ENS Event | |
|---|---|
06:00 Nov 16, 2020 | |
| Title | |
| Event Description | The following information was obtained from the State of Iowa via email:
A maintenance technician at the 3M facility in Knoxville, Iowa discovered that a Thermo Fisher Scientific model SULP-77A fixed gauging device containing 661 milliCuries of Krypton-85 had a shutter that was stuck open and would not close. This discovery occurred when the production line was shutdown for routine maintenance. The RSO [Radiation Safety Officer] and backup RSO were notified and the gauge was isolated with caution tape to prevent personnel from getting close to the device. 3M maintenance personnel are authorized to perform shutter repair under the supervision of the RSO or backup RSO by Iowa radioactive materials license number 0042-1-63-FG. The licensee will provide a written follow-up report once repairs have been completed and the cause of the failure identified. The licensee had a service provider operating under reciprocity with Iowa onsite November 17, 2020 to troubleshoot and repair the gauge. The root cause of the stuck shutter was a broken shutter return spring. A new shutter operating cylinder with a new return spring was installed and the gauge shutter was tested and found to be operating correctly. To minimize the chance of future shutter closure failures, the shutter operating cylinders will be replaced for all beta gauges of the same model that are currently in use at the site. Cylinder replacement will occur during future planned maintenance activities. These failures are exceedingly rare. This is the first occurrence in more than 20 years of using these gauges. The site is considering implementing a preventative maintenance replacement of these cylinders every 10 years. Iowa report number: IA200004 |
| Where | |
|---|---|
| 3M Knoxville, Iowa (NRC Region 3) | |
| License number: | 0042163FG |
| Organization: | Iowa Department Of Public Health |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+363.92 h15.163 days <br />2.166 weeks <br />0.498 months <br />) | |
| Opened: | Randal Dahlin 09:55 Dec 1, 2020 |
| NRC Officer: | Howie Crouch |
| Last Updated: | Dec 8, 2020 |
| 55015 - NRC Website | |
3M with Agreement State | |
WEEKMONTHYEARENS 559842022-07-07T20:15:0007 July 2022 20:15:00
[Table view]Agreement State Stuck Open Shutter ENS 550152020-11-16T06:00:00016 November 2020 06:00:00 Agreement State Stuck Open Shutter ENS 550012020-11-16T05:00:00016 November 2020 05:00:00 Agreement State Gauge Shutter Stuck Open 2022-07-07T20:15:00 | |