ML15314A031
| ML15314A031 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 10/23/2015 |
| From: | Woolard S Engine Systems |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 10CFR21-0113, Rev. 0 | |
| Download: ML15314A031 (5) | |
Text
ES)ENGINE 17reigh Road SYSTEMS, INC.
Rocky Mount, NC 27804 Telephone: 252/977-2720 Fax: 252/446-1134 October 23, 2015 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555-0001
Subject:
10CFR21 Reporting of Defects and Non-Compliance -
Engine Systems, Inc. Report No. 10CFR21-0113, Rev. 0 Speed Switch Capacitor Failure P/N ESI50267B
Dear Sir:
The enclosed report addresses a reportable notification of a capacitor failure in a speed switch, P/N ESI50267B, supplied to Progress Energy - Harris Nuclear Plant.
A copy of the report has been mailed to our affected nuclear customer.
Please sign below, acknowledging receipt of this report, and return a copy to the attention of Document Control at the address above (or, fax to number 252/446-1134) within 10 working days after receipt.
Yours very truly, ENGINE SYSTEMS, INC.
Susan Woolard Document Control Please let us know if ANY of your mailing information changes - name of recipient, name of company/facility, address, etc. Mark the changes on this acknowledgment form and send to us by mail or FAX to the number above.
RECEIVED:__________
93 DATE: __ _ _ _ _ _ _ _ _
Quality Performance With Pride
(S)ENGINE SYSTEMS, INC. 175 reiht RadRock Mont, C 2804Telephone: 252/977-2720 Fax: 252/446-1134 Report No. 10CFR2I-0113 Rev. 0: 10/23/15 10CFR21 REPORTING OF DEFECTS AND NON-COMPLIANCE COMPONENT: Speed Switch Capacitor Failure P/N ESI50267B SYSTEM: Emergency Diesel Generator CONCLUSION: Reportable in Accordance With 10CFR21 Prepared By:- Date: /0/,23//5" E*ngineerin'g Manager Reviewed By:- Date: __-,____-/_-
Quality Manager Quality Performance With Pride
Report No. 10CFR21-0113 Record of Revisions Page: 1 of 1 REV DATE PAGE DESCRIPTION 0 10/23/15 Initial issue.
Report No. 10CFR21-0113 Revision: 0 Date: 10/23/15 Page: 1 of 2 Component:
Capacitor installed in speed switch P/N ESI50267B.
Su mmary:
Engine Systems Inc. (ESI) began a 10CFR21 evaluation on August 26, 2015 upon notification by Harris Nuclear Plant of a ground fault condition after installing two speed switches, P/N ESI50267B, supplied by ESI. Subsequent investigation revealed the condition was due to a failed capacitor installed across the relay output to ground within each speed switch. The evaluation was concluded on October 22, 2015 and it was determined that this issue is a reportable defect as defined by 10CFR Part 21. The speed switch output contacts are utilized in the engine's start circuitry and failure of the contacts to function properly could adversely affect the safety-related operation of the emergency diesel generator set.
Discussion:
The speed switch, P/N ESI50267B, is a later design switch that operates at nominal 125 VDC and is also EMI/RFI compliant per EPRI TR-1 02323, rev.3. Previous design speed switches operated at 24 VDC and required a separate 125/24 VDC power supply for applications using 125 VDC supply voltage. During the course of EMI/RFI qualification for the 125 VDC unit, it was determined that some modifications to the manufacturer's design were required to meet the susceptibility requirements of RS103. One of these modifications was the installation of eight (8) capacitors across the relay output contacts to ground. In cooperation with the speed switch manufacturer, capacitors were selected for EMI/RFI compliance and testing was completed to verify conformance to EPRI TR-1 02323, rev.3.
ESI continued with all remaining qualification activities and supplied the speed switches as dedicated, safety-related items to Harris Nuclear Plant. Following installation of two of the speed switches, Harris reported a ground fault condition in the DC voltage system. Troubleshooting determined that the normally open contact of relay 2 on both speed switches had an internal short to ground. The speed switches were returned to ESI and on September 8, 2015 a joint failure analysis was performed with Harris and ESI representatives. Troubleshooting confirmed a low resistance to ground and determined the failed component to be a capacitor that was installed across the relay 2 output contact to ground on both speed switches.
impact on Operability:
If the resistance path to ground were sufficiently low, the ability of the relay output contacts to pick-up associated components would be compromised. In the case of Harris plant, the speed switch relays are used in the safety-related EDG start circuitry to energize electrically operated solenoid valves and relays. Failure to actuate any of these components could adversely affect the safety-related operation of the emergency diesel generator.
