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Electromagnetic experiment to map in situ water in heated welded tuff: Preliminary results

Description: An experiment was conducted in Tunnel Complex G at the Nevada Test Site to evaluate geotomography as a possible candidate for in situ monitoring of hydrology in the near field of a heater placed in densely welded tuff. Alterant tomographs of 200 MHz electromagnetic permittivity were made for a vertical and a horizontal plane. After the 1 kilowatt heater was turned on, the tomographs indicated a rapid and strong drying adjacent to the heater. Moisture loss was not symmetric about the heater, but seemed to be strongly influenced by heterogeneity in the rock mass. The linear character of many tomographic features and their spatial correlation with fractures mapped in boreholes are evidence that drying was most rapid along some fractures. When the heater was turned off, an increase in moisture content occurred around the heater and along the dry fractures. However, this process is much slower and the magnitude of the moisture increase much smaller than the changes observed during heating of the rock. The interpretation of the tomographs is preliminary until they can be processed without the restrictive assumption of straight ray paths for the signals through the highly heterogeneous rock mass. 15 refs., 4 figs.
Date: March 16, 1987
Creator: Ramirez, A.L. & Daily, W.D.
Partner: UNT Libraries Government Documents Department

Impact of phase stability on the corrosion behavior of the austenitic candidate materials for NNWSI [Nevada Nuclear Waste Storage Investigations]

Description: The Nuclear Waste Management Program at Lawrence Livermore National Laboratory is responsible for the development of the waste package design to meet the Nuclear Regulatory Commission licensing requirements for the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. The metallic container component of the waste package is required to assist in providing substantially complete containment of the waste for a period of up to 1000 years. Long term phase stability of the austenitic candidate materials (304L and 316L stainless steels and alloy 825) over this time period at moderate temperatures (100-250{sup 0}C) can impact the mechanical and corrosion behavior of the metal barrier. A review of the technical literature with respect to phase stability of 304L, 316L and 825 is presented. The impact of martensitic transformations, carbide precipitation and intermediate ({sigma}, chi, and eta) phase formation on the mechanical properties and corrosion behavior of these alloys at repository relevant conditions is discussed. The effect of sensitization on intergranular stress corrosion cracking (IGSCC) of each alloy is also addressed. A summary of the impact of phase stability on the degradation of each alloy in the proposed repository environment is included. 32 refs., 6 figs.
Date: October 1, 1987
Creator: Bullen, D.B.; Gdowski, G.E. & McCright, R.D.
Partner: UNT Libraries Government Documents Department

Test concept for waste package environment tests at Yucca Mountain

Description: The Nevada Nuclear Waste Storage Investigations Project is characterizing a tuffaceous rock unit at Yucca Mountain, Nevada to evaluate its suitability for a repository for high level radioactive waste. The candidate repository horizon is a welded, devitrified tuff bed located at a depth of about 300 m in the unsaturated zone, over 100 m above the water table. As part of the project, Lawrence Livermore National Laboratory is responsible for designing the waste packages and for assessing their expected performance in the repository environment. The primary region of interest to package design and performance assessment is the portion of the rock mass within a few meters of waste emplacement holes. Hydrologic mechanisms active in this unsaturated near-field environment, along with thermal and mechanical phenomena that influence the hydrology, need to be understood well enough to confirm the basis of the waste package designs and performance assessment. Large scale in situ tests (called waste package environment tests) are being planned in order to develop this understanding and to provide data sets for performance assessment model validation (Yow, 1985). Exploratory shafts and limited underground facilities for in-situ testing will be constructed at Yucca Mountain during site characterization. Multiple waste package environment tests are being planned for these facilities to represent horizontal and vertical waste emplacement configurations in the repository target horizon. These approximately half-scale tests are being designed to investigate rock mass hydrologic conditions during a cycle of thermal loading.
Date: June 1, 1987
Creator: Yow, J. L., Jr.
Partner: UNT Libraries Government Documents Department

The performance of actinide-containing SRL 165 type glass in unsaturated conditions

Description: As part of the effort by the Nevada Nuclear Waste Storage Investigations (NNWSI) Project to evaluate the volcanic tuff beds of Yucca Mountain, Nevada, as a repository for the permanent storage of high-level nuclear waste, the interaction of actinide-doped Savannah River Laboratory (SRL) 165 type glass with the unsaturated repository environment has been studied. The NNWSI Unsaturated Test method has been used, and the results from batch and continuous tests completed through 18 months demonstrate that several interactions are important for controlling both the reaction of the glass and the release of radionuclides. These interactions include (1) the reaction between the glass and moist air with interludes of liquid water contact, which results in the release of alkali metals from the glass; and (2) the reaction between standing water, glass, and presensitized 304 L type stainless steel which results in breakdown of the glass matrix and the release of radionuclides from the glass-metal assemblage. A comparison of the results of the Unsaturated Test with those of parametric experiments illustrates the importance of presensitized steel in enhancing the glass reaction, and demonstrates the applicability of the Unsaturated Test to those conditions anticipated to exist in the NNWSI repository horizon. 10 refs., 8 figs., 1 tab.
Date: December 31, 1987
Creator: Bates, J.K. & Gerding, T.J.
Partner: UNT Libraries Government Documents Department

Hydrogen speciation in hydrated layers on nuclear waste glass

Description: The hydration of an outer layer on nuclear waste glasses is known to occur during leaching, but the actual speciation of hydrogen (as water or hydroxyl groups) in these layers has not been determined. As part of the Nevada Nuclear Waste Storage Investigations Project, we have used infrared spectroscopy to determine hydrogen speciations in three nuclear waste glass compositions (SRL-131 & 165, and PNL 76-68), which were leached at 90{sup 0}C (all glasses) or hydrated in a vapor-saturated atmosphere at 202{sup 0}C (SRL-131 only). Hydroxyl groups were found in the surface layers of all the glasses. Molecular water was found in the surface of SRL-131 and PNL 76-68 glasses that had been leached for several months in deionized water, and in the vapor-hydrated sample. The water/hydroxyl ratio increases with increasing reaction time; molecular water makes up most of the hydrogen in the thick reaction layers on vapor-phase hydrated glass while only hydroxyl occurs in the least reacted samples. Using the known molar absorptivities of water and hydroxyl in silica-rich glass the vapor-phase layer contained 4.8 moles/liter of molecular water, and 0.6 moles water in the form hydroxyl. A 15 {mu}m layer on SRL-131 glass formed by leaching at 90{sup 0}C contained a total of 4.9 moles/liter of water, 2/3 of which was as hydroxyl. The unreacted bulk glass contains about 0.018 moles/liter water, all as hydroxyl. The amount of hydrogen added to the SRL-131 glass was about 70% of the original Na + Li content, not the 300% that would result from alkali=hydronium ion interdiffusion. If all the hydrogen is then assumed to be added as the result of alkali-H{sup +} interdiffusion, the molecular water observed may have formed from condensation of the original hydroxyl groups.
Date: January 15, 1987
Creator: Aines, R. D.; Weed, H. C. & Bates, J. K.
Partner: UNT Libraries Government Documents Department

Geochemical simulation of reaction between spent fuel waste form and J-13 water at 25{sup 0} and 90{sup 0}C.

Description: Geochemical simulations of the degradation of spent fuel waste form in the presence of groundwater at the candidate Yucca Mountain, Nevada repository have been carried out to attempt to predict elemental concentrations in solution and to identity potential radionuclide-bearing precipitates. Spent fuel was assumed to dissolve congruently into a static mass of J-13 groundwater at 25{sup 0}C and 90{sup 0}C. Simulation results inidcate that haiweeite, soddyite, Na{sub 2}U{sub 2}O{sub 7}(c) and schoepite are potential U-bearing precipitates. Na{sub 2}U{sub 2}O{sub 7}(c) is only predicted to occur at 90{sup 0}C. U concentrations in solution and the identity of the U-bearing precipitate depend on the activity of SiO{sub 2}(aq) in solution. U concentrations are limited to < 1 mg/kg when sufficient SiO{sub 2}(aq) exists in solution to precipitate uranyl silicates. Depletion of SiO{sub 2}(aq) in solution by the precipitation of silicates results in predicted increases of U concentrations to 87 and 619 mg/kg at 25{sup 0}C and 90{sup 0}C, respectively. Subsequent reaction and precipitation of schoepite cause U concentrations to decrease. Radionuclide other than U commonly precipitate as oxides in the simulations. The precipitation of solid phases appears to be extremely effective in limiting the concentrations of some radionuclides, such as Pu and Th, in solution. Increasing the temperature from 25{sup 0}C to 90{sup 0}C does not impact greatly the identify of precipitated phases or solution composition, except in the case of U. 7 refs., 7 figs., 2 tabs.
Date: November 1, 1987
Creator: Bruton, C.J. & Shaw, H.F.
Partner: UNT Libraries Government Documents Department

Infiltration at Yucca Mountain, Nevada, traced by {sup 36}Cl

Description: Measurements of chloride and {sup 36}Cl in soils from two locations near Yucca Mountain, Nevada, have been used to trace the infiltration of precipitation in this arid region. The results show that the {sup 36}Cl fallout from nuclear weapons testing formed a well-defined peak at one location, with a maximum 0.5m below the surface. The structure of the {sup 36}Cl bomb pulse at the other location was much more complex, and quantity of {sup 36}Cl in the bomb pulse was <1% of the 6 x 10{sup 12} atoms {sup 36}Cl/m{sup 2} in the bomb pulse at the first location. The data indicate hydrologic activity subsequent to the {sup 36}Cl bomb pulse fallout at one location, but none at the other location. 11 refs.
Date: April 1, 1987
Creator: Norris, A.E.; Wolfsberg, K.; Gifford, S.K.; Bentley, H.W. & Elmore, D.
Partner: UNT Libraries Government Documents Department

Summary of results from the Series 2 and Series 3 NNWSI [Nevada Nuclear Waste Storage Investigations] bare fuel dissolution tests

Description: The Nevada Nuclear Waste Storage Investigations (NNWSI) Project is studying dissolution and radionuclide release behavior of spent nuclear fuel in Nevada Test Site groundwater. Specimens were tested for multiple cycles in J-13 well water. The Series 2 tests were run in unsealed silica vessels under ambient hot cell air (25{sup 0}C) for five cycles for a total of 34 months. The Series 3 tests were run in sealed stainless steel vessels at 25{sup 0}C and 85{sup 0}C for three cycles for a total of 15 months. Selected summary results from Series 2 and Series 3 tests with bare fuel specimens are reported. Uranium concentrations in later test cycles ranged from 1 to 2 {mu}g/ml in the Series 2 Tests versus about 0.1 to 0.4 {mu}g/ml in Series 3 with the lowest concentrations occurring in the 85{sup 0}C tests. Preferential release of fission products Cs, I, Sr and Tc, and activation product C-14, was indicated relative to the actinides. Tc-99 and Cs-137 activities measured in solution after Cycle 1 increased linearly with time, with the rate of increase greater at 85{sup 0}C than at 25{sup 0}C. 8 refs., 8 figs., 3 tabs.
Date: November 1, 1987
Creator: Wilson, C. N.
Partner: UNT Libraries Government Documents Department

The influence of copper on Zircaloy spent fuel cladding degradation under a potential tuff repository condition

Description: This paper reports the results of an experiment designed to detect the influence of copper on Zircaloy spent fuel cladding degradation in one possible repository environment. Copper and copper alloys are being considered for use in a tuff repository. The compatibility of a copper waste package container and the Zircaloy cladding on spent fuel has been questioned essentially because copper ion has been observed to accelerate zirconium alloy corrosion in acid environments, as does ferric iron, and a phenomenon called "crud-induced localized corrosion" is observed in some Boiling Water Reactors where thorugh-the-wall corrosion pits develop beneath copper-rich crud deposits. 16 refs., 6 figs., 2 tabs.
Date: March 1987
Creator: Smith, H. D.
Partner: UNT Libraries Government Documents Department

Preliminary results on the hydrolysis and carbonate complexation of dioxoplutonium(V)

Description: The hydrolysis and carbonate complexation reactions of dioxoplutonium (V) were studied in near neutral aqueous systems. These experiments involved the addition of hydroxide or carbonate to Pu(V) in a perchorate medium. Change in the electronic adsorption spectra provided information about the chemical properties of Pu(V). The results indicate the Pu(V) does not hydrolyze below pH 7.15. In the carbonate complexation studies, log {beta}{sub 11} was measured to be 4.4 +- 0.7. 5 figs., 3 tabs.
Date: November 1, 1987
Creator: Bennett, D.A.; Hoffman, D.C.; Nitsche, H. & Silva, R.J.
Partner: UNT Libraries Government Documents Department

