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Advanced Recovery and Integrated Extraction System (ARIES) Fiscal Year 1996 Annual Report

Description: President Clinton issued Nonprolferation and Export Control Policy in September 1993 in response to the growing threat of nuclear proliferation. Four months later, in January 1994, President Clinton and Russia's President Yeltsin issued a Joint Statement Between the United States and Russia on Nonprollfieration of Weapons of Mass Destruction and the Means of Their Delivery. President Clinton announced on 1 March 1995, that approximately 200 metric tons of US- origin weapons-usable fissile materials had been declared surplus to US defense needs. The Advanced Recovery and Integrated Extraction System (ARIES) Demonstration Project is one part of the scientific response to President Clinton's promise to reduce the nuclear weapons stockpile. The work accomplished on the ARIES Demonstration Project during fiscal year 1996, 10ctober 1995 through 30 September 1996, is described in this report. The Department of Energy (DOE), by forming the Office of Fissile Materials Disposition (OFMD), has initiated a Fissile Materials Disposition Program. The first step is the disassembly and conversion of weapons pits. Of the 200 metric tons of US surplus fissile material, approximately 50 tons are weapons plutonium, and of these 50 tons, 2/3 is contained in pits. Weapons plutonium wili be extracted from pits, rendered to an unclassified form, and converted to oxide. The plutonium oxide will then be dispositioned either by immobilization in a ceramic matrix or blended with uranium oxide, fabricated into ceramic pellets of mixed oxide (MOX) fuel, and "burned" in a commercial light water reactor. The purpose of ARIES is to demonstrate two major activities: (1) dismantlement of nuclear weapons, and (2) conversion of weapons-grade plutonium into a form required for long-term storage or in preparation for the disposition (immobilization m MOX fuel) that allows for international inspection and verification, and in accordance with safeguards regimes. Plutonium does not have to be declassified before ...
Date: October 1, 1998
Creator: Dennison, David; Massey, Pamela W. & Nelson, Timothy O.
Partner: UNT Libraries Government Documents Department

Corrective Action Plan for Corrective Action Unit No. 427: Area 3 Septic Waste Systems 2 and 6 Tonopah Test Range, Nevada

Description: This Corrective Action Plan provides the closure methods for Corrective Action Unit 427: Area 3 Septic Waste Systems (SWS) 2 and 6, located at the Tonopah Test Range. SWS 2 consists of Septic Tanks 33-4, 33-5, 33-6, and two associated leachfields. SWS 6 consists of one associated leachfield. The Area 3 SWS 2 and 6 are also known as Corrective Action Sites (CASs) 03-05-002-SW02 and 03-05-002-SW06 respectively. Site investigation activities were completed in February 1998 and are documented in the Corrective Action Decision Document (CADD). The site characterization found septage in Septic Tank 33-5. Septic Tank 33-4 is closed. Septic Tank 33-6 is still active and in line with the Sandia National Laboratories consolidated system. This site was investigated for volatile organic compounds, semivolatile organic compounds, polychlorinated biphenyls, RCRA metals, and total petroleum hydrocarbons. Characterizations of the three leachfields associated with these septic tanks were characterized and not detected above the Preliminary Action Levels. During the characterization, it was determined that Septic Tank 33-5 had not been closed. Therefore, closure activities will consist of removal of the residual septage and closure-in-place. Septic Tank 33-5 will be closed by filling of the emptied tank with clean inert material (sand) and sealing the top with a concrete cap.
Date: November 1, 1998
Creator: Nelson, Jerel G.
Partner: UNT Libraries Government Documents Department

Inversion of Passive Electromagnetic Fields to Locate Weapons of Mass Destruction

Description: A resolution study, employing a 3D nonlinear optimization technique, has been undertaken to study the viability of magnetotelluric (MT) measurements to detect and characterize buried facilities that make weapons of mass destruction. A significant advantage of the MT method is that no active source is required because the method employs passive field emissions. Thus measurements can be carried out covertly. Findings indicate it is possible to image WMD facilities, including depth of burial and lateral extent if a sufficient number of measurements are taken on the perimeter of the facility. Moreover if a station measurement can be made directly over the facility then the resolution is improved accordingly. In all cases it was not possible to image the base of the facility with any confidence as well as provide any precise inferences on the facility electrical conductivity. This later finding, however, is really not that critical since knowledge of facility geometry is far more important than knowledge of its conductivity. For the WMD problem it is recommended that MT measurements be made solely with the magnetic field ratios. In this context it would then be possible to deploy with far greater ease small coils about a suspected facility and would allow for the measurements to be conducted in a more covert manner. Before testing such a measurement system in the field, however, it would be necessary to carry out a similar resolution analysis as was done with MT measurements based on electric and magnetic fields. This is necessary to determine sensitivity of the proposed measurement to underground facilities along with needed data coverage and quality. Such a study is indispensable in producing useful reconstructions of underground facilities.
Date: December 24, 1998
Creator: Day, D.M. & Newman, G.A.
Partner: UNT Libraries Government Documents Department

