核电厂安全壳极限抗压承载力及影响因素分析

Ultimate Capacity and Influenced Factors Analysis of Reactor Containment Subjected to Internal Pressure

核电厂安全壳极限抗压承载力、影响因素及其规律是核电结构安全评估、事故处理和结构设计的关键问题。本文以某安全壳为例,采用损伤塑性模型模拟混凝土的力学性能,双线形应力-应变模型模拟钢衬里和预应力钢束的材料非线性,基于ABAQUS软件系统地分析了核安全壳极限抗压承载力,并给出结构自重、预应力、钢衬里等因素的影响规律。研究表明,当内压增大到0.87MPa时,安全壳筒壁上部混凝土开始进入塑性;当内压增大到1.02MPa时,钢衬里最大拉应变超过限值3 000×10-6,安全壳达到极限状态。在各种影响因素中,预应力和钢衬里对安全壳的极限内压和破坏形式起着关键作用。本文研究结果对核安全壳极限承载能力分析、结构设计和安全评定等方面具有一定的参考价值。

Ultimate compressive bearing capacity, influenced factors and its rules of reactor containment are key problems of safety assessment, accident treatment and structure design, etc. Ultimate compressive bearing capacity of reactor containment is shown by concrete damaged plasticity model and steel double liner model of ABAQUS. The study shows that the concrete of reactor containment cylinder wall begins to enter plasticity when internal pressure is up to 0.87 MPa, the maximum tensile strain of steel liner exceeds 3 000 ×10 -6, and reactor containment reaches ultimate status when internal pressure is up to 1.02 MPa. The result shows that reactor containment is in elastic condition under design internal pressure and bearing capacity meets requirement. Prestress and steel liner play key parts in ultimate internal pressure and failure mode of reactor containment. The study results have reference value for ultimate compressive bearing capacity analysis, structure design and safety assessment.