Session: 08-03: Computational Fluid Dynamics (CFD) and Applications - III

Paper Number: 134729

134729 - Numerical Simulation Study on Cladding Blister of Parallel Fuel Plates Under Subcooled Boiling 

Abstract: 

Plate fuel elements have the characteristic of more efficient heat transfer and are a potential new type of fuel assembly. In the case of subcooled boiling flow of coolant, the thermalhydraulic characteristics of plate fuel elements after cladding blister have received little attention. However, cladding blister is a problem that must be faced in the design and development of fuel assemblies. This paper investigated the thermal-hydraulic characteristics of plate fuel elements after cladding blisters using numerical simulation methods. The research results showed that the cladding blister significantly impacts the wall temperature and void fraction distribution of the blister cladding, the blister back cladding, and the blister opposite cladding. The fuel meat temperature under the blister coverage area significantly increased. Further research revealed the effects of blister area, height, and number on plate fuel elements. 1. In the blister corresponding area, the wall temperature and void fraction of the blister cladding and the blister opposite cladding decrease to the minimum value, while the wall temperature and void fraction of the blister back cladding increase to the maximum value. 2. For blister cladding, the wall temperature and void fraction downstream of the blister will be lower than normal; For the blister back cladding, the wall temperature and void fraction downstream of the blister will be higher than normal; For the blister opposite cladding, the downstream wall temperature and void fraction of the blister are initially lower than normal, but higher than normal when approaching the outlet, and are the maximum values at the outlet of all the claddings; The wall temperature and void fraction distribution of other claddings are weakly affected by the blister, which is equivalent to normal. 3. The temperature peak of the fuel meat under the blister coverage area is more than 80 K higher than normal, and the peak position shifts from the center to the interface between the fuel meat and the gas gap. The temperature gradient inside the gas gap is relatively large. 4. The larger the blister area, the lower the wall temperature and void fraction of the blister cladding, the higher the wall temperature and void fraction of the blister back cladding, and the higher the temperature peak of the fuel meat under the blister coverage area. 5. The higher the blister height, the lower the wall temperature and void fraction of the blister cladding, but it has little effect on the wall temperature and void fraction of the blister back cladding and temperature peak of the fuel meat under the blister coverage area. 6. When there are multiple blisters, the wall temperature and void fraction in the area between the blisters will also be affected. The more blisters there are, the lower the wall temperature and void fraction of the blister cladding. Besides, the impact of multiple blisters is more like a simple superposition of multiple single blisters. 7. The leeward of the blister will experience vapor phase backflow, and the smaller the blister area and the higher the blister height, the stronger the backflow effect. The number of blisters has little effect on the backflow.

Presenting Author: Kexin Liu Harbin Engineering University

Presenting Author Biography: Kexin Liu is currently a Ph.D student at Harbin Engineering University.

Authors:

Kexin Liu Harbin Engineering University
Jianjun Xu Nuclear Power Institute of China
Ming Ding Harbin Engineering University
Xiaxin Cao Harbin Engineering University