Influence of Depletion on Reactivity Insertion Transients for Xi’an Pulsed Reactor
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摘要: 研究了一种精确模拟反应堆燃耗相关瞬态行为的新方法。基于三维物理热工耦合的堆芯瞬态计算程序,与采用微观燃耗的三维精确燃耗计算程序相耦合,针对西安脉冲堆控制棒移动过程,分析了不同燃耗深度下由于反应性引入的不同形式和大小而引起的堆芯功率和燃料温度等参数的瞬态特性。进行了堆芯脉冲功率响应对反应性引入量的敏感性分析,研究了堆芯动态参数的变化机理。数值结果表明:随着燃耗的加深,脉冲堆芯布置时脉冲功率有减小的趋势,而堆芯稳态布置时脉冲功率明显增大,达到脉冲功率峰值的时间有所提前。Abstract: In this paper, a new method is presented to accurately simulate the transient behavior of reactor burnup. The core transient calculation code based on three-dimensional physical and thermal coupling is coupled with the three-dimensional precise micro burnup calculation code. According to the control rod movement process of Xi'an Pulsed Reactor (XAPR), the transient characteristics of different parameters such as core power and fuel temperature due to the different form and magnitude of reactivity insertion at different burnup depth are analyzed. The sensitivity of core pulse power response to reactivity insertion is analyzed, and the change mechanism of core dynamic parameters is studied. The numerical results show that with the burnup of nuclear fuel, the peak pulse power tends to decrease when the core is arranged with pulse state, while the peak pulse power increases obviously with the steady state core arrangement, and the time to reach the peak pulse power is advanced.
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Key words:
- Transient /
- Burnup /
- Dynamic parameters /
- Coupling
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表 1 瞬发中子能群结构
Table 1. Prompt Neutron Energy Group Structure
瞬发中子能群编号中子能量上界 /eV 1 107 2 5.00×105 3 9.118×103 4 4.00 5 0.625 6 0.14 7 0.058 表 2 缓发中子相对份额和衰减常数
Table 2. Relative Fraction and Decay Constant of Delayed Neutrons
缓发中子能群编号 缓发中子相对份额/% 缓发中子衰减常数/s−1 1 3.20 0.0125 2 16.64 0.0318 3 16.13 0.1094 4 45.96 0.3170 5 13.35 1.3540 6 4.72 8.6364 表 3 不同控制棒位置和价值堆芯临界计算keff与参考值对比
Table 3. Comparison of Core Criticality Calculated and Referenced keff with Different Control Rod Positions
控制棒位置 keff 偏差/% 计算值 参考值 D控制棒全插 0.99479 0.99725 −0.25 D控制棒全提 1.02502 1.02584 −0.08 表 4 XAPR引入不同反应性时脉冲参数与实验值对比
Table 4. Comparison between Calculated and Experimental Pulse Parameters with Different Reactivity Insertion of XAPR
引入反应性 /$ 堆芯布置方式 脉冲峰功率/MW 脉冲峰功率偏差 / % 脉冲半高宽/ms 脉冲半高宽偏差 / % 计算值 实验值 计算值 实验值 0.95 脉冲堆芯 1.43 1.5 −4.67 3485.0 3716 −6.22 1.11 脉冲堆芯 12.12 13.2 −8.18 167.8 154.8 8.40 2.0 脉冲堆芯 601.61 636.5 −5.48 16.5 17.58 −6.14 3.45 脉冲堆芯 4157.92 4301.3 −3.33 7.15 7.214 0.88 1.14 稳态堆芯 14.30 13.8 3.60 272.5 296.4 −8.06 表 5 引入反应性的量变化1%时,脉冲峰功率和半高宽的变化量
Table 5. Sensitivity of Pulse Peak Power and FWHM with Reactivity Insertion Change of 1%
引入反应性 /$ 堆芯布置方式 脉冲峰功率变化量 /% 半高宽变化量 /% 0.95 脉冲堆芯 6.54 8.08 1.11 脉冲堆芯 13.23 10.56 2.0 脉冲堆芯 4.08 2.15 3.45 脉冲堆芯 1.80 3.12×10−4 1.14 稳态堆芯 12.60 9.60 表 6 中子消失的途径和平均时间
Table 6. Path and Average Time for Neutron Disappearance
中子消失途径 泄漏 俘获 裂变 平均消失时间 /s 9.132×10−5 1.208×10−4 4.473×10−5 中子份额(0 EFPD)/% 0.32 58.17 41.51 中子份额(120 EFPD)/% 0.31 60.40 39.29 -
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