Event Notification Report for February 14, 2022

EN Revision Imported Date: 2/14/2022

EN Revision Text: PART 21 INTERIM REPORT - FAILURE OF AMETEK 300V, 250A CLAMP DIODES

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

"COMPONENT DESCRIPTION - 300V, 250 A clamp diodes with Vishay/International Rectifier part numbers IN3737 and IN3737R and Ametek part numbers 07-600250-00 and 07-600251-00, respectively. Diode failures occurred in 20kVA Inverters, Ametek part number 85-VC0200-41 with serial numbers C84733-0211 and C84733-0511. Two failed diodes returned for evaluation were manufactured in India in 2004.

"PROBLEM EXPERIENCED - TVA has experienced 5 diode failures since November of 2017. The diode failures experienced at TVA resulted in alarms for abnormal conditions and equipment alarms for fan failure, inverter fuse blown, and inverter failure. The equipment will transfer to bypass when a diode fails.

"POTENTIAL CAUSE - Diodes installed in the TVA equipment were shorted in most cases and degraded in one instance. Only two of the shorted diodes were sent to AMETEK SCI for evaluation.

"While the precise cause of this failure is unknown, diode failures are generally attributed to transient voltage spikes and overheating. TVA did indicate there have not been any transient events on the DC bus that could have caused this failure.

"The inverters at TVA are loaded below 50%. This could contribute to increased heat and stress on the diodes due to increased current draw. However, test data from the original testing of the equipment at no load did not show elevated temperatures on the diodes.

"EFFECT ON SYSTEM PERFORMANCE - Failures described above could result in loss of output voltage and transfer of the static switch to the bypass source which could result in potential loss of load.

"EVALUATION OF THE POTENTIAL DEFECT - AMETEK is sending the parts to the original manufacturer for further evaluation with the intent to obtain more insight on the interior condition of the diodes. The targeted completion date for this evaluation of the two diodes returned is June 1, 2021."


* * * UPDATE FROM ETHAN SALSBURY TO DONALD NORWOOD AT 0648 EDT ON 4/6/2021 VIA E-MAIL* * *

What is being classified as a 'minor adjustment' is being made to the notification originally submitted on 4/1/2021.

"All diodes TVA identified as failed were shorted. None were degraded."

Notified R2DO (Miller) and the Part 21/50.55 Reactors E-mail group.

* * * UPDATE FROM ETHAN SALSBURY TO THOMAS HERRITY AT 1145 EST ON 02/11/2022 VIA EMAIL * * *

The following excepts provide a synopsis of information provided by AMETEK in the final report.

"... The failure was caused by electrical overstress, but the specific root cause is indeterminate.

"PROBLEM YOU COULD SEE: A diode failure could occur and will result in the equipment transferring to bypass, a loss of output voltage, blown fuses, and unexpected alarms such as fan failure, inverter fuse blown, and inverter failure alarms. There are no conclusive warning signs that a failure is imminent, or detection method for predicting an approaching failure.

"CAUSE: Diodes that failed in the TVA equipment were shorted according to the summaries provided by TVA. Only two of the shorted diodes were sent to AMETEK SCI for evaluation. The condition of all other diodes is unknown.

"While the precise cause of this failure is unknown, diode failures are generally attributed to transient voltage spikes and overheating. TVA did indicate there have not been any transient events on the DC bus that could have caused this failure. Additionally, AMETEK sent a representative to the site to review the equipment and operating conditions. The field service technician concluded that there were no abnormalities apparent in the operating conditions or the equipment itself.

"According to TVA, the inverters at TVA are loaded below 50%. The AMETEK field service representative determined load was at 25% of full load during the site visit in August of 2021. This could contribute to increased heat and stress on the diodes due to increased current draw. However, there was no indication of overheating of the diode at no load or 25% of unit C84733- 0511 (1-II). All diodes were within acceptable temperature conditions on the equipment evaluated.

"EFFECT ON SYSTEM PERFORMANCE: Failures described above could result in loss of output voltage and transfer of the static switch to the bypass source which could result in potential loss of load.

"ACTION REQUIRED: AMETEK Solidstate Controls recommends that each facility evaluate the potential risk and performs replacement as determined necessary. Evaluation could include oscilloscope measurements across the diodes and temperature measurements of the diodes and the equipment. Voltage readings from the oscilloscope measurement should not exceed the rating of the diode. Temperatures should be compared to original test data and should not exceed 100ø C.

"Recent evaluations have been unable to pinpoint a failure mode and there are no conclusive connections to previous failures. Only the failures provided in this report have surfaced for the subject part numbers and the failure rate has been low.

