Efficiency improvement features of recent abb-alstom HP-L turbine retrofit at southern calfornia edison's san onofre nuclear generating station

摘要

A large US nuclear utility was faced with a necessity to perform numerous plant physical and operational modifications during the 1999 refueling outages. In particular, it repalced low-pressure (LP) turbines, high-pressure (HP) turbine diaphragms, reduced steam generator operating temperature and pressure and made modifications to the main condenser. The significant performance improvements obtained fro mthe LP turbine retrofit have offset the performance loss necessary to preserve steam generator life. the LP turbines have been retrofitted to address reliability problems associated with stress corrosion cracking (SCC). This opportunity was used to boost their performance with innovative ABB-ALSTOM design features. These included the unique "optiflow" steam flow arrangement, six stages of integrally shrouded blades, a new 47" last stage blade, and generously sized aerodynamically efficient hoods with customized diffusers.