低衰变功率乏燃料棒喷淋冷却实验研究

摘要

本文基于超设计基准事故,建立1套乏燃料水池喷淋冷却实验装置,选用5×5电加热棒束模拟局部乏燃料组件,分析当乏燃料水池池水完全排空状况下,维持乏燃料包壳温度在300℃时所需的最小喷淋流量密度以及周围棒束对单棒的影响效果,并开展了低衰变功率下的喷淋冷却实验.结果表明:单棒加热功率小于25 W的加热棒束无需额外冷却操作,仍处于安全状态.分别采用流量密度2.393、2.950、3.876(m3/h)/m2进行喷淋冷却,可使单棒加热功率为100、125、150 W的加热棒束最高温度稳定在300℃左右.目标棒外围第1、2层棒束对其温度影响较大,第3层及其以外的加热棒束对目标棒的影响较弱.%The spray cooling experiment device was built based on beyond design basis event,and the electric heated rod bundle of 5×5 was used to simulate spent fuel assem-blies.The purpose of this experiment is to research the minimum spray flow density which can maintain temperature of cladding in 300 ℃ and the influence to single-rod from around heated bundle when the water of spent fuel pool is completely lost.The spray experiment to spent fuel with low decay heat was carried out in the paper.The results show that heating bundles with the power less than 25 W are in safe condition without any cooling.The spray flow density of 2.393,2.950 and 3.876 (m3/h)/m2 can keep the temperature of heating bundles with the power of 100,125 and 150 W in 300 ℃.The greatest impact comes from the first and the second floor bundles to the temperature of target rod and the third floor bundle and others have weak influence.