A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Authority of a county to donate money, property, or services to nonprofit corporations that conduct local festivals (RQ-1911)

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Effective date of amendments to section 144(b) of article 6701d, V. T. C. S., which allocates to municipalities money received from traffic fines, and related questions (RQ-2033)

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Authority of the Veterans' Land Board to make certain investments (RQ-1833)

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Whether the Texas Department of Health is required to inspect and license as a personal care home a boarding facility registered by the Department of Mental Health and Mental Retardation, and related questions (RQ-1974)

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Whether a commissioners court may prescribe a prevailing wage for certain contracts, and related questions (RQ-1977)

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Gross receipts assessment for for telephone companies under sections 78 through 82 of article 1446c, V. T. C. S., the Public Utility Regulatory Act (RQ-2090)

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Whether a commissioners court may appoint a licensed attorney to advise the sheriff or an individual commissioner (RQ-1774)

Letter opinion issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification.

Letter opinion issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Opinion regarding the proper interpretation of section 54.208 of the Education Code.

Letter opinion issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Jim Mattox, regarding a legal question submitted for clarification: Whether the Texas Commission on Jail Standards can amend its jail standards to require testing of individuals for tuberculosis.

The analytical expression used to model glass reaction in computer simulations such as EQ6 is compared to experiments used to support the simulations. The expression correctly predicts the acceleration observed in experiments performed at high glass surface area/leachant volume ratios (SA/V) upon the formation of secondary phases. High resolution microscopal analysis of reacted glass samples suggests that the accelerated nature of the reaction after secondary phase formation is due to changes in the reaction affinity (i.e., is a solution affect) and not a change in the glass reaction mechanism. Solutions generated on samples reacted in steam are consistent with the effects of the secondary phases predicted in the model. Experiments which lead to the generation of secondary phases within short reaction times can be used to identify important secondary phases which must be included in the data base of computer simulations to correctly project long-term glass reaction behavior. 6 refs., 1 fig., 1 tab.

The chemical interactions of dissolved radionuclides with mineral surfaces along flowpaths from the proposed repository to the accessible environment around Yucca Mountain constitute one of the potential barriers to radionuclide migration at the site. Our limited understanding of these interactions suggests their details will be complex and will involve control by numerous chemical and physical parameters. It appears unlikely that we will understand all the details of these reactions or obtain all the site data required to evaluate each of them in the time available for site characterization. Yet, performance assessment calculations will require some form of coupling of chemical interaction models will hydrologic flow models for the site. Clearly, strategies will be needed to bound the problem without compromising the reliability of the performance assessment calculations required for site suitability analysis. The main purpose of this paper is to describe such a strategy. 39 refs., 7 figs., 5 tabs.

A formalism is presented for generating probability distributions of parameters used in performance-assessment modeling. The formalism is used when data are either sparse or nonexistent. The appropriate distribution is a function of the known or estimated constraints and is chosen to maximize a quantity known as Shannon`s informational entropy. The formalism is applied to a parameter used in performance-assessment modeling. The functional form of the model that defines the parameter, data from the actual field site, and natural analog data are analyzed to estimate the constraints. A beta probability distribution of the example parameter is generated after finding four constraints. As an example of how the formalism is applied to the site characterization studies of Yucca Mountain, the distribution is generated for an input parameter in a performance-assessment model currently used to estimate compliance with disposal of high-level radioactive waste in geologic repositories, 10 CFR 60.113(a)(2), commonly known as the ground water travel time criterion. 8 refs., 2 figs.

The importance of paleohydrology to the Yucca Mountain Site Characterization Project derives from the role water will play in radioactive-waste repository performance. Changes in hydrologic conditions during the lifetime of the repository may be estimated by investigating past hydrologic variations, including changes in the static water-level position. Based on the distribution of vitric and zeolitized tuffs and the structural history of the site, the highest water levels were reached and receded downward 11.6 to 12.8 myr ago. Since that time, the water level at central Yucca Mountain has probably not risen more than about 60 m above its present position. The history of the high potentiometric gradient running through northern Yucca Mountain may be partly elucidated by the study of tridymite distribution in rocks that have experienced saturated conditions for varying periods of time.

