基于修改后RELAP5/MOD3.2的氟盐高温堆实验回路分析

大型热工流体整体效应系统实验(CIET)台架是为模拟氟盐冷却高温堆(FHR)热工水力响应而设计的实验回路,采用DOWTHERM A模拟氟盐作为冷却剂。通过在RELAP5/MOD3.2程序中加入DOWTHERM A物性参数以及传热关系式,计算FHR实验回路CIET在两种工况下的热工水力行为,并与实验结果进行对比,计算工况包括强迫循环条件与自然循环条件。计算结果表明:在强迫循环条件下,堆芯热量主要靠盘管式空气换热器(CTAH)排出,堆芯进出口冷却剂温度及CTAH出口冷却剂温度与实验值符合良好,CTAH进口冷却剂温度与实验值有些微偏差;在自然循环工况中,堆芯热量主要通过DHX与堆芯辅助冷却系统(DRACS)回路的换热带走,DHX及DRACS的流量与实验值接近,相对误差在10%左右,验证了修正后RELAP5/MOD3.2的正确性。

Transient Analysis of Fluoride-salt-cooled High-temperature Reactor Test Facility Based on Modified RELAP5/MOD3.2

The compact integral effects test (CIET) facility was designed to investigate the thermal hydraulic responses of fluoride-salt-cooled high-temperature reactor.CIET facility uses DOWTHERM A fluid to simulate fluoride salt.Thermo-physical properties and transport of DOWTHERM A were implemented into the RELAP5/MOD3.2.The modified RELAP5 code was adopted to study thermal hydraulic behavior of DOWTHERM A under forced circulation operation and natural circulation operation of CIET facility respectiv-ely.Calculation results of core inlet and outlet temperatures and the coiled tube air heater outlet temperature are in good agreement with the corresponding experimental data under forced circulation operation.The inlet temperatures of coiled tube air heater are slightly different from the experiment data.In natural circulation the computational results indicate that the decay heat is mainly removed through the DRACS.The computational flow rates of DHX and DRACS are close to the experiment data.Furthermore, the relative error of flow rate between calculation results and experiment data is about 10%.The results prove the accuracy of the modified RELAP5/MOD3.2.