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Information Notice No. 83-58: Transamerica Delaval Diesel Generator Crankshaft Failure
SSINS No. 6835 IN 83-58 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 August 30, 1983 Information Notice No. 83-58: TRANSAMERICA DELAVAL DIESEL GENERATOR CRANKSHAFT FAILURE Addressees: All nuclear power facilities holding an operating license (OL) or a construction permit (CP). Purpose: This information notice is provided to bring to the attention of licensees and construction permit holders a recent event at the Shoreham Nuclear Station in which a diesel generator crankshaft failed during post-modification full load testing. The Nuclear Regulatory Commission staff is reviewing the problem and its effects. If the evaluation so indicates, the NRC may request explicit licensee or CP holder action. In the interim, we expect the addressees of this information notice to review the information herein for applicability to their facilities. No specific action or response is required at this time. Description of Circumstances: After installation of eight new cylinder heads, emergency diesel generator (EDG) No. 102 failed during post-modification testing when its crankshaft assembly fractured at the crankpin and crankarm (web) on the generator side of the Cylinder No. 7 crank. This failure occurred during the last 15 minutes of testing at the two-hour overload rating. EDG-102 had a total of 12 hours and 25 minutes of two-hour overload testing when failure occurred. Its installed crankshaft assembly has a crankshaft diameter of 13" and a crankpin diameter of 11". Replacement crankshaft assemblies with 12" diameter crankpins are being procured. Subsequent to this failure of EDG-102, the licensee examined the crankshafts of the two other diesel generator units at the Shoreham site, EDG-101 and EDG-103, by opening the crankshaft area. The examination of the EDG-101 crankshaft assembly showed cracking on the Cylinder No. 7 crankweb (generator side) and dye penetrant indications on the cranks at Cylinder Nos. 3 and 5. Examination of the EDG-103 crankshaft assembly identified a crack about 2" long and 3/8" deep on the Cylinder No. 6 crankweb (governor side) and a connecting rod to crankpin bearing failure on Cylinder No. 5. The bearing failure involved breaking off of approximately a 1" x 3" piece and overheating of 8308040044 . IN 83-58 August 30, 1983 Page 2 of 2 the surrounding area for about 2". Most of the other cracks found are similar in location and orientation to the one which resulted in EDG-102 crankshaft assembly fracture. Transamerica Delaval reported that the following nuclear sites have Transamerica Delaval diesel generators: Shoreham Perry Midland Grand Gulf Bellefonte Hartsville Catawba WPPS Phipps Bend San Onofre Comanche Peak River Bend Vogtle Rancho Seco Shearon Harris Clinch River The preliminary information from the manufacturer is that the diesels at Shoreham, River Bend, and Rancho Seco* are eight cylinder in-line engines. However, the crankpin diameter is 11" in the Shoreham units and 12" in the units at the other two sites. The diesel engines at the remainder of the sites listed above are of a "V" design and have 12, 16, or 20 cylinders. The shaft material for all the engines is the same, with the possible exception of the 20 cylinder engines. All the engines are designed to have approximately the same brake mean effective pressure. The torsional systems of the engines differ. At this time it is not clear to what extent other diesel generators manufactured by Transamerica Delaval are vulnerable to the same or similar failures as these experienced by the Shoreham engines. If you have any questions regarding this matter, please contact the Regional Administrator of the appropriate NRC Regional Office, or this office. Edward L. Jordan, Director Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement Technical Contact: W. Laudan, IE (301) 492-9759 Attachment: List of Recently Issued IE Information Notices *The Rancho Seco units are not installed; they will be used to replace the existing diesel generators. .
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