Report No. 10CFR21-01 13 Revision: 0 Date: 10/23/15 Page: 2 of 2 Root cause evaluation:
During selection of the components required for the switch to meet EMI/RFI compliance, capacitors were selected that had a voltage rating less than the system voltage of the intended application. The capacitors selected had 100 VDC rating whereas the system voltage is 125 VOC nominal, with voltages as high as 140 VDC. Failure analysis performed on the capacitors determined the failure was due to an Electrical Over Stress (EOS) event; whereby high voltage caused the electric charge to concentrate near the edge of the inner electrode print pattern which generated a stress failure at that location. Continued application of current at the shorted location generated heat and lead to crack propagation, as visibly noted on the failed capacitors.
Evaluation of previous shipments:
This issue only affects one part number (qty 6) supplied on one customer purchase order:
ESI Sales PatNme utmrCustomer ESI Serial Order PatNme utmrP.O. Numbers11 ) C-of-C Date Qty 3013598-1.1 -1 3013598-1.1 -2 3013958 ES150267B Duke Energy Progress - 3013598-1.1-3, 215 Harris Nuclear Plant 00761175pril10,10154 3013598-1.1-5
________________ ________ 3013598-1.1-6 _ _ _ _ _ _ _
Note (1): All six of the speed switches supplied to Harris have been returned to ESI under warranty. Serial numbers 3013598-1.1-5 and 3013598-1.1-6 were the failed assemblies. The remaining four speed switches were inspected and tested by ESI and no abnormal conditions were noted.
Corrective Action:
No action is required by the customer. All six affected speed switches have been returned to ESI under warranty.
To prevent reoccurrence the following actions are being implemented by ESI:
- For the specific Harris application to which P/N ESI50267B was supplied, the customer only requires compliance to the Electrically-Fast Transient/Burst testing (EFT) portion of EPRI TR-102323, rev.3. Therefore, the modifications that were performed to the speed switch to meet the entire EPRI TR-1 02323, rev.3 requirements will be removed. The only modifier remaining will be the metal oxide varistors (MOVs) that are installed for surge protection. This has been denoted internally via a manufacturer's part number change; however ESI will supply the speed switch under existing part number ESI50267B since this is an application specific part number that has only been supplied one time and all affected switches have been reworked.
This action has been completed.
- For all other applications requiring full compliance with EPRI TR-1 02323, rev.3, the capacitors installed across the relay outputs to ground will be upsized from 100 VDC to 200 VDC rating; thereby encompassing the system operating voltage upper limit. This action is being completed by the manufacturer and will be incorporated on all speed switches of this style going forward.
ES)ENGINE 17reigh Road SYSTEMS, INC.
Rocky Mount, NC 27804 Telephone: 252/977-2720 Fax: 252/446-1134 October 23, 2015 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555-0001
Subject:
10CFR21 Reporting of Defects and Non-Compliance -
Engine Systems, Inc. Report No. 10CFR21-0113, Rev. 0 Speed Switch Capacitor Failure P/N ESI50267B
Dear Sir:
The enclosed report addresses a reportable notification of a capacitor failure in a speed switch, P/N ESI50267B, supplied to Progress Energy - Harris Nuclear Plant.
A copy of the report has been mailed to our affected nuclear customer.
Please sign below, acknowledging receipt of this report, and return a copy to the attention of Document Control at the address above (or, fax to number 252/446-1134) within 10 working days after receipt.
Yours very truly, ENGINE SYSTEMS, INC.
Susan Woolard Document Control Please let us know if ANY of your mailing information changes - name of recipient, name of company/facility, address, etc. Mark the changes on this acknowledgment form and send to us by mail or FAX to the number above.
RECEIVED:__________
93 DATE: __ _ _ _ _ _ _ _ _
Quality Performance With Pride
(S)ENGINE SYSTEMS, INC. 175 reiht RadRock Mont, C 2804Telephone: 252/977-2720 Fax: 252/446-1134 Report No. 10CFR2I-0113 Rev. 0: 10/23/15 10CFR21 REPORTING OF DEFECTS AND NON-COMPLIANCE COMPONENT: Speed Switch Capacitor Failure P/N ESI50267B SYSTEM: Emergency Diesel Generator CONCLUSION: Reportable in Accordance With 10CFR21 Prepared By:- Date: /0/,23//5" E*ngineerin'g Manager Reviewed By:- Date: __-,____-/_-
Quality Manager Quality Performance With Pride
Report No. 10CFR21-0113 Record of Revisions Page: 1 of 1 REV DATE PAGE DESCRIPTION 0 10/23/15 Initial issue.
Report No. 10CFR21-0113 Revision: 0 Date: 10/23/15 Page: 1 of 2 Component:
Capacitor installed in speed switch P/N ESI50267B.
