CAJ | 학술논문

在美国 TMI-2发生严重事故时，反应堆下封头内累积了大量的熔融物，经过一段时间观察，下封头未被熔融物熔穿。因此提出了一些可能的冷却机理，其中间隙冷却机理被认为是最有可能的一种。本文进行了窄通道流动换热与冷却能力的试验，旨在探索窄缝的传热机理和冷却能力。试验中半球形采用向下加热，并观察流动换热现象。在分组试验过程中窄缝间隙选取为2 mm 和4 mm 两种，采用不同的加热功率对铜球进行加热。试验结果表明：在窄通道试验中，冷却过程与壁面加热、间隙大小有着不可分割的关系；壁面温度对窄通道冷却有着较大的影响；在窄通道流动换热与冷却过程中，对于单相对流换热，强制对流冷却的效果大于自然对流的冷却效果；对于多相对流换热，强制对流的冷却效果也大于自然对流的冷却效果。
재미국 TMI-2발생엄중사고시，반응퇴하봉두내루적료대량적용융물，경과일단시간관찰，하봉두미피용융물용천。인차제출료일사가능적냉각궤리，기중간극냉각궤리피인위시최유가능적일충。본문진행료착통도류동환열여냉각능력적시험，지재탐색착봉적전열궤리화냉각능력。시험중반구형채용향하가열，병관찰류동환열현상。재분조시험과정중착봉간극선취위2 mm 화4 mm 량충，채용불동적가열공솔대동구진행가열。시험결과표명：재착통도시험중，냉각과정여벽면가열、간극대소유착불가분할적관계；벽면온도대착통도냉각유착교대적영향；재착통도류동환열여냉각과정중，대우단상대류환열，강제대류냉각적효과대우자연대류적냉각효과；대우다상대류환열，강제대류적냉각효과야대우자연대류적냉각효과。
Many molten corium relocated in the lower head of TMI-2 reactor after severe accident.The lower head was not pene-trated during the accident.There are some cooling mechanisms have been suggested and a gap cooling mechanism is considered to be the most plausible one which plays a major role in the cooling of the corium.A narrow gap flow and heat transfer experiment was done to investigate mechanisms of heat transfer and the coolability.Hemispherical copper was heated downward and the flow heat transfer behavior was investigated.The gaps between the copper shell and plastic vessel were 2 mm and 4 mm,respectively. The effect of the gap cooling was investigated.In the experiment,the copper was heated with different powers,and the effects on the heat transfer should be noticed.The experimental results show that the coolability is affected by the wall heat and the gap width.The wall temperature is important for the coolability of the narrow gap.The effect of the forced convection is more markedly than that of the nature convection in single phase convection heat transfer and multi-phase convection heat transfer ex-periments.