"AMETEK SOLIDSTATE CONTROLS CORRECTIVE ACTION: AMETEK Solidstate Controls will work with you to arrange replacements and spare parts for your application as needed. Please contact our Client Services group at 1-800-222-9079 or 1- 614-846-7500, extension 1."

Notified R2DO (Miller) and the Part 21/50.55 Reactors E-mail group.

EN Revision Imported Date: 2/14/2022

EN Revision Text: AGREEMENT STATE REPORT - LOST PACKAGE CONTAINING RADIOACTIVE MATERIAL

The following was received via email from the Massachusetts Radiation Control Program:

"On 01/18/22 the Massachusetts Radiation Control Program (the `Agency') received a telephone report of a missing shipment of radioactive material. The package contained 28 mCi of S-35 (half-life of 87.3 days) in liquid form, in 4 vials at 0.561 mL per vial, in one White-I package, and was sent by PerkinElmer, Inc. (the `licensee') to Associated Regional and University Pathologists, Inc. (the `customer') via [common courier]. The package was sent from the licensee on 12/15/21 and tracking information showed it arrived at the courier's facility on 12/16/21 but never left. The customer notified the licensee on 12/21/21 that they never received the package. The licensee was periodically contacting the courier for status updates in an attempt to recover the package. The licensee informed the courier of the importance of maintaining custody of radioactive material shipments until they are delivered.

"On 02/02/22 the licensee notified the Agency that their internal investigation to locate the package was closed and that the licensee considers the package lost for good. The licensee estimates that no person received greater than 1 mrem TEDE [total effective dose equivalent] as a result of the missing package.

"The Agency considers this event to be closed."

THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf

EN Revision Imported Date: 2/14/2022

EN Revision Text: AGREEMENT STATE REPORT - STOLEN TRITIUM EXIT SIGNS

The following information was received from the state of Arizona via email:

"The Department received a call from a construction project manager who stated that 110-116 tritium exit signs were stolen by a contractor and are being held at his residence in Flagstaff, Arizona. A police report has been filed with the Coconino Police Department.

"Additional information will be provided as it is received in accordance with SA-300."

AZ report no.: 22-001

EN Revision Imported Date: 2/14/2022

EN Revision Text: AGREEMENT STATE REPORT - MISSING SOURCE

The following information was received from the state of Ohio via email:

"On 1/28/22 a verification of source inventory indicated a sealed source was missing. The source is an Sr-90 sealed source, activity of 0.32 milliCi, used in a Model 2210 irradiator. Subsequent surveys were performed in the area where the source should be and where it may have been handled, as well as a visual search of the entire facility was conducted and the source could not be located. A voicemail was left with the Ohio Department of Health (ODH) as a "heads up" of the ongoing investigation. A follow-up call was made to ODH on the morning of 1/31/22 to ensure that the message had been received.

"An investigation was conducted including interviews with personnel who have access to the locked cabinet the 2210 irradiator was stored in. The previous inventory check conducted on 7/20/2021 indicated the 2210 irradiator was stored in a secure cabinet. Access is limited to 3 employees only. The employee who indicated he most likely handled the irradiator last in the August 2021 timeframe could not remember if he removed the source holder and cap from the irradiator or not. There was also no communication to the Radiation Safety Officer to indicate movement of the source took place.

"It was also determined that a radioactive waste shipment was made on 12/6/2021 (Veolia Environmental Services/Alaron Nuclear Services). Alaron was called to determine if the shipment was still available. The shipment is still at the Alaron facility and the contents will be verified the week of 2/7/2022. There is a chance the source was included in the shipment since it is an old source with an assay date of approximately 2003. The employee who handled the source last also assisted in determining and gathering the older sources for disposal.

"To insure employee safety and find the missing source, surveys of all areas of the building were started utilizing a calibrated Bicron Microrem. Employees of all departments were asked to search their areas for the missing source and irradiator. Additional discussions and a meeting were conducted to further investigate what could have happened. The employee cannot be sure if he disassembled the irradiator or not. If the source holder and cap were removed, he would have placed it in a white plastic pig and applied a label with the serial number on it. The source capsule is received from our source supplier already in the holder and cap. We do not remove the actual source capsule from the holder and cap. Photos of the source holder and cap as well as the white plastic pig have been sent to Alaron for their reference when they inventory the waste shipment.

"Surveys of all bench tops and storage areas have been conducted and all are at their normal background levels.

"As of this writing, the source has not been located."

OH report no.: OH220002

THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf