bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Material Properties in Adhesion
Authors: Buckley Donald H.
Published: March 2011

When two solid surfaces are brought into contact strong adhesive bond forces can develop between the materials. The magnitude of the forces will depend upon the state of the surfaces, cleanliness and the fundamental properties of the two solids, both surface and bulk. Adhesion between solids is addressed from a theoretical consideration of the electronic nature of the surfaces and experimentally relating bond forces to the nature of the interface resulting from solid state contact. Surface properties correlated with adhesion include, atomic or molecular orientation, reconstruction and segregation as well as the chemistry of the surface specie. Where dissimilar solids are in contact the contribution of each is considered as is the role of their interactive chemistry on bond strength. Bulk properties examined include elastic and plastic behavior in'the surficial regions, cohesive binding energies, crystal structure, crystallographic orientation and state. Materials examined with respect to interfacial adhesive interactions include metals, alloys, ceramics, polymers and diamond. They are reviewed both in single and polycrystalline form. The surfaces of the contacting solids are studied both in the atomic or molecularly clean state and in the presence of selected surface contaminants. Topography effects are obviously complex and their detailed consideration is beyond the scope of this paper.
Processing of Low Alpha-Particle Emitting Ceramics
Authors: Morris P. A. , Handwerker C. A. , Coble R. L. , Gabbe D. R. , Howard R. T.
Published: March 2011

The raw materials and clean-room processing techniques required to produce a low alpha-particle emitting insulating material have been investigated with the goal of producing a dense fired alumina ceramic with a reproducible, low alpha-particle flux (≤ 0.01 α/cm2hr). Various sources of A12 O3, MgO, and SiO2, the primary constituents of the alumina body, were tested for the alpha-particle emitting elements, U and Th, and for total alpha-particle flux. Many materials contain U concentrations with corresponding alpha-particle fluxes of 0.01α/cm2hr. Die pressing, filter casting and isopressing have been used under class 100 clean-room conditions to process powder compacts and the benefits and problems of each were evaluated. Analysis of the material before, at various stages during processing, and after firing has shown that dense fired Al2O3 ceramics can be produced with no detectable increase above that of the source powder in the U and Th contents, or the alpha-particle flux.
Growth of thin Pb Layers on Cu(001)
Authors: Culbertson R. J. , Kuk Y. , Feldman L. C.
Published: March 2011

The growth of thin Pb layers (<12 monolayers) was studied in ultrahigh vacuum by high energy ion scattering/channeling, low energy electron diffraction (LEED)), and Auger electron spectroscopy (AES). Deposition and analysis were performed at 300 K and 140 K. The Pb coverage was determined quantitatively by ion scattering. The results indicated a clear transition in the growth mode as a function of temperature. At 300 K, two-dimensional island growth was observed up to 1.0 monolayer, followed by three-dimensional epitaxial growth of strained islands. Two-dimensional island growth was observed up to 5 monolayers at 140 K. The relative positions of the overlayer atoms relative to the substrate was studied to understand two-dimensional phase transitions above room temperature.
Diffraction Studies of the Atomic Structure of Grain Boundaries
Authors: Milkove K. R. , Lamarre P. A. , Schmückle F. , Vaudin M. D. , Sass S. L.
Published: March 2011

The application of diffraction techniques to study the atomic structure of grain boundaries is reviewed. The determination of the projected structure of a large angle [001] twist boundary is described. The influence of f.c.c. metal type and bonding type on boundary structure is examined. Generalizations are made concerning the structure of large angle [001] twist boundaries based on the results of the diffraction studies.
Stem Probe Spreading
Authors: Marks L. D.
Published: March 2011

The theoretical ideas for STEM probe spreading using spherical wave X-ray diffraction theory and expel imental results of diffractive probe spreading are briefly described. Clear evidence is found for two beam Bormann fan effects arising from nigh order diffracted beams.
Characterization of Defects and Interfaces by the Ion Channeling Technique
Authors: Chu W. K. , Picraux S. T.
Published: March 2011

Channeling of fast, light ions in crystals has been widely used as a tool for studying crystal defects. This subject has been reviewed earlier at MRS-1980. During MRS-1980, principles of ion channeling, and examples of channeling analysis on bulk defects and surface structures, lattice location of impurities, and clustering phenomena were given. In this review, we give a brief overview of defect studies by the channeling technique and then elaborate on recent developments in channeling analysis of interfacial structure. The ion beam channeling technique permits characterization of heteroepitaxial growth starting at monolayer coverages and allows quantitative measurement of the lattice strain in heteroepitaxial layers. The strain analysis has been developed for multilayer structures and, for example, the tetragonal distortions of strained-layer superlattices can be determined for lattice mismatches as low as 0.2% corresponding to lattice distortions of 0.01Å.
Local Distortions Around Highly Mobile Defects
Authors: Dosch H. , Peisl J.
Published: March 2011

Hydrogen in metals is a textbook example for fast diffusing defects in solids. The jumping frequency is in the case of H in Nb (Stump et al, 1975) even at room temperature in the range of 1011 1/s – 1012 1/s.
Perturbed Angular Correlation Measurements of Vacancy Trapping at Indium Atoms in Quenched Aluminum
Authors: Swanson M. L. , Wichert T. H. , Howe L. M. , Quenneville A. F. , Westcott O. M.
Published: March 2011

