核电机组汽轮机快速冷却技术研究

Research on Rapid Cooling Technology for Steam Turbines in 1,000 MW Nuclear Power Units

摘要:

针对某百万千瓦级压水堆核电汽轮机,依托计算机辅助工程(CAE)平台 ABAQUS 构建高中压缸全三维精细化有限元模型,结合边界条件与在线测温数据,开展快冷过程耦合仿真,实现温度场、应力场及动静间隙变化的高精度预测。并结合 Manson-Coffin 曲线与线性疲劳累积损伤理论,量化快冷引起的寿命损耗。结果表明:快冷平均降温速率为 1.26?℃/h,满足限值要求；各部件最大应力远低于材料屈服强度；动静间隙变化处于设计范围内；且单次快冷寿命损耗可忽略不计。方案可缩短冷却约 63 小时,显著提升机组可用率。所提出的“三进一抽”布局设计,有效缓解局部热滞问题,首次实现该型机组合缸结构的三维耦合模拟,为核电汽轮机智能运维与快速检修提供了数字化、可控化的技术路径。

Abstract:

For a pressurized water reactor (PWR) nuclear steam turbine with a capacity of one million kilowatts, a high-fidelity full three-dimensional finite element model of the high- and intermediate-pressure cylinders was developed using the computer-aided engineering (CAE) platform ABAQUS. Coupled simulations of the fast-cooling process were performed by integrating boundary conditions and online temperature measurement data, enabling high-accuracy predictions of the temperature field, stress field, and dynamic-static clearance variations. Furthermore, the Manson-Coffin curve combined with the linear fatigue cumulative damage theory was employed to quantify the life consumption induced by fast cooling. Results show that: (1) the average cooling rate during fast cooling is 1.26?°C/h, satisfying the prescribed limit; (2) peak stresses in all components remain well below the material yield strength; (3) dynamic-static clearance changes stay within the design tolerance; and (4) the life consumption from a single fast-cooling event is negligible. The proposed approach reduces the cooling duration by approximately 63 hours, significantly enhancing unit availability. Additionally, the novel “three-inlet, one-extraction” layout design effectively mitigates local thermal stagnation issues. This study presents the first-ever three-dimensional coupled simulation of the combined-cylinder structure for this type of turbine, establishing a digital and controllable technical pathway for intelligent operation and rapid maintenance of nuclear steam turbines..