CFD Analysis on the Influence of Coolant Distribution Blocks on the Core Hot Spot Temperature in a Prismatic Very High Temperature Reactor

2011 ◽  
Author(s):  
Min-Hwan Kim ◽  
Nam-il Tak ◽  
Jae Man Noh ◽  
Goon-Cherl Park
Keyword(s):  
High Temperature ◽  
Hot Spot ◽  
Maximum Velocity ◽  
Unit Cell ◽  
Normal Operation ◽  
The Core ◽  
Very High Temperature Reactor ◽  
Velocity Deviation ◽  
High Temperature Reactor ◽  
Very High

Two design options of core distribution block (CDB) for a cooled-vessel design in the Very High Temperature Reactor (VHTR) were developed and the influence on the core hot spot was investigated by the commercial computational fluid dynamics (CFD) code, CFX-11. Isothermal CFD analyses were performed to estimate the coolant flow variation at the inlet of the coolant channel. The results predicted about 5% of the maximum velocity deviation when applying the core pressure drop of NHDD PMR200. A unit-cell CFD model was used to access the effect of the velocity deviation on the core hot spot. The unit-cell analyses were carried out for the velocity deviation of 0%, 5%, and 10%. Not only a constant power but also a local maximum power profile was considered. According to the results, the maximum fuel temperature was increased by about 30°C for the velocity deviation of 10% but still below the normal operation limit of 1250°C.

scholarly journals Computational Fluid Dynamics Analyses on Very High Temperature Reactor Air Ingress

2009 ◽  
Author(s):  
Chang H. Oh ◽  
Eung S. Kim ◽  
Richard Schultz ◽  
David Petti ◽  
Hyung S. Kang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Temperature ◽  
System Analysis ◽  
Onset Time ◽  
The Core ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Air Ingress ◽  
Very High

A preliminary computational fluid dynamics (CFD) analysis was performed to understand density-gradient-induced stratified flow in a Very High Temperature Reactor (VHTR) air-ingress accident. Various parameters were taken into consideration, including turbulence model, core temperature, initial air mole-fraction, and flow resistance in the core. The gas turbine modular helium reactor (GT-MHR) 600 MWt was selected as the reference reactor and it was simplified to be 2D geometry in modeling. The core and the lower plenum were assumed to be porous bodies. Following the preliminary CFD results, the analysis of the air-ingress accident has been performed by two different codes: GAMMA code (system analysis code, Oh et al. 2006) and FLUENT CFD code (Fluent 2007). Eventually, the analysis results showed that the actual onset time of natural convection (∼160 sec) would be significantly earlier than the previous predictions (∼150 hours) calculated based on the molecular diffusion air-ingress mechanism. This leads to the conclusion that the consequences of this accident will be much more serious than previously expected.

Computational Fluid Dynamics Assessment of the Local Hot Core Temperature in a Pebble-Bed Type Very High Temperature Reactor

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Min-Hwan Kim ◽  
Hong-Sik Lim ◽  
Won Jae Lee
Keyword(s):  
Nusselt Number ◽  
High Temperature ◽  
Pressure Drop ◽  
Core Temperature ◽  
Normal Operation ◽  
Face Centered Cubic ◽  
Pebble Bed ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Very High

Assessment of the local hot core temperature during normal operation in a pebble-bed type very high temperature reactor has been carried out by using the computational fluid dynamic (CFD) method for which the boundary conditions were obtained from the results of a macroscopic analysis of the core using a system thermal analysis code, GAMMA. Three pebble arrangements are selected, which are simple cubic (SC), body-centered cubic, and face-centered cubic. The results showed that the SC arrangement having the lowest porosity gives the highest fuel temperature of 1237°C but still below the normal operational fuel limit of 1250°C. Comparison of the CFD results with an empirical correlation was made for the pressure drop and Nusselt number. Both results showed a similar tendency that the pressure drop and the Nusselt number increases as the porosity decreases but there were large differences in their absolute values. The benchmark calculation for the pressure drop of the packed particles in a square channel indicated that the correlation for the full core used in the system code is not appropriate for the prediction of a local thermal-fluid behavior in an ordered pebble arrangement.

CFD Assessment of the Local Hot Core Temperature in a Pebble-Bed Type Very High Temperature Reactor

2008 ◽  
Author(s):  
Min-Hwan Kim ◽  
Hong-Sik Lim ◽  
Won Jae Lee
Keyword(s):  
High Temperature ◽  
Pressure Drop ◽  
Core Temperature ◽  
Normal Operation ◽  
Face Centered Cubic ◽  
Pebble Bed ◽  
Benchmark Calculation ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Very High

Assessment of the local hot core temperature during normal operation in a pebble-bed type of Very High Temperature Reactor (VHTR) has been carried out by using the Computational Fluid Dynamic (CFD) method for which the boundary conditions were obtained from the results of a macroscopic analysis of the core using a system thermal analysis code, GAMMA. Three pebble arrangements are selected, which are Simple Cubic (SC), Body-Centered Cubic (BCC), and Face-Centered Cubic (FCC). Results showed that the SC arrangement having the lowest porosity gives the highest fuel temperature of 1237°C but still below the normal operational fuel limit of 1250°C. Comparison of the CFD results with an empirical correlation was made for the pressure drop and the Nusselt number but there were large differences between them. The benchmark calculation of a pressure drop for packed particles in a square channel indicated that the correlation for the full core used in the system code is not appropriate for the prediction of a local thermal fluid behavior.

scholarly journals Characterization of 2D-C/C Composite for Application of Very High Temperature Reactor(M & M 2009 Conference)

2010 ◽  
Vol 76 (764) ◽  
pp. 383-385 ◽  
Author(s):  
Taiju SHIBATA ◽  
Junya SUMITA ◽  
Taiyo MAKITA ◽  
Takashi TAKAGI ◽  
Eiji KUNIMOTO ◽  
...  
Keyword(s):  
High Temperature ◽  
Special Issue ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Very High
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