Home NRC Library Document Collections Events, Reports Associated with Part 21 Reports 1997

Part 21 Report - 1997-283

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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