Information Notice No. 83-58: Transamerica Delaval Diesel Generator Crankshaft Failure

                                                           SSINS No. 6835  
                                                           IN 83-58        

                                UNITED STATES
                           WASHINGTON, D.C. 20555 
                               August 30, 1983

                                   CRANKSHAFT FAILURE 


All nuclear power facilities holding an operating license (OL) or a 
construction permit (CP). 


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 


                                                            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

List of Recently Issued IE Information Notices

*The Rancho Seco units are not installed; they will be used to replace the 
existing diesel generators. 

Page Last Reviewed/Updated Friday, May 22, 2015