Institutional Strain and Precarious Values in Meeting Future Nuclear Challenges

Description: This paper explores the implications of moderately expanding plutonium "pit" production capability within the strongly R&D culture of Los Alamos National Laboratory, especially in terms of the lab's current capacity or "fitness for the future" in which institutional stewardship of the nation's nuclear deterrent capability becomes a primary objective. The institutional properties needed to assure "future fitness" includes the organizational requisites highly reliable operations and sustained institutional constancy in a manner that evokes deep public trust and confidence. Estimates are made of the degree to which the key Division and most relevant Program office in this evolution already exhibits them.
Date: November 1, 1998
Creator: Matthews, Bruce & LaPorte, Todd R.
Partner: UNT Libraries Government Documents Department

Freedom to mix vulnerable offensive and defensive forces

Description: The freedom to mix offense and defense to expand without diminishing either side`s second strike capability is shown to be counterproductive at large numbers of missiles; effective at intermediate numbers; and progressively less effective at modest numbers. Solutions are less stable for large second strikes.
Date: September 1, 1998
Creator: Canavan, G. H.
Partner: UNT Libraries Government Documents Department

External Q studies for APT superconducting cavity couplers

Description: Coupling coefficients for the APT superconducting cavity couplers have been predicted using an improvement of the method previously developed for the French Trispal project. The authors here present the method and a proof of the formula used to compute the external Q. Measurements on a single-cell copper cold model exhibited a very good agreement against simulation. Then, they established that the original coupler design lead to an insufficient coupling in {beta} = 0.64 cavities. Different solutions were proposed to fix this problem, like combining impedance discontinuities in the line and an off-centered disc end tip. Finally, it was decided to increase the beam tube diameter though it has some influence on the cavity end-cell performance.
Date: December 31, 1998
Creator: Balleyguier, P.
Partner: UNT Libraries Government Documents Department

Safety issues in fabricating mixed oxide fuel using surplus weapons plutonium

Description: This paper presents an assessment of the safety issues and implications of fabricating mixed oxide (MOX) fuel using surplus weapons plutonium. The basis for this assessment is the research done at Los Alamos National Laboratory (LANL) in identifying and resolving the technical issues surrounding the production of PuO{sub 2} feed, removal of gallium from the PuO{sub 2} feed, the fabrication of test fuel, and the work done at the LANL plutonium processing facility. The use of plutonium in MOX fuel has been successfully demonstrated in Europe, where the experience has been almost exclusively with plutonium separated from commercial spent nuclear fuel. This experience in safely operating MOX fuel fabrication facilities directly applies to the fabrication and irradiation of MOX fuel made from surplus weapons plutonium. Consequently, this paper focuses on the technical difference between plutonium from surplus weapons, and light-water reactor recycled plutonium. Preliminary assessments and research lead to the conclusion that no new process or product safety concerns will arise from using surplus weapons plutonium in MOX fuel.
Date: July 1, 1998
Creator: Buksa, J.; Badwan, F.; Barr, M. & Motley, F.
Partner: UNT Libraries Government Documents Department

Corrective Action Plan for Corrective Action Unit 453: Area 9 UXO Landfill, Tonopah Test Range, Nevada

Description: This corrective action plan proposes the closure method for the area 9 unexploded Ordnance landfill, corrective action unit 453 located at the Tonopah Test Range. The area 9 UXO landfill consists of corrective action site no. 09-55-001-0952 and is comprised of three individual landfill cells designated as A9-1, A9-2, and A9-3. The three landfill cells received wastes from daily operations at area 9 and from range cleanups which were performed after weapons testing. Cell locations and contents were not well documented due to the unregulated disposal practices commonly associated with early landfill operations. However, site process knowledge indicates that the landfill cells were used for solid waste disposal, including disposal of UXO.
Date: September 30, 1998
Creator: Bechtel Nevada
Partner: UNT Libraries Government Documents Department