The perturbed angular correlation (PAC) method was used to study vacancy trapping at 111In atoms in quenched Al single crystals containing up to 10 ppm In. During annealing from 200–230 K, two different electric field gradients appeared, characterized by the interaction frequencies ν 01 = 67 MHz with asymmetry parameter η = 0.41, and νQ2 = 133 MHz with η = 0. The assignment of ν01 to a single vacancy-In atom pair is discussed. The results indicate that the migration energy of single vacancies in Al is = 0.55 eV.
Unusual Scattering Intensities Due to Nitrogen in Niobium
Authors: Dosch H. , Peisl J.
Published: March 2011

Previous neutron scattering studies on nominally pure Nb (Chang et al, 1977, Werner et al) showed unusual diffuse scattering peaks at Q = (4/3 4/3 4/3)2π/a with varying intensities from sample to sample.
On the Resolvability of Defect Ensembles with Positron Annihilation Studies
Authors: Fluss M. J. , Howell R. H. , Rosenberg I. J. , Meyer P.
Published: March 2011

Recent advances in the use of positron annihilation to study defect ensembles in and on the surfaces of metals, are pointing the way towards studies where particular positron-electron annihilation modes may be identified and studied in the presence of one another. Although a great deal is understood about the annihilation of positrons in ostensibly defect free metals, much less is understood when the positron annihilates in complex defect systems such as liquid metals, amorphous solids, or at or near the vacuum-solid interface. In this paper the results of three experiments, all of which demonstrate means by which we can resolve various positron annihilation channels from one another, will be discussed.
The Influence of Pore-Strucrure on the Campressive Strength of Hardened Cement Paste
Authors: Yiun-Yuan Huang , Wei Ding , Ping Lu
Published: March 2011

The pore-structure strongly influences the carpressive strength of hardened cement paste (hcp) and other porous materials, as well as other mechanical properties. The simplest but most currently used expression representing the relationship between the pore-structure and compressive strength is fram Balshin: σ = σ0 (l-P)A, in which only the total porosity P is involved as a single parameter and σ0 and A are empirical constants. The influence of pore size distribution and pore shapes etc. are not considered.

The authors introduce second parameter w - the factor of relative specific surface area of the pores other than the total porosity P into consideration and a new expression is proposed:σc=K11-p/1+2p(K2(1-p))K3w+K4 all the constants K1 - K4 can be determined experimentally. By using of this expression the new information relating the influence of pore-structure on the caopressive strength of hcp can be predicted.
Very High Strength Cement for Very High Strength Concrete
Authors: Aftcin Pierre-Claude , Bédard Claude , Plumat M. A. Sc. Marc , Haddad Gilbert
Published: March 2011

During 1984 summer, an experimental concrete column was cast in a 26-story high-building using a 100 MPa silica fume concrete. Only the coarse aggregate was selected specifically for this concrete. The cement used was an ordinary type 1 Portland cement. The superplasticizer was a naphthalene base. The field conditions were among the most unfavourable, the transportation was about 3/4 of an hour. The placing lasted 15 minutes. However, after 1 h 00 the slump of this concrete having a water/cementitious ratio of 0.25 was still higher than 100 mm so that the concrete was placed without any problems.
High Strength Concrete and Mortars in High Temperature Environments
Authors: Williamson Robert B. , Rashed Ahmed I.
Published: March 2011

A number of new materials are presently being introduced for application in high temperature environments. Though some of these are old materials fabricated with new methods or processes, many are actually new. This paper focuses on the use of high strength concretes or mortars for application to high temperature environments, such as furnaces or boilers for coal gasification and similar processes requiring high pressure and temperature. This paper reports the results of an investigation on the high.temperature performance of mortar of different strengths incorporating 0%, 8% and 16% of condensed silica fume (CSF). The experiments described have been carried out to compare the performance of different strength level mortars with different CSF contents. Generally speaking, it was found that low strength mortar with CSF is less susceptible to strength loss after high temperature exposure than mortar without CSF. On the other hand, high strength mortar with CSF seems to be more sensitive to high temperature than high strength mortar without CSF since it retains only 65% of its room temperature strength after heating to 3200C as compared to regular high strength mortar which retains 95% of its room temperature strength.

Though there may be a possible practical problem in using high strength CSF concrete, this shown loss of strength in high strength CSF concrete upon heating may prove very important in giving us insight into the fundamental mechanisms of strengthening concrete with CSF. An explanation is hypothesized on the observed behavior of high strength CSF concrete, which will produce a theory for one of the ways in which CSF strengthens portland cement paste. It is theorized that the CSF touohens the portlandite in high strength paste, but after heating to 320 C, the CSF particles which have been converted to C-S-H have lost their ability to toughen the portlandite.
Microstructure of High Strength Cement Paste Systems
Authors: Regourd M.
Published: March 2011

High strength cement pastes include hot pressed, autoclaved, impregnated low water/cement ratio, macrodefect free, ultrafine particles arrangement systems. The densification of the microstrucure is mainly related to a low porosity and to the formation of poorly crystalline hydrates. In composite systems like mortars and concretes, the interfacial bond between the cement paste and aggregates is moreover less porous and more finely crystallized than the normal “auréole de transition”.
Characterisation of Microstructure as a Systematic Approach to High Strength Cements
Authors: Scrivener Karen L. , Baldie K. D. , Halse Yick , Pratt P. L.
Published: March 2011

