Part 21 Report - 1998-452
ACCESSION #: 9808030076
150 Lincoln Avenue
Grove City, PA 16127-1898
Tel 412 458 8000
Fax 412 458 3574
Ajax [Registered Trademark]
Coberra [Registered Trademark]
COOPER Cooper-Bessemer [Registered Trademark]
ENERGY SERVICES Enterprise [Trademark]
En-Tronic [Registered Trademark]
Penn [Trademark]
Superior [Registered Trademark
July 29, 1998
Our reference: QCG-10496 (K5fb69)
Document Control Desk
U.S. Nuclear Regulatory Commission
Washington, D.C. 20555
Subject: QCG 10483 (K5fa43)
10 CFR Notification, Enterprise DSR-4 and DSRV-4 Emergency Diesel
Generators
Dear Sir,
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 Southern Nuclear Company's Plant
Vogtle and Texas Utilities' Comanche Peak.
An interim letter was sent on May 22, 1998 describing a 10 CFR Part 21
investigation concerning the use of revision level "G" Woodward 701
governing systems (Cooper Energy Services P/N 2-02G-110-001) supplied to
Southern Nuclear Company's Plant Vogtle and Texas Utilities' Comanche Peak
generating stations. A problem arose when the originally supplied
revisions of the Woodward governor DSC (digital speed control) were removed
and replaced with a revision "G" DSC. The revision "G" DSC output to the
governor 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. 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 electromagnetic 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 both the revision "B" and "G" DSC meet the
EMI / RFI (Radio Frequency Interference) design specifications, MIL
Standard 461 C, that the units were qualified to as per CES contractual
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 excess margin
was reduced to where specific plant conditions (as found during post
installation testing) exceeded tolerable EMI levels.
Page 2
July 29, 1998
REF: QCG-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 governor 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 unshielded 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 nuclear 701 revision "G"
units installed in Taiwan do not utilize the same multiconductor 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 governor actuator to enable the 701 Woodward governing system
to meet the new EPRI EMI / RFI guidelines (EPRI 102323-R1).
Anyone having any questions or concerns may contact Bob Boyles (724-458-
3446) or Terry Sintkowski (724-458-3433) at CES.
Affected Sites:
Southern Nuclear Company, Plant Vogtle
Texas Utilities, Commanche Peak Station
STP Nuclear Operating Company (Houston Light and Power Co.)
Sincerely,
COOPER ENERGY SERVICES
Peter DeFronzo
General Manager
Copies to:
Mr. Louis Ward, Southern Nuclear Company (Fax 205-992-7885)
Page 3
July 29, 1998
REF: QCG-10496 (K5fb-69)
Southern Nuclear Operating Company
Vogtle Project
P.O. Box 1295
Birmingham, AL 35201
Attn: Mgr., Nuclear Engineering and Licensing
Mr. Stephen Alexander
Nuclear Regulatory Commission
QA Vendor Insp. & Maintenance Branch
One White Flint North
Mailstop 9A1
Washington, DC 20555
TU Electric Company
P.O. Box 1002
Glen Rose, TX 76043
Attn: Group Vice President, Nuclear
STP Nuclear Operating Company
South Texas Project Electric
P.O. Box 289
Wadsworth, TX 77483
Attn: General Manager
Nuclear Assurance and Licensing
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