Study On The Most Vulnerable Rupture Location Of The Main Steam Pipes And The Main Water Pipes In Tianwan Nuclear Power Plants

Developing nuclear power is always a basic policy of our country to solve theenergy crisis and the energy security issues. With the development, we must solve thesecurity problems of the nuclear power plants. The main steam pipes and the main waterpipes in the conventional island have a long-term service at elevated temperature andpressure conditions. If there is an event of breakage, whipping phenomenon will begenerated by the jet reaction force of the fluid inside. And it will threaten the safety ofthe pipes, the structural, the equipment and the staff nearby. Even worse, it may bringthe nuclear leaks and other serious secondary disasters. In view of the seriousconsequences of the rupture of the main steam pipes and the main water pipes, the studyof its most vulnerable rupture location in the operating conditions, for taking measuresto limit the whipping phenomenon, has been a major subject in the field of nuclearpower construction.The development and utilization of nuclear energy and the construction of nuclearpower plants was first developed in America, Russia,France and other countries. Theystudy on the most vulnerable rupture location of the main steam pipes and the mainwater pipes early, and their technology is relatively mature and advanced. They havemonopolized the nuclear power construction market for a long time.“PWR NuclearPower Plant Accident Prevention Guidelines of Imaginary Pipe Breakage (EJ335-88)",the specification of our country in this field, refers to ANSI/ANS-58.2-1988publishedby the American Nuclear Society substantially, and some of the provisions still can't befully understood. This is contrary to the autonomous nuclear power developmentstrategy proposed in our “nuclear power long-term development plan (2005-2020)”.In this thesis, the analysis of the most vulnerable rupture location of conventionalisland's main steam pipes and main water pipes in Tianwan Nuclear Power PlantExpansion Project Unit5and6, is carried out, with the fracture criterion for pressurepipe proposed by some western scholars and some of the provisions inANSI/ANS-58.2-1988. Further more, the comparative analysis of the two results isconducted, too. In addition, we also study the effects of the earthquake on the mostvulnerable rupture location of the main steam pipes and the main water pipes. Theresearch mainly includes the following parts:1. the methods based on fracture theory and fracture criterion, of analyzing themost vulnerable rupture location and the break type of the main steam pipes and mainwater pipes in the conventional island of the nuclear plants, are proposed to solve theanti-whip issue of the pipes. Then we compare these two methods and strength theoryby a numerical example.2. With the idea based on the fracture criterion and the relevant provisions in ANSI/ANS-58.2-1988, the analysis of the most vulnerable rupture location ofconventional island's main steam pipes and main water pipes in Tianwan Nuclear PowerPlant Expansion Project Unit5and6is carried out. We also compare the two resultsaccording to the relevant criterion information and the J integral results, and extract amore comprehensive and reliable conclusion.3. The method combined with the “Code for Seismic Design of Nuclear PowerPlants” and the provisions of SH/T3039-2003, is put foreward to consider the seismicload on the main steam pipes and the main water pipes. Using this method, we take theanalysis of the most vulnerable rupture location of the main steam pipes and the mainwater pipes in the conventional island of the Tianwan Nuclear Power Plant ExpansionProject Unit5and6. Further more, We also compare the two results and extract a morecomprehensive and reliable conclusion.Finally, we carry on a summary of the whole research work in this thesis and putforeward the prospects.