Ultimately the strength of cement is determined by the properties, amounts and distributions of the phases it contains and by the'way these are bonded together. Here an example is presented of the determination of the amount and distribution of calcium hydroxide, by BEI and quantitative image analysis, in a cement paste and cement/fly ash mixture which had previously been studied by TGA. Examination of crack paths on BEIs of polished cement surfaces gives some indication as to the importance of calcium hydroxide in determining the properties of the cement.
The Flexural Strength and Fracture Toughness of a Normal and a High Strength Polymer Modified Portland Cement
Authors: Eden N. B. , Bailey J. E.
Published: March 2011

A model has been developed for the flexural strength of Portland cement pastes, based upon observed fracture behaviour of both normal and high strength pastes. Fibrillar or foil-like elements pull apart at a yield stress which is characteristic of the number of elements and interfacial shear strength. The former can be maximised by using a low water/cement ratio and the latter by inclusion of water-soluble polymer, followed by suitable drying. It is proposed that this is the mechanism by which high strength may be attained in Portland cement.
The Role of Boron in Monitoring the Leaching of Borosilicate Glass Waste Forms
Authors: Scheetz Barry E. , Freeborn W. Phelps , Smith Deane K. , Anderson Christine , Zolensky Michael , White William B.
Published: March 2011

In the absence of any identified solid phase host (other than the original glass), boron has been assumed to accumulate in the fluid during the reaction of borosilicate glass waste forms with aqueous fluids. Using this assumption, it is possible to define a boron index which can be used to monitor the amount of glass that has been dissolved and to provide a worst-case measure of the degradation of the primary glass waste form. Several boron-containing silicate phases have been identified thus invalidating the assumption that boron does not precipitate. The effect is apparently small and the assumption that boron release is a direct measure of degree of alteration of borosilicate glass is still probably a good one.
Leaching of Devitrified Glass Containing Simulated SRP Nuclear Waste
Authors: Jantzen Carol M. , Bickford Dennis F.
Published: March 2011

Time-temperature-transformation curves have been determined for SRL-165 and SRL-131 waste glasses for all potential waste compositions. SRL-165 glasses, which contain less alkali, exhibit less complex devitrification and higher overall durability than SRL-131 waste glasses. Devitrification was found to have less effect on the durability of waste glasses than changes in composition. Non-uniform dissolution at the glass leached layer interface is observed. However, leached layers formed after 28 days shield the crystal interfaces from further dissolution.
Alterability of the French LWR Solution Reference Glass in Repository Conditions
Authors: Nogues J. L. , Vernaz E. Y. , Jacquet-Francillon N. , Pasquini S.
Published: March 2011

The disposal of glass blocks containing fission products in granitic geological formations is one of the options currently investigated in France. This paper discusses the major criteria selected to develop models of such repositories and gives the first results obtained with the corresponding experimental test. Five laboratory mockups corresponding to different alternatives regarding the fill materials were prepared. The following materials were used to encase the French LWR reference glass:

- Test I : Granite, sand, stainless steel;

- Test 2 : Granite, sand, illite, stainless steel;

- Test 3 : Granite, sand, bentonite, stainless steel;

- Test 4 : Granite, sand, Al2O3, ceramic, stainless steel;

- Test 5 : Granite, sand, haitalloy C4.

Samples were taken of the solutions obtained in the preconditioning cell and in contact with the glass to assess the glass corrosion behavior in each of these media. The experiments were completed by surface analyses designed to compare the morphology of the surface layers that develop with and without the environmental materials.
The Behavior of Actinide Containing Glasses During Gammirar Adiation in a Saturated Tuff Environment
Authors: Bates John K. , Oversby Virginia M.
Published: March 2011

The influence of gamma irradiation on the reaction of actinide doped SRL 165 and PNL 76–68 glasses in a saturated tuff environment has been studied in a series of tests lasting up to 56 days. The reaction, and subsequent actinide release, of both glasses depends on the dynamic interaction between radiolysis effects which cause the solution pH to become more acidic and glass reaction which drives the pH more basic. The use of large gamma irradiation dose rates to accelerate reactions that would occur in an actual repository radiation field may affect this dynamic balance by unduly influencing the mechanism of the glass-water reaction. Comparisons are made between the present results and data obtained by reacting the same or similar glasses using MCC-1 and NNWSI rock cup procedures.
Effect of Grande Ronde Basalt Groundwater Composition and Temperature on the Corrosion of Low-Carbon Steel in the Presence of Basalt-Bentonite Packing
Authors: Anantatmula R. P.
Published: March 2011

