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Scanning tunneling microscopy and atomic force microscopy of Au implanted in highly ordered pyrolytic graphite

Description: Surfaces of highly oriented pyrolytic graphite implanted with gold were studied by both constant current STM, constant force, and tapping mode AFM. Gold colloids were observed by both constant current STM and tapping mode AFM. The surfaces can be modified by applying currents of {plus_minus}4 V and 1 nA. In addition, pyramidal and faceted structures were observed on sample surfaces suggesting the presence of diamond microcrystals.
Date: January 1, 1996
Creator: Tung, Y.S.; Ueda, A.; Henderson, D.O.; Mu, R.; Gu, Z.; White, C.W. et al.
Partner: UNT Libraries Government Documents Department

Comparison of the electrochemical properties of several commercial graphites with a templated disordered carbon

Description: A templated carbon was prepared by the pyrolysis of pyrene impregnated into pillared clay (PILC). The electrochemical performance of this was evaluated with the goal of using this material as an anode in Li-ion cells. The reversible capacity was measured as a function of C rate and the cycling characteristics were determined for various intercalation protocols. The performance of this material was compared to that of several commercial graphites tested under the same conditions. The PILC carbon shows great promise as a Li-ion anode if the fade and first-cycle losses can be controlled.
Date: April 11, 2000
Creator: Guidotti, R. A.; Reinhardt, F. W. & Sandi, G.
Partner: UNT Libraries Government Documents Department

Accelerator-Based Irradiation Creep of Pyrolytic Carbon Used in TRISO Fuel Particles for the (VHTR) Very Hight Temperature Reactors

Description: Pyrolytic carbon (PyC) is one of the important structural materials in the TRISO fuel particles which will be used in the next generation of gas-cooled very-high-temperature reactors (VHTR). When the TRISO particles are under irradiation at high temperatures, creep of the PyC layers may cause radial cracking leading to catastrophic particle failure. Therefore, a fundamental understanding of the creep behavior of PyC during irradiation is required to predict the overall fuel performance.
Date: July 30, 2010
Creator: Wang, Lumin & Was, Gary
Partner: UNT Libraries Government Documents Department

Raman spectroscopy of C-irradiated graphite

Description: Highly oriented pyrolytic graphite samples were irradiated with C{sup +} ions at 35 keV in a direction normal to the basal plane and subsequently annealed up to 1373 K. Substantial surface topography changes were observed at fluences of 5 {times} 10{sup 18} ions/m{sup 2} and higher using scanning electron and atomic force microscopies. Intricate networks of surface cracks and ridges developed after high dose implantation. A systematic study of the irradiation effects was conducted using Raman spectroscopy. Microstructural changes in irradiated regions were first detected at a dose of 1 {times} 10{sup 17} ions/m{sup 2} through the appearance of the Raman D-line at {approx}1360 cm{sup {minus}1}. The intensity of this line increases while that of the Raman G-line at 1580 cm{sup {minus}1} decreases as the irradiation dose is increased or the irradiation temperature is decreased. After irradiation at 280K to a fluence of 5 {times} 10{sup 19} ions/m{sup 2} or higher the first order spectrum exhibits one single line at a wavelength intermediate between the D- and G-lines. Damage recovery upon thermal annealing depends not only on the initial damage state but also on the annealing temperature sequence. Samples irradiated to a damage level where two distinct Raman peaks are no longer resolvable exhibited upon direct annealing at a high temperature two distinct Raman lines. By contrast, pre-annealing these highly irradiated specimens at lower temperatures produced less pronounced changes in the Raman spectra. Pre-annealing appears to stabilize damage structures that are more resistant to high-temperature annealing than those induced by irradiation.
Date: September 1, 1994
Creator: Hembree, D. M. Jr.; Pedraza, D. F.; Romanoski, G. R.; Withrow, S. P. & Annis, B. K.
Partner: UNT Libraries Government Documents Department

Comparison of the electrochemical properties of several commercial graphites with a templated disordered carbon

Description: A templated carbon was prepared by the pyrolysis of pyrene impregnated into pillared clay (PILC). The electrochemical performance of this was evaluated with the goal of using this material as an anode in Li-ion cells. The reversible capacity was measured as a function of C rate and the cycling characteristics were determined for various intercalation protocols. The performance of this material was compared to that of several commercial graphites tested under the same conditions. The PILC carbon shows great promise as a Li-ion anode if the fade and first-cycle losses can be controlled.
Date: March 22, 2000
Creator: GUIDOTTI,RONALD A.; REINHARDT,FREDERICK W. & SANDI,GISELLE
Partner: UNT Libraries Government Documents Department

Recovery of Technetium and Iodine from Spent ATW TRISO Type Fuels.

