Evaluation of Vibration and Vibration Fatigue Life for Small Bore Pipe in Nuclear Power Plants

The assessment method of the steady state vibration and vibration fatigue life of the small bore pipe in the supporting system of the nuclear power plants is proposed according to the ASME-OM3 and EDF evaluation methods.The GGR supporting pipe system vibration is evaluated with this method.The evaluation process includes the filtration of inborn sensitivity,visual inspection,vibration tests,allowable vibration effective velocity calculation and vibration stress calculation.With the allowable vibration effective velocity calculated and the vibration velocity calculated according to the acceleration data tested,the filtrations are performed.The vibration stress at the welding coat is calculated with the spectrum method and compared with the allowable value.The response of the stress is calculated with the transient dynamic method,with which the fatigue life is evaluated with the Miners linear accumulation model.The vibration stress calculated with the spectrum method exceeds the allowable value,while the fatigue life calculated from the transient dynamic method is larger than the designed life with a big safety margin.