The Basalt Waste Isolation Project (BWIP) is being conducted for the U.S. Department of Energy (DOE) by Rockwell Hanford Operations. The effect of Grande Ronde Basalt groundwater composition and temperature on the corrosion rate of American Iron and Steel Institute (AISI) 1020 steel in basalt-bentonite packing was investigated as part of the Containment Materials Testing Program of the BWIP. The studies were based on a Plackett-Burman statistical screening design, the purpose of which is to identify the important variables affecting a process and to use this information to guide future investigative efforts. For the present studies, four anions (Cl−, F−, SO4−, and CO3−) and temperature were selected as the initial variables affecting corrosion. A minimum and a maximum value was chosen for each variable. The minimum value was 0 mg/L for the anions and 100 °C for the temperature. The maximum values were 780, 76, 576, and 120 mg/L, respectively, for Cl−, F−, SO4−, and CO3−, and 250 °C for the temperature. Analysis of the data revealed that temperature is the only statistically significant variable affecting corrosion of low-carbon steel in basalt groundwater in the composition range of the anions tested. Increasing the temperature from 100 °C to 250 °C decreased the total corrosion by a factor of seven to ∼5O mg/dm2 independent of the water composition. This is attributed to a strongly adherent layer of iron- and silicon-rich clay on the surface of the steel formed by a reaction of the steel surface with the packing material as observed in previous studies.
Corrosion Behavior of Carbon Steels Under Tuff Repository Environmental Conditions
Authors: McCright R. Daniel , Weiss H.
Published: March 2011

Carbon steels may be used for borehole liners in a potential high-level nuclear waste repository in tuff in Nevada. Borehole liners are needed to facilitate emplacement of the waste packages and to facilitate retrieval of the packages, if required. Corrosion rates of low carbon structural steels AISI 1020 and ASTM A-36 were determined in J-13 well water and in saturated steam at 100°C. J-13 well water is representative of water which has percolated through the tuff horizon where the repository would be located. Tests were conducted in air-sparged J-13 water to attain stronger oxidizing conditions. A limited number of irradiation corrosion and stress corrosion tests were performed. Chromium-molybdenum alloy steels and cast irons were also tested. These materials showed lower general corrosion but were susceptible to stress corrosion cracking when welded.
Control of Oxidation Potential for Basalt Repository Simulation Tests
Authors: Jantzen Carol M. , Wicks George G.
Published: March 2011

Borosilicate waste glass durability in simulated repository environments can be assessed by use of static tests in leach vessels fabricated of the representative geomedia. Control of the oxidation potential during the test simulates a basalt repository environment. Under very anoxic conditions (i.e. at negative Eh values), the interactions between basalt and SRP waste glass in silica-saturated basaltic groundwaters are the same as those of basalt and groundwater when no waste glass is present. The lack of significant leaching of ions from the waste glass and the lack of any significant changes in either the leached surfaces of glass or basalt under anoxic conditions suggests that the components of this system are at equilibrium when oxygen is absent.
Permeability Changes in Crystalline Rocks Due to Temperature: Effects of Mineral Assemblage
Authors: Morrow C. A. , Moore D. E. , Byerlee J. D.
Published: March 2011

The change in permeability with time of granite, quartzite, anorthosite and gabbro was measured while these rocks were subjected to a temperature gradient. The highest temperature (at the heat source) was fixed at 250°C, while low temperatures ranged from 60 to 111°C, depending on rock type. Permeability reductions of up to two orders of magnitude were observed, with the greatest reactions occurring in the quartzite. These changes are thought to be caused by dissolution of minerals at high temperatures, and redeposition of the dissolved material at lower temperatures. Quartz appears to be an important mineral in this self-sealing process. If very low permeability is desired around a nuclear waste repository in crystalline rocks, then a quartz-rich rock may be the most appropriate host.
Parametric Study of the Corrosion Behaviour in Static Distilled Water of Simulated European Reference High Level Waste Glasses
Authors: Iseghem Pierre Ph. Van , Timmermans W. , Batist R. De
Published: March 2011

The corrosion behaviour in distilled water of five simulated European reference high level waste glasses has been investigated for times up to 8 months. The glasses were chosen in accordance with the Joint European Community research programme on HLW form characterization: two French glasses (SON58, SON64), one British glass (UK209) and two glasses designed to incorporate HLW stored at the Eurochemic plant in Belgium (SM58 and SAN60). In the reference condition (90°C, SA.V−1 = 1 cm−1) the leaching was characterized mainly by diffusion processes and by the onset of saturation in the leachate (these saturation effects were found to depend on glass composition). In more dilute conditions (SA.V−1 = 0.1 cm−1), matrix dissolution was the rate controlling mechanism. Increasing the leachant temperature to 150°C and higher lead to pronounced surface crystallization and, at least for one glass (SAN60), to an increased corrosion.
Behavior of Nuclear Waste Elements During Hydrothermal Alteration of Glassy Rhyolite in an Active Geothermal System: Yellowstone National Park, Wyoming
Authors: Sturchio Neil C. , Seitz Martin G.
Published: March 2011

The behavior of a group of nuclear waste elements (U, Th, Sr, Zr, Sb, Cs, Ba, and Sm.d)u ring hydrothermal alteration of glassy rhyolite is investigated through geochemaical analyses of whole rocks, glass and mineral separates, and thermal waters. Significant enrichments of U, Sr, Sb, Cs, and Ba are found in altered rock relative to unaltered rock. Excess Sr, Cs, and Ba are concentrated in zeolites in altered rock. Excess U is associated with titanomagnetite surfaces. Th, Zr, and Sm are relatively immobile during alteration, and are strongly concentrated in celadonite.
The Salton Sea Geothermal Field as a Natural Analog for the Near-Field in a Salt High-Level Nuclear Waste Repository
Authors: Elders Wilfred A. , Moody Judith B.
Published: March 2011

The Salton Sea Geothermal Field (SSGF), on the delta of the Colorado River in southern California, is being studied as a natural analog for the near-field environment of proposed nuclear waste repositories in salt. A combination of mineralogical and geochemical methods is being employed to develop a three dimensional picture of temperature, salinity, lithology, mineralogy, and chemistry of reactions between the reservoir rocks and the hot brines. Our aim is to obtain quantitative data on mineral stabilities and on mobilities of the naturally occurring radionuclides of concern in Commercial High-Level Waste (CHLW). These data will be used to validate the EQ3/6 geochemical code under development to model the salt near-field repository behavior.