Description: The Accelerator Transmutation of Waste (ATW) program is being developed to determine the feasibility of separating and transmutating the transactinides (Pu-Cm) and long-lived fission product (99Tc and 129I) from spent LWR fuel. Several types of ATW fuels have been suggested to transmutate the Pu-Cm fraction including TRISO type fuels. An ATW TRISO fuel would consist of a Pu-Cm oxide kernel surrounded by several layers of pyrolytic carbon, a layer of SiC, and an outer layer of pyrolytic carbon. Processing of the spent ATW fuel would involve the crush, burn, and leach approach used on normal TRISO fuels. This report describes experiments that determine the potential behavior of the two long-lived fission products, 99Tc and 129I, in this processing. Iodine can be removed and trapped during the burning of the carbon from the fuel. Some technetium may volatilize in the latter stages of the burn but the bulk of it will have to be recovered after dissolution of the oxide residue.
Date: January 1, 2001
Creator: Schroeder, N. C. (Norman C.) & Attrep, Moses
Partner: UNT Libraries Government Documents Department

TRISO-Fuel Element Performance Modeling for the Hybrid LIFE Engine with Pu Fuel Blanket

Description: A TRISO-coated fuel thermo-mechanical performance study is performed for the hybrid LIFE engine to test the viability of TRISO particles to achieve ultra-high burnup of a weapons-grade Pu blanket. Our methodology includes full elastic anisotropy, time and temperature varying material properties for all TRISO layers, and a procedure to remap the elastic solutions in order to achieve fast fluences up to 30 x 10{sup 25} n {center_dot} m{sup -2} (E > 0.18 MeV). In order to model fast fluences in the range of {approx} 7 {approx} 30 x 10{sup 25} n {center_dot} m{sup -2}, for which no data exist, careful scalings and extrapolations of the known TRISO material properties are carried out under a number of potential scenarios. A number of findings can be extracted from our study. First, failure of the internal pyrolytic carbon (PyC) layer occurs within the first two months of operation. Then, the particles behave as BISO-coated particles, with the internal pressure being withstood directly by the SiC layer. Later, after 1.6 years, the remaining PyC crumbles due to void swelling and the fuel particle becomes a single-SiC-layer particle. Unrestrained by the PyC layers, and at the temperatures and fluences in the LIFE engine, the SiC layer maintains reasonably-low tensile stresses until the end-of-life. Second, the PyC creep constant, K, has a striking influence on the fuel performance of TRISO-coated particles, whose stresses scale almost inversely proportional to K. Obtaining more reliable measurements, especially at higher fluences, is an imperative for the fidelity of our models. Finally, varying the geometry of the TRISO-coated fuel particles results in little differences in the scope of fuel performance. The mechanical integrity of 2-cm graphite pebbles that act as fuel matrix has also been studied and it is concluded that they can reliable serve the entire LIFE burnup cycle without ...
Date: February 18, 2010
Creator: DeMange, P; Marian, J; Caro, M & Caro, A
Partner: UNT Libraries Government Documents Department

The optical constants and spectral specular reflectivity of highly oriented pyrolytic graphite (HOPG). Revision 1

Description: Measurements of the specular reflectivity and the optical constants of highly ordered pyrolytic graphite (HOPG) have been made using two independent optical systems. The first measures reflectance (at 1.06 {mu}m and 293 K) by comparing the intensity of a laser beam before and after reflecting off the sample. The second determines the complex index of raft-action (from 0.55 to 8.45 {mu}m, with sample temperatures of 293, 480, 900 and 1300 K) by ellipsometry. Agreement between the two methods is good. Moderate reflectivities are observed over the full spectral range of measurement: the spectral directional-hemispherical reflectivity at normal incidence varies from 0.41 at 0.55 {mu}m to 0.74 at 8.45 {mu}m. The components of the complex index of refraction increase smoothly with wavelength. The index of refraction increases from 3.10 at 0.55 {mu}m to 7.84 at 8.45 {mu}m. The extinction coefficient varies from 2.01 to 6.66 over the same range.
Date: August 1, 1993
Creator: Havstad, M. A.; Schildbach, M. A. & McLean, W. II
Partner: UNT Libraries Government Documents Department

