Requirement Description for R.G.1.20 Addenda ‘Comprehensive Vibration Assessment Program for Reactor Internals During Preoperational and Initial Startup Test’

The new revision of R.G.1.20 ’Comprehensive Vibration Assessment Program for Reactor Internals during Preoperational and Initial Startup Test’ was issued by NRC in 2007.In this paper,the back-ground for the new revision of R.G.1.20 is demonstrated.Major notes of addenda are stated in contrast with the former revision,including CFD analysis and supplementary analysis in flow-induced vibration analysis,and evaluation requirement for acoustic resonance problem of main steam system（pipe line,relief valve and dryer）.Some typical examples are presented for flow-induced vibration failure cause.It’s shown that the new comprehensive vibration assessment program is crucial for the safety operation and economics in nuclear power plants.