Numerical Simulation Study of Hold-down Force of Leaf Spring Hold-down System of Fuel Assembly in Reactor Environment
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摘要: 为了对核燃料组件板弹簧压紧系统设计寿期内的压紧力进行准确预测,结合受快中子辐照影响的板弹簧材料塑性模型和蠕变模型,基于精细化结构模型,提出了堆内环境下板弹簧压紧系统全寿期的压紧力数值模拟方法,并通过与燃料组件板弹簧压紧系统分析软件HOFA计算结果对比的方式,验证了该数值模拟方法的合理性(压紧力最大误差为8.83%)。影响性对比结果表明,在考虑辐照蠕变的情况下,压紧力最大降低4.34%;循环长度增加后,各循环末的压紧力略有增加。Abstract: In order to accurately predict the hold-down force during the design lifetime of the leaf spring hold-down system of nuclear fuel component, considering the plastic model and creep model of the leaf spring material under fast neutron irradiation, numerical simulation method for the hold-down force of the leaf spring hold-down system in the reactor environment was established based on the fine structure model. By comparing the calculation results with the calculation results of the fuel assembly leaf spring hold-down system analysis software HOFA, the rationality of the numerical simulation method is verified (the maximum error of hold-down force is 8.83%). The influence comparison results show that the maximum hold-down force is reduced by 4.34% when radiation creep is considered; When the cycle length increases, the hold-down force at the end of each cycle increases slightly.
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Key words:
- Fuel assembly /
- Leaf spring /
- Hold-down force /
- Irradiation relaxation
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表 1 约束条件定义
Table 1. Definition of Constraints
分析
步骤上管座模拟
结构参考点固定螺钉
下端面弹簧片
侧面区域堆芯上板
模拟结构1 X=0,Y=0,
Z=0X=0,Y=0,
Z=−0.01X=0,Y=0,
Z=0X=0,Y=0,
Z=02 X=0,Y=0,
Z=0X=0,Y=0,
Z=−0.01X=0 X=0,Y=0,
Z=03 X=0,Y=0,
Z=0X=0,Y=0,
Z=−0.01X=0 X=0,Y=0,
Z=U表 2 Inconel 718 弹性模量及泊松比
Table 2. Elastic Modulus and Poisson Rate of Inconel 718
温度/℃ 弹性模量/MPa 泊松比 20 200000 0.294 340 184000 0.272 表 3 全寿期压紧力计算状态点
Table 3. State Points of Lifetime Hold-down Force Calculation
状态序号 状态描述 运行时刻/s 压缩量/mm 1 寿期初冷态 0.01 31.45 2 寿期初热态 0.02 20.546 3 第1循环末热态 3.87×107 24.22 4 第1循环后停堆冷态 3.87×107+0.01 35.124 5 第2循环初热态 3.87×107+0.02 24.22 6 第2循环末热态 7.96×107 25.752 7 第2循环后停堆冷态 7.96×107+0.01 36.656 8 第3循环初热态 7.96×107+0.02 25.752 9 寿期末热态 11.90×107 27.892 10 寿期末冷态 11.90×107+0.01 38.796 表 4 各状态点压紧力误差
Table 4. Hold-Down Force Error for Each State Point
状态 1 2 3 4 5 误差/% 4.29 −6.29 2.55 0.64 −7.39 状态 6 7 8 9 10 误差/% −2.30 0.76 −8.83 −1.92 0.37 表 5 长循环压紧力计算状态点
Table 5. State Points of Long Circle Hold-down Force Calculation
状态序号 状态描述 运行时刻/s 压缩量/mm 1 寿期初冷态 0.01 31.45 2 寿期初热态 0.02 20.55 3 第1循环末热态 5.16×107 24.65 4 第1循环后停堆冷态 5.16×107+0.01 35.56 5 第2循环初热态 5.16×107+0.02 24.65 6 第2循环末热态 10.61×107 27.13 7 第2循环后停堆冷态 10.61×107+0.01 38.03 8 第3循环初热态 10.61×107+0.02 27.13 9 寿期末热态 15.87×107 30.82 10 寿期末冷态 15.87×107+0.01 41.73 -
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