CFD Aided Design of the Experimental Helium Loop for VHTR Simulation
NURETH-14 - 2011 September 25-30

Presented at:
2011 September 25-30
Toronto, Canada
Session Title:
G4-1 - Gas Cooled Fast Reactors and Very High Temperature Reactors; CFD Calculations

Churl Yoon (Korea Atomic Energy Research Institute)
Sung Deok Hong (Korea Atomic Energy Research Institute)
Jae Man Noh (Korea Atomic Energy Research Institute)
Yong Wan Kim (Korea Atomic Energy Research Institute)
Jong Hwa Chang (Korea Atomic Energy Research Institute)


A medium-scale helium loop for simulating a VHTR (Very High Temperature Reactor) is now

under construction in KAERI (Korea Atomic Energy Research Institute). Two electric heaters of

the test helium loop heat the helium fluid up to 950°C at a pressure of 1 ~ 9MPa. To optimize the

design specifications of the experimental helium loop, conjugate heat transfer in the hightemperature

helium heater was analyzed by using CFD (Computational Fluid Dynamics)

simulation. The main factors tested in this CFD analysis were the effects of turbulence, radiation,

gravity, and geometrical configuration of the heater. From the analysis results, the optimum

design configuration was selected confirming that thermal characteristics of the heater well meet

the design requirements. In this study, the interrelated effects of buoyancy forces and radiation

heat transfer on the geometrical configuration were closely investigated. It was concluded that the

buoyancy effects on the helium flows of the heater would be suppressed by the radiation heat

transfer inside the heating channel. Various emissivity values of the reflector material emissivity

were also tested. Gravity had greater effects on the temperature distribution for the lower

emissivity, but the maximum temperature variations due to the emissivity changes from 0.1 to

0.9 were limited to within a few tens of degrees. Finally, more detailed analyses on the HTH of

the medium scale helium loop including the spacers were performed and it is confirmed that the

thermal-fluidic characteristics of the HTH satisfied the design requirements.

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