Multilayered nuclear fuel element

Description: A nuclear fuel element is described which is suitable for high temperature applications comprised of a kernel of fissile material overlaid with concentric layers of impervious graphite, vitreous carbon, pyrolytic carbon and metal carbide. The kernel of fissile material is surrounded by a layer of impervious graphite. The layer of impervious graphite is then surrounded by a layer of vitreous carbon. Finally, an outer shell which includes alternating layers of pyrolytic carbon and metal carbide surrounds the layer of vitreous carbon.
Date: December 1, 1996
Creator: Schweitzer, Donald G. & Sastre, Cesar
Partner: UNT Libraries Government Documents Department

Carbon based prosthetic devices

Description: This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.
Date: December 31, 1998
Creator: Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T.; Klawitter, J.J.; Ogilvie, W. et al.
Partner: UNT Libraries Government Documents Department

Novel carbonaceous materials for lithium secondary batteries

Description: Carbonaceous materials have been synthesized using pillared clays (PILCs) as templates. The PILC was loaded with organic materials such as pyrene in the liquid and vapor phase, styrene in the vapor phase, trioxane, ethylene and propylene. The samples were then pyrolyzed at 700 C in an inert atmosphere, followed by dissolution of the inorganic template by conventional demineralization methods. X-ray powder diffraction of the carbons showed broad d{sub 002} peaks in the diffraction pattern, indicative of a disordered or turbostratic system. N{sub 2} BET surface areas of the carbonaceous materials range from 10 to 100 m{sup 2}/g. There is some microporosity (r < 1 nm) in the highest surface area carbons. Most of the surface area, however, comes from a mixture of micro and mesopores with radii of 2--5 nm. Electrochemical studies were performed on these carbons. Button cells were fabricated with capacity- limiting carbon pellets electrodes as the cathode a/nd metallic lithium foil as the anode. Large reversible capacities (up to 850 mAh/g) were achieved for most of the samples. The irreversible capacity loss was less than 180 mAh/g after the first cycle, suggesting that these types of carbon materials are very stable to lithium insertion and de-insertion reactions.
Date: July 1, 1997
Creator: Sandi, G.; Winans, R.E.; Carrado, K.A. & Johnson, C.S.
Partner: UNT Libraries Government Documents Department

Pore structure and growth kinetics in carbon materials

Description: Pore structure of glassy carbon (GC) and pyrolytic graphite (PG) have been investigated. GC is one of the most impervious of solids finding applications in prosthetic devices and fuel cells while PG is used extensively in the aerospace industry. One third of the microstructure of GC consists of closed pores inaccessible to fluids. The microstructure of this material has been characterized using x-ray diffraction (XRD) and high resolution electron microscopy. Small angle x-ray scattering (SAXS) has been used to measure the angstrom sized pores and to follow the evolution of pore surface area as a function of heat treatment temperature (HTT) and heat treatment time (HTt) at constant temperature. From these measurements an analysis of the surface area kinetics was made to find out if rate processes are involved and to locate graphitization occurring at pore surfaces. PG on the other hand has been found to have larger sized pores that comprise five percent of its volume. In addition to being closed these pores are oriented. Some pore models are proposed for PG and the existing scattering theory from oriented ellipsoids is modified to include the proposed shapes.
Date: April 1, 1978
Creator: Bose, S.
Partner: UNT Libraries Government Documents Department

Sound velocity of carbon at high pressures

Description: We have measured the sound velocity in shock compressed graphite. The data are consistent with a model of solid diamond from 0.8 to 1.4 Mbar. 18 references.
Date: September 11, 1984
Creator: Shaner, J.W.; Brown, J.M.; Swenson, C.A. & McQueen, R.G.
Partner: UNT Libraries Government Documents Department

