液态燃料熔盐堆系统分析程序及安全特性研究

发布时间：2018-04-22 20:31

本文选题：液态燃料熔盐堆 + RELAP5　；参考：《中国科学院研究生院(上海应用物理研究所)》2017年博士论文

【摘要】：熔盐堆是第四代先进核能系统之一,具有良好的经济性、固有安全性、在线加料以及在线后处理优势。液态燃料熔盐堆的核燃料是作为液体在一回路中流动,这就使得液态燃料熔盐堆的中子物理和热工水力特性不同于传统的固态燃料反应堆。反应堆安全问题是核工程发展最重要的研究课题,安全分析的任务是研究不同工况下反应堆的安全性,是反应堆设计和建造过程中的一项重要内容。开发液态燃料熔盐堆系统安全分析程序和构建液态燃料熔盐堆安全评估准则是反应堆安全分析的重要基础,对于保障和提高反应堆安全性和可靠性具有重要的意义。本论文基于液态燃料熔盐堆点堆动力学模型、热工水力模型和时滞方程组的求解算法,对RELAP5/MOD4.0程序进行功能扩展,并采用美国橡树岭国家实验室(ORNL)熔盐实验堆(MSRE)启泵、停泵、自然循环和功率提升瞬态过程实验数据验证了模型和程序的正确性,为液态燃料熔盐堆安全分析提供了工具支持。同时,依据国内HAF、HAD法规标准以及国际上IAEA、NRC和ORNL的相关评估报告,参考压水堆、钠冷快堆、高温气冷堆的始发事件分类方法,对液态燃料熔盐堆的始发事件进行了分类;根据反应堆材料的属性,确定了液态燃料熔盐堆的安全限值;采用考虑不确定度的保守单通道热管评估模型,获得堆芯燃料熔盐和石墨慢化剂的最高温度,构建了液态燃料熔盐堆安全评估准则,为液态燃料熔盐堆的安全分析奠定基础。为进一步验证扩展的液态燃料熔盐堆系统分析程序和安全评估准则的适用性,分别对小功率2 MWt熔盐实验堆TMSR-LF1和大功率2250 MWt熔盐增殖堆MSBR系统进行安全特性的研究,计算了在反应性瞬态、二回路排热量减小、二回路排热量增加工况下的反应堆瞬态响应,得出了反应堆在不同工况下的安全特性。计算结果显示,TMSR-LF1的安全裕度大于MSBR。TMSR-LF1在控制棒失控抽出、二回路熔盐失流工况下反应堆的温度会超出安全限值范围,而MSBR在控制棒失控插入、加料过程中意外超临界、冷却熔盐失流、负载功率增加工况下温度会超出安全限值范围,需要及时采取措施以免反应堆的损毁。分析结果表明,扩展的RELAP5/MOD4.0程序和构建的安全评估准则适用于不同功率的液态熔盐堆安全评估分析。基于RELAP5/MOD4.0的液态燃料熔盐堆系统分析程序的开发、安全评估准则的构建以及它们的应用分析,对中国科学院先进核能创新研究院液态燃料熔盐堆的进一步工程设计和安全分析具有重要的工程参考价值。
[Abstract]:Molten salt reactor is one of the fourth generation advanced nuclear power systems, which has the advantages of good economy, inherent safety, on-line feeding and on-line post-processing. The nuclear fuel of liquid fuel molten salt reactor flows in a loop as a liquid, which makes the neutron physical and thermohydraulic characteristics of liquid fuel molten salt reactor different from those of conventional solid fuel reactor. Reactor safety is one of the most important research topics in the development of nuclear engineering. The task of safety analysis is to study the safety of reactors under different conditions, and it is an important content in the process of reactor design and construction. The development of safety analysis program for liquid fuel molten salt reactor system and the construction of safety assessment criteria for liquid fuel molten salt reactor are the important basis of reactor safety analysis, which is of great significance to ensure and improve the safety and reliability of the reactor. Based on the solution algorithm of liquid fuel molten salt reactor dynamic model, thermohydraulic model and time-delay equations, this paper extends the function of RELAP5/MOD4.0 program, and uses Oak Ridge National Laboratory (Oak Ridge National Laboratory) MSRE) start-up pump to stop the pump. The experimental data of natural cycle and power boost transient process verify the correctness of the model and program, and provide a tool support for the safety analysis of liquid fuel molten salt reactor. At the same time, according to the domestic Hafer had code standard and the international IAEAA NRC and ORNL evaluation reports, referring to the classification method of the origin events of PWR, NRC and HTGR, the initial events of liquid fuel molten salt reactor are classified. According to the properties of reactor materials, the safety limit of liquid fuel molten salt reactor is determined, and the maximum temperature of core fuel molten salt and graphite moderator is obtained by using a conservative single-channel heat pipe evaluation model considering uncertainty. The safety evaluation criteria of liquid fuel molten salt reactor are established, which lays a foundation for the safety analysis of liquid fuel molten salt reactor. In order to further verify the applicability of the extended liquid fuel molten salt reactor system analysis program and safety evaluation criteria, the safety characteristics of the low power 2 MWt molten salt test reactor (TMSR-LF1) and the high power 2250 MWt molten salt breeder (MSBR) system were studied, respectively. The transient response of the reactor under the condition of reactive transient, the secondary loop heat emission decreases and the secondary loop heat emission increases is calculated, and the safety characteristics of the reactor under different operating conditions are obtained. The calculation results show that the safety margin of TMSR-LF1 is greater than that of MSBR.TMSR-LF1 when the control rod is out of control, the temperature of the reactor will exceed the safety limit under the secondary loop molten salt loss condition, and the MSBR is inserted out of control control rod and accidentally supercritical during the feeding process. When the cooling molten salt is out of current, the temperature will exceed the safety limit under the condition of increasing load power, so it is necessary to take measures in time to avoid the reactor damage. The analysis results show that the extended RELAP5/MOD4.0 program and the constructed safety evaluation criteria are suitable for the safety assessment analysis of liquid molten salt reactor with different power. The development of liquid fuel molten salt reactor system analysis program based on RELAP5/MOD4.0, the construction of safety evaluation criteria and their application analysis, It has important engineering reference value for further engineering design and safety analysis of liquid fuel molten salt reactor in Advanced Nuclear Energy Innovation Research Institute of Chinese Academy of Sciences.
【学位授予单位】：中国科学院研究生院(上海应用物理研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TL426

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