Numerical Simulation And Simplified Analysis On Whipping Of The Main Pipe-restraint System In Nuclear Power Plant

The main steam, main feedwater pipes working under the condition of hightemperature and high pressure in nuclear power plants are likely to rupture due tointernal defects, aging pipes or accidental events such as an earthquake in thelong-term service span. Pipe rupture may make the high pressure fluid inside thepipes ejecting at high speed. In reaction of the huge jet impingement, pipes willwhip in a great range, which cause damage to nuclear power plants. Therefore, it isnecessary to set up anti-whip restraints to protect nuclear power plants from pipewhipping. Study on the whipping of pipe-restraint system is of great significance foranti-whip design of pipes in nuclear power plants.Several developed countries with advanced nuclear technology, especially theUnited States and France, have already carried out a lot of theoretical andexperimental study on pipe whip problem in the60’s of last century. Their analysissoftware for pipe whip has monopolize domestic nuclear power construction marketfor a long time. At present, China is vigorously promoting the construction ofnuclear power plants. In order to reduce dependence on foreign technology, moreand more domestic scholars began to study on pipe whip problem in recent years.The modern computer science and finit element theory provides a promissingway to deeply study the pipe whip problem. A series of researches on numericalsimulation and simplified analysis on whipping of pipe-restraint system are carriedout in this paper, mainly including:Part1: A finit element model of pipe-restraint system is established based onABAQUS. The reliability of the finite element model is further verified throughcomparison with the experimental results of Japan Atomic Energy ResearchInstitute.Part2: Numerical simulation on whipping of pipe-restraint system undercircumferential break has been performed. Moreover, a simplified calculation modelis also established. Three simplified analysis methods including the dynamicsmethod, the energy balance method and the moment balance method for pipe whipanalysis under circumferential break are thoroughly summarized and compared.Part3: Based on cantilever beam model, the influence of restraint location, theinitial gap and friction effect on the performance of pipe-restraint system areanalyzed. The optimized arrangement of anti-whip restraint is also recommended forpratical engineering.Part4: Numerical simulation on whipping of pipe-restraint system underlongitudinal break has been carried out. Three simplified calculation models, which are derived from the principle of energy balance and can be applied to varioussituations, are further established and validated.