Maximum temperatures encountered in wells in the SSGF equal or exceed peak temperatures expected in a salt repository. Brines produced from these wells have major element chemistry similar to brines from candidate salt sites. Relative to the rocks, these brines are enriched in Na, Mn, Zn, Sr, Ra and Po, depleted in Ba, Si, Mg, Ti, and Al, and strongly depleted in U and Th. However the unaltered rocks contain only about 2–3 ppm of U and 4–12 ppm of Th, largely in detrital epidotes and zircons. Samples of hydrothermally altered rocks from a wide range of temperature and salinity show rather similar uniform low concentrations of these elements, even when authigenic illite, chlorite, epidote and feldspar are present. These observations suggest that U and Th are relatively immobile in these hot brines. However Ra, Po, Cs and Sr are relatively mobile. Work is continuing to document naturally occurring radionuclide partitioning between SSGF minerals and brine over a range of temperature, salinity, and lithology.
An Investigation of Metamict And Annealed Natural Pyrochlores by XRAY Absorption Spectroscopy
Authors: Greegor R. B. , Lytle F. W. , Chakoumakos B. C. , Lumpkin G. R. , Ewing R. C.
Published: March 2011

The pyrochlore structure type, A1−2 B2 O6 Y0−1, is a common phase in polycrystalline waste forms. A principal concern has been the effect of alpharecoil events on the longterm stability of these phases. Naturally occurring minerals of the pyrochlore group provide an example of the full range of radiation effects from fully crystalline to xray diffraction amorphous (the metamict state). Xray absorption spectroscopy is used to investigate the coordination geometry of Tisites in metamict and annealed (1,000°C) pyrochlores. The principal effects in the fullydamaged material (∼4026 alpha events/m3) compared to annealed samples include an increase in the asymmetry of the Tisite and a slight reduction in bond length and coordination number.
Irradiation-Induced Reduction of Microcracking in Zirconolite
Authors: Clinard F. W. , Tucker D. S. , Hurley G. F. , Kise C. D. , Rankin J.
Published: March 2011

238Pu-substituted zirconolite (CaPuTi 2O7 ) was stored near ambient temnerature for 231 days, equivalent to an aipha decay dose of 3.1×1025 α/m3 or 3×105 years of storage time for SYNROC ceramic nuclear waste. Periodic indentation testing showed that hardness was decreased by alpha decay-induced conversion to the metamict state, while fracture toughness and resistance to cracking were increased, apparently as a consequence of the formation of a heterogeneous microstructure. These results imply improved stability of this nuclear waste phase as a result of self-irradiation damage.
Hot Cell Preparation of Tesiing Materials
Authors: Thornhill R. E. , Knox C. A.
Published: March 2011

It is important in nuclear waste repository development that testing be done with materials containing a radionuclide spectrum representative of actual wastes. To meet the need for such materials, the Materials Characterization Center (MCC) has prepared simulated high level waste (HLW) glasses with radionuclides representative of about 10-, 300-, and 1000-year-old waste. A quantity of well characterized spent fuel also has been acquired for the same purpose. Glasses containing 10- and 300-year-old wastes, and the spent fuel specimens, must be fabricated in a hot cell. Hot cell conditions (high radiation field, remote operation, and difficulty of repairs) require that procedures and equipment normally used in materials preparation out-of-cell be modified for hot cell applications.

This paper discusses the fabrication of two glasses, and the preparation of test specimens of these glasses and spent fuel. One of the glasses is a 76–68 composition, which is fully loaded with actual commercial reactor fission product waste. The other glass contains simulated Barnwell Nuclear Fuel Plant waste, doped with different combinations of fission products and actinides. The spent fuel is a 10-year-old PWR material. Special techniques have been used to achieve high quality, well characterized testing materials, including specimens in the form of segments, wafers, cylinders, and powders of these materials.
The Role of Statistics in Characterizing Nuclear Waste Package Behavior
Authors: Bowen William M.
Published: March 2011

The characterization of nuclear waste package behavior is primarily based on the outcome of laboratory tests, where components of a proposed waste package are either individually or simultaneously subjected to simulated repository conditions. At each step of a testing method, both controllable and uncontrollable factors contribute to the overall uncertainty in the final outcome of the test. If not dealt with correctly, these sources of uncertainty could obscure or distort important information that might otherwise be gleaned form the test data. This could result in misleading or erroneous conclusions about the behavior characteristic being studied. It could also preclude estimation of the individual contributions of the major sources of uncertainty to the overall uncertainty. Statistically designed experiments and sampling plans, followed by correctly applied statistical analysis and estimation methods will yield the most information possible for the time and resources spent on experimentation, and they can eliminate the above concerns. Conclusions reached on the basis of such information will be sound and defensible. This presentation is intended to emphasize the importance of correctly applied, theoretically sound statistical methodology in characterizing nuclear waste package behavior.
Current Technical Issues Related to Near-Field Materials Testing
Authors: Shade John W.
Published: March 2011

