ENS 52963
ENS Event | |
|---|---|
18:30 Sep 11, 2017 | |
| Title | Shutter Stuck in the Open Position |
| Event Description | License No 21-32682-01
Fixed Gauge Stuck Shutter-Stuck in the open/normal operating position No exposures Vega America Source Holder Model SHLG-2-45 Radionuclide: Cesium-137 5000mCi Source serial number 1485CO Source holder serial number 19509171 At approximately 1430 hrs (EDT) on 9/11/2017 the site RSO attempted to operate the shutter on source holder 10071949 (Hemlock identifier). The shutter operation failed; the shutter is stuck in the open position. There were no exposures as a result of the failed shutter operation. Operating the shutter was part of a field training program for area operations personnel. The source holder is located on site on the HP DPR Tank. [The RSO is] in contact with Vega Americas, the manufacturer, to determine a resolution plan. [The RSO] will follow up with a detailed report within 7 days and a complete investigation/resolution report once the gauge manufacturer has performed repairs on the gauge.
Reference: Fixed Gauge Stuck Shutter (written report) License No. 21-32682-01 Event No. 52963 Radionuclide: Cesium-137 5000 mCi Manufacturer: VEGA Americas (Cincinnati, Ohio 45209) Model Source Holder: SHLG-2-45 VEGA Americas Source Serial Number: 1485CO VEGA Americas Source Holder Serial Number: 19509171 Hemlock Semiconductor SAP Equipment Number: 10071949 On Tuesday, September 11, 2017 at approximately 1430 EDT, the RSO was conducting radiation training for operations personnel in the area. While attempting to operate the shutter on the source holder located on S-557 HP DPR tank, the shutter mechanism would not close. The shutter is stuck fully open, in the normal operating position. [The RSO] contacted the manufacture, Vega Americas, and they suggested applying lubricant to the shutter mechanism to attempt to operate the shutter mechanism. The shutter mechanism was lubricated multiple times throughout the day. The following morning the shutter would still not operate. The NRC was contacted to report the incident at that time. The NRC was contacted via phone and the incident was reported on September 12 at 0930 EDT. There were no radiological exposures as a result of the shutter malfunction. As part of a preventative maintenance plan the source shutters are lubricated and operated every 6 months. April 2017 was the last time scheduled routine maintenance was performed. This specific source was operated approximately 30 days with no issues being noted. Because this source is located at the top of a tower, a cover was previously built to help protect the source holder from the weather. There has been no loss of production as a result of the shutter malfunction. Hemlock Semiconductor Operations is in contact with Vega Americas, the manufacturer who is licensed with the NRC to repair the source holders. Vega's technician is scheduled to be on site September 18th, 2017 to perform repairs on the stuck shutter; we will not attempt to operate the shutter until repairs have occurred. The state of the stuck shutter has been thoroughly communicated to all personnel that are assigned to the general area. All operators assigned to the specific tower where the gauge is located, are Authorized Gauge Users. Area leaders, emergency response department and plant management have also been communicated to in reference to the stuck shutter. Any individual not assigned to the tower must badge into the area and contact an authorized gauge user to gain access to the tower where the gauge is located. The authorized gauge user will then contact the RSO or assistant RSO for approval for tower access. The gauge is located and operating in a manner consistent with our normal operating status. The normal signs and barriers are in place. This incident, any findings by Vega and any subsequence action items will be documented in our GIMS database (incident reporting and action item tracking tool), and a follow up email will be sent to the NRC.
Vega Americas field technician arrived at Hemlock Semiconductor on 9/18/2017. The following is directly from his field report: "'9/18/2017: [The Repair Technician] arrived on site and met with [RSO]. The customer has a stuck shutter on a SHLG-2-45 with a 5000mCi Cs-137 source, S/N 1485CO, CO# 6121698, TAG# LX-577007-A, dated 1/11 and with source holder S/N 19509171. [The Repair Technician] freed the shutter mechanism. Some water was released from the shaft well when the shutter was freed. Water intrusion appears to be the cause of the stuck mechanism. There was some buildup of either corrosion products or other material accumulated on the shaft of the operating mechanism. [The Repair Technician] cleaned the shaft using a scrub pad. [The Repair Technician] reattached the rubber top seal using spray adhesive. [The Repair Technician] operated the shutter multiple times without further issue. [The Repair Technician] performed a leak test and a survey at the customer's request. [The Repair Technician] recommended operating the shutter mechanism once a week for the next 2 months. If there are no further issues, then [the Repair Technician] recommended no further action. Shutter checks can be returned to a normal 6 month schedule. If the shutter becomes stuck again then [the Repair Technician] recommended the source holder be removed from service and repaired.' Per the recommendation we have been operating the shutter mechanism weekly. There have been no issues and the shutter is operating freely. Leak test and survey checks showed no issues with the source holder. This incident has been documented internally and will continue to be monitored. If the shutter continues to operate freely, Hemlock Semiconductor will consider this incident closed. Notified R3DO Daley and NMSS Events Notifications |
| Where | |
|---|---|
| Hemlock Semiconductor Operations Hemlock, Michigan (NRC Region 3) | |
| License number: | 21-32682-01 |
| Organization: | Hemlock Semiconductor Operations |
| Reporting | |
| 10 CFR 30.50(b)(2), Licensed Material Protection Equipment Failure | |
| Time - Person (Reporting Time:+15.27 h0.636 days <br />0.0909 weeks <br />0.0209 months <br />) | |
| Opened: | Kelley Deering 09:46 Sep 12, 2017 |
| NRC Officer: | Jeff Herrera |
| Last Updated: | Oct 17, 2017 |
| 52963 - NRC Website | |
Hemlock Semiconductor Operations with 10 CFR 30.50(b)(2) | |
WEEKMONTHYEARENS 529632017-09-11T18:30:00011 September 2017 18:30:00
[Table view]10 CFR 30.50(b)(2) Shutter Stuck in the Open Position 2017-09-11T18:30:00 | |