北方核电站热阱低温适应性改进与研究

发布时间：2019-05-29 06:13

【摘要】：伴随着能源危机的不断加剧,环境问题的日益突出,核电有着清洁、经济、可持续等优点,将成为我国经济社会发展中能源选择上的必然对象。在我国核电的发展史上,核电机组的选址一直以南方沿海地区居多。但在十一五规划以来,随着核电站需求量增加,核电机组的选址开始向北方中纬度地区延伸。而北方冬季海水温度过低,将影响核电站的安全运行。热阱系统是核电站将余热释放到自然界中的媒介,保证机组正常运行及事故工况下的安全运行。本文简要介绍了国内外应对低温热阱系统的设计改进以及研究进展；提出了换热器旁路及热水回流两种改进方案,并以工程实践为例,重点说明了系统在工程建设中遇到的新问题及解决方案。本文针对换热器旁通方案,从改进的必要性、系统布置方案、系统运行方式、改进控制方案等方面阐述设计改进的合理性和可行性。其中改进控制方案中包括了新增孔板对运行的影响、海水潮位的影响、热负荷调控盲点的分析等。针对热水回流方案,通过与换热器旁通方案的比较,阐述了热水回流方案的优点。并从档位流量计算、档位负荷分析、系统运行控制等方面进一步阐述改进方案的可行性。最后从设计改进对其他专业的影响角度进行了分析。以工程实践为例,列举了系统改进后在调试启动阶段发现的一系列新问题,对新问题的处理方案的分析。其中包括了换热器旁路方案的换热器结冰问题、超声波流量计显示问题、核功率波动问题；热水回流方案的备用列热水回流管线积气问题、RRI/SEC启停瞬态压力相互影响问题、冬季模式低档位无法满足安全准则问题等,并对热水回路管线进行了补充改造。以及冬季进行板式换热器效率试验问题等。获得了热阱系统在不同改进方案的运行不同点及基础数据,增强了高纬度寒冷地区热阱系统设计与运行的认识,为高纬度寒冷地区核电站热阱的设计及安全评价提供基本依据。
[Abstract]:With the aggravation of the energy crisis and the increasingly prominent environmental problems, nuclear power has the advantages of cleanliness, economy, sustainability and so on, which will become the inevitable object of energy choice in the economic and social development of our country. In the history of nuclear power development in China, the location of nuclear power units has always been in the southern coastal areas. However, since the 11th five-year Plan, with the increase of nuclear power plant demand, the site selection of nuclear power units began to extend to the middle latitudes of the north. However, the low temperature of sea water in winter in the north will affect the safe operation of the nuclear power plant. The heat trap system is the medium for nuclear power plants to release waste heat into nature to ensure the normal operation of the unit and the safe operation of the unit under accident conditions. In this paper, the design improvement and research progress of low temperature heat trap system at home and abroad are briefly introduced. Two improvement schemes of heat exchanger bypass and hot water reflux are put forward, and taking the engineering practice as an example, the new problems and solutions encountered in the engineering construction of the system are emphasized. Aiming at the bypass scheme of heat exchanger, this paper expounds the rationality and feasibility of the design improvement from the aspects of the necessity of improvement, the arrangement scheme of the system, the operation mode of the system and the improved control scheme. The improved control scheme includes the influence of new orifice plate on operation, the influence of seawater tide level, the analysis of blind spot of heat load regulation and so on. In view of the hot water reflux scheme, the advantages of the hot water reflux scheme are expounded by comparing with the heat exchanger bypass scheme. The feasibility of the improved scheme is further expounded from the aspects of gear flow calculation, gear load analysis, system operation control and so on. Finally, the influence of design improvement on other majors is analyzed. Taking the engineering practice as an example, this paper enumerates a series of new problems found in the debugging and starting stage after the improvement of the system, and analyzes the treatment schemes of the new problems. It includes the problem of heat exchanger icing, ultrasonic Flowmeter display and nuclear power fluctuation. The gas accumulation problem of standby hot water reflux pipeline in hot water reflux scheme, the interaction of transient pressure between RRI/SEC start and stop, and the low gear position in winter mode can not meet the safety criteria, etc., and the hot water loop pipeline has been replenished and modified. And the efficiency test of plate heat exchanger in winter and so on. The different operation points and basic data of the heat trap system in different improvement schemes are obtained, which enhances the understanding of the design and operation of the heat trap system in the high latitude cold region, and provides the basic basis for the design and safety evaluation of the nuclear power plant heat trap in the high latitude cold region.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM623

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