某核电站穹顶模块吊装预案设计分析

Dome module lifting pre-design and analysis of nuclear power station

为降低核电站穹顶吊装施工风险,保证核岛建造质量,结合第三代核电站工程实际,针对穹顶薄壁、整体模块质量大、对接精度高、吊装要求严格、构件重心与形心偏离等特点,设计钢箱梁吊具及焊接H型钢桁架吊具两套预吊装系统,采用多吊点垂直起吊方案。基于Ansys有限元分析软件,对吊装方案进行分析评价。结果表明:钢箱梁吊装方案吊具结构难以满足大型穹顶吊装要求,焊接H型钢桁架吊装方案吊具结构质量轻、造价低,强度刚度好。桁架吊装系统整体最大等效应力273.761 MPa,小于材料许用应力值;最大位移21.9 mm,符合起重机设计规范要求的挠度值,满足刚度要求;三阶屈曲系数均大于2,吊装系统稳定性良好。分析数据验证吊装系统参数设计基本合理,吊具结构设计可行。

This paper is targeted at reducing project risks associated with nuclear power station dome lifting and ensuring the construction quality of nuclear island. This research involves addressing dome-lifting challenges,such as a thinner wall,a heavier weight,a higher docking precision and a stringent lifting requirement,and deviation between center of gravity and centroid,as in case of the dome lifting of third-generation nuclear power plant. The solution does so by designing two sets of lifting systems: steel box girder and H-beam welding truss,and adopting mulit-points & vertical lifting scheme. The scheme is validated by the analysis and evaluation based on FEA software like Ansys. The results show that,in contrast to steel box girder lifting program thwarted by the spreader inadequate to meet large dome lifting requirements,H-beam welding truss program boasts such advantages as a lighter weight,a lower cost and a better strength & stiffness. H-beam welding truss has the maximum overall stress of 273. 761 MPa,less than the material allowable stress value; the max displacement of 21. 9 mm,consistent with the deflection value of crane design regulatory requirements; three orders of buckling coefficients larger than 2 and a more stable lifting system. The lifting preplan analysis data proves that the lifting system has reasonable design parameters and feasible spreader structure design.