Many large simulations may be required to assess the performance of Yucca Mountain as a possible site for the nations first high level nuclear waste repository. A boundary integral equation method (BIEM) is described for numerical analysis of quasilinear steady unsaturated flow in homogeneous material. The applicability of the exponential model for the dependence of hydraulic conductivity on pressure head is discussed briefly. This constitutive assumption is at the heart of the quasilinear transformation. Materials which display a wide distribution in pore-size are described reasonably well by the exponential. For materials with a narrow range in pore-size, the exponential is suitable over more limited ranges in pressure head. The numerical implementation of the BIEM is used to investigate the infiltration from a strip source to a water table. The net infiltration of moisture into a finite-depth layer is well-described by results for a semi-infinite layer if {alpha}D > 4, where {alpha} is the sorptive number and D is the depth to the water table. the distribution of moisture exhibits a similar dependence on {alpha}D. 11 refs., 4 figs.,

Construction of well-posed scenarios for the range of conditions possible at any proposed repository site is a critical first step to assessing total system performance. Event tree construction is the method that is being used to develop potential failure scenarios for the proposed nuclear waste repository at Yucca Mountain. An event tree begins with an initial event or condition. Subsequent events are listed in a sequence, leading eventually to release of radionuclides to the accessible environment. Ensuring the validity of the scenarios requires iteration between problems constructed using scenarios contained in the event tree sequence, experimental results, and numerical analyses. Details not adequately captured within the tree initially may become more apparent as a result of analyses. To illustrate this process, the authors discuss the iterations used to develop numerical analyses for PACE-90 (Performance Assessment Calculational Exercises) using basaltic igneous activity and human-intrusion event trees.

A waste package consisting of a container and high-level nuclear waste is being developed for the permanent disposal of radioactive waste. Yucca Mountain, Nevada, is being studied as a potential site for the underground high-level nuclear waste repository. A major consideration for choosing Yucca Mountain is the presence of zeolite in tertiary ash-flow tuffs. The presence of zeolites could provide geological barriers to radionuclide migration. The suitability of the tuffaceous rocks at Yucca Mountain for the repository is being investigated since the properties of the environment around a waste site must be well characterized to reliably predict performance. The results of experiments at Lawrence Livermore National Laboratory (LLNL) to assess the possibility of imaging water in Nevada Test Site welded tuff samples showed that nuclear magnetic resonance imaging is not viable. This leaves neutron tomography and high-frequency electromagnetic geotomography as possibilities for the practical imaging of distribution and flow of fluids in rock, including tuff specimens. Water tracers are needed in electromagnetic tomography techniques since the contrast for detecting water in cracks of tuff is lower than in granite because of the higher porosity in tuff. The results of preliminary testing with geotomography by LLNL indicates relatively low spatial resolution. …

This study presents a generic methodology that can be used to evaluate the uncertainty in the calculated accidental offsite doses at the Yucca Mountain repository during the preclosure period. For demonstration purposes, this methodology is applied to two specific accident scenarios: the first involves a crane dropping an open container with consolidated fuel rods, the second involves container failure during emplacement or removal operations. The uncertainties of thirteen parameters are quantified by various types of probability distributions. The Latin Hypercube Sampling method is used to evaluate the uncertainty of the offsite dose. For the crane-drop scenario with concurrent filter failure, the doses due to the release of airborne fuel particles are calculated to be 0.019, 0.32, and 2.8 rem at confidence levels of 10%, 50%, and 90%, respectively. For the container failure scenario with concurrent filter failure, the 90% confidence-level dose is 0.21 rem. 20 refs., 4 figs., 3 tabs.

