United States Nuclear Regulatory Commission - Protecting People and the Environment


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.



*** END OF DOCUMENT ***



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