Evaluation of Calcine Disposition Path Forward (open access)

Evaluation of Calcine Disposition Path Forward

This document describes an evaluation of the baseline and two alternative disposition paths for the final disposition of the calcine wastes stored at the Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory. The pathways are evaluated against a prescribed set of criteria and a recommendation is made for the path forward.
Date: February 26, 2003
Creator: Birrer, S. A. & Heiser, M. B.
System: The UNT Digital Library
Truncated Thermal Equilibrium Distribution for Intense Beam Propagation (open access)

Truncated Thermal Equilibrium Distribution for Intense Beam Propagation

An intense charged-particle beam with directed kinetic energy ({lambda}{sub b}-1)m{sub b}c{sup 2} propagates in the z-direction through an applied focusing field with transverse focusing force modeled by F{sub foc} = -{lambda}{sub b}m{sub b}{omega}{sub beta}{sup 2} {perpendicular} x {perpendicular} in the smooth focusing approximation. This paper examines properties of the axisymmetric, truncated thermal equilibrium distribution F(sub)b(r,p perpendicular) = A exp (-H Perpendicular/T perpendicular (sub)b) = (H perpendicular-E(sub)b), where A, T perpendicular (sub)b, and E (sub)b are positive constants, and H perpendicular is the Hamiltonian for transverse particle motion. The equilibrium profiles for beam number density, n(sub)b(r) = * d{sup 2}pF(sub)b(r,p perpendicular), and transverse temperature, T perpendicular (sub)b(r) = * d{sup 2}p(p{sup 2} perpendicular/2 lambda (sbu)bm (sub)b)F(sub)b(r,p perpendicular), are calculated self-consistently including space-charge effects. Several properties of the equilibrium profiles are noteworthy. For example, the beam has a sharp outer edge radius r(sub)b with n(sub)b(r greater than or equal to rb) = 0, where r(sub)b depends on the value of E(sub)b/T (sub)perpendicular(sub)b. In addition, unlike the choice of a semi-Gaussian distribution, F{sup SG}(sub)b = A exp (-p{sup 2}(sub)perpendicular/2lambda(sub)bm(sub)bTperpendicular(sub)b) = (r-r(sub)b), the truncated thermal equilibrium distribution F(sub)b(r,p) depends on (r,p) only through the single-particle constant of the motion Hperpendiuclar and is therefore a …
Date: February 26, 2003
Creator: Davidson, Ronald C.; Qin, Hong & Lund, Steven M.
System: The UNT Digital Library
Kinetic Description of Intense Beam Propagation Through a Periodic Focusing Field for Uniform Phase-Space Density (open access)

Kinetic Description of Intense Beam Propagation Through a Periodic Focusing Field for Uniform Phase-Space Density

The Vlasov-Maxwell equations are used to investigate the nonlinear evolution of an intense sheet beam with distribution function f{sub b}(x,x{prime},s) propagating through a periodic focusing lattice k{sub x}(s+S) = k{sub x}(s), where S = const is the lattice period. The analysis considers the special class of distribution functions with uniform phase-space density f{sub b}(x,x{prime},s) = A = const inside of the simply connected boundary curves, x{prime}{sub +}(x,s) and x{prime}{sub -}(x,s), in the two-dimensional phase space (x,x{prime}). Coupled nonlinear equations are derived describing the self-consistent evolution of the boundary curves, x{prime}{sub +}(x,s) and x{prime}{sub -}(x,s), and the self-field potential {psi}(x,s) = e{sub b}{phi}(x,s)/{gamma}{sub b}m{sub b}{beta}{sub g}{sup 2}c{sup 2}. The resulting model is shown to be exactly equivalent to a (truncated) warm-fluid description with zero heat flow and triple-adiabatic equation-of-state with scalar pressure P{sub b}(x,s) = const x [n{sub b}(x,s)]. Such a fluid model is amenable to direct analysis by transforming to Lagrangian variables following the motion of a fluid element. Specific examples of periodically focused beam equilibria are presented, ranging from a finite-emittance beam in which the boundary curves in phase space (x,x{prime}) correspond to a pulsating parallelogram, to a cold beam in which the number density of beam particles, n{sub …
Date: February 26, 2003
Creator: Davidson, Ronald C.; Qin, Hong; Tzenov, Stephan I. & Startsev, Edward A.
System: The UNT Digital Library
Status of ceramic waste form degradation and radionuclide release modeling. (open access)

Status of ceramic waste form degradation and radionuclide release modeling.

As part of the spent fuel treatment program at Argonne National Laboratory (ANL), a ceramic waste form is being developed for disposition of the salt waste stream generated during the treatment process. Ceramic waste form (CWF) degradation and radionuclide release modeling is being carried out for the purpose of estimating the impact of the CWF on the performance of the proposed repository at Yucca Mountain. The CWF is composed of approximately 75 wt% salt-loaded sodalite encapsulated in 25 wt% glass binder. Most radionuclides are present as small inclusion phases in the glass. Since the release of radionuclides can only occur as the glass and sodalite phases dissolve, the dissolution rates of the glass and sodalite phases are modeled to provide an upper bound to radionuclide release rates from the CWF. Transition-state theory for the dissolution of aluminosilicate minerals provides a mechanistic basis for the CWF degradation model, while model parameters are obtained by experimental measurements. Performance assessment calculations are carried out using the engineered barrier system model from the Total System Performance Assessment--Viability Assessment (TSPA-VA) for the proposed repository at Yucca Mountain. The analysis presented herein suggests that the CWF will perform in the repository environment in a manner that …
Date: February 26, 2003
Creator: Fanning, T. H.; Ebert, W. L.; Frank, S. M.; Hash, M. C.; Morris, E. E.; Morss, L. R. et al.
System: The UNT Digital Library
Southern California Earthquake Center - SCEC1: Final Report Summary Alternative Earthquake Source Characterization for the Los Angeles Region (open access)