Yucca Mountain is being studied to determine its suitability as a location for a high-level nuclear waste repository. Amter and Ross developed a model called TGIF (Topographic Induced Flow) to simulate gas flow under Yucca Mountain. The TGIF model differs significantly from previous gas flow models. It uses a governing equation that is based on the concept of freshwater head, thus avoiding the numerical problems associated with the near-cancellation of the forces due to gravity and the pressure gradient. Unlike most other models, dipping, layered media can be simulated. This paper describes a systematic sensitivity study that was designed to test several aspects of the TGIF model when used to simulate gas flow under Yucca Mountain. Values of three important inputs to the model were systematically varied to form a matrix of 80 runs. The matrix consisted of five values of permeability contrast between a bedded tuff layer and surrounding welded units (in all cases, bulk permeabilities were used to represent the combined effect of both fractures and matrix permeability), four temperature profiles representing different stages of repository cooldown, and four finite-difference grids.

There is an immediate need to begin to validate models that can be used for assessing the performance of waste package materials in an unsaturated repository environment. This paper examines available testing information and testing approaches that could support validation of models for engineering barrier system (EBS) radionuclide release. The content is presented in the context of the general methodology that has been proposed for validating performance assessment models. Available experimental observations are used to test some of the EBS release rate modeling premises. These observations include evidence of fluid film formation on waste glass surfaces in isothermal humid environments, accelerated waste glass reaction rates under repository service conditions of large glass surface area to water volume ratio, and mobilization of radionuclides as solutes and colloids. It is concluded that some important modeling premises may not be consistent with available experimental information. However, it is also concluded that future laboratory testing, which simulates the integrated waste package systems, is needed to evaluate the significance of these inconsistencies and to test the system level models. A small-scale apparatus which was developed and tested to examine the feasibility of laboratory analog testing for the unsaturated Yucca Mountain repository environment is described. 16 …

This report presents data collected to determine the hydrologic characteristics of tuffaceous rocks penetrated in test hole USW UZ-1. The borehole is the first of two deep, large-diameter, unsaturated-zone test holes dry drilled using the vacuum/reverse-air-circulation method. This test hole was drilled in and near the southwestern part of the Nevada Test Site, Nye County, Nevada, in a program conducted in cooperation with the US Department of Energy. These investigations are part of the Yucca Mountain Project (formerly the Nevada Nuclear Waste Storage Investigations) to identify a potentially suitable site for the storage of high-level radioactive wastes. Data are presented for bit and casing configurations, coring methods, sample collection, drilling rate, borehole deviation, and out-of-gage borehole. Geologic data for this borehole include geophysical logs, a lithologic log of drill-bit cuttings, and strike and distribution of fractures. Hydrologic data include water-content and water-potential measurements of drill-bit cuttings, water-level measurements, and physical and chemical analyses of water. Laboratory measurements of moisture content and matric properties from the larger drill-bit cutting fragments were considered to be representative of in-situ conditions. 3 refs., 5 figs., 10 tabs.

In accordance with the requirements of Section 113(b)(3) of the Nuclear Waste Policy Act of 1982 (Pub. L. No. 97-425), as amended, the US Department of Energy (DOE) has prepared this report on the progress of scientific investigation activities at Yucca Mountain in southern Nevada for October 1, 1989, through March 31, 1990. This report is the second of a series of reports that are issued at intervals of approximately six months during the period of scientific investigation. The progress report presents short summaries of the status of scientific investigation activities and cites technical reports and research products that provide more detailed information on the activities. The report provides highlights of work started during the reporting period, work in progress, and work completed and documented during the reporting period. In addition, the report is the vehicle for discussing major changes, if any, to the DOE`s scientific investigation program. The progress report conveys information in a convenient summary form to be used for informational purposes only. It is not intended to be the mechanism for controlling and documenting technical or policy positions regarding changes in schedules or the technical program. Such changes are controlled through rigorous DOE change-control procedures. The progress …