A CRITERION FOR THE ONSET OF AIR INGRESS IN VHTR BY AIR INTRUSION
The projected prismatic and pebble-bed pre-conceptual designs for the Very High Temperature Reactor (VHTR) both have large diameter, horizontally-oriented, exit ducts that lead hot helium from the core exit through the lower plenum to the balance-of-plant. In the event a significant leak is present in the exit duct the system will depressurize and the possibility of air ingress into first the lower plenum and then the core must be considered. The intrusion of air against helium flow is driven by the weight difference between the two fluids. Thus the potential for air intrusion always exists. Whether such a phenomenon will actually occur is not as clear. This paper proposes a simple criterion for the onset of air intrusion. The criterion is expressed in terms of a densimetric Froude number (the inverse of the bulk Richardson number) and a scaled pressure difference between the duct exit and the containment. The pressure difference is rendered dimensionless by dividing it with the product of the duct radius and the difference of specific weight of the two fluids. The dimensionless variables in the criterion enable its validity be verified by experiments using fluids other than helium and air. This paper presents the development of this criterion and experimental validation using water and biodiesel as the testing fluids. The relevance and application of this criterion to VHTR air ingress scenarios are described.
Jim C.P.Liou Donald L.Parks Richard R.Schultz
University of Idaho Moscow, Idaho 83844, USA Idaho National Laboratory Idaho Falls, Idaho 83415, USA
国际会议
18th International Conference on Nuclear Engineering(第18届国际核能工程大会 ICONE 18)
西安
英文
1-7
2010-05-17（万方平台首次上网日期，不代表论文的发表时间）