Data Compilation for AGR-3/4 Driver Particle Composite LEU03-09T

Description: This document is a compilation of characterization data for the AGR-3/4 driver fuel coated particle composite LEU03-09T, a composite of four batches of TRISO-coated, nominally 350 {micro}m diameter, 19.7% low enrichment uranium oxide/uranium carbide kernels (LEUCO). The AGR-3/4 driver fuel particles were fabricated using the AGR-1 baseline coating conditions and consist of a spherical kernel coated with an {approx}50% dense carbon buffer layer (100 {micro}m nominal thickness) followed by a dense inner pyrocarbon layer (40 {micro}m nominal thickness) followed by a SiC layer (35 {micro}m nominal thickness) followed by another dense outer pyrocarbon layer (40 {micro}m nominal thickness). the coated particles were produced by ORNL for the Advanced Gas Reactor Fuel Development and Qualification (AGR) program to be put into compacts, along with designed-to-fail particles, for insertion in the AGR-3 and AGR-4 irradiation test capsules. The kernels were obtained from BWXT and identified as composite G73V-20-69303. The BWXT kernel lot G73V-20-69303 was riffled into sublots for characterization and coating by ORNL and identified as LEU03-?? (where ?? is a series of integers beginning with 01).
Date: March 1, 2007
Creator: Hunn, John D & Lowden, Richard Andrew
Partner: UNT Libraries Government Documents Department

INERI-2006-003-F FY07 Annual Report

Description: Project Title: Comparison of Characterization Methods for Anisotropy and Microstructure of TRISO Particle Layers This INERI was created to support a comparative study between the newly developed two modulator generalized ellipsometry microscope (2-MGEM) at the Oak Ridge National Laboratory (ORNL) and the more traditional optical polarimeter (RAPAX) at the Commissariat l' nergie Atomique (CEA). These two systems are used to measure the anisotropy of the pyrocarbon layers in tri-isotropic (TRISO) coated particle fuel, which is an important parameter related to fuel performance. Although this project was only just started in June 2007, good progress has already been made. A kickoff meeting was held at ORNL on July 30-31, 2007 to present early progress and discuss details of the proposed work plan. This meeting was of great benefit to the participants, offering an opportunity to overcome the language barrier and more thoroughly communicate project relevant information. Each technical lead gave a presentation explaining the analysis techniques used in his task and presented data on early measurements of the German reference fuels. Plans were finalized regarding what work needed to be done and how to proceed with the comparative study. Possibilities for the inclusion of other coated particle samples, in addition to the two German reference fuels originally proposed, were also discussed. A list of these additional sample has now been generated and approved. Coating fragments from this series of different TRISO particle fuels have been sent from ORNL to the CEA and TEM analysis is in progress. Comparisons have already been made between the microstructure of the two German reference fuels which are the primary samples for this project. Specimens have also been prepared from the German reference fuels for comparative analysis between the 2-MGEM and RAPAX devices and initial measurements performed. Plans are to exchange specimens of the various fuel ...
Date: October 1, 2007
Creator: Hunn, John D
Partner: UNT Libraries Government Documents Department

Data Compilation for AGR-1 Variant 3 Coated Particle Composite LEU01-49T

Description: This document is a compilation of characterization data for the AGR-1 variant 3 coated particle composite LEU01-49T, a composite of three batches of TRISO-coated 350 {micro}m diameter 19.7% low enrichment uranium oxide/uranium carbide kernels (LEUCO). The AGR-1 TRISO-coated particles consist of a spherical kernel coated with a {approx} 50% dense carbon buffer layer (100 {micro}m nominal thickness) followed by a dense inner pyrocarbon layer (40 {micro}m nominal thickness) followed by a SiC layer (35 {micro}m nominal thickness) followed by another dense outer pyrcoarbon layer (40 {micro}m nominal thickness). The coated particles were produced by ORNL for the Advanced Gas Reactor Fuel Development and Qualification (AGR) program to be put into compacts for the fuel shakedown irradiation (AGR-1) experiment. The kernels were obtained from BWXT and identified as composite G73D-20-6302. The BWXT kernel lot G73D-20-69302 was riffled into sublots for characterization and coating by ORNL and identified as LEUO01-?? (where ?? is a series of integers beginning with 01).
Date: July 1, 2006
Creator: Hunn, John D & Lowden, Richard Andrew
Partner: UNT Libraries Government Documents Department

