核电站非能动余热排出方案仿真研究

发布时间：2018-08-06 11:15

【摘要】：非能动安全的设计简化了系统,降低了投资,具有更高的安全性。非能动余热排出系统是核电站非能动安全设计的重要组成部分,其主要功能是当反应堆的正常排热系统失效时导出堆芯衰变热。非能动余热排出系统对于核电站的安全运行具有重大意义,是目前的研究重点和热点。本文的主要内容是基于RELAP5系统分析程序的蒸汽发生器二次侧非能动余热排出方案仿真研究。以第三代先进压水堆核电站AP1000为研究对象。借助REALP5完成了非能动余热排出热交换器的参数设计;在全厂断电事故和单侧主给水管道断裂事故工况下,计算分析二次侧余热排出系统的运行特性,验证其事故工况下排出停堆余热,保证反应堆安全的能力;对二次侧非能动余热排出系统设计负荷及其启动特性进行对比分析;本文同时介绍了一种改进的二次侧非能动余热排出方案,进行事故工况下的仿真计算,对其缓解事故的能力进行验证。仿真计算结果表明:(1)以满功率3.6%作为二次侧非能动余热排出系统的设计负荷时,在全厂断电事故和单侧主给水管道断裂事故工况下,非能动余热排出系统的投入确保了堆芯剩余释热的有效导出,保证了反应堆的安全。(2)以满功率2.4%、3%、3.6%、4%、4.6%的5种不同设计负荷作事故工况下的对比分析时,在全厂断电事故下,工况1-5的非能动余热排出系统均可保证反应堆安全,但只有工况1冷却剂平均温度下降速率符合标准要求;在发生单侧主给水管道断裂事故下,工况2-5的非能动余热排出系统均可保证反应堆安全,工况1无法导出堆芯释热,主冷却剂出现汽化。(3)在启动瞬间,非能动余热排出系统蒸汽侧采用瞬开阀门会引起系统压力和流量的剧烈震荡,会对热交换器和管路造成冲击;降低蒸汽侧阀门的开启速度和在回水侧增设氮气稳压箱的方法均可达到降低压力震荡幅度的目的。(4)对传统二次侧非能动余热排出方案作出改进,改进后的非能动余热排出方案为非能动辅助给水系统+设计负荷为2%满功率的非能动余热排出系统。在全厂断电事故和单侧主给水管道断裂事故工况下,改进后的方案可以有效导出堆芯剩余释热,保证反应堆的安全,且全厂断电事故工况下的冷却剂平均温度下降速率符合标准要求。
[Abstract]:The design of inactive safety simplifies the system, reduces the investment, and has higher security. Passive residual heat discharge system is an important part of the passive safety design of nuclear power plant. Its main function is to derive core decay heat when the normal heat removal system of the reactor fails. Inactive residual heat removal system is of great significance for the safe operation of nuclear power plants, and is the focus and hotspot of current research. The main content of this paper is the simulation study of the secondary side inactive residual heat removal scheme of steam generator based on RELAP5 system analysis program. The AP1000 of the third generation advanced PWR nuclear power station is taken as the research object. With the help of REALP5, the parameter design of the passive residual heat exhaust heat exchanger is completed, and the operating characteristics of the secondary side residual heat discharge system are calculated and analyzed under the condition of the power failure of the whole plant and the failure of the main water supply pipeline on one side. To verify the capacity of discharging the waste heat from the shutdown reactor under the accident condition and to ensure the safety of the reactor, the design load and start-up characteristics of the secondary side inactive residual heat discharge system are compared and analyzed. At the same time, this paper introduces an improved secondary side passive residual heat discharge scheme, and carries out the simulation calculation under the accident condition, and verifies its ability to alleviate the accident. The simulation results show that: (1) when the design load of the secondary inactive residual heat discharge system is 3.6% of the full power, under the conditions of the power failure and the failure of the main water supply pipeline on one side, The input of inactive residual heat discharge system ensures the effective derivation of residual heat release from the reactor core and the safety of the reactor. (2) in the case of a power loss of the whole plant, 5 different design loads of 4. 6% with a full power of 2. 4% and 3. 6% are used for comparative analysis. The passive residual heat discharge system under working conditions 1-5 can guarantee the safety of the reactor, but only the coolant average temperature drop rate meets the standard requirement under the condition 1. In the case of the failure of the main water supply pipeline on one side, The passive residual heat discharge system under working conditions 2-5 can guarantee the safety of the reactor. In case 1, the core heat release can not be derived, and the main coolant vaporizes. (3) at the start up moment, The use of instantaneous valve on steam side of inactive waste heat exhaust system will cause severe shock of pressure and flow rate of the system and impact on heat exchanger and pipeline. Reducing the opening speed of steam side valve and adding nitrogen stabilizer on backwater side can reduce the amplitude of pressure oscillation. (4) the traditional secondary side inactive residual heat discharge scheme is improved. The improved passive residual heat removal scheme is designed for the inactive auxiliary water supply system with a full load of 2% full power. Under the condition of power failure and failure of one side main water supply pipeline, the improved scheme can effectively derive the residual heat release from the reactor core and ensure the safety of the reactor. The average temperature drop rate of coolant under the condition of power failure in the whole plant is in line with the standard requirement.
【学位授予单位】：中国舰船研究院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM623

【相似文献】