Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 46356 | 23 October 2010 14:07:00 | A Troxler portable density gauge was run over by a forklift at a construction site. The source rod was retrieved into the gauge by the RSO. The damaged gauge was surveyed and then the gauge was removed for transport to the company office. The construction site was surveyed to ensure both sources were in the gauge. The licensee is reviewing their procedures to determine what can be done to reduce the risk of this type of incident happening again. The density gauge is a Model 3430 Troxler with a nominal 8 mCi Cs-137 gamma source and a 40 mCi Am-241:Be neutron source. North Dakota Incident #: ND10005 |
| ENS 45949 | 24 May 2010 12:05:00 | 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 hours, 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 hours. 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. |
| ENS 44340 | 9 July 2008 17:03:00 | Midwest Industrial X-ray, Inc. was performing radiography at an ethanol plant in Casselton County, ND. After taking a shot, the radiographer was retracting the source when it became detached. The radiographer covered the source with a lead blanket and contacted the company Radiation Safety Officer. The camera contained a 24.5 Ci Ir-192 source. The licensee transported the source back to their facility. The licensee performed calculations that indicated the radiographer received approximately 4 Rem exposure while securing the source. No calculations were reported concerning the assistant radiographer. The calculations performed by the State of North Dakota indicate that the radiographer received greater than 5 Rem. Both individual's film badges were sent to Landauer laboratories for processing. The State of North Dakota will be investigating this incident.
The doses for the lead radiographer are as follows: The badge reading for this monitoring period (June 20 - Jul 8) 575 mR. The yearly total deep dose is 827 mR. Notified FSME (Lewis) and R4DO (Hay)
This agreement state report update was received via e-mail: Initial Assumption: the source was full exposed in the source tube between the camera and the collimator; the exposure time estimate was 2 minutes; estimated average distance to source was 0.3 meters; gamma constant = 0.59; source strength = 24.5 Ci; and estimated exposure was 5.3 mR. Investigation Results - Hardware: The camera was a QSA 660B. Maintenance had been performed on this camera two days prior to this event. The source became detached from the wire and lodged inside the camera at or near the connection between the camera and the guide tube. The survey meters used were NDS-2000. Both had recently been calibrated. The one that failed had been sent in for repair in November 2007. The RA-500 worn by (the assistant radiographer) had been sent in twice for repair. We will follow up with asking the company to review the maintenance records for these two devices to determine if they should be replaced ahead of schedule. Investigation Results - Personnel and Dose update: the primary person exposed was (the assistant radiographer). By Thursday afternoon his annual badge exposure data had been compiled, including the expose for this event. This data is as follows: deep total - 825 mR, lens - 839 mR and Shallow - 835 mR. The badge for the period June 20 - July 19 was read by Landauer on July 11, 2008, and indicated 575 mR. Dosimeter data for the badge period showed a dose of 88 mR. The badge reading - the badge period dosimeter data shows an exposure of 487 mR for this event. There were four other personnel involved in the actual event and source retrieval. They are (job lead radiographer, dose: 40 mR); (radiographer, dose: 40 mR), (intern, dose: 32 mR) and (RSO, dose: 55 mR). These data were taken from the pocket dosimeters. Investigation Results - Source Recovery: There are some inconsistencies between what was stated to have happened and what the investigators believe could have happened. Most relate to positions with respect to the camera/source. We expect to have these resolved by Friday, July 18, 2008. Notified FSME (Lewis) and R4DO (Johnson).
Investigation Results - Hardware: The QSA Model 660B camera and control cable was returned to QSA for evaluation. QSA's evaluation determined the problem was a 'misconnect' not a 'disconnect' of the source assembly from the drive cable. The 'misconnect' was due to wear on the plug assembly, the male connector and the apparent age of the drive cable. The NDS 2000 survey meter used by (the assistant radiographer) failed to respond due to a loose battery connection. The Alarm Rate Meter worn by (the assistant radiographer) failed to alarm. This meter had been sent to NDS to have the audio transducer replaced in December and was calibrated at that time. After the incident, the meter was tested in Midwest's lab and the meter did not chirp until 750 mR/hr and was continuous at 1000 mR/hr. According to NDS, this is a 'Low Battery' indication. The rate meter (the assistant radiographer) used did not have a low battery indicator light. Investigation Results - Conclusions: 1) The alarm rate meter failed due to a low battery condition. 2) The survey meter failed due to a battery disconnect. 3) (The assistant radiographer) read his survey meter while on the platform, next to the camera, saw it read '0', but did not realize the significance of the reading and get off the platform and back on the ground. The survey meter was repaired and the battery was replaced in the alarm rate meter. Both devices were returned to service. Investigation Results - Department Actions: The North Dakota Department of Health considers this investigation closed. No penalties will be assessed against Midwest Industrial X-Ray, Inc. Notified R4DO (Bywater) and FSME EO (Bradford). |