Research On Prestressing Construction Mechanical Properity And Damage Mechanism After Loss Of Coolant Accident In Nuclear Power Plant Containment

In response to the impact of energy crisis and environmental crisis,nuclear power as a clean energy has attracted more and more attentions around the world,and occupies an important position in the world energy structure.After the development of the the first generations and the second generations of nuclear power technology,the third generation of nuclear power plant technology is widely recognized and applied because of its safety and economy.The power plant,which use the third generation of nuclear power plant technology,is a double shell structure.The outer containment is a high-strength reinforced concrete structure,while the inner containment is a prestressed concrete structure.Based on the background of the third nuclear power plant,the prestressing construction simulation and LOCA(Loss of Coolant Accident)of large complex prestressed tank structure are researched by ABAQUS.The main contents of this paper are as follows:1.The refinement model of prestressed concrete inner containment with the 270 beams of complex space curve tensons was established accurately by the multi-dimensional three-dimensional space modeling technology and block modeling method.And the mechanics performance of large complex prestressed tank structure under the construction scheme of site prestressed tendon was researched.Then the effectiveness of the simulation method of prestressing comstruction was verified by comparing with the measured data.Based on the influence of different tensioning processes on prestressing construction,a new prestressed tendons sequence was proposed,which can optimize the mechanical performance of the large complex prestressed tank structure.2.Based on GB50010-2010,BS EN 1992-1-1: 2004 and A.H.Nielson formula,the prestress loss of containment was analyzed.Then the effects of prestress loss and prestress failure on the mechanical properties of the structure were discussed.3.The simulation of the internal pressure failure test of the 1: 4 prestressing construction in the Sandia laboratory was carried out to verify the effectiveness of numerical simulation method of the internal pressure.On the basis of these,the internal pressure failure analysis of the large complex prestressed tank structure was carried out without considering the temperature effect,and the mechanical properties of the structure under the internal pressure load were obtained to reveal the internal pressure destruction mechanism of large complex prestressed tank structure.Then the influence of prestressed tendon stress,ordinary steel bar and steel liner on the failure mechanism of internal pressure was analyzed.4.After analyzing the change of the temperature field of the containment under the LOCA accident,the mechanical properties of the structure were analyzed under the condition of operating temperature and LOCA.On the basis of these,the LOCA in large complex prestressed tank was analyzed systematically to obtain the mechanical properties of the structure under the coupling of temperature and internal pressure and reveal the failure mechanism of structural under LOCA.