燃料包壳表面沉积层对汽化核心密度影响的实验研究  

Experimental Study of Influence of CRUD Layer on Active Nucleation Site Density on Surface of Fuel Cladding

作　　者：蔡杰进[1] 胡致平 邓日宁 CAI Jiejin;HU Zhiping;DENG Rining(School of Electric Power,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学电力学院,广东广州510640

出　　处：《原子能科学技术》2024年第4期790-800,共11页Atomic Energy Science and Technology

基　　金：国家自然科学基金面上项目(12275088);广东省基础与应用基础研究基金(2021A1515010340)。

摘　　要：燃料包壳表面沉积层在压水堆常规运行中形成,其对包壳沸腾传热的影响尚不清楚。为了探索包壳表面沉积层对汽化核心密度的影响规律,本文基于常压下的流动沸腾可视化实验台架,以锆-4合金为基板,采用逐层沉积的方法形成不同厚度的SiO_(2)沉积层,通过开展流动沸腾实验对比不同沉积层厚度下的汽化核心密度差异。研究发现,SiO_(2)沉积表面与未沉积表面相比汽化核心密度增大,Koncar模型可较好地预测本实验工况条件下的汽化核心密度。In nuclear reactors,the fuel cladding is exposed to high temperature and high pressure for a long period of time.Chalk River Unidentified Deposits(CRUD)will form on the surface of the fuel cladding during the conventional operation of pressurized water reactors,and the formation of the CRUD will affect the flow heat transfer on the surface of the fuel rods.In order to investigate the effect of surface fouling on the flow characteristics of the CRUD,as well as to explore the influence of cladding surface deposition layer on the active nucleation site density(NSD),the present study was based on the flow-boiling under atmospheric pressure.The flow boiling visualization experiment was conducted to simulate the actual fuel rod cladding with CRUD by using layer-by-layer deposition of SiO_(2),under two mass flow rates(0.12 m/s and 0.17 m/s)and three degrees of subcooling conditions(0,3,5 K),investigating the flow boiling heat transfer characteristics of fuel cladding Zr-4 non-deposition with two Zr-4 SiO_(2) depositions(1μm and 3μm).Focus on the relationship between the active nucleation site density Na with wall superheat,and analyze the main reasons for the differences under different operating conditions,and contrast differences in the active nucleation site density on the different of SiO_(2) deposited thicknesses,then compare it with existing models for the active nucleation site density.The results show that the deposited Zr-4 has a higher flow heat transfer capacity than the undeposited Zr-4,and this difference is mainly caused to the difference in surface porosity.The active nucleation site density increases on SiO_(2) deposited surfaces compared to undeposited surfaces,with a maximum in the 3μm SiO_(2 )deposited experimental group.Enhancing wall superheat increases the active nucleation site density,and the increase is more pronounced on surfaces with SiO_(2) deposits.For the same sample,under the condition that one of the degree of subcooling and flow rate is the same and the other is different,the differen

关 键 词：流动沸腾实验 表面沉积层 汽化核心密度 

分 类 号：TL331[核科学技术—核技术及应用]