT on a contract basis using equipment owned by a second NRC licensee, Connell Partnership, Ltd. (CPL), which is authorized to possess and use byproduct material at YHT's facility. YHT has a dedicated room (exposure vault) used for radiography. Although the exposure vault is not categorized as a permanent radiographic installation, it is equipped with audible and visualindicators (lights) to indicate the presence of radiation. CPL maintains an Amersham / Tech Ops Model 680B exposure device at YHT. On November 20, the exposure device was loaded with a cobalt-60 source of approximately 48 curies.
4 On November 20,1996, a radiographer employed by CPL performed several radiographic exposures on a pressure vessel. At approximately 4:00 p.m., the radiographer concluded his last exposure for the day and prepared to leave the facility. He was to be relieved by a TGR radiographer who would finish specified radiographs on the same pressure vessel. The CPL radiographer retracted the source (although the radiographer believed the source was fully retracted, it was later found to be partially exposed), exited the vault, and locked the door.
He subsequently returned to the vault to retrieve something and locked the door again on his
- way out of the vault.
i The TGR radiographer reported for work at approximately 4:35 p.m and met with CPL's radiation safety officer (RSO) to discuss his work assignment. He then proceeded to the exposure vault and noted that the exposure device, drive controls and source guide tube were already assembled in the exposure vault, having been left by the CPL radiographer. The TGR radiographer also neted that the alarm system for the vault was not working (it malfunctioned on November 18 and had not yet been repaired). The TGR radiographer unlocked the vault door and retrieved a survey instrument which had been left inside by the CPL radiographer.
The TGR radiographer entered the exposure vault at approximately 4:55 p.m. The TGR radiographer tested his personal monitoring devices to ensure that 9612090259 961209 PDR I&E PNO-IV-96-065 PDR 090095
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they were working and positioned his ear plugs because hearing protection is required at the facility. He next proceeded to retrieve film and other equipment needed to complete his work and positioned the source guide tube for the next exposure.
At approximately 5:20 p.m., '.he break whistle blew a:nf YHT employees temporarily suspended work. At this point, the noise levelin the facihty was greatly reduced, and the TGR radiographer noted that his alarm ratemeter was activated. He checked his pocket ,
dosimeter and found it offscale. The TGR radiographer exited the vault and attempted to retract the source; approximately 6 turns of the drive cable cranks were required to fully retract the source. The radiographer confirmed, by survey, that the source was fully retracted to it shielded position and promptly notified a TGR manager and the CPL radiographer of the incident.
The CPL RSO, TGR representative and both radiographers met at the f acility on November 20 to perform a re-enactment of the incident. Dose calculations were completed and both radiographers' film badges were sent for processing. TGR received a report from the film badge vendor for both badges during the week of November 25. The TGR representative stated that the reported dose for a film badge worn by the TGR radiographer during the month of November was 6.465 rems, bringing his annual dose for 1996 to a total of 8.3 rems. The CPL RSO reported during a subsequent telephone conversation that the dose reported by the undor for a film badge worn by the CPL radiographer during the month of November was 630 l rmilirems. The CPL RSO stated that his radiographer failed to perform a survey of the l
exposure device after the last exposure completed on his shift. The radiographer apparently believed that the source was fully retracted because he felt resistance in the drive cables; I however, the CPL RSO noted that the 21-foot guide tube was positioned such that it was flexed at one point as it exited the pressure vessel.
l Region IV has dispatched an inspector to begin an inspection today. The inspection will l include a review of both licensees' activities.
l The state of Oklahoma has been informed.
Region IV received notification of this occurrence by telephone from a TGR manager at approximately 3:30 p.m. The CPL RSO was subsequently contacted by telephone by Region IV staff. Region IV has informed NMSS.
This information herein has been discussed with the licensee and is current as of 5:00 p.m.
on December 6,1996.
Contact:
Linda L. Howell Mark Shaffer (8171860 8213 (8171860-8287
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