Su mmary:
Engine Systems Inc. (ESI) began a 10CFR21 evaluation on August 26, 2015 upon notification by Harris Nuclear Plant of a ground fault condition after installing two speed switches, P/N ESI50267B, supplied by ESI. Subsequent investigation revealed the condition was due to a failed capacitor installed across the relay output to ground within each speed switch. The evaluation was concluded on October 22, 2015 and it was determined that this issue is a reportable defect as defined by 10CFR Part 21. The speed switch output contacts are utilized in the engine's start circuitry and failure of the contacts to function properly could adversely affect the safety-related operation of the emergency diesel generator set.
Discussion:
The speed switch, P/N ESI50267B, is a later design switch that operates at nominal 125 VDC and is also EMI/RFI compliant per EPRI TR-1 02323, rev.3. Previous design speed switches operated at 24 VDC and required a separate 125/24 VDC power supply for applications using 125 VDC supply voltage. During the course of EMI/RFI qualification for the 125 VDC unit, it was determined that some modifications to the manufacturer's design were required to meet the susceptibility requirements of RS103. One of these modifications was the installation of eight (8) capacitors across the relay output contacts to ground. In cooperation with the speed switch manufacturer, capacitors were selected for EMI/RFI compliance and testing was completed to verify conformance to EPRI TR-1 02323, rev.3.
ESI continued with all remaining qualification activities and supplied the speed switches as dedicated, safety-related items to Harris Nuclear Plant. Following installation of two of the speed switches, Harris reported a ground fault condition in the DC voltage system. Troubleshooting determined that the normally open contact of relay 2 on both speed switches had an internal short to ground. The speed switches were returned to ESI and on September 8, 2015 a joint failure analysis was performed with Harris and ESI representatives. Troubleshooting confirmed a low resistance to ground and determined the failed component to be a capacitor that was installed across the relay 2 output contact to ground on both speed switches.
impact on Operability:
If the resistance path to ground were sufficiently low, the ability of the relay output contacts to pick-up associated components would be compromised. In the case of Harris plant, the speed switch relays are used in the safety-related EDG start circuitry to energize electrically operated solenoid valves and relays. Failure to actuate any of these components could adversely affect the safety-related operation of the emergency diesel generator.
Report No. 10CFR21-01 13 Revision: 0 Date: 10/23/15 Page: 2 of 2 Root cause evaluation:
During selection of the components required for the switch to meet EMI/RFI compliance, capacitors were selected that had a voltage rating less than the system voltage of the intended application. The capacitors selected had 100 VDC rating whereas the system voltage is 125 VOC nominal, with voltages as high as 140 VDC. Failure analysis performed on the capacitors determined the failure was due to an Electrical Over Stress (EOS) event; whereby high voltage caused the electric charge to concentrate near the edge of the inner electrode print pattern which generated a stress failure at that location. Continued application of current at the shorted location generated heat and lead to crack propagation, as visibly noted on the failed capacitors.
Evaluation of previous shipments:
This issue only affects one part number (qty 6) supplied on one customer purchase order:
ESI Sales PatNme utmrCustomer ESI Serial Order PatNme utmrP.O. Numbers11 ) C-of-C Date Qty 3013598-1.1 -1 3013598-1.1 -2 3013958 ES150267B Duke Energy Progress - 3013598-1.1-3, 215 Harris Nuclear Plant 00761175pril10,10154 3013598-1.1-5
________________ ________ 3013598-1.1-6 _ _ _ _ _ _ _
Note (1): All six of the speed switches supplied to Harris have been returned to ESI under warranty. Serial numbers 3013598-1.1-5 and 3013598-1.1-6 were the failed assemblies. The remaining four speed switches were inspected and tested by ESI and no abnormal conditions were noted.
Corrective Action:
No action is required by the customer. All six affected speed switches have been returned to ESI under warranty.
To prevent reoccurrence the following actions are being implemented by ESI:
- For the specific Harris application to which P/N ESI50267B was supplied, the customer only requires compliance to the Electrically-Fast Transient/Burst testing (EFT) portion of EPRI TR-102323, rev.3. Therefore, the modifications that were performed to the speed switch to meet the entire EPRI TR-1 02323, rev.3 requirements will be removed. The only modifier remaining will be the metal oxide varistors (MOVs) that are installed for surge protection. This has been denoted internally via a manufacturer's part number change; however ESI will supply the speed switch under existing part number ESI50267B since this is an application specific part number that has only been supplied one time and all affected switches have been reworked.
This action has been completed.
- For all other applications requiring full compliance with EPRI TR-1 02323, rev.3, the capacitors installed across the relay outputs to ground will be upsized from 100 VDC to 200 VDC rating; thereby encompassing the system operating voltage upper limit. This action is being completed by the manufacturer and will be incorporated on all speed switches of this style going forward.