Review of Progress in Coated Fuel Particle Performance Analysis

A fuel performance analysis code for a very high temperature gas-cooled reactor (VHTR) COPA (Coated Particle) is being developed at the Korea Atomic Energy Research Institute (KAERI). The COPA code consists of nine modules: BURN, TEMTR, TEMPEB, TEMBL, MECH, FAIL, FPREL, ABAQ, and MPRO. The BURN determines neutron flux and fluence at a location of a reactor core, and then calculates a fuel burnup, a fission rate per volume and a fission product inventory throughout a fuel particle and a fuel element. The TEMTR, TEMPEB and TEMBL calculate the temperature distributions in a coated fuel particle, a pebble and a fuel block by using a one-dimensional finite difference method, respectively. The MECH performs mechanical calculations on a coated fuel particle by using a finite element method. The FAIL performs probabilistic calculations to estimate the failure probabilities of the coating layers during an experiment or a reactor operation. The FPREL estimates the migrations of gaseous and metallic fission products through a fuel particle and a fuel element by using a one-dimensional finite difference method. The ABAQ performs the analysis of the crack and debonding in a coated fuel particle. The MPRO calculates the material properties of the kernel, low-density pyrocarbon, high-density pyrocarbon, silicon carbide, matrix graphite, and structural graphite. Each module is used to produce input data for other modules or is inserted into other modules. The COPA code is one of the computer codes taking part in the IAEA-CRP-6 benchmarking program. The stresses and failure fractions calculated by the COPA-MECH and COPA-FAIL showed good agreements with the results by the other countries’ codes. In order to establish a good database of the related material properties, KAERI is participating in an international irradiation experiment, is planning its own irradiation and post-irradiation experiments, and will perform ab-initio calculations on the fuel materials.

Download Full-text

Investigation of Irradiation Behavior of SiC-Coated Fuel Particle at Extended Burnup

Nuclear Technology ◽

10.13182/nt03-a3387 ◽

2003 ◽

Vol 142 (3) ◽

pp. 250-259 ◽

Cited By ~ 11

Author(s):

Kazuhiro Sawa ◽

Tsutomu Tobita

Keyword(s):

Fuel Particle ◽

Coated Fuel Particle ◽

Irradiation Behavior

Download Full-text

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.697.852 ◽

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.

Download Full-text

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

Journal of the American Ceramic Society ◽

10.1111/j.1551-2916.2006.01367.x ◽

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

Download Full-text

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

MRS Proceedings ◽

10.1557/opl.2015.119 ◽

2015 ◽

Vol 1769 ◽

Cited By ~ 1

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.

Download Full-text

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

ASME 2015 Nuclear Forum ◽

10.1115/nuclrf2015-49695 ◽

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.

Download Full-text

Comparative Study of Coated Particle Stresses With Different Coating Layer Performance

Volume 1: Operations and Maintenance, Aging Management and Plant Upgrades; Nuclear Fuel, Fuel Cycle, Reactor Physics and Transport Theory; Plant Systems, Structures, Components and Materials; I&C, Digital Controls, and Influence of Human Factors ◽

10.1115/icone24-60046 ◽

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.

Download Full-text