CAP1400反应堆压力容器下降段内气-液逆向流试验研究

为研究真实工况下CAP1400反应堆压力容器下降段气-液逆向流现象,以CAP1400为原型,搭建压力容器下降段高度和直径比为1:1、60°切片的试验台架。试验工质为空气和水,试验研究了不同安注(DVI)供水量、不同气量的气-液两相流动和应急堆芯冷却剂(ECC)旁通现象。试验结果表明,DVI供水量相同时,随着供气量的增加,气-液逆向流现象明显,当质量流速达到4kg/s及以上时,安注水不能全部进入堆芯;Kutateladze经验关系式和UPTF经验关系式都与试验结果存在较大偏差,不适用于CAP1400压力容器下降段试验;基于试验数据,拟合了新的经验关系式,且通过比较有无DVI挡块的试验数据,验证了DVI挡块可以降低ECC旁通水量,增强安注能力。

Experimental Investigation of Counter-Current Flow in Downcomer of CAP1400

In order to study the phenomenon of counter-current flow in the downcomer of the CAP1400 reactor under real working conditions, a test bench with the height and diameter ratio of 1:1 of the downcomer of the pressure vessel and a 60° slice was built using CAP1400 as a prototype. The test working medium was air and water, and the two-phase gas-liquid flow and ECC bypass phenomenon with different mass flow rate and gas flow rate were experimentally studied. The results show that the gas-liquid reverse flow(CCFL) phenomenon is obvious with the increasing of gas injection rate, and when the gas volume reaches 4 kg/s or more, the injection water cannot be in the core completely. In addition, comparing the experimental results with the theoretical formula of CCCL, Kutateladze empirical correlation and UPTF empirical correlation could not accurately describe the CCFL phenomena in the downcomer of CAP1400. Therefore, based on the experimental data, the new correlations were fitted. The comparison of the test data with and without U-type reflector shows that the U-type reflector can reduce ECC bypass water and enhance the injection ability.