Southern California Earthquake Center - SCEC1: Final Report Summary Alternative Earthquake Source Characterization for the Los Angeles Region

The objective my research has been to synthesize current understanding of the tectonics and faults of the Los Angeles Basin and surrounding region to quantify uncertainty in the characterization of earthquake sources used for geologically- and geodetically-based regional earthquake likelihood models. This work has focused on capturing epistemic uncertainty; i.e. uncertainty stemming from ignorance of the true characteristics of the active faults in the region and of the tectonic forces that drive them. In the present context, epistemic uncertainty has two components: First, the uncertainty in source geometrical and occurrence rate parameters deduced from the limited geological, geophysical and geodetic observations available; and second. uncertainties that result from fundamentally different interpretations of regional tectonic deformation and faulting. Characterization of the large number of active and potentially active faults that need to be included in estimating earthquake occurrence likelihoods for the Los Angeles region requires synthesis and evaluation of large amounts of data and numerous interpretations. This was accomplished primarily through a series of carefully facilitated workshops, smaller meetings involving key researchers, and email groups. The workshops and meetings were made possible by the unique logistical and financial resources available through SCEC, and proved to be extremely effective forums for the …
Date: February 26, 2003
Creator: Foxall, B
System: The UNT Digital Library
XFEM: Exploratory Research into the Extended Finite-Element Method, FY02 LDRD Final Report (open access)

XFEM: Exploratory Research into the Extended Finite-Element Method, FY02 LDRD Final Report

This report is one of two components, the first an overview document outlining the goals and results of the XFEM LDRD project, and the other (titled ''Structured Extended Finite Element Methods of Solids defined by Implicit Surfaces'') detailing the scientific advances developed under FY01/FY02 LDRD funding. The XFEM (Extended Finite-Element Method) Engineering LDRD/ER Project was motivated by three research and development goals: (1) the extensions of standard finite-element technology into important new research venues of interest to the Engineering Directorate, (2) the automation of much of the engineering analysis workflow, so as to improve the productivity of mesh-generation and problem setup processes, and (3) the development of scalable software tools to facilitate innovation in XFEM analysis and methods development. The driving principle behind this LDRD project was to demonstrate the computational technology required to perform mechanical analysis of complex solids, with minimal extra effort required on the part of mechanical analysts. This need arises both from the growing workload of LLNL analysts in problem setup and mesh generation, and from the requirement that actual as-built mechanical configurations be analyzed. Many of the most important programmatic drivers for mechanical analysis require that the actual (e.g., deformed, aged, damaged) geometric configuration of …
Date: February 26, 2003
Creator: Mish, K.
System: The UNT Digital Library
High beta, Long Pulse, Bootstrap Sustained Scenarios on the National Spherical Torus Experiment (NSTX) (open access)

High beta, Long Pulse, Bootstrap Sustained Scenarios on the National Spherical Torus Experiment (NSTX)

Long-pulse, high-beta scenarios have been established on the National Spherical Torus Experiment (NSTX). Beta(sub)t(always equal to 2{mu}(sub)0{center_dot}<P>/B{sup 2}(sub)t0) {approx} 35% has been achieved during transient discharges. The machine improvements that lead to these results, including error field reduction and high-temperature bakeout of plasma-facing components are described. The highest Beta(sub)t plasmas have high triangularity (delta = 0.8) and elongation (k = 2.0) at low-aspect ratio A always equal to R/a = 1.4. The strong shaping permits large values of normalized current, I(sub)N(always equal to I(sub)p /(aB(sub)t0)) approximately equal to 6 while maintaining moderate values of q(sub)95 = 4. Long-pulse discharges up to 1 sec in duration have been achieved with substantial bootstrap current. The total noninductive current drive can be as high as 60%, comprised of 50% bootstrap current and {approx}10% neutral-beam current drive. The confinement enhancement factor H89P is in excess of 2.7. Beta(sub)N * H(sub)89P approximately or greater than 15 has been maintained for 8 * tau(sub)E {approx} 1.6 * tau(sub)CR, where tau(sub)CR is the relaxation time of the first radial moment of the toroidal current density. The ion temperature for these plasmas is significantly higher than that predicted by neoclassical theory.
Date: February 26, 2003
Creator: National Spherical Torus Experiment (Project)
System: The UNT Digital Library
Corrective Action Investigation Plan for Corrective Action Unit 529: Area 25 Contaminated Materials, Nevada Test Site, Nevada, Rev. 0, Including Record of Technical Change No. 1 (open access)

Corrective Action Investigation Plan for Corrective Action Unit 529: Area 25 Contaminated Materials, Nevada Test Site, Nevada, Rev. 0, Including Record of Technical Change No. 1

This Corrective Action Investigation Plan contains the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office's approach to collect the data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit (CAU) 529, Area 25 Contaminated Materials, Nevada Test Site (NTS), Nevada, under the Federal Facility Agreement and Consent Order. CAU 529 consists of one Corrective Action Site (25-23-17). For the purpose of this investigation, the Corrective Action Site has been divided into nine parcels based on the separate and distinct releases. A conceptual site model was developed for each parcel to address the translocation of contaminants from each release. The results of this investigation will be used to support a defensible evaluation of corrective action alternatives in the corrective action decision document.
Date: February 26, 2003
Creator: United States. National Nuclear Security Administration. Nevada Site Office.
System: The UNT Digital Library