池式钠冷快堆主热传输系统瞬态研究

Transient analysis of the main heat-transfer system of the pool-type sodium-cooled fast reactor

钠冷快堆是第四代先进核能系统的首选堆型,它因具有可增殖核燃料、嬗变放射性废物,以及高热效率发电等优势,成为先进核能技术发展的重要方向和标志.目前,我国正在设计和建造第二座钠冷快堆.快中子的物理特性、液态金属钠的热工水力学、复杂热交换器传热技术,以及钠-水蒸汽发生器技术等关键核心技术,给钠冷快堆技术的工程化带来特殊复杂的科学问题.文本中以钠冷快堆能量传输过程为对象,研究并建立用于分析各种能量传输和转换过程中大范围瞬态的数学物理模型,并采用凤凰堆自然循环和FFTF失流实验国际基准例题对模型进行了验证与确认,模型计算值与实验数据趋势一致且吻合较好.针对某典型池式钠冷快堆,综合采用工程评价和演绎分析法对电厂的四类瞬态事件进行了确定.其中,正常运行瞬态9个,偏离正常的预期瞬态23个,异常瞬态10个,紧急瞬态7个.采用所建立的数学物理模型,给出了每一类典型瞬态的分析结果,为系统和设备/部件的设计提供了重要依据,并为完成钠冷快堆瞬态工况和运行模式设计以及安全评价奠定了科学技术基础.

Sodium-cooled fast reactors are the first choice of the fourth generation of advanced nuclear energy systems. They have attracted significant attention in the development of advanced nuclear energy technology owing to their advantages of proliferative nuclear fuel, transmutation of radioactive waste, and high thermal efficiency power generation. The design and construction of the secondary sodium-cooled fast reactor are ongoing in China. The physical characteristics of fast neutrons and the special thermal, physical, and chemical properties of liquid sodium metal cause special and complex scientific problems in the design of sodium-cooled fast reactors. In this study, taking the energy transfer process of sodium-cooled fast reactors as the object, we establish mathematical and physical models for analyzing large-scale transients in various energy transfer and conversion processes. The model is verified and validated by the natural circulation test of the Phoenix reactor and the international benchmark of the fast flux test facility loss in flow tests. The trend of the calculated values is consistent with that of the test data, and the results are in good agreement. For a typical pool-type sodium-cooled fast reactor, four types of transient events in the power plant are determined by engineering evaluation and deductive analysis. Among them, there are nine normal operation transients, 23 expected transients, 10 abnormal transients, and 7 emergency transients. Based on the established mathematical and physical models, the analysis results of each type of typical transient are given, which provide an important basis for the design of the system and equipment/components and lay a scientific and technological foundation for completing the design of the transient condition and operation mode of the sodium-cooled fast reactor as well as safety evaluation.