Low amplitude insult project: PBX 9501 high explosive violent reaction experiments

Description: The Modified Steven test geometry has been used with several different target designs to investigate the mechanical loading behavior of PBX 9501 to a low velocity impact. A 2 kg. mild steel spigot projectile is launched via a new powder driven gun design, from {approximately} 20 to 105 m/s, at lightly confined, steel targets. Brief descriptions of the gun design and operation are given. The threshold velocity to reaction for various target designs, different PBX 9501 lots, and different high explosive (HE) thicknesses are reported and compared. Various diagnostics have been employed to evaluate the pressure profile and timing, and target strain behavior relative to projectile impact. The violence of reaction, as measured by both passive and active techniques, is reported relative to a steady state detonation in PBX 9501. Experimental results suggest slightly different ignition mechanisms dominate based on (HE) thickness, resulting in delayed reactions from {approximately} 0.2- to 2.8-ms after impact. Post-test analyses of the PBX 9501 are briefly summarized.
Date: December 31, 1998
Creator: Idar, D.J.; Lucht, R.A.; Straight, J.W.; Scammon, R.J.; Browning, R.V.; Middleditch, J. et al.
Partner: UNT Libraries Government Documents Department

Dynamic measurement of the influence of projectile radius and velocity on strain localization during impact of an energetic material

Description: A new technique for measuring the dynamic displacement fields during deformation has been developed. The method uses high speed laser-induced fluorescence speckle photography. The authors report the effect of projectile velocity and radius on the strain fields in a quasi-two dimensional confined sample of PBX 9501.
Date: December 31, 1998
Creator: Asay, B.W.; Dickson, P.M.; Henson, B.; Fugard, C.; Funk, D.J. & Idar, D.J.
Partner: UNT Libraries Government Documents Department

Structural and magnetic characterization of actinide materials

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors have successfully used neutron scattering techniques to investigate physicochemical properties of elements, compounds, and alloys of the light actinides. The focus of this work is to extend the fundamental research capability and to address questions of practical importance to stockpile integrity and long-term storage of nuclear material. Specific subject areas are developing neutron diffraction techniques for smaller actinide samples; modeling of inelastic scattering data for actinide metal hydrides; characterizing actinide oxide structures; and investigating aging effects in actinides. These studies utilize neutron scattering supported by equilibrium studies, kinetics, and x-ray diffraction. Major accomplishments include (1) development of encapsulation techniques for small actinide samples and neutron diffraction studies of AmD{sub 2.4} and PuO{sub 2.3}; (2) refinement of lattice dynamics model to elucidate hydrogen-hydrogen and hydrogen-metal interactions in rare-earth and actinide hydrides; (3) kinetic studies with PuO{sub 2} indicating that the recombination reaction is faster than radiolytic decomposition of adsorbed water but a chemical reaction produces H{sub 2}; (4) PVT studies of the reaction between PuO{sub 2} and water demonstrate that PuO{sub 2+x} and H{sub 2} form and that PuO{sub 2} is not the thermodynamically stable form of the oxide in air; and (5) model calculations of helium in growth in aged plutonium predicting bubble formation only at grain boundaries at room temperature. The work performed in this project has application to fundamental properties of actinides, aging, and long-term storage of plutonium.
Date: December 31, 1998
Creator: Cort, B.; Allen, T.H. & Lawson, A.C.
Partner: UNT Libraries Government Documents Department

Explosive morphology from fractal analysis of micrographs

Description: The effect of particle size on the details of the initiation and detonation of condensed explosives has long been known. The effect of the three-dimensional nature of explosive particles as a neat pressings (with voids), or as dispersed in a second (or third) phase (with or without voids), has been the subject of many investigations of detonation phenomena. However, succinct and accurate descriptions of the compacts and pressings are difficult to achieve because the morphology and size distributions are generally altered by processing into useful configurations and densities. Three-dimensional measurements of near-full-density pressings are not easy and have not been done with great accuracy. The authors explore the analysis of various particle-size and morphological measurements using the formalisms of fractal geometry. They intend to show, by a combination of modeling and data analysis, that a three-dimensional description of the explosive, the binder, and the voids can be constructed from one- and two-dimensional measurements of surface. In the long term, they hope to correlate these descriptions with the measurements of explosive behavior.
Date: December 31, 1998
Creator: McAfee, J.M. & Nelson, R.A.
Partner: UNT Libraries Government Documents Department

