ML20236V312
| ML20236V312 | |
| Person / Time | |
|---|---|
| Site: | Vogtle, Comanche Peak  |
| Issue date: | 07/29/1998 |
| From: | Defronzo P COOPER ENERGY SERVICES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-PT21-98 QCG-10496(K5FB6, NUDOCS 9808030076 | |
| Download: ML20236V312 (3) | |
Text
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150 Uncoln Avenue Grove City, PA 16127 1898 Tel 412 458 8000 Fax 412 458 3574 I
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July 29,1998 Our reference: OCG-10496 (K5fb69) j Document Control Desk a
U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
OCG 10483 (K5fa43) 10 CFR Notification, Enterprise DSR-4 and DSRV-4 Emergeacy Diesel Generators
Dear Sir,
1 In accordance with the requirements of the Nuclear Regulatory Commission Title 10, Chapter 1, Code of Federal Regulations, Part 21, Cooper Energy Services (CES), a division of Cooper Cameron Corporation, provides a final status report of the 10 CFR Part 21 evaluation associated with the 701 Digital Speed Control, Rev. G provided to Southem Nuclear Company's l
Plant Vogtle and Texas Utilities' Comanche Peak.
An interim letter was sent on May 22,1998 describing a 10 CFR Part 21 investigation conceming the use of revision level"G" Woodward 701 goveming systems (Cooper Energy Services P/N 2-02G-110-001) supplied to Southem Nuclear Company's Plant Vogtle and Texas Utilities' Comanche Peak generating stations. A problem arose when the originally supplied revisions of the Woodward govemor DSC (digital speed control) were removed and replaced with a revision "G" DSC. The revision "G" DSC output to the govemor actuator exhibited short-term instability when generator voltage was adjusted remotely from the control room. The revision "G" DSC operated properly when in local operation from the diesel generator room.
1 As an immediate corrective action, the revision "G" DSC's were removed, and the originally supplied DSC's were put back into service and are operating satisfactorily, investigations revealed that the revision "G" DSC's were more susceptible to electro-magnetic (g
interference (EMI) induced by the long runs of cable to and from the control room, specifically feeding back into the low voltage output (terminal 5) of the DSC than were the revision "A" and "B" DSC's. The short term instability was found during post installation testing and setup as part of the design modification / post work testing process. Subsequent testing verified that
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both the revision "B" and "G" DSC meet the EMI / RFI (Radio Frequency Interference) design
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j specifications, MIL Standard 461C, that the units were qualified to as per CES contractual i
agreements with Comanche Peak and Plant Vogtle. Based on the aforementioned findings, it is judged that the subject anomaly is not reportable from Cooper Cameron's basis under 10 CFR Part 21. The revision "G" design met all EMI / RFI design specifications, however the y
excess margin was reduced to where specific plant conditions (as found during post installation testing) exceeded tolerable EMI levels.
9808030076 980729 PDR ADOCK 05000424 S
Page 2 July 29,.1998 REF: OCG-10496 (K5fb69)
Cooper Energy Services (CES) and Woodward in conjunction with Comanche Peak personnel were able to recreate conditions similar to those in the field in a laboratory environment producing the same govemor output instability. Plant Vogtle and Comanche Peak generating stations both have multi-conductor cables from the Diesel room to the Control room with the generator voltage raise / lower conductors in the same cable as the 701 speed raise / lower conductors. These long runs of urchielded conductors allowed EMI from the generator raise /
lower conductors to be induced into the 701 speed raise / lower conductors producing EMI levels greater than what the 701 revision G" DSC is qualified to.
None of the several hundred commercial 701 units utilize these long runs of multi-conductor cabling and none of the several hundred commercial units in operation have experienced this problem. Three riuclear 701 revision *G" units installed in Taiwan do not utilize the same multi-conductor cable for speed and voltage raise / lower conductors from the Diesel room to the Control room and also do not experience this problem.
Different methods were developed to correct the problem with the most viable option being the use of an EMI / RFI filter on terminal 5 of the DSC. Testing at Woodward substantiates elimination of the 701 DSC output spikes with the utilization of the EMI / RFI filter on terminal 5 of the DSC. CES is in the process of qualifying the filter for nuclear use and will recommend its usage on all new 701 units. CES also is providing the option of two additional filters to be used on the DSC power input and the DSC output to the govemor actuator to enable the 701 Woodward goveming system to meet the new EPRI EMI / RFI guidelines (EPRI 102323-R1).
i Anyone having any questions or concems may contact Bob Boyles (724-458-3446) or Terry Sintkowski (724-458-3433) at CES.
Affected Sites:
Southem Nuclear Company, Plant Vogtle l
Texas Utilities, Commanche Peak Station STP Nuclear Operating Company (Houston Light and Power Co.)
I Sincerely, I
i COOPER ENERGY SERVICES l
Peter DeFronzo l
General Manager 1
i 1
l Copies to:
Mr. Louis Ward, Southem Nuclear Company (Fax 205-992-7885) l
Page 3 Jwly 29,4998 REF: OCG 10496 (K5fb-69)
Southern Nuclear Operating Company l
Vogtle Project P.O. Box 1295 l
Birmingham, AL35201 i
Attn: Mgr., Nuclear Engineering and Licensing Mr. Stephen Alexander Nuclear Regulatory Commission OA Vendor Insp. & Maintenance Branch j
One White Flint North l
Mailstop 9A1
' Washington, DC 20555 l
TU Electric Company P.O. Box 1002 Glen Rose, TX 76043 Attn: Group Vice Presider:t, Nuclear STP Nuclear Operating Company South Texas Project Electric P.O. Box 289 l
Wadsworth, TX 77483 Attn:
General Manager Nuclear Assurance and Licensing l
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