Some test parameters have become issues in test development either because they are difficult to measure and control or because the significance of their effect on waste form dissolution and alteration is unknown. Issues identified by the MCC are Eh/pH system effects, SA/V effects, temperature effects on sampling, waste package composition effects, colloid formation and stability, radiolysis, and formation kinetics and stability of secondary reaction products. These issues are addressed by the MCC through literature reviews, workshops, and direct investigation with the objective of recommending methods for resolving them. This paper summarizes their status and attempts to identify needs required for their resolution.
Cleanout of Waste Storage Tanks at Oak Ridge National Laboratory
Authors: Weeren H. O. , Lasher L. C. , McDaniel E. W.
Published: March 2011

In 1943, six storage tanks were built at the Clinton Laboratories [later to become Oak Ridge National Laboratory (ORNL)] to contain wastes generated by wartime research and development operations. During the following years, these tanks became an integral part of the ORNL waste system and accumulated ∼1.5 × 106 L (400,000 gal) of sludge containing radioactive wastes. Recently, over a period of ∼18 months, these tanks were sluiced, the radioactive sludge resuspended, and the resuspended slurry pumped to the ORNL Hydrofracture Facility for underground disposal.

In this paper, a summary of the development work is given, and the process design and constraints are described. The operating difficulties encountered and overcome included grinder blade erosion, malfunctioning instruments, pump suction plugging, and slurry settling. About 90% of the settled sludge (containing ∼715,000 Ci) was removed from the system.
Technetium Volatilization During HLLW Vitrification
Authors: Lammertz H. , Merz E. , Halaszovich S. T.
Published: March 2011

The volatilization of technetium in the course of high-level waste vitrification may be considerable, depending on process variations. A series of experiments has been performed in order to gain more insight into the vaporization behavior of Tc during HLLW vitrification. No losses have been observed during chemical denitration or drying of the solutions on a drum drier at moderate temperatures. However, substantial volatilization (40–60 %) occurred during high temperature processing which applied either liquid feeding or feeding as a dehydrated product into the glass melter. Details of parameters investigated are described, and consequences for technical process application are discussed.
Sorption of Cesium, Strontiuli, Iodine and Carbon in Concrete and Sand
Authors: Hietanfn Raija , Jaakkola Timo , Miettinen Jorma K.
Published: March 2011

Concrete is a potential construction, waste package and backfill, material for disposal- of low and intermediate level nuclear wastes. Sorption of 90Sr, 137Cs, 129I and 14C in concrete and in sand ballast used as aggrepte of concrete was determined by measurement of 85Sr, 134Cs, 125I and 14C isotopes using the batch method. Natural ground waters from planned disposal sites were used, and for aggregate also ground water equilibrated with concrete. The sorption order of the different samples for cesium and strontium was Kd (aggregate + ground water) > Kd (concrete + ground water)> Kd (aggregace + ground water equilibrated with concrete). For iodine and carbon the order was Kd (concrete + ground water)> Kd (aggregate + ground water equilibrated with concrete)> K (aggregate + ground water). In the case of cesium the K -values were > 100 ml/g for all samples. The Kd -values of strontium were <25 ml/g and of iodine< 10 ml./g. The Kd -values of carbon were about 2 and 100 and 2 000 ml/g for aggregates with around water, aggregates with ground water equilibrated with concrete and concrete with ground water, respectively.
The Interaction of Bituminized Ion-Exchange Resins With Different Leachants
Authors: Valkiainen M. , Vuorinen Ulla , Uotila Paula
Published: March 2011

Leaching tests on bituminized ion-exchange resins from Olkiluoto power plant were made according to ISO/DIS 6961 in deionized water and groundwater. Simulated waste products including Cs and Sr were leached in cement water. A clear difference is seen between the water types. With cobalt in granular resins the leach rate in groundwater is three orders of magnitude higher than in deionized water, the latter being in the order of 10–15 m/s.

The bituminized cation exchanger is still operating and changing ions with the surrounding water. Bitumen provides a hindering diffusion barrier.

Bituminized resin absorbs water from the surroundings and the weight (and volume) of the product increases 10–80 % in 898 days compared to the original value. The weight increase is slower with bituminized powdered resins than with granular resins.

Due to differencies in densities between bitumen and both anion and cation ion-exchangers, a distinct sedimentation effect of granular mixed bed exchangers is observed. The cation exchanger is separated on the bottom of the 200 1 drum while the anion exchanger is separated in the upper part of the drum.
Oxygen Implanted Layers in Silicon Electrical and Microstructural Characterization
Authors: Varker C. J. , Wilson S. R. , Chan S. S. , Whitfield J. D. , Krause S. J.
Published: March 2011