Thermochemical Investigations of Associated Solutions: 5. Calculation of Solute-Solvent Equilibrium Constants from Solubility in Mixtures Containing Two Complexing Solvents

Description: Article on thermochemical investigations of associated solutions and the calculation of solute-solvent equilibrium constants from solubility in mixtures containing two complexing solvents.
Date: July 1, 1987
Creator: Acree, William E. (William Eugene) & McCargar, James W.
Partner: UNT College of Arts and Sciences

Comment on "Thermochemical Investigations of Associated Solutions: Calculation of Solute-Solvent Equilibrium Constants from Solubility Measurements"

Description: This article provides comments on "Thermochemical Investigations of Associated Solutions: Calculation of Solute-Solvent Equilibrium Constants from Solubility Measurements," published in the Journal of Pharmaceutical Sciences in 1983.
Date: July 1, 1987
Creator: Acree, William E. (William Eugene)
Partner: UNT College of Arts and Sciences

Effect of ionizing radiation on moist air systems

Description: The radiation chemistry of nitrogen/oxygen/water systems is reviewed. General radiolytic effects in dry nitrogen/oxygen systems are relatively well characterized. Irradiation results in the formation of steady state concentrations of ozone, nitrous oxide and nitrogen dioxide. In closed systems, the concentration observed depends on the total dose, temperature and initial gas composition. Only three studies have been published that focus on the radiation chemistry of nitrogen/oxygen/water homogeneous gas systems. Mixed phase work that is relevant to the gaseous system is also summarized. The presence of water vapor results in the formation of nitric acid and significantly changes the chemistry observed in dry air systems. Mechanistic evidence from the studies reviewed are summarized and discussed in relation to characterizing the gas phase during the containment period of a repository in tuff.
Date: December 1987
Creator: Reed, D. T. & Van Konynenburg, R. A.
Partner: UNT Libraries Government Documents Department

Influence of stress-induced deformations on observed water flow in fractures at the Climax granitic stock

Description: Three examples of stress-induced displacement influence on fracture-dominated hydrology were noted in drifts 1400 ft below surface in granite. Seepage into drifts was limited to portions of shears near a fault zone. No water entered the drifts from the fault itself, although its orientation relative to Basin and Range extension is favorable for fracture opening. Localization of seepage appears to result from excavation block motion that increased apertures of the shear zones in contrast to the fault where asperities had been destroyed by earlier shearing thus minimizing aperture increases. Seepage was also noted, in an adjoining drift, from a set of shallow-dip healed fractures that intersected the rib, and from vertical fractures that increased the crown. The restricted location of this seepage apparently was a result of shear opening of the joints that occurred because of cantilevered support of tabular rock between joints. Interpretation of paleostresses based on joint chronologies and orientations indicates that sets subjected to shear stresses at a time when normal stresses were low contained mineral infilling. Sets subjected to shear stresses at a time when the normal stresses were significant had minimal mineral infilling. 8 refs., 7 figs.
Date: June 1, 1987
Creator: Wilder, D.G.
Partner: UNT Libraries Government Documents Department

Preliminary geochemical/geophysical model of Yucca Mountain

Description: A comprehensive geochemical/geophysical model incorporates the current and relevant stratigraphic, petrologic, hydrogeologic, geochemical, and material data associated with a candidate repository at Yucca Mountain, Nevada. A geochemical/geophysical model will provide support and confidence to the Systems Performance calculations, determine whether the data collected as part of the site characterization provide the information needed by the design and performance assessment task, and provide the most accurate and referenced foundation on which to base the radionuclide transport calculations. In this report, the known repository data are compiled and unknown parameter values are estimated based on the available data. It is concluded that more data are needed before the geochemical/geophysical model of Yucca Mountain can be regarded as satisfactory and suitable base for multidimensional predicative flow and transport simulations. Recommendations for future studies concerning site characterization and data acquisition are presented. 36 refs., 1 fig., 2 tabs.
Date: December 31, 1987
Creator: Greenwade, L.E. & Cederberg, G.A.
Partner: UNT Libraries Government Documents Department