Event Notification Report for December 10, 2020

EN Revision Imported Date: 12/10/2020

EN Revision Text: PART 21 REPORT - AMETEK 85-RP2675-01 POWER SUPPLY MOUNTING HARDWARE

The following is a synopsis of a Part 21 report received by email:

"SUMMARY - AMETEK Solidstate Controls recently discovered a concern with the structural integrity of the 85-RP2675-01 Rack Mounted Power supply. While qualifying a replacement part for an obsolete breaker, the left panel of the power supply came loose after the hardware had sheared during the seismic simulation testing of the qualification. The loss of structural integrity of the power supply led to internal shorting and a premature stoppage of the simulation testing.

"PROBLEM - During a seismic event, a structural failure of the power supply enclosure resulting in a loss of output could occur. At this point, it is suspected that the failure is related to a variation in the components that increased strain on the power supply enclosure, and it is indeterminate if there is a widespread deviation. It is also possible that the cause of the failure is attributed to inadequately sized hardware that supports the bottom panel of the power supply. In the current design, there are 3 #10-32 machine screws through each of the side panels that fasten to the bottom panel to support the transformer.

"AMETEK is unable to identify the actual structural support of power supplies in the field. In the recent testing performed, no support was provided under the power supply during the testing. If there is support in the end application from the bottom of the power supply, there may not be a structural concern as the connection screws would not be exposed to the same forces. In this instance, the power supply had been exposed to a peak acceleration of approximately 4.8 giga second. It should also be noted that acceptable results have been obtained in previous seismic tests and changes have not been made to the structure of the power supply since its initial design in 1996.

"ACTION RECOMMENDED - At this time, there are no actions to take as the evaluation is ongoing. The next step is to determine if the screws are likely to become overstrained with enough seismic force. To do this, AMETEK is repeating the test with two new power supplies. One power supply will not have any changes made to the structure while the second power supply will be enhanced to improve its seismic withstand capabilities.

"The enhancement is an increase in the size of the hardware to 1/4 inch bolts that connects the side panels to the bottom panel through 5/16 inch through holes with a nut and washers. In combination, these changes will increase the force required to shear the hardware [and] reduce the force on the bolt itself by allowing some movement to dampen the forces during a seismic event. While AMETEK believes this solution will be suitable, it has not been validated with a follow up seismic simulation test. Additionally, AMETEK is unable to determine the criticality of the applications the power supplies are installed in and if the safety function is required to be maintained during a seismic event, which will determine the need to take corrective actions.

"A report of the next seismic test results will follow upon completion as a final evaluation. The current expected date for completion is May, 2020. For questions or clarifications in the meantime, please contact Ethan Salsbury, Quality Director, at 1-614-410-6293."

* * * UPDATE ON 12/09/2020 AT 0819 EST FROM ETHAN SALSBURY TO OSSY FONT * * *

The following is an update of a Part 21 report received by email:

"ACTION RECOMMENDED - AMETEK does not consider this to be a likely failure based on these test results. Additionally, AMETEK is unable to determine the criticality of the applications the power supplies are installed in and if the safety function is required to be maintained during a seismic event, which will determine the need to take corrective actions. The following enhancements can be applied to power supplies in operation:
- Add a #10-32 nut to each of the six (6) mounting screws to avoid any lateral movement of the sheet metal parts that would lead to potential elongation or striping of the fastener.
- Add support to the bottom of the transformer to prevent horizontal forces on the support screws

"Although recent testing did not result in a similar failure, AMETEK is taking actions to enhance the design of the power supply. On new power supplies, the mounting hardware will use ¬" bolts that connect the side panels to the bottom panel through 5/16" through holes with a nut and washers. In combination, these changes will increase the force required to shear the hardware reduce the force on the bolt itself by allowing some movement to dampen the forces during a seismic event."

Notified R1DO (Bower), R2DO (Miller), R3DO (Feliz-Adorno), and R4DO (Kellar) and Part 21/50.55 Reactors via email.

EN Revision Imported Date: 12/8/2020

EN Revision Text: AGREEMENT STATE REPORT - STUCK OPEN SHUTTER

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

AGREEMENT STATE REPORT - STUCK IRRADIATOR SOURCE RACK

The following information was received via E-mail:

"The Agency [Illinois Emergency Management Agency] was contacted on 12/1/20 by Sterigenics U.S., LLC to advise that one of their pool irradiator source racks at the Schaumburg location had become stuck in the unshielded position on 11/30/20. The source rack, containing approximately 1.3 MCi of Co-60, was successfully returned to the shielded position and no exposures to personnel or the public resulted. All safety interlocks functioned as designed. This event did not result in any compromises to source security or to any safety or security systems. There is no indication of intentional misuse, theft or diversion at this time.

"On 12/1/2020, the Agency was contacted by the Radiation Safety Officer for Sterigenics U.S., LLC, to advise that in the middle of performing scheduled routine safety checks on 11/30/2020, authorized engineers reported that the east source rack failed to return to the shielded position as designed upon completion of a check. The west source rack lowered as designed without incident. Sources contained in the east source rack remained unshielded from approximately 1400 CST until 1648 CST. The event was immediately reported to the Radiation Safety Officer by the two authorized engineers performing the safety checks that day. The Radiation Safety Officer immediately responded to the site to assist in assessment and formulation of an action plan. After consultation with the Corporate Radiation Safety Officer, the Radiation Safety Officer and staff engineers were able to use a hand winch to successfully lower the rack of sources into the shielded position within the pool. Safety and security systems remain operational and functioned as designed throughout the source lowering process. There is no immediate hazard to workers or members of the public as a result of this incident.

"This morning [12/1/2020], source modules were removed without incident from the east source rack and are currently shielded and in safe storage at the bottom of the pool. Sterigenics staff are continuing their investigation into the cause for the stuck rack. All interlocks and safety systems were reported as operational. An action plan was formulated in conjunction with Corporate staff to safely and slowly raise the empty east rack using a hand winch so that it can be adequately inspected. IEMA staff will follow up later this afternoon for an update.

"A reactive inspection by inspectors is planned for later this week."

Illinois Reference Number: IL200024

AGREEMENT STATE REPORT - PORTABLE DENSITY GUAGE RUN OVER

The following was received from the State of Washington via email:

"On Monday, November 30, 2020, at a construction site at 2800 MLK Jr South, Seattle, WA, a density gauge was run over by a mini dozer. The source was extended and in use at the time. When the device was run over, the handle that is used to extend and retract the source rod broke off from the gauge completely, leading to concern that the source rod had also broken off. Personnel on site were evacuated and the area secured.

"Because of the concern that the source rod had broken off, it was necessary to wait until a licensed entity that had the ability to handle the unshielded source arrived on site to continue recovery operations. Also, shortly after the incident, Northwest Technical Services (NTS), was hired for remedial action.

"When NTS personnel arrived, they were able to determine that the source rod had not detached as feared. A leak test to check the integrity of the source revealed no leakage and the source rod was able to be retracted back into the shielded gauge. Radiation readings and additional leak tests in the area were conducted to ensure there were no remaining safety concerns. There were none.

"The damaged source was taken to Northwest Technical Services in Snohomish, WA and has been secured while awaiting disposal."

Washington Incident Number: WA-20-026.