Applications of direct chemical oxidation to demilitarization

Description: Research is reported concerning an aqueous process for oxidative destruction of solid- and liquid organic wastes, including ongoing work relevant to demilitarization This process uses acidified ammonium- or sodium peroxydisulfate and operates at ambient pressure and at temperatures of 80- 100 C The oxidant may be regenerated by electrolysis of the sulfate by- product at Pt anodes at roughly 80% coulombic efficiency, even in the presence of inorganic contaminants (e g , nitrate, phosphate or chloride) found in the original waste and entrained in the recycle stream Integral rate constants have been determined for the oxidation of diverse organic compounds at low concentrations (50 ppm, C), with rate constants (based on equivalents) of 0 004-O 02 miri Higher concentrations generally react at a 2-4X higher rate. The process has been carried through full- scale laboratory tests and initial pilot plant tests on chlorinated solvents, using a hydrolysis pretreatment Integral rate data indicate throughput rates of about 200 kg- C/m3-day The process may benefit the demilitarization efforts in various specialized applications destruction of solvents; destruction of trace propellants and explosives in shell casings remaining after bulk removal, destruction of red and pink waters, in situ remediation of soils at open pit burning/detonation sites; and as a regenerative filter for offgas carrying toxic or explosive substances.
Date: June 1, 1998
Creator: Cooper, J.F., LLNL
Partner: UNT Libraries Government Documents Department

Laser-sheet imaging of HE-driven interfaces

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors made substantial progress in developing the MILSI (Multiple Imaging of Laser-Sheet Illumination) technique for high explosive (HE)-driven fluid interfaces. They observed the instability, but have not yet measured the instability growth rate. They developed suitable sample containers and optical systems for studying the Rightmyer-Meshkov instability of perturbed water/bromoform interfaces and they successfully fielded the new MILSI diagnostic at two firing-site facilities. The problem continues to be of central importance to the inertial confinement fusion (ICF) and weapons physics communities.
Date: December 31, 1998
Creator: Benjamin, R.F.; Rightley, P.M.; Kinkead, S.; Martin, R.A.; Critchfield, R.; Sandoval, D.L. et al.
Partner: UNT Libraries Government Documents Department

Development of weld closure stations for plutonium long-term storage containers

Description: Weld closure stations for plutonium long-term storage containers have been designed, fabricated, and tested for the Advanced Recovery and Integrated Extraction System (ARIES) at the TA-55 Plutonium Facility of the Los Alamos National Laboratory. ARIES is a processing system used for the dismantlement of the plutonium pits from nuclear weapons. ARIES prepares the extracted-plutonium in a form which is compatible with long-term storage and disposition options and meets international inspection requirements. The processed plutonium is delivered to the canning module of the ARIES line, where it is packaged in a stainless steel container. This container is then packaged in a secondary container for long-term storage. Each of the containers is hermetically sealed with a full penetration weld closure that meets the requirements of the ASME Section IX Boiler and Pressure Vessel Code. Welding is performed with a gas tungsten arc process in an inert atmosphere of helium. The encapsulated helium in the nested containers allows for leak testing the weld closure and container. The storage package was designed to meet packaging requirements of DOE Standard 3013-96 for long-term storage of plutonium metal and oxides. Development of the process parameters, weld fixture, weld qualification, and the welding chambers is discussed in this paper.
Date: December 31, 1998
Creator: Fernandez, R.; Martinez, D.A.; Martinez, H.E.; Nelson, T.O.; Ortega, R.E.; Rofer, C.K. et al.
Partner: UNT Libraries Government Documents Department

