ML17333A379
| ML17333A379 | |
| Person / Time | |
|---|---|
| Site: | Vogtle, Farley  |
| Issue date: | 11/21/2017 |
| From: | Horner T Engine Systems |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML17333A379 (5) | |
Text
1111 05:09:11 p.m.
11-21-2017 ENGINE SYSTEMS, INC.
175 Freight Road Rocky Mount, NC 27604 Date:
Company:
Fax Number:
Verification No.:
Reference:
From:
Page:
Dear Sir:
TELEFAX November 21, 2017 NRC Operations Center 301/816-5151 301/816-5100 Report No. 1 OCFR21-0119, Rev. 0 Tom Horner 1 of 5 Following this cover is a copy of our report 10CFR21-0119, Telephone: 252/977-2720 Fax: 252/446-1134 Rev. 0, for a 1 OCFR21 reportable notification on a power supply, P/N 2938604.
A copy of this report will be mailed to the NRG Document Control Desk and to our affected nuclear customers.
Should you have questions, pl~ase let us know.
Sincerely, ENGINE SYSTEMS, INC.
~£/r-L_
Tom Horner
- Quality Manager Quality Performance With Pride 1 /5
1111 ENGINE SYSTEMS, INC.
175 Freight Road, Rocky Mount, NC 27604 05:09:24 p.m.
11-21-2017 Telephone: 252/977-2720 Fax: 252/446-1134 Report No.
10CFR21-0119 Rev. O:
11/21/17 10CFR2' REPORTING OF DEFECTS AND NON-COMPLIANCE.
COMPONENT:
Power Supply Part Number 2938604 SYSTEM:
Emergency Steam Turbine CONCLUSION:
Reportable in Accordance With 1 OCFR21 Prepared By: --f'"----~---=~'--*--*--------
VEnglneering Manager Reviewed By:~~---
Quality Manager Quality Performance With Pride Date:
11 /z, /17 Date: //-:Z/-/7 2 /5
1111 05:09:35 p.m.
11-21-2017 3/5 Report No.
10CFR21-0119 Record of Revisions Page:
1 of 1 REV DATE PAGE DESCRIPTION 0
11/21/17 Initial issue.
1111 Component:
Power supply P/N 2938604.
Summary:
05:09:43 p.m.
11-21-2017 4/5 Report No.
Revision:
- Date:
Page:
1 OCFR21-0119 0
11/21/17 1 of 2 Engine Systems Inc. (ESI) began a 10CFR21 evaluation on October 17, 2017 upon notification of a potential issue with power supply P/N 2938604 supplied to Vogtle Nuclear Plant. The power supply is Installed In a safety-related control panel for the Terry Turbine driven auxiliary feedwater pump.
Analysis determined the power supply failure was due to an internal rectifier diode failure which resulted in a short circuit on the power supply output.
The evaluation was concluded on November 20, 2017 and it was determined that this issue Is a reportable defect as defined by 1 OCFR Part 21. The power supply failure will adversely affect speed control of the turbine driven auxiliary feedwater pump and therefore may prevent safe shutdown of the nuclear reactor.
Discussion:
The failed power supply, Phoenix Contact part number 2938604, is a QUINT series with 24 VDC, 1 OA output. In a typical application, such as with the Vogtle control panel, the device is used to convert 125 VDC to 24 VDC. The serial number of the failed device Is 366020 with a date code of 0705. The power supply was provided by ES! in June 2007 as a safety-related replacement component for the Terry Turbine control panel upgrade previously supplied in 2005. The power supply remained in Vogtle Inventory until 2017 when the previously Installed power supply was replaced. After less than 4 weeks In service, the power supply failed on October 4, 2017. The method of failure was a short circuit on the output.
Vogtle contacted Phoenix Contact and was informed that there Is a potential Issue with power supplies manufactured between December 2006 and October 2007. Specifically, there is a possibility that the secondary rectifier diodes (designated D20 and D21) on the output of the supply may be prone to premature failure. The supptler of the diodes changed the diode technology from wlre bond to copper clip and this process change contributed to an unusual silver migration effect. The power supply date code range affected by this issue is 0648 through 0723.
The failed power supply was sent to Exelon Powerlabs for analysis and it was confirmed that the power supply output was shorted. As part of the analysis, the D20 and D21 diodes were tested and found to be shorted. This confirmed the failure mode was the same as suspected by Phoenix Contact. Powerlabs issued their report on October 27, 2017.
On October 16, 2017, a second power supply failed at Vogtle (S/N 366019).
This was the replacement for the first failed power supply and was installed on October 4, 2017. Investigation revealed that the second power supply exhibited the same fallure mode, shorted diode, as the first failure.. Both the first and second failed power supplies were provided by ESI in June 2007 and both were the same 0705 date code.
I
1111 05:10:12p.m.
11-21-201i'.
5/5 Report No.
Revision:
1 OCFR21-0119 0
Date:
11/21/17 Page:
2 of2 Impact on Operability:
In the case of the Vogtle control panel, the power supply provides 24 VDC to the PGPL Driver. The Driver receives a proportional control signal from the 505 control and, in conjunction with the feedback signal from a remote servo, provides a position control *signal to the PGPL actuator to position the steam control valve.
Loss of the power supply, and thus the PGPL Driver, would adversely affect operation of the steam valv~ which would prevent control of the turbine driven auxiliary feedwater pump. Since the feedwater pump is a safety system within the nuclear plant, failure of the power supply could adversely affect safe shutdown of the nuclear reactor.
Root cause evaluation:
The root cause of the failure is a premature fallure of the 020/021 rectifier diodes.
Evaluation of previous shipments:
This Issue applies to all customers that have power supply P/N 2938604 within the date code range 0648 through 0723. ESI has supplied power supplies within the suspect date code range to the following sites:
ESI Sales c-of-C Mfg Serial Mfg End User End User P.0.
Qty Date Order Date Numbers Code 3003318 Southern Nuclear-Vogtle Plant 7077729
.2 06/01/2007 366019 &
366020 Southern Nuclear - Farley Plant1 QP070019/003 392902 &
8000969 (supplied through Dresser-Rand) 131013 (D-R) 2 01/31/2008 392904 Table 1: Listing of Sites with Suspect Power Supply_P/N 2938604 Note (1 ): The units for Farley were Installed in control panel assemblies P/N 8000969-01 (qty 1 per panel).
Corrective Action:
For Vogtle: Both power supplies provided by ESI have failed and been removed from service. No further action Is required.
For Farley: If the power supplies are currently Installed they should be removed from service and replaced with newer power supplies from a different date code. Phoenix Contact has Indicated that determining when a power supply from the suspect date code range will fail is difficult. Therefore, It is recommended that replacement be performed as soon as possible.
0705 0720