Vibration Optimization Of Emergency Diesel Engines In Daya Bay And Ling AO Nuclear Power Stations

Based on the analysis of the major types of SACM UD45 diesel engines vibration faults in DAYA Bay NPP (nuclear power plant) and Ling Ao NPP, the root-cause analysis is under research. Abnormal vibration of exhaust-gas turbochargers are due to the forced vibration and structural stress caused by the top H type support. The welding crack of pre-heating water injection pipe is due to the design deficiency of struction, which caused the stress concentration in the welding over the fatigue strength of carbon steel. The high vibration of the main cooling water pipes is due to the improper arrangement of the rigid supports. The vibration insulation researches and inherent characteristics of the diesel engine main components are discussed, and some measurement of the vibration insulation and isolation are raised. The top H type supports of the turbochargers are cancelled, and the bottom U type supports are added. The flexible hose and isolation valve upstream the pre-heating water injection pipe are exchanged, the vibration isolation boundary is optimized. The rigid support of the main cooling water pipes are cancelled, the elastic packing and rubber elements are added into the supports. It's showed by results that the overall vibration of diesel engines are improved.