We report on an investigation of ‘buried’ oxygen implants formed by 0+ implantation at 400 KeV and 3.5 MeV into p-type CZ (100) wafers with a dopant density NA 1015 cm−3. Peak concentrations of 1 × 1019 cm−3 to 2 × 1020 cm−3. were investigated. Test devices were fabricated on implanted and annealed wafers using conventional wafer processing. For the 400 keV implants, a 4 µm epitaxial buffer layer was grown subsequent to the 0+ implant. For a dose of 3 × 1015 cm−2 the lifetime reduction ratio for the effective generation lifetime τg at the implant peak is greater than 103 relative to an unimplanted region where τg = 150 µS. C-V and SRP profiles show evidence for oxygen donor compensation. TEM analysis reveals a well defined layer at 1 µm with respect to the original implant surface containing a relatively high density of small precipitates and dislocation loops. DLTS measurements on diodes reveal 2 electron traps designated as E1 and E2. The trap energy ∆E and capture cross section σ are (EC-ET)1 = 0.41 ± 0.020 eV and (EC-ET)2 = 0.22 ± 0.030 eV with σ 1019 cm-3. The estimated trap density NT for the dominant trap is 8.2 × 1013 cm−3 for a calculated peak 0+ implant concentration of 6.8 × 1019 cm−3. The values of ∆E are in good agreement with values for unimplanted CZ wafers subjected to 2-step precipitation anneals. The experimental results provide direct evidence that ion implantation provides an effective method of introducing atomic oxygen in silicon at concentration exceeding its solid solubility during processing to produce a buried low lifetime region.
The Effect of Incomplete Collision Cascades on The Angle of Ion Incidence Behaviour of Interface Mixing
Authors: Webb R.P. , Wilson I.H.
Published: March 2011

A new geometrical theory of sputtering is extended to investigate the behaviour of interface mixing as a function of the angle of ion incidence. It is found that the amount of mixing peaks with the angle of incidence at different angles depending upon the depth of the interface. When the interface is at the surface the mixing parameter behaves as the sputtering yield and maximises around 70°, whilst deeper interfaces, around the damage range, have maximum mixing at normal incidence.
A Self-Annealing Technique for Simultaneous Titanium Silicide and N+/P Junction Formation
Authors: Finetti Manuela , Gabilli E. , Lotti R. , Lulli G. , Merli P.G. , Nipoti R. , Antisari M. Vittori
Published: March 2011

- P+ self-annnealing implantations through evaporated Ti is performed to simultaneously form the silicide and the junction underneath, avoiding the need for further post-implantation thermal treatments. The formation of the TiSi2, phase and the good quality of the silicon-silicide interface are observed, when operating at power densities ≤ 16 W/cm2. Deep phosphorus distributions extending below the silicide down to 480÷600 nm are obtained.
Recent Advances in The Application of Focused Ion Beams
Authors: Gamo Kenji , Namba Susumu
Published: March 2011

Recent advances of focused ion beam systems and their applications are presented. The applications include maskless ion implantation and various maskless patterning techniques which make use of ion induced chemical effects. These are ion beam assisted etching, deposition and ion beam modification techniques and are promising to improve patterning speed and extend applications of focused ion beams.
Boltzmann Transport Equation Analysis of Ion Implantation Range and Damage Distributions
Authors: Gibbons James F. , Christel Lee A. , Giles Martin D.
Published: March 2011

The Boltzmann transport equation has been used to calculate range anddamage distributions in multilayer targets of general interest for semiconductor fabrication. A comprehensive review of the calculations will be presented, with particular emphasis on how large angle scattering events and channeling phenomena may be included. Examples of the quality of fit between the theory and experiment show that difficult phenomena (such as residual channeling) can be reasonable modelled.
Line-Shaped Electron Beam System and Soi Films Prepared by The System
Authors: Hayafuji Y. , Shibata A. , Yanada T. , Sawada A. , Usui S. , Kawado S. , Hayashi H.
Published: March 2011

The line-shaped electron beam annealing system which generates an electron beam of a length of 4 cm and a width af less than 100 um with a high energy density exceeding well over 100 kW/cm2 was developed for the first time with a purpose of SOI processing as its primary application. An pccelaration voltage of up to 20 kV can be used in this system. Seeded single crystalline islands with areas several mm long and 30 to 100 um in width were obtained by a single scan of the electron beam. The electron beam is generated in a pulsed way in the system due to the power restriction of the power supplies. An area of 4×5 cm2 was processed by a single scan of an electron beam at a sample speed of 530 cm/sec and a beam duration of 9.5 msec. The scanning area for one scan is determined by the beam length and the duration of the beam and sample speed.

The present system could give single crystalline silicon films without any grain boundaries. The electron mobility of the electron beam recrystallized films, obtained from FETs made as a vehicle to test the electrical properties of the films, was comparable to that of the bulk silicon. A very rapid migration of silicon atoms in solid polycrystalline silicon films, which is controllable by process parameters, was also found with a migration speed of the order of 1 m/sec in a capped structure. The present electron beam system is useful in studying basic mechanisms of crystal growth in thin films. The system can have a very high throughput, a desirable feature in semiconductor industry. The present system can also be used to study the rapid thermal treatment of materials other than semiconductors including rapidly solidified materials.
Determination of Optimal Rapid Thermal Annealing Exposure Time and Pulse Rising Rate for Minimum Impurity Redistribution
Authors: de Araujo Carlos A. Paz , Ting-Ao Tang
Published: March 2011

A simple relationship for rapid thermal annealing exposure time for the case of annealing of boron and arsenic high dose shallow implants is found from first principles. The percentage of redistribution is found to be intrinsically dependent on exposure time and rate of temperature rise in the heat pulse. An upper bound of pulse rising rate for a given percentage tolerance in redistribution is also found. Extensive SIMS analysis shows very good agreement of these formulae with experimental data.
A Model of Amorphous Silicon Layer Regrowth
Authors: Ling P. , Washburn J.
Published: March 2011

