Multiscale analysis of heat transfer in coated fuel particle compacts – Application to the HTTR

2015 ◽  
Vol 282 ◽  
pp. 106-115 ◽  
Author(s):  
X. Garnaud ◽  
X. Han ◽  
P. Jacquet ◽  
J.-M. Ndombo ◽  
I. Limaiem
Keyword(s):  
Heat Transfer ◽  
Multiscale Analysis ◽  
Fuel Particle ◽  
Coated Fuel Particle

Effect of PyC Thermal Behavior on the Stress of TRISO-Coated Fuel Particles

2016 ◽  
Vol 697 ◽  
pp. 852-857
Author(s):  
Rong Li ◽  
Bing Liu ◽  
Chun He Tang
Keyword(s):  
Pressure Vessel ◽  
Elastic Strain ◽  
Fission Products ◽  
Fuel Particle ◽  
Coated Particles ◽  
Inner Pressure ◽  
Higher Temperature ◽  
Fuel Particles ◽  
Coated Fuel Particle ◽  
Increasing Temperature

TRISO coated fuel particle is the most important component in HTR fuel, the silicon carbide (SiC) coating layer is regarded as the pressure vessel to contain the fission products. During reactor operation, the inner pressure resulting from fission products and pyrocarbon (PyC) thermal effect will contribute to the failure of TRISO-coated particles. The higher temperature will result in the increasing of inner pressure and PyC thermal expansion, which will then change the stress of SiC layer. Considering the effects of temperature on inner-pressure expansion and elastic strain into the pressure vessel failure model, thermal effects on the stress of TRISO-coated particles were studied with analytical solution. The results indicated that the effects of inner pressure on the particle stresses were increasingly highlighted at the late stage of irradiation. And the increasing temperature caused a slight effect on PyC elastic modulus while elastic strain is unaffected greatly, either. Therefore, CFP stresses remain unchanged basically.

Evaluation of the Fracture Strength for Silicon Carbide Layers in the Tri-Isotropic-Coated Fuel Particle

2006 ◽  
Vol 0 (0) ◽  
pp. 061205002105002-???
Author(s):  
Seong-Gu Hong ◽  
Thak-Sang Byun ◽  
Richard A. Lowden ◽  
Lance L. Snead ◽  
Yutai Katoh
Keyword(s):  
Silicon Carbide ◽  
Fracture Strength ◽  
Fuel Particle ◽  
Coated Fuel Particle

Review of Progress in Coated Fuel Particle Performance Analysis

2019 ◽  
Vol 194 (3) ◽  
pp. 169-180
Author(s):  
Nairi Baghdasaryan ◽  
Tomasz Kozlowski
Keyword(s):  
Performance Analysis ◽  
Fuel Particle ◽  
Coated Fuel Particle

Understanding the 1600°C Fuel Temperature Limit of TRISO Coated Fuel Particles

2015 ◽  
Vol 1769 ◽  
Author(s):  
Félix Cancino Trejo ◽  
Mariana Sáenz Padilla ◽  
Eddie López-Honorato
Keyword(s):  
Fission Products ◽  
Chemical Vapor ◽  
Pyrolytic Carbon ◽  
Temperature Limit ◽  
Inert Atmosphere ◽  
Effect Of Temperature ◽  
Fuel Particle ◽  
Fuel Temperature ◽  
Water Reactors ◽  
Coated Fuel Particle

ABSTRACTThe TRISO (tristructural isotropic) coated fuel particle is made of a uranium oxide kernel coated with three layers of pyrolytic carbon and one of silicon carbide. This fuel, originally used in High Temperature Reactors, has been proposed as accident tolerant fuel for Light Water Reactors after the accident in Fukushima. Although this fuel is capable of retaining fission products within the particle up to 1600°C, little is known on the origin of this temperature limit. Therefore, in order to increase the safety of this type of fuel, it is necessary to understand the origin of the degradation of the materials that compose this fuel. We have studied the effect of temperature on the microstructure and diffusion of silver in pyrolytic carbon coatings produced by fluidized bed chemical vapor deposition. Samples were heat treated at 1000°C, 1400°C and 1700°C for 200 hrs. under inert atmosphere. The effect of temperature on the microstructure and silver diffusion behavior were analyzed by Raman spectroscopy, X-Ray diffraction, optical microscopy, SEM and TEM. We observed that the microstructure of PyC changed drastically above 1400°C, showing the increase in anisotropy and the re-orientation of the graphene planes. The diffusion of silver appears to be also correlated with this change in microstructure.

scholarly journals Fission Products Distribution in TRISO Coated Fuel Particles Irradiated to 3.22 X 1021 n/cm2 Fast Fluence at 1092°C

2015 ◽  
Author(s):  
Haiming Wen ◽  
Isabella J. Van Rooyen ◽  
Connie M. Hill ◽  
Tammy L. Trowbridge ◽  
Ben D. Coryell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Beam ◽  
Fission Products ◽  
Fuel Particle ◽  
Next Generation ◽  
Research Activities ◽  
Transmission Electron ◽  
Fuel Particles ◽  
Coated Fuel Particle

