Reliability Improvement of Medium Speed Diesels in Nuclear Standby Applications

Emergency standby diesel generators manufactured by Transamerica Delaval, Inc. experienced a number of major problems during preoperational qualification testing at several U.S. nuclear sites. Most notably these have included a complete fracture of a crankshaft, an engine block failure, piston failures, and cracked and leaking cylinder heads. These problems appear to stem from deficiencies in design and manufacturing quality by the engine manufacturer. This paper discusses some of the more significant problems experienced and actions taken by the nuclear utility owners and the NRC to reestablish confidence in the reliability of these engines and to qualify these engines for nuclear service.