ENS 45949
ENS Event | |
|---|---|
19:00 May 21, 2010 | |
| Title | Agreement State Report- Calibration Source Not Returned To Its Storage Holder |
| Event Description | The following information was received by e-mail:
About 0930 Weatherford International, LTD. (ND Lic # 33-45901-01) reported that at about 1500, May 21, 2010, in Williston, Williams County, ND, a well logging tool was [returned to] the truck with the calibration source still in the tool. The calibration source is Cs-137, strength about 55.5 GBq. This error was discovered about 1500, May 21, 2010. The source, when in the tool is highly collimated, restricting significant potential dose to a limited volume. The dosimeter badges for those working in the vicinity of the truck and those in an adjacent office have been sent in to Landauer for analysis. Drawings and estimated doses will be forwarded to NRC as soon as received from Weatherford. ND Incident #: ND10003
The information below is a summary of a report provided from Weatherford to the State of North Dakota. On May 21, 2010, a 1.5 Ci [55.5 GBq] Cs-137 source was placed into a logging tool for calibrations. After calibrations were complete, the tool containing the source was placed into a logging truck and left for approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, potentially exposing two Well Logging Supervisors, one District Manager and one Well Logging Assistant. On May 22, 2010 at approximately 1400 (MDT), one of the Well Logging Supervisors, while trying to perform after [job] calibrations for the job which he had returned, noted high gamma ray background readings and, using a survey meter, began searching the area looking for a reason why the background readings were higher than normal. At approximately 1600 (MDT), he began searching the shop and noted that the readings as he approached logging truck were extremely high. He and the Well Logging Assistant removed the density logging tool from the wireline unit and found that the density source was still in the tool. At this point, the 1.5 Ci Cs-137 source had been in the tool loaded on logging truck for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The facility employs twelve individuals, of which eight were not present at the facility during the period of 1600 on May 21, 2010 and 1600 May 22, 2010. On May 24, 2010, the dosimeters for the [two Well Logging Supervisors, the Well Logging Assistant,] one spare located in the office, one control and an employee's dosimeter, which was left on the desk, were sent to Landauer for analysis. It should be noted that one of the Well Logging Supervisors was not wearing his dosimeter during the incident. The incident was reconstructed and surveys were taken to aid in identifying the possibility of excess exposure to the District Manager and the Well Logging Supervisor that were not wearing dosimeters. The incident investigation uncovered many procedural issues including failure to document the removal of radioactive material (RAM) from storage (i.e., utilization records), failure to properly secure storage areas, failure to properly return RAM to storage and failure to establish a radiation area during calibration procedures. Because of not following proper procedures, [personnel actions were taken for one of the individuals involved]. [In addition], written corrective action has been given to one of the Well Logging Supervisors for not wearing a dosimeter while on duty and failure to notify management of an improperly secured storage area. All facility employees have been given a verbal corrective action on radiation procedures. Although there were many procedural violations, after analysis of the dosimeters and incident reconstruction surveys, Weatherford has no reason to believe an overexposure incident has taken place. Based on event reconstruction and available dosimeter readings, it is believed that none of the four employees exposed by this event received in excess of 18 mRem total effective dose equivalent. R4DO (Powers) and FSME EO (Watson) notified. |
| Where | |
|---|---|
| Weatherford International Limited Williston, North Dakota (NRC Region 4) | |
| License number: | 33-46901-01 |
| Organization: | North Dakota Department Of Health |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+65.08 h2.712 days <br />0.387 weeks <br />0.0891 months <br />) | |
| Opened: | Dan Harman 12:05 May 24, 2010 |
| NRC Officer: | Vince Klco |
| Last Updated: | Jun 15, 2010 |
| 45949 - NRC Website | |
Weatherford International Limited with Agreement State | |
WEEKMONTHYEARENS 459492010-05-21T19:00:00021 May 2010 19:00:00
[Table view]Agreement State Agreement State Report- Calibration Source Not Returned to Its Storage Holder 2010-05-21T19:00:00 | |