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

Part 21 Report - 1997-281

ACCESSION #: 9704010450 150 Lincoln Avenue Glove City, PA 16127-1898 Tel 412 458 8000 Fax 412 458 3574 Ajax Coberra COOPER Cooper Bessemer ENERGY SERVICES Enterprise [Trademark] En-Tronic [Registered Trademark] Penn [Trademark] March 25, 1997 Superior Our Ref: QCG-10373 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Subject: Commonwealth Edison Company, Zion Station, EDG Piston and Liner 10 CFR 21 Interim Report Dear Sir: The purpose of this letter is to provide initial notification and interim report of a 10 CFR 21 evaluation associated with the Cooper-Bessemer KSV Emergency Diesel Generators installed at Commonwealth Edison (CECo) Zion Station. On January 27, 1997 CECo 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, namely, the liner failure causing the event and the piston crown thickness. Each is discussed below. KSV Power Cylinder Liner Cooper-Bessemer part number G18-9-12A#3 (safety-related) and G18-9-12A#2 (commercial, non-safety related). Page 2 March 25, 1997 QCG-10373 This is the only known failure of subject liner. Evaluation activities include sectioning of the liner, metallurgical analysis and finite element analysis. CECo has taken the primary role in this investigation, assisted by Cooper-Bessemer. Initial analysis has determined acceptable stress levels. Additional analysis is being conducted based on review of the initial analysis by Cooper-Bessemer/CECo. This liner design is only in use on "early" KSV engines in use at Commonwealth Edison Company's Zion Station and Nebraska Public Power District's Cooper Nuclear Station. "Later" vintage KSV engines utilize liners of different design and are not affected by this evaluation. An improved design has been developed by Cooper-Bessemer which, in essence, retrofits the "earlier" engines to the "later" design. (New part number KSV-9-3F#1). Use of this liner as a replacement will be recommended and is not dependent on the outcome of this evaluation. It is expected that this evaluation will be completed before May 28, 1997. KSV Power Piston Cooper-Bessemer part number 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). Failure of this piston was a direct result of the liner failure. No other such failure has been documented. It has been determined that the subject piston crown thickness at the point of failure was below drawing requirements. Investigation has determined that the pattern for the piston casting was incorrect. Preliminary stress analysis indicates that stresses are relatively low in this area even for crown thickness considerably below the drawing requirements. Any piston operated for 600 hours or greater has experienced 10 X 10**6 stress cycles and thus is unlikely to fail under normal loading. Finite element analysis is being conducted by Cooper-Bessemer to determine acceptable minimum thicknesses for the piston crown section. This evaluation could affect the following KSV users: 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 Page 3 March 25, 1997 QCG-10373 It is expected that this evaluation will be completed before May 28, 1997. 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 :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 File: K5fa40 Page 4 March 25, 1997 OCG- 10373 Copies to: Mr. Walter Haass Mr. Doug Mullen U.S. Nuclear Regulatory Nebraska Public Power District Commission Cooper Nuclear Station One White Flint North P. O. Box 98 Washington, DC 20555 Brownville, Nebraska 68321 Houston Lighting and Power Co. Mr. Terry O'Brien South Texas Project Electric Commonwealth Edison Co. P. O. Box 289 1400 Opus Place Wadsworth, TX 77483 Downers Grove, IL 60515 Attn: General Manager Nuclear Assurance & Mr. David Zink Licensing Niagara Mohawk Power Corp. Nine Mile Road - Unit 2 Mr. James Kenny P. O. Box 63 Licensing Group Supervisor Lycoming, NY 13093 Pennsylvania Power and Light Two North Ninth Street Annex 6 1 Ms. Kathleen Russo Allentown, PA 18101 Niagara Mohawk Power Corp. Nine Mile Road - Unit 2 Mr. Matthew Heidorn P. O. Box 63 Pennsylvania Power and Light Lycoming, NY 13093 Susquehanna Steam Electric Station P. O. Box 467 Arizona Public Service Berwick, PA 18603 P. O. Box 52034 Mail Station 6325 Phoenix, AZ 85072-2034 Mr. Terence Banno Attn: Department Leader Licensing Group ALPHA 6 1 Nuclear Materials Management Pennsylvania Power and Light 2 North Ninth Street Ms. Angela Krainik Allentown, PA 18101 Manager, Nuclear Regulatory Affairs Arizona Public Service Mr. David Baran P. O. Box 52034 Mail Station 7636 Commonwealth Edison Co. Phoenix, AZ 85072-2034 Byron Nuclear Power Station 4450 North German Church Rd. Mr. Terry Vandevoort Byron, IL 61010 Commonwealth Edison Zion Generating Station Mr. Michael Kneble 101 Shiloh Blvd. Energy Associates Zion, IL 60099 Louisiana Power and Light Waterford 3 SES Mr. Arthur G. Killinger Highway 18 MPR Associates, Inc. Taft, LA 70006 320 King Street Alexandria, VA 22314-3238 Mr. Dave Gustafson Commonwealth Edison Co. Braidwood Nuclear Power Station Tech Staff Electrical Group Route 1, Box 84 Braceville, IL 60407 *** END OF DOCUMENT ***

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