Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
ACCESSION #: 9706050193
150 Lincoln Avenue
Grove City, PA 16177-1898
Tel 412 458 8000
Fax 412 458 3574
Ajax [Registered]
Caberra [Registered]
COOPER Cooper-Bessemer [Registered]
ENERGY SERVICES Enterprise [Trademark]
En-Tronic [Registered]
Penn [Trademark]
Superior [Registered]
May 29, 1997
Our Ref: QCG-10389
Document Control Desk
U.S. Nuclear Regulatory Commission
Washington, D.C. 20555
Subject: 10 CFR 21 Notification, Cooper-Bessemer
KSV Emergency Diesel Generator Power Piston Failure
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, hereby
notifies the Commission of a potential manufacturing defect of the
Cooper-Bessemer KSV Emergency Diesel Generators (EDG's).
On January 27, 1997 Commonwealth Edison Company (CECo), Zion Station
identified a significant drop in crankcase lube oil level. Subsequent
investigation revealed that a crack had developed in the cylinder liner
wall allowing jacket water to enter The combustion chamber. Jacket water
in the combustion chamber is incompressible and caused a hydraulic lock,
which resulted in a fracture in an area of the piston crown relieving the
hydraulic lock. Upon review of the failed piston it was noted That the
piston crown thickness in the area of failure was below drawing
specifications.
While the EDG continued to operate, the potential long term effect of the
above could be dilution of the crankcase oil with jacket water,
accompanied. by a reduction in lubrication, ultimately resulting in
seizure of critical assemblies.
This event resulted in two distinct investigations, the liner failure
causing the event and the pisTon crown thickness below specification.
This notification is specific to the potential piston deficiency.
KSV Power Piston Potential Deficiency
Cooper-Bessemer part numbers KSV-5-A, KSV-5-A#1, KSV-5-3A#1 (commercial,
nonsafety) and KSV-5-A#2, KSV-5-2A, KSV-5-2A#1 (safety-related) supplied
by CES are affected.
Page 2
QCG-10389
May 29,1997
The potential defect concerns the thickness of the piston crown in the
valve cutout area (see attachment) that provides clearance for the intake
and exhaust valves. The nominal design thickness for this area is .438.
The failed piston at CECo had an area that tapered down to a minimum
thickness of .040.
Discussion:
Finite Element Analysis performed by CES subsequent to the failure has
indicated an acceptable minimum thickness in the valve cutout area of
.100. The analysis also indicated that a .040 thick piston should not
fail in normal operation, but the factor of safety is below normally
accepted values. Examination of pistons in CES stores noted many in the
.25-.31 range and one as low as .070.
The root cause of the deficient condition was an incorrect foundry
pattern.
User Recommendations:
Users are advised to perform the following:
Using Ultrasonic or similar measuring equipment, the crown thickness at
the valve cutout should be verified to be .100 minimum. For pistons
currently installed in engines this can be done during normal maintenance
activities when the pistons become accessible. Immediate verification is
not considered necessary based on the following:
o The piston failure was caused by an extraordinary event (hydraulic
lock).
o No other reported failures of this type in the KSV operating
history.
o Consideration of logged time for each piston, 600 hours of piston
operation corresponds to 10 x 10**6 stress cycles and thus is
unlikely to fail under normal loading. Many installed pistons will
have significantly more hours of operation.
o The limited inspection performed on CES in stores pistons indicates
that the mean thickness is well above the .100 minimum thickness.
Ultrasonic inspection performed by CECo on 74 pistons (in stores and
in use) resulted in none below the .100 minimum.
Users with spare pistons in stores should verify the subject
thickness prior to installation.
Corrective Action:
The following activities are being undertaken by CES:
o Revision of the foundry pattern to correct crown thickness.
Page 3
QCG-10389
May 29, 1997
o Inclusion of specific verification of crown thickness in the valve
cutout area during the production process.
o Inclusion of specific verification of crown thickness in the valve
cutout area during the refurbishment process of used pistons.
Affected Sites:
All pistons in Cooper-Bessemer KSV EDG's at the Following sites are
affected.
Arizona Public Service- Palo Verde
Commonwealth Edison - Braidwood
Commonwealth Edison - Byron
Commonwealth Edison - Zion
Entergy Operations - Waterford III
Houston Lighting and Power - STP
Nebraska Public Power District - Cooper Nuclear Station
Niagara Mohawk - NMP2
Pennsylvania Power and Light - SSES
Please contact Andrew Steffan at 412-458-3455 or John Horne at
412-458-3543, if you have any questions.
Sincerely,
COOPER CAMERON CORPORATION
R. M. Cote
Vice President and General Manager
Attachment
:kll
cc: D. T. Blizzard - CES/GC
J. M. Horne - CES/GC
T. W. Kearns - CES/GC
W. H. A. Lambert
A. P. Steffan - CES/GC
G. S. Mishler - CES/GC
P. J. Shimek - CES/GC
File: KShimek-CES/GC
Figure "ATTACHMENT TO QCG-10389" omitted.
Page 4
QCG-10389
May 29, 1997
Copies to: (List revised 5/29/97)
Mr. Walter Haass Mr. Roman Estrada
U.S. Nuclear Regulatory Commission Nebraska Public Power District
One White Flint North Cooper Nuclear Station
Washington, DC 20555 P. O. Box 98
Brownville, Nebraska 68321
Houston Lighting and Power Co.