Current radiological status of Utirik Atoll

Description: A preliminary radiological survey was conducted at Utirik Atoll in 1978 as part of the Northern Marshall Islands Radiological Survey (NMIRS). A dose assessment based on these limited data indicated a relatively low dose of about 0.12 mSv to people living on Utirik in 1978 (Robison et al., 1982). A much more detailed radiological survey was conducted in April of both 1993 and 1994. Aerial photos of the islands of Utirik Atoll were taken as part of the 1978 NMIRS. The sampling grids for the 1993 and 1994 surveys are shown overlaid on these aerial photos in Figures 1, 2, 3, and 4. External gamma measurements and a collection of either drinking coconuts or copra coconuts were made at each location. Pandanus, breadfruit, lime, and banana were collected where available. Ground water was collected in 1993/94 from four wells on Utirik Island and two wells on Aon Island. Surface soil and soil profiles were collected at some of the grid points on each of the islands at the atoll in 1993/94. A comparison of the number of samples collected in 1978 and 1993/94 are shown in Table 1. A detailed listing of the samples collected in the 1993/94 radiological survey at Utirik Atoll is given in Table 2. The number of vegetation samples collected in 1993/94 is nearly a factor of 7 greater than in 1978. Soil samples collected in 1993/94 exceeded the number collected in 1978 by more than a factor of 4. Consequently, extensive data are now available for the islands at Utirik Atoll and form the basis for the current dose assessment for the atoll.
Date: August 1, 1998
Creator: Robison, W L
Partner: UNT Libraries Government Documents Department

Discussion of nuclear explosive operation process changes generated by a preliminary hazard assessment

Description: Hazard assessments (HAs) are being used to support the US Department of Energy (DOE) Integrated Safety Process (SS-21), Nuclear Explosive Safety Study Group (NESSG), and Environmental Safety and Health (ES and H) initiatives. The HAs are used to identify hazards associated with nuclear explosive operations involving tooling and procedural processes. In general, a HA is a formal, systematic, in-depth method for evaluating a set of possible accident scenarios associated with a process. Two assessments of a nuclear explosive surveillance process have been performed or are in progress: (1) a preliminary HA of current operations to focus efforts on maximizing safety improvements during subsequent process redesign and track overall improvement following process redesign (completed) and (2) a rolling assessment of hazards present in conceptual solutions and solutions to improve safety (in progress). The preliminary HA was used to focus the process design teams on problem areas. The rolling assessment is evaluating how well problem areas were eliminated or mitigated. This paper summarizes the preliminary HA, how it focused the design teams on problem areas found by the assessment, and the rolling assessment of solutions generated by the process design team.
Date: September 1998
Creator: O`Brien, D. & Fischer, S. R.
Partner: UNT Libraries Government Documents Department

Enhanced surveillance program annual report FY98. Dynamic behavior of Pu and U (intermediate strain rates) -- LA12

Description: The Kolsky-Hopkinson Bar Dynamic Test Facility in Building PF-4 at TA-55 recently became operational and the first series of plutonium samples from a baseline alloy were successfully tested on December 8, 1997 through the dedicated efforts of a large number of people in groups NMT-9, NMT-11, MST-8, NMT-5, and JCI. The Enhanced Surveillance Program provided the necessary support for this achievement. The Kolsky-Hopkinson bar is an instrument designed to measure the uniaxial compression stress-strain characteristics of special nuclear materials (SNM) in a glovebox environment at intermediate strain rates (typically 500 s{sup {minus}1} to 10,000 s{sup {minus}1}), over a wide temperature range (cryogenic up to near-melting temperatures), and up to strains of about 50% per test. Due to radiation contamination hazards, SNM samples are contained within a specially designed glovebox with only a small portion of the bar system. The uniaxial high-strain-rate deformation behavior of SNM materials is revealed by stress-strain-strain rate curves calculated from strain signals acquired by gauges on the pressure bars. The compressive stress-strain mechanical behavior of a range of weapons-relevant SNM materials (both baseline and stockpile-aged plutonium and enriched uranium), measured over a wide range of strain rates and temperatures, is necessary to support the development of predictive constitutive models and allows assessment of the mechanical response of SNM as a function of age, processing, and composition. Accurate constitutive material models are essential for simulating the high-rate deformation response of weapon materials. Most FY98 milestones and deliverables were successfully met or were partially completed on schedule. In the case of enriched uranium, testing began six months ahead of schedule. Upgrading the testing temperature capability took six months more than originally planned as a result of the highly formalized and rigorous design change plan (DCP) requirements at TA-55. Specimen availability continues to be a bottle-neck due to over-subscribed ...
Date: December 31, 1998
Creator: Blumenthal, W.R.
Partner: UNT Libraries Government Documents Department

Detonation spreading in fine TATBs

Description: A test has been devised that permits rapid evaluation of the detonation-spreading (or corner-turning) properties of detonations in insensitive high explosives. The test utilizes a copper witness plate as the medium to capture performance data. Dent depth and shape in the copper are used as quantitative measures of the detonation output and spreading behavior. The merits of the test are that it is easy to perform with no dynamic instrumentation, and the test requires only a few grams of experimental explosive materials.
Date: December 31, 1998
Creator: Kennedy, J.E.; Lee, K.Y.; Spontarelli, T. & Stine, J.R.
Partner: UNT Libraries Government Documents Department

