非能动余热排出系统敏感性分析

Sensitivity Analysis of Passive Residual Heat Removal System

以中国改进型压水堆核电站CPR1000为研究对象,在其蒸汽发生器二次侧设计了一套非能动余热排出系统(PRHRS),该系统采用在蒸汽发生器二次侧建立自然循环的方式间接带走堆芯余热,确保事故条件下堆芯安全。用RELAP5/MOD3.2程序对系统进行了合理的简化并建模,在全场断电(SBO)事故条件下模拟了PRHRS的瞬态响应过程,并对高位水箱的容积、PRHRS换热器的换热面积、冷热中心高度差以及PRHRS的投入时间等影响PRHRS工作特性的相关参数进行了敏感性分析。计算结果表明:增加高位水箱的容积和增大换热面积均有助于二次侧余热排出系统带走一回路的堆芯余热;降低冷热中心高度差对PRHRS的自然循环能力影响不大;余热排出系统投入时间越早,蒸汽发生器二次侧水位越高,越有利于一次侧余热的排出。

A new passive residual heat removal system（PRHRS） on the secondary side of the steam generator was designed for CPR1000,which can remove residual heat in the core by natural circulation in the secondary side of steam generator and ensure core safety under accident conditions.The model of the simplified system for CPR1000 was established by using RELAP5/MOD3.2 code,and the transient characteristic of PRHRS was simulated under the station blackout（SBO） accident.The sensitivity analysis was performed for the related parameters which affect the working characteristics of PRHRS,such as the volume of high-level tanks,area of heat exchanger,height difference of cold and hot centers and the initiating time of PRHRS.The calculation results show that increasing volume of high-level tanks and area of heat exchanger helps to remove residual heat of the core;but reducing height difference of cold and hot centers has little influence on the capacity of natural circulation for PRHRS;the earlier the initiation of PRHRS is,the higher the water level in the secondary side of steam generator is,the better the PRHRS removes residual heat in the core.