South Texas Project Electric Mr. Terry O'Brien
P. O. Box 289 Commonwealth Edison Co.
Wadsworth, TX 77483 1400 Opus Place
Attn: General Manager Downers Grove, IL 60515
Nuclear Assurance & Licensing
Mr. James Kenny Mr. David Zink
Licensing Group-Supervisor Niagara Mohawk Power Corp.
Pennsylvania Power and Light Nine Mile Road - Unit 2
Two North Ninth Street Annex 6 1 P. O. Box 63
Allentown, PA 18101 Lycoming, NY 13093
Ms. Kathleen Russo
Ms Violet D'Angelo Niagara Mohawk Power Corp.
Pennsylvania Power and Light Nine Mile Road - Unit 2
Susquehanna Steam Electric Station P. O. Box 63
P. O. Box 467 Lycoming, NY 13093
Serwick, PA 18603
Mr. Terence Bannon Arizona Public Service
Licensing Group ALPHA 6 1 P. O. Box 52034 Mail Station 6325
Pennsylvania Power and Light Phoeniz, AZ 850-72-2034
2 North Ninth Street Attn: Department Leader
Allentown, PA 18101 Nuclear Materials Management
Mr. David Baran Ms. Angela Krainik
Commonwealth Edison Co. Manager, Nuclear Regulatory
Affairs
Byron Nuclear Power Station Arizona Public Service
4450 North German Church Rd. P. O. Box 52034 Mail Station 7636
Byron, IL 61010 Phoeniz, AZ 85072-2034
Mr. Michael Kneble Mr. Terry Vandavoori
EnTergy Associates Commonwealth Edison
Louisiana Power and Light Zion Generating Operation
Waterford 3 SES 101 Shiloh Blvd,
Highway 18 Zion, IL 60099
Taft, LA 70000
Mr. Dave Gustafson Mr. Arthur G. Killinger
Commonwealth Edison Co. MPR Associates, Inc.
Braidwood Nuclear Power Station 320 King Street
Tech Staff Electrical Group Alexandria, VA 22314-3238
Route 1, Box 84
Braceville, IL 60407 Entergy Operations Inc.
P.O. Box 31995
Jackson, MS 29286-1995
Attn: Mr. Joe Pennington
Supervisor of Material
Requirements
GENERAL INFORMATION or OTHER EVENT NUMBER: 32416
LICENSEE: COOPER ENERGY NOTIFICATION DATE: 05/30/97
SERVICES NOTIFICATION TIME: 14:53 [ET]
CITY: GROVE CITY REGION: 1 EVENT DATE: 05/30/97
COUNTY: STATE: PA EVENT DATE: 00:00 [EDT]
LICENSE#: AGREEMENT: N LAST UPDATE DATE: 05/30/97
DOCKET:
NOTIFICATIONS
LAURIE PELUSO, REG 1 RDO
NRC NOTIFIED BY: COTE (FAX) JOHN PELLET, REG 4 RDO
HQ OPS OFFICER: CHAUNCEY GOULD JOHN JACOBSON, REG 3 RDO
CHARLES HOSEY, REG 2 RDO
EMERGENCY CLASS: NOT APPLICABLE VERN HODGE, RVIB NRR
10 CFR SECTION:
CCCC 21.21 UNSPECIFIED PARAGRAPH
NINF INFORMATION
EVENT TEXT
- PART 21 - POTENTIAL MANUFACTURING DEFECT IN COOPER-BESSEMER KSV
EDGS -
COPPER ENERGY SERVICES MADE A 10 CFR PART 21 NOTIFICATION FOR THEIR
COOPER-BESSEMER KSV EMERGENCY DIESEL GENERATORS DUE TO A
POTENTIAL
MANUFACTURING DEFECT. THE POTENTIAL DEFECT CONCERNS THE THICKNESS
OF THE
PISTON CROWN IN THE VALVE CUTOUT AREA THAT PROVIDES CLEARANCE FOR
THE
INTAKE AND EXHAUST VALVES. THE NOMINAL DESIGN THICKNESS OF THIS
AREA IS
0.438, BUT A FAILED PISTON HAD AN AREA THAT TAPERED DOWN TO A MINIMUM
THICKNESS OF 0.040.
FINITE ELEMENT ANALYSIS PERFORMED SUBSEQUENT TO THE FAILURES HAS
INDICATED AS ACCEPTABLE MINIMUM THICKNESS IN THE VALVE CUTOUT AREA
OF
0.100. THE ANALYSIS ALSO INDICATED THAT A 0.040 THICK PISTON SHOULD NOT
FAIL IN NORMAL OPERATION, BUT THE FACTOR OF SAFETY IS BELOW
NORMALLY
ACCEPTED VALUES. EXAMINATION OF PISTON IN COOPER ENERGY SERVICES
STORES
NOTED MANY IN THE 0.25 TO 0.31 RANGE AND ONE AS LOW AS 0.070. THE ROOT
CAUSE OF THE DEFICIENT CONDITION WAS AN INCORRECT FOUNDRY PATTERN.
THE FOLLOWING PLANTS ARE AFFECTED: PALO VERDE, BRAIDWOOD, BYRON,
ZION,
WATERFORD, SOUTH TEXAS, COOPER, NINE MILE POINT UNIT 2, AND
SUSQUEHANNA.
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