Information Notice No. 83-58: Transamerica Delaval Diesel Generator Crankshaft Failure
SSINS No. 6835
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
August 30, 1983
Information Notice No. 83-58: TRANSAMERICA DELAVAL DIESEL GENERATOR
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
August 30, 1983
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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
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
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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