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Regulatory Closure Options for the Residue in the Hanford Site Single-Shell Tanks
No full textLiquid, mixed, high-level radioactive waste (HLW) has been stored in 149 single-shell tanks (SSTS) located in tank farms on the U.S. Department of Energy's (DOE's) Hanford Site. The DOE is developing technologies to retrieve as much remaining HLW as technically possible prior to physically closing the tank farms. In support of the Hanford Tanks Initiative, Sandia National Laboratories has addressed the requirements for the regulatory closure of the radioactive component of any SST residue that may remain after physical closure. There is significant uncertainty about the end state of each of the 149 SSTS; that is, the nature and amount of wastes remaining in the SSTS after retrieval is uncertain. As a means of proceeding in the face of these uncertainties, this report links possible end-states with associated closure options. Requirements for disposal of HLW and low-level radioactive waste (LLW) are reviewed in detail. Incidental waste, which is radioactive waste produced incidental to the further processing of HLW, is then discussed. If the low activity waste (LAW) fraction from the further processing of HLW is determined to be incidental waste, then DOE can dispose of that incidental waste onsite without a license from the U.S. Nuclear Regulatory Commissions (NRC). The NRC has proposed three Incidental Waste Criteria for determining if a LAW fraction is incidental waste. One of the three Criteria is that the LAW fraction should not exceed the NRC's Class C limits
Calendar Year 1997 Annual Groundwater Monitoring Report For The Upper East Fork Poplar Creek Hydrogeologic Regime At The U.S. Department of Energy Y-12 Plant, Oak Ridge, Tennessee
No full textThis report contains the groundwater monitoring data obtained during calendar year (CY) 1997 in compliance with the Resource Conservation Wd Recovery Act (RCRA) post-closure permit (PCP) for the Upper East Fork Poplar Creek Hydrogeologic Regime (East Fork Regime) at the U.S. Department of Energy (DOE) Y-12 Plant in Oak Ridge, Tennessee. Issued by the Tennessee Department of Environment and Conservation (TDEC), the PCP defines the RCRA post-closure corrective action monitoring requirements for the portion of the groundwater contaminant plume that has migrated into the East Fork Regime ftom the S-3 Ponds, a closed RCW-regulated former surface impoundment located in Bear Creek Valley near the west end of the Y-12 Plant. In addition to the RCIL4 post-closure corrective action monitoring results, this report contains the groundwater and surface water monitoring data obtained during CY 1997 to fulfill requirements of DOE Order 5400.1
Assessment of the Meteorological Characterization Used in the ADROIT Code
No full textThe ADROIT Analysis of Dispersal Risk Qccurring in transportation code is the primary tool used to perform probabilistic risk assessments for the Transportation Safeguards Division of the Department of Energy. The current version of ADROIT uses a Pasquill-Gifford stability-class approach to meteorological characterization. In order to assess the affect that this simplified approach to weather characterization has on ADROIT'S predictions of consequence and risk, the Pasquill-Gifford stability-class approach was replaced with a direct use of radiosonde data from the National Climatic Data Center (NCDC). A comparison of results obtained for the two weather characterizations shows that, under certain circumstances, the use of the stability-class approach can result in a significant underprediction of consequence and risk values. Since such an underprediction is non-consewative, it is recommended that the stability-class approach currently used by ADROIT be replaced with a more detailed characterization of meteorological conditions. Specifically, the NCDC database was found to have sufllcient temporal and spatial resolution for ADROIT applications. Understanding that an attempt to use of all of the NCDC data in ADROIT would be prohibitive, a sampling scheme is presented as a viable alternative for instituting the recommendation of this study
An overview of the NREL/SNL flexible turbine characterization project
No full textThere has been a desire to increase the generating capacity of the latest generation of wind turbine designs. In order to achieve these larger capacities, the dimensions of the turbine rotors are also increasing significantly. These larger structures are often much more flexible than their smaller predecessors. This higher degree of structural flexibility has placed increased demands on available analytical models to accurately predict the dynamic response to turbulence excitation, In this paper we present an overview and our progress to date of a joint effort of the National Renewable Energy Laboratory (NREL) and the Sandia National Laboratory (SNL). In this paper we present an overview and status of an ongoing program to characterize and analytically model the dynamics associated with the operation of one of the most flexible turbine designs currently available, the Cannon Wind Eagle 300 (CWE-300). The effort includes extensive measurements involving a detailed inventory of the turbine's physical properties, establishing the turbine component and fill-system vibrational modes, and documenting the dynamic deformations of the rotor system and support tower while in operation
Calendar Year 1997 Annual Groundwater Monitoring Report For The Bear Creek Hydrogeologic Regime at the U.S. Department of Energy Y-12 Plant, Oak Ridge, Tennessee
No full textThis report contains the groundwater and surface water monitoring data obtained during calendar year (CY) 1997 in compliance with the Resource Conservation and Recovery Act (RCIU) post- closure permit (PCP) for the Bear Creek Hydrogeologic Regime (Bear Creek Regime), and as otherwise required by U.S. Department of Energy (DOE) Order 5400.1. In July 1997, the Temessee Department of Environment and Conservation (TDEC) approved several modifications to the RCRA post-closure corrective action monitoring requirements specified in the PCP. This report has been prepared in accordimce with these modified requirements