Data Compilation for AGR-1 Variant 3 Compact Lot LEU01-49T-Z

Description: This document is a compilation of characterization data for the AGR-1 vriant 3 fuel compact lot LEU01-49T-Z. The compacts were produced by ORNL for the Advanced Gas Reactor Fuel Development and Qualification (AGR) program for the first AGR irradiation test train (AGR-1). This compact lot was fabricated using particle composite LEU01-49T, which was a composite of three batches of TRISO-coated 350 {micro}m diameter 19.7% low enrichment uranium oxide/uranium carbide kernels (LEUCO). The AGR-1 TRISO-coated particles consist of a spherical kernel coated with an {approx} 50% dense carbon buffer layer (100 {micro}m nominal thickness), followed by a dense inner pyrocarbon layer (40 {micro}m nominal thickness), followed by a SiC layer (35 {micro}m nominal thickness), followed by another dense outer pyrocarbon layer (40 {micro}m nominal thickness). The kernels were obtained from BWXT and identified as composite G73D-20-69302. The BWXT kernel lot G73D-20-69302 was riffled into sublots for characterization and coating by ORNL and identified as LEU01-?? (where ?? is a series of integers beginning with 01). A data compilation for the AGR-1 variant 3 coated particle composite LEU01-49t CAN BE FOUND IN ornl/tm-2006/022.
Date: August 1, 2006
Creator: Hunn, John D; Montgomery, Fred C & Pappano, Peter J
Partner: UNT Libraries Government Documents Department

Results from ORNL Characterization of HRB-21 Reference Fuel

Description: This document is a compilation of the characterization data produced by ORNL for coated UCO fuel particles (350 {micro}m kernel diameter) fabricated by GA for the HRB-21 irradiation test capsule. The archived fuel particles form the batch used in HRB-21 were obtained by the Advanced Gas Reactor Fuel Development and Qualification (AGR) program for use as a reference material. The GA characterization data for this batch of fuel particles is presented in document GT-HTGR-88357, Rev. C, 'Capsule HRB-21 Preirradiation Report'. The archived fuel particles obtained by the AGR Program are from batch 8876-70, which was the parent batch for batch 8876-70-O, which was actually irradiated in HRB-21. The difference between batches 8876-70 and 8876-70-L is that the particles in batch 8876-70 do not have the seal coat and protective pyrocarbon coating (PPyC) that were deposited over the OPyC layer in batch 8876-70-O. The ORNL designation for the material characterized is AGR-10. This document summarizes characterization of the HRB-21 fuel for size, shape, coating thickness, and density. Fracture behavior and microstructural analysis of the layers and interfaces is compared to previous analyses of the German proof test particles (EU 2358-2365) published in ORNL/CF-04/06. Further detailed comparative study of the microstructure of these two reference materials would be valuable to continue to define the property differences between particles which exhibited good irradiation performance (the German particles) and poor irradiation performance (the HRB-21 particles).
Date: August 1, 2004
Creator: Hunn, John D
Partner: UNT Libraries Government Documents Department

Effects of deposition conditions on the properties of pyrolytic carbon deposited in a fluidized bed

Description: The high-density, isotropic pyrolytic carbon layer beneath the silicon carbide (IPyC) plays a key role in the irradiation performance of coated particle fuel. The IPyC layer protects the kernel from reactions with chlorine during deposition of the SiC layer, provides structural support for the SiC layer, and protects the SiC from fission products and carbon monoxide. The process conditions used by the Germans to deposit the IPyC coating produced a highly isotropic, but somewhat permeable IPyC coating. The permeability of the IPyC coating was acceptable for use with the dense German UO{sub 2} kernels, but may not be suitable when coating UCO kernels. The UCO kernels are typically more porous and thus have a larger surface area than UO{sub 2} kernels. The lower density and the higher surface area of UCO kernels could make them more susceptible to attack by HCl gas during the silicon carbide (SiC) coating process, which could result in heavy metal dispersion into the buffer and IPyC coatings and a higher level of as-manufactured SiC defects. The relationship between IPyC deposition conditions, permeability, and anisotropy must be understood and the appropriate combination of anisotropy and permeability for particle fuel containing UCO kernels selected. A reference set of processing conditions have been determined from review of historical information and results of earlier coating experiments employing 350 and 500 {micro}m UO{sub 2} kernels. It was decided that a limited study would be conducted, in which only coating gas fraction (CGF) and temperature would be varied. Coatings would be deposited at different rates and with a range of microstructures. Thickness, density, porosity and anisotropy would be measured and permeability evaluated using a chlorine leach test. The results would be used to select the best IPyC coating conditions for use with the available natural enrichment uranium carbide/uranium oxide (NUCO) kernels. ...
Date: September 1, 2005
Creator: Lowden, Richard Andrew; Hunn, John D; Nunn, Stephen D; Kercher, Andrew K; Price, Jeffery R & Jellison Jr, Gerald Earle
Partner: UNT Libraries Government Documents Department

