Research on Operation Characteristics of Heat Pipe Reactor Coupled with Open-Air Brayton Cycle
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摘要: 为探究热管堆与开式布雷顿循环耦合的核电转换系统在堆芯功率和负荷变化时的运行特性,基于Modelica语言建立系统仿真模型,包括堆芯模型、热管传热模型和布雷顿循环模型,并验证了各模型的准确性。采用建立的模型对甩负荷工况和升、降功率过程进行了瞬态仿真和计算。计算结果表明,在瞬态过程中,负荷或堆芯功率的变化将导致转速的改变,需通过旁通调节阀控制涡轮流量使转速恢复稳定。在甩负荷工况中,甩负荷导致堆芯温度下降,反应性反馈将导致堆芯功率升高2.3%、燃料最高温度升高1.7 K。在升、降功率过程中,反应性反馈导致的归一化堆芯功率峰值分别为102.6%和100.7%。本文研究结果可为热管堆与开式布雷顿循环耦合带来的安全风险及其安全分析提供参考。Abstract: In order to explore the operation characteristics of nuclear power conversion system with open-air Brayton cycle coupled with heat pipe reactor when the core power and load change, the system simulation model is established based on Modelica language, including the sub-models of the reactor core, the heat pipe and the Brayton cycle, and the accuracy of each model is verified. The transient simulation and analysis of loss of load (LOL) and power increment and reduction processes are carried out by using the established model. The calculation results show that in the transient process, the change of load or core power will lead to the change of rotating speed, and it is necessary to control the turbine flow through the bypass control valve to restore the rotating speed to stability. Under LOL condition, the core temperature will drop, and the reactivity feedback will increase the core power by 2.3% and the maximum fuel temperature by 1.7 K. During the reactor power increment and reduction, the peak normalized core power caused by reactivity feedback is 102.6% and 100.7% respectively. The results of this paper provide a reference for the safety analysis of the heat pipe reactor coupled with open-air Brayton cycle.
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Key words:
- Heat pipe reactor /
- Open-air Brayton cycle /
- Modelica /
- Operation characteristics
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表 1 单元二维传热模型与堆芯三维模型计算结果对比
Table 1. Comparison of Results between 2-D Unit Model and 3-D Core Model
参数 单元二维
传热模型堆芯三维
模型[13]误差/K 燃料最高温度/K 1029.5 1025.6 +3.9 基体最高温度/K 970.7 969.4 +1.3 表 2 零负荷不同转速和堆芯功率下换热器出口温度和流量计算结果
Table 2. Heat Exchanger Outlet Temperatures and Mass Flows in the Conditions of Zero Load, Different Rotating Speeds and Different Reactor Power
转速/% 功率/% 换热器出口温度/℃ 温度误差/% 总流量/(kg·s−1) 流量误差/% 计算值 设计值 计算值 设计值 70 62.2 503.3 520.0 −3.2 2.06 1.99 3.9 80 70.5 497.5 520.0 −4.3 2.62 2.47 6.1 80 70.6 498.2 520.0 −4.2 2.62 2.48 5.8 90 78.5 499.8 520.0 −3.9 3.25 3.12 4.2 98 77.5 508.9 520.0 −2.1 3.57 3.52 1.5 100 80.2 523.6 530.0 −1.2 3.63 3.60 0.9 100 101.2 588.8 610.0 −3.5 3.64 3.51 3.9 100 105.8 603.3 610.0 −1.1 3.65 3.61 1.1 100 106.6 605.6 610.0 −0.7 3.65 3.62 0.8 表中的转速、功率为相对于额定数值的百分比,下同 表 3 降功率和升功率过程控制流程
Table 3. Procedures of Reactor Power Reduction and Increment
时间/h 降功率过程 升功率过程 负荷/% 外部反应性/pcm 转速/% 负荷/% 外部反应性/pcm 转速/% 0 100 1171.1 100 0 609.0 70 4 75 1171.1 100 0 658.7 70 6 75 1097.9 100 5 658.7 70 8 55 1097.9 100 5 731.9 70 10 55 1024.7 92 10 731.9 70 12 40 1024.7 92 10 805.1 80 14 40 951.5 92 15 805.1 80 16 25 951.5 92 15 878.3 80 18 25 878.3 80 25 878.3 80 20 15 878.3 80 25 951.5 92 22 15 805.1 80 40 951.5 92 24 10 805.1 80 40 1024.7 92 26 10 731.9 70 55 1024.7 92 28 5 731.9 70 55 1097.9 100 30 5 658.7 70 75 1097.9 100 32 0 658.7 70 75 1171.1 100 34 0 609.0 70 100 1171.1 100 -
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