The application of integrated computer programs to the solution of steam/water hammer problems in power stations

The integrated computer programs DIS/WAVENET/ADLPIPE are used to analyse the effects of fluid transients on the structural response of piping systems in both the Nuclear and Non Nuclear power industries. Very large pipe networks such as typical steam piping systems pose their own unique problems, especially regarding the definition of boundary conditions at boilers, bypass valves, safety and relief valves, turbines, etc. Problems of data management exist due to the large quantities of data to be passed between programs and there are problems in defining or agreeing suitable acceptance criteria, particularly stress and nozzle load limits. A recent rapid valve closure analysis is described in detail. The results obtained from the WAVENET fluid transient analysis are the pressure, velocity and force time histories. The force time histories are automatically applied to ADLPIPE to derive the structural response i.e. the movements, forces and stresses in the system. Where necessary it is shown how the analysis was checked at various stages, and a discussion of the acceptance criteria is included. Lessons are drawn which should affect the initial design concepts of pipelines subjected to severe fluid transients. (author)