Mechanisms by which fission products (especially silver [Ag]) migrate across the coating layers of tristructural isotropic (TRISO) coated fuel particles designed for next generation nuclear reactors have been the subject of a variety of research activities due to the complex nature of the migration mechanisms. This paper presents results obtained from the electron microscopic examination of selected irradiated TRISO coated particles from fuel compact 1-3-1 irradiated in the first Advanced Gas Reactor experiment (AGR-1) that was performed as part of the Next Generation Nuclear Plant (NGNP) project. It is of specific interest to study particles of this compact as they were fabricated using a different carrier gas composition ratio for the SiC layer deposition compared with the baseline coated fuel particles reported on previously. Basic scanning electron microscopy (SEM) and SEM montage investigations of the particles indicate a correlation between the distribution of fission product precipitates and the proximity of the inner pyrolytic carbon (IPyC)-silicon carbide (SiC) interface to the fuel kernel. Transmission electron microscopy (TEM) samples were sectioned by focused ion beam (FIB) technique from the IPyC layer, the SiC layer and the IPyC-SiC interlayer of the coated fuel particle. Detailed TEM and scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDS) were performed to identify fission products and characterize their distribution across the IPyC and SiC layers in the areas examined. Results indicate the presence of palladium-silicon-uranium (Pd-Si-U), Pd-Si, Pd-U, Pd, U, U-Si precipitates in the SiC layer and the presence of Pd-Si-U, Pd-Si, U-Si, U precipitates in the IPyC layer. No Ag-containing precipitates are evident in the IPyC or SiC layers. With increased distance from the IPyC-SiC interface, there are less U-containing precipitates, however, such precipitates are present across nearly the entire SiC layer.

Experimental Study on Heat Transfer of Fuel-Particle Mixtures in a Vertical Tube at Supercritical Pressure

2013 ◽  
Author(s):  
Xiao-Yu Wu ◽  
Dan Huang ◽  
Wei Li ◽  
Guo-Qiang Xu ◽  
Zhi Tao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Cooling System ◽  
High Heat ◽  
Vertical Tube ◽  
Solid Particles ◽  
Fuel Particle ◽  
High Heat Flux ◽  
Step Method ◽  
Working Pressure

Regenerative cooling system is thought to be an effective and practical solution to better thermal management for high heat flux applications. In this paper, we examined the effects of solid particles mixed with fuels on the heat transfer performances of supercritical fuel coolant. Two-step method was applied to prepare Fe3O4-kerosene fluids. Experiments were carried out to study the heat transfer characteristics of fuel-particle mixtures flowing in a vertical tube at supercritical pressures. Results show that there are three different heat transfer mechanisms at the in-, mid- and ex-sections along the tube; increasing the flow rate or the working pressure could enhance the heat transfer performances, yet higher heat flux leads to poorer heat transfer performances. Besides, the addition of solid particles deteriorates the heat transfer performances of the fuel coolant through the modification of inner wall surfaces. As the particle content increases, the heat transfer performance becomes worse.

Comparative Study of Coated Particle Stresses With Different Coating Layer Performance

2016 ◽  
Author(s):  
Rong Li ◽  
Bing Liu ◽  
Chunhe Tang
Keyword(s):  
Coating Layer ◽  
Fuel Particle ◽  
Reactor Irradiation ◽  
Coated Particle ◽  
Shrinkage And Creep ◽  
Fuel Design ◽  
Fuel Behavior ◽  
Coated Fuel Particle ◽  
High Temperature Gas ◽  
Good Agreement

Tristructural-isotropic coated fuel particle is an important fuel design for high-temperature gas-cooled reactor. Irradiation-induced pyrocarbon (PyC) shrinkage and creep behavior will affect greatly the stresses of a TRISO-coated particle. In this study, 5 cases under different conditions by analytical solution were studied to calculate the particle stresses with different fuel behavior. These cases varied in particle geometries, the mount of gas pressure or fuel behavior. A comparison between the results and other benchmarking studies among different codes was made. The results indicated that the calculated results in this study were in good agreement with other codes.

A Modeling Analysis of Non-Melting Solid Fuel Particle Heating

2003 ◽  
Author(s):  
Ali A. Rostami ◽  
Susan E. Wrenn ◽  
Mohammad R. Hajaligol
Keyword(s):  
Heat Transfer ◽  
Weight Loss ◽  
Solid Particle ◽  
Convection Heat Transfer ◽  
Total Weight ◽  
Fuel Particle ◽  
Total Weight Loss ◽  
Convection Heat ◽  
Particle Heating ◽  
Internal Convection

The heating of fuel particles is generally the first step in the process of gasification or combustion of solid fuels such as coal and biomass. The particle heating that is achieved via combined convection and radiation effects requires a rigorous analysis of heat transfer within as well as outside of the particle, which makes the lumped capacity approximation unsuitable. A more adequate representation of the heating-up process requires the inclusion of the internal convection within the solid particle, the blowing effects on the particle surface, the spatial and temporal variations of the solid thermal conductivity as well as the heat of pyrolysis reactions. The internal convection tends to equalize the temperature distribution within the solid, while the blowing effect contributes to the boundary layer thickening and eventually to a reduction in the convection heat transfer to the particle. To include the above-mentioned effects, a kinetic model for the total weight loss of the solid material was coupled with the heating model. A simple first-order reaction model for the total weight loss was utilized in this study. For materials with high moisture contents, the heat of pyrolysis reactions is an important factor in the heating rate and non-uniform heating of the solid particle. Thermal equilibrium between the solid and evolved gases was assumed within the particle and the equations for the conservation of mass and energy were solved numerically. Results show that surface blowing which is due to the devolatilization of the particle tends to reduce the convection heat transfer from the hot gases to the particle. Internal convection contributes to thermal uniformity in the particle. Heat of pyrolysis reactions plays an important role in the heating profile of the particle. It delays the temperature rise of the particle until most of the volatile materials is released.

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