GaN: Defect and Device Issues
No full textThe role of extended and point defects, and key impurities such as C, O and H, on the electrical and optical properties of GaN is reviewed. Recent progress in the development of high reliability contacts, thermal processing, dry and wet etching techniques, implantation doping and isolation and gate insulator technology is detailed. Finally, the performance of GaN-based electronic and photonic devices such as field effect transistors, UV detectors, laser diodes and light-emitting diodes is covered, along with the influence of process-induced or grown-in defects and impurities on the device physics
An Overview of HATS: A Language Independent High Assurance Transformation System
No full textTransformations that are based on syntax directed rewriting systems can have a significant impact on the construction of high assurance systems. However, in order for a transformational approach to be useful to a particular problem domain, a (general) transformation system must be adapted to the notation of that particular domain. A transformation system that can be easily adapted to various domain notations has the potential of having a wide range of applicability. In this paper we dissus why transforrmtion is attractive horn a high assurance perspective, as well as some issues surrounding automated transformation within specific problem domains. We then give an overview of a language independent High Assurance Transformation System (HATS) that is being developed at Sandia National Laboratories
Performance Assessment in Support of the 1996 Compliance Certification Application for the Waste Isolation Pilot Plant
No full textThe conceptual and computational structure of a performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) is described. Important parts of thk structure are @ maintenance of a separation between stochastic (i.e., aleatory) and subjective (i.e., epistemic) uncertain, with stochastic uncefinty arising from the many possible disruptions that could occur over the 10,000 Y regulatory period fiat applies to the WIPP and subjective uncertainty arising from `the imprecision with which many of the quantities rquired in tie `hdysis are known, (ii) use of Latin hypercttbe sampling to incorporate the effects of subjective uncefirtty, (iii) use of Monte Carlo (i.e., random) sampling to incorporate the effects of stochastic uncetinty, and OV) efficient use of tie necessarily limited number of mechanistic calculations that can be performed to SUPPOII the analysis. The WIPP is under development by the U.S. Department of Ener~ (DOE) for the geologic (i.e., deep underground) disposal of transuranic (TRU) waste, with the indicated PA supporting a ~Compliance Certification Application (CCA) by the DOE to the U.S. Environmental Protection Agency (EPA) in October 1996 for tie necessary certifications for the WIPP to begin operation. If certified, the WIPP will be the first operational faciliv in tie United States for the geologic disposal of ra&oactive waste
Electrical Potential Transfer Through Grounding and the Concern for Facility and Worker Safety
No full textElectrical grounding is probably the most over-looke~ ignored, and misunderstood part of electrical energy source circuits. A faulty ground circuit am have lethal potential to the worker, can damage electrical equipment" or components, and can lead to higher consequences. For example, if the green-wire ground return circuit (in a three-wire power circuit) is fhulty or is open (someone cut the prong, etc.) a person can receive an electrical shock by touching the conductive enclosure, and the result can be lethal. If high explosives are involved m the process, sneak electrical energy paths may cause electrical threats that lead to ignition, which results to higher damage consequences. Proper electrical grounding is essential to mitigate the electrical hazard and improve work place safety. A designer must ask the question, "What grounding is proper?" continuously through a process design and in its application. This question must be readdressed with any process change, including tiom layout, equipment, or procedure changes. Electrical grounding varies ilom local work area grounding to the multi-point grounding found in large industrial areas. These grounding methods become more complex when the designer adds bonding to the grounding schemes to mitigate electrostatic discharge (ESD) and surfkce potentials resulting from lightning currents flowing through the facility structure. Figure 1 shows a typical facility power distribution circuit and the current flow paths resulting ffom a lightning discharge to a facility. This paper discusses electrical grounding methods and their characteristics and identifies potential sneak paths into a process for hazardous electrical energy
A dense out-of-core solver (DOCS) for complex-valued linear systems
No full textDense systems of linear equations are quite common in many science and engineering applications. Such linear systems place extreme storage and computational demands on computer resources and, in many cases, may severely limit the subsequent analysis. A dense out-of-core solver (DOCS) that operates on a partitioned coefficient matrix can reduce the in-core storage requirements of the linear system while spreading the associated computational burden over multiple processors (which reduces run time as well). In this report, I describe a DOCS that operates on a partitioned coefficient matrix that maybe distributed over multiple external storage devices. I have implemented this solver using Message-Passing Interface (MPI) protocols. This report presents petiormance data from a series of run time trials that compare the run time of both sequential and parallel implementations of the DOCS