Shock compression of pyrolytic, ceylon natural, and a hot-pressed synthetic graphite to 120 GPa

Description: Recent improvements have made the two-stage, light-gas gun at Lawrence Livermore Laboratory into a dependable source of very energetic planar shocks. Also, the inclined-prism technique has proved useful in observing anomalous behavior of materials, especially at low pressure. The availability of these improved techniques presented an opportunity to re-examine the low pressure, shock-compression characteristics for graphite and, in a search for an additional transformation, to extend some of the data to higher pressures.
Date: June 6, 1977
Creator: Gust, W. H. & Young, D. A.
Partner: UNT Libraries Government Documents Department

Compatibility/Stability Issues in the Use of Nitride Kernels in LWR TRISO Fuel

Description: The stability of the SiC layer in the presence of free nitrogen will be dependent upon the operating temperatures and resulting nitrogen pressures whether it is at High Temperature Gas-Cooled Reactor (HTGR) temperatures of 1000-1400 C (coolant design dependent) or LWR temperatures that range from 500-700 C. Although nitrogen released in fissioning will form fission product nitrides, there will remain an overpressure of nitrogen of some magnitude. The nitrogen can be speculated to transport through the inner pyrolytic carbon layer and contact the SiC layer. The SiC layer may be envisioned to fail due to resulting nitridation at the elevated temperatures. However, it is believed that these issues are particularly avoided in the LWR application. Lower temperatures will result in significantly lower nitrogen pressures. Lower temperatures will also substantially reduce nitrogen diffusion rates through the layers and nitriding kinetics. Kinetics calculations were performed using an expression for nitriding silicon. In order to further address these concerns, experiments were run with surrogate fuel particles under simulated operating conditions to determine the resulting phase formation at 700 and 1400 C.
Date: February 1, 2012
Creator: Armstrong, Beth L & Besmann, Theodore M
Partner: UNT Libraries Government Documents Department

Thermophysical properties: some experience in research, development and applications

Description: Accurate measurements of thermophysical properties, understanding exactly any use requirements, and understanding the behavior of the material are all potential ingredients for in-depth research and development projects. The work reported here is but a brief description of some of the many LASL and SLA projects and their chain-branching manifestations.
Date: January 1, 1977
Creator: Wagner, P. & Acton, R. U.
Partner: UNT Libraries Government Documents Department

Evaluation of Codisposal Viability for TH/U Carbide (Fort Saint Vrain HTGR) DOE-Owned Fuel

Description: There are more than 250 forms of US Department of Energy (DOE)-owned spent nuclear fuel (SNF). Due to the variety of the spent nuclear fuel, the National Spent Nuclear Fuel Program has designated nine representative fuel groups for disposal criticality analyses based on fuel matrix, primary fissile isotope, and enrichment. The Fort Saint Vrain reactor (FSVR) SNF has been designated as the representative fuel for the Th/U carbide fuel group. The FSVR SNF consists of small particles (spheres of the order of 0.5-mm diameter) of thorium carbide or thorium and high-enriched uranium carbide mixture, coated with multiple, thin layers of pyrolytic carbon and silicon carbide, which serve as miniature pressure vessels to contain fission products and the U/Th carbide matrix. The coated particles are bound in a carbonized matrix, which forms fuel rods or ''compacts'' that are loaded into large hexagonal graphite prisms. The graphite prisms (or blocks) are the physical forms that are handled in reactor loading and unloading operations, and which will be loaded into the DOE standardized SNF canisters. The results of the analyses performed will be used to develop waste acceptance criteria. The items that are important to criticality control are identified based on the analysis needs and result sensitivities. Prior to acceptance to fuel from the Th/U carbide fuel group for disposal, the important items for the fuel types that are being considered for disposal under the Th/U carbide fuel group must be demonstrated to satisfy the conditions determined in this report.
Date: September 28, 2001
Creator: Radulescu, H.
Partner: UNT Libraries Government Documents Department