A new model which combines heterogenous nucleation and growth process to explain the mechanism of the crystal regrowth of amorphous silicon, in contact with a Si single crystal substrate, is presented. This model explains the effects of substrate orientation and impurity concentration on the kinetics of crystal regrowth. A comparison of experimental results with the predictions of the model is also included.
Prediction of High Dose Ion Implantation Profiles as Influenced by Radiation Induced Transport and Sputtering
Authors: Rangaswamy M. , Farkas D.
Published: March 2011

Various models for predicting high fluence ion collection profiles are reviewed. Recent calculations based on the diffusion approximation are described. The solute and defect probability distributions are calculated by a MONTECARLO code, TRIM. The method takes into account the effects of sputtering, including preferential sputtering of one of the components, and lattice dilation. In addition, the effects of radiation enhanced diffusion and radiation induced segregation are also considered. The calculations include the coupling of solute and defect fluxes. The described formalism can account for observed maximum attainable concentrations and distributions in high fluence implantation conditions of practical interest.
Electronic-Structure Calculation of 3d Transition-Metal Point Defects in Silicon
Authors: Beeler Franz , Andersen Ole K. , Scheffler Matthias
Published: March 2011

The states of lowest energy have been calculated for iron-group (3d) transition-metal impurities in silicon. The donor and acceptor levels reproduce all experimentally observed transitions and trends. The theory predicts that the ground states of the early 3d interstitials and late 3d substitutionals have low spin. This is in conflict with the generally accepted model of Ludwig and Woodbury, if applied to these impurities, but not with existing experiments.
Detailed Analysis of DLTS Signal of EL2 in LEC n-GaAs Crystals
Authors: Yahata A. , Sato T. , Kikjta T. , Ishida K.
Published: March 2011

Detailed DLTS measurements have revealed the presence of threedifferent midgap levels, labeled EOI, EO2 and EO3, in LEC n-GaAs. The variations of EOl and EO2 concentrations, which are EL2 and ELO in Lagowski's terminology, do not correlate with the distributions of the optical absorption coefficient across wafers, while that of EO3 exhibits good correlation. This suggests that EO3 is the optically detected midgap level. Furthermore, preliminary charged particle activation analysis of oxygen content in GaAs shows that the presence of EO2 (ELO) is not attributed to oxygen. Concentrations of these levels all increase with arsenic mole fraction in the melt.
Electron Paramagnetic Resonance of Intrinsic Defects in III-V Semiconductors
Authors: Wilsey N. D. , Kennedy T. A.
Published: March 2011

The use of electron paramagnetic resonance to investigate intrinsic defects in the III-V semiconductors is reviewed. Particular attention is given to lattice vacancies, antisites and their complexes in GaP, GaAs, and InP. The role of EPR in arriving at an understanding of these defects is emphasized and the interplay between experiment and theory is discussed.
An ODMR Study of The Killer Center Fe in GaP:O
Authors: Lee K. M. , Kimerling L. C. , Sturge M. D.
Published: March 2011

The role of the luminescence killer center iron in GaP has been studied by the optically detected magnetic resonance technique. Observations of strong Fe°(3d5) and O0 resonance in the (Zn,O) donor-acceptor pair (DAP) and the 0.841 eV electron capture (EC) luminescence bands show that the luminescence killing action is via (Fe,O) DAP recombination.

Two distinct but similar (Fe,O) DAP processes were detected: The (Fe0,O0) process with a slower recombination rate and (Fe0,O0*) process, with a faster effective relaxation rate, involving the oxygen excited state.
Absolute Photoionization Cross Sections of the Acceptor State Level of Chromium in Indium Phosphide
Authors: Bremond Georges , Guillot G. , Nouailhat A. , Picoli G.
Published: March 2011

We have analyzed the photoionization of Cr2+ in InP by the Deep Level Optical Spectroscopy (D.L.O.S.). The σ°n cross section exhibits both a resonant and non resonant character. The former corresponds to the internal transition 5T2-5E of Cr2+ while the threshold of the second allows us to locate the Cr2+/Cr3+ level below the conduction band. The absolute photoionization cross sections towards the two bands are very similar. In particular no selection rule seems to work.
Electronic Defect Characterization
Authors: Grimmeiss H.G.
Published: March 2011

Knowledge concerning the electronic properties of defects is crucial for the understanding of the behaviour of these defects in semiconductors. Considering the important role defects play in most currently used devices it is not surprising that a great number of different measurement techniques have been developed with the aim of not only quantitatively determining the electronic parameters but also of identifying the defect chemically and evaluating the local environment of such defects. In most cases this goal can not be achieved by applying only a single (defect property) measuring technique.

In this paper an attempt is made, using two different examples, to show what achievements in defect characterization and identification can be obtained by combining two or more different measurement techniques. The first example is a single substitutional impurity, sulfur in silicon, while the second example deals with a more complex defect, the oxygen-vacancy center in silicon. In both cases a number of techniques such as different junction space charge measurements, Hall effect, absorption, ESR, photo-ESR, ENDOR photoconductivity, irradiation and annealing processes, and even theory were used to study the defect. The advantages and limitations of various methodologies will be discussed.