Research On Constrution Temperature Field Characteristics And Effect Of Nuclear Island Outer Containment

EPR (European pressurized water reactor) is one of the leading modes of thethird-generation pressurized water reactor, which are under construction around theworld, and two of them are in China. The outer containment is an important part of EPRnuclear power plant, which is not only the last barrier to keep radioactive material fromescaping, but also the protective structure to withstand external or internal extremeloads and effects, such as hurricane, earthquake, tsunami, and collision by airplane etc.,so there are many strict requirements for construction quality. Due to the large volumeof its concrete structure, how to reduce the thermal stress generated by hydration heat tocontrol cracks is always a key issue in construction process. A lot of researching workshave been done on the crack control of mass concrete, but works on outer containmentof nuclear plant is still very few. This thesis takes the Nuclear power plant of Tai Shan,Guang Dong province (using French technology-EPR) for example to explore the rulesof temperature distribution and stress distribution in outer containment.Firstly, on the basis of extensive references, this paper describes research methodsof mass concrete temperature field and expounds the principles of finite elementanalysis which considers concrete shrinkage and creep. According to the actual situationof the project, we discuss the simplification of model, selection of the materialparameters such as hydration heat curve, application of boundary conditions, etc. anddetermine an effective and reasonable finite element analysis model eventually.Secondly, based on the large finite element software ABAQUS, we simulate andanalysis the temperature field of nuclear island outer containment, and obtain the timehistory curve of temperature field. At the same time, we compare and research theinfluence of different construction layer heights and thicknesses on temperature field,and explore the rules of temperature field distribution around the holes. After that, thechanging rules of the containment temperature field are summarized. On the basis ofthese works, we propose reasonable control measures from two angles: curing conditionand time of heat preservation.Lastly, combined with the results of analysis on temperature field, investigationabout the thermal stress of outer containment is carried out. Elastic constitutive andshrinkage, elastic creep constitutive are selected as the concrete material models. Basedon the above-mentioned material models, we analysis the temperature stress incontainment of lowest layer and obtain the rules of temperature stress distribution indifferent models. Following, we analysis temperature stress distribution around theholes and normal layers. Eventually we make a prediction about the overall and partialcracking in outer containment precisely, and provide theoretical basis and technical support for actually construction works of nuclear power plant.