Mechanical Property Evaluation Of Primary Side Manway Of Nuclear Power Plant Steam Generator

As the third generation of nuclear power technology,such as AP1000,is getting mature,nuclear power has been attached great importance to the rapid economic development of our country.However,The Chernobyi accident in Soviet Union,fukushima accident in Japan and other accidents make people become afraid of the nuclear power plant all over the world.Now,the research of improving the safety of the nuclear island and ensuring stable operation of the plant,will directly determine the future development of the nuclear power.The steam generator is an important equipment which transport the thermal energy from primary circuit loop to the secondary circuit.The stress concentration of the slots in the change is a worthy issues of which should pay attention to among the factors that restrict the safty and stable operation of the steam generator.Especially,if the slot is on the shell cover or barrel of the steam generator,the stress states would be more complicated because it not only increases local membrane stress by reducing load area due to the cylinder hole,but also due to take over with the head,the connected components such as cylinder caused by the edge stress concentration problems of these processes are causing stress gradient component increases,such as equipment damage problem source,thus opening part of the steam generator for detailed stress analysis and strength evaluation is one of the important link to ensure the safe operation of the steam generator.Two-dimensional axial symmetric steam generator finite element model with different sealing pattern is built in this paper.The stress analysis and the fatigue analysis are conduct with Ansys.The beam element,stick element,solid element,contact element and harmonic element are used to simplifying the finite element model.The key points should be selected in accordance with the characteristics of the temperature and stress.The primary stress,the secondary stress and the fatigue should be assessed according to the ASME-NB standard.The results showed that the sealing pattern of clapboard owns the bigger bolt stress and the bigger manhole cover stress.And the stress of the other parts of the model with the clapboard sealing is similar to the stress of the model with the twine sealing pattern.At the same time,we can conclude that temperature has a lot influence on the primary stress,the secondary stress and the fatigue coefficient.This article research results provide practical reference for the design and manufacture of follow-up work.