Parameter identification and on-line estimation for reduced kinetic model

Description: The base hydrolysis process for the destruction of energetic or explosive materials results is a high pH hydrolysate solution with reaction products that include a series of carboxylic acid salts, glycolates, amines, and nitrates. The hydrolysate solutions obtained from this process contain from two to ten wt% of organic carbon and nitrogen compounds that must be further treated before disposal. Hydrothermal oxidation at elevated temperatures (450 C) and pressure (14,000 psi) was selected as the treatment process for the hydrolysate solutions obtained from hydrolysis of the high explosive PBX 9404 at the Department of Energy Pantex facility in Amarillo, Texas. In this work, the authors describe the use of receding horizon identification and estimation techniques to determine the model parameters for a reduced kinetic model describing the oxidation-reduction reactions in a hydrothermal oxidation reactor. This model is used in a model predictive controller that minimizes the total aqueous nitrogen in the hydrothermal oxidation reactor effluent.
Date: August 7, 1998
Creator: Littel, J.D.; Muske, K.R.; Del`Orco, P.C.; Le, L.A. & Flesner, R.L.
Partner: UNT Libraries Government Documents Department

Nevada Test Site annual site environmental report for calendar year 1997

Description: Monitoring and surveillance, on and around the Nevada Test Site, (NTS) by US Department of Energy (DOE) contractors and NTS user organizations during 1997, indicated that operations on the NTS were conducted in compliance with applicable DOE, state, and federal regulations and guidelines. All discharges of radioactive liquids remained onsite in containment ponds, and there was no indication of potential migration of radioactivity to the offsite area through groundwater. Surveillance around the NTS indicated that airborne radioactivity from diffusion, evaporation of liquid effluents, or resuspension of soil was not detectable offsite, and exposure above existing background to members of the offsite population was not measured by the offsite monitoring program. Using the US Environmental Protection Agency`s (EPA`s) Clean Air Package 1988 (CAP88)-PC model and NTS radionuclide emissions and environmental monitoring data, the calculated effective dose equivalent (EDE) to the maximally exposed individual offsite would have been 0.089 mrem. Hazardous wastes were shipped offsite to approved disposal facilities.
Date: October 1, 1998
Creator: Black, S.C. & Townsend, Y.E.
Partner: UNT Libraries Government Documents Department

Modeling the interacting detonation fronts observed by low energy radiography

Description: We have completed a series of experiments in which we made radiographs of interacting detonation fronts in a high explosive. Although the fronts and interactions were observed, the experimental data were insufficient to distinguish between two computer models which we employed to simulate the experiments.
Date: September 18, 1998
Creator: Aufderheide, M; Egan, P O; Morgan, D L & Vantine, H C
Partner: UNT Libraries Government Documents Department

Gradient-Drive Diffusion of Multi-Atom Molecules Through Macromolecules and Membranes: LDRD 96-0021 Close-Out Report

Description: The goals of this Laboratory Directed Research and Development (LDRD) effort were to develop and prototype a new molecular simulation method and companion parallel algorithm able to model diffusion of multi-atom molecules through macromolecules under conditions of a chemical potential gradient. At the start of the project no such method existed, thus many important industrial and technological materials problems where gradient driven diffusion of multi-atom molecules is the predominant phenomenon were beyond the reach of molecular simulation (e.g. diffusion in polymers, a fundamental problem underlying polymer degradation in aging weapons).
Date: December 1, 1998
Creator: Ford, D.M.; Heffelfinger, G.S.; Martin, M.G. & Thompson, A.
Partner: UNT Libraries Government Documents Department

Thermal chemical-mechanical reactive flow model of shock initiation in solid explosives

Description: The three dimensional Arbitrary Lagrange Eulerian hydrodynamic computer code ALE3D with fully coupled thermal-chemical-mechanical material models provides the framework for the development of a physically realistic model of shock initiation and detonation of solid explosives. The processes of hot spot formation during shock compression, subsequent ignition of reaction or failure to react, growth of reaction in individual hot spots, and coalescence of reacting hot spots during the transition to detonation can now be modeled using Arrhenius chemical kinetic rate laws and heat transfer to propagate the reactive flow. This paper discusses the growth rates of reacting hot spots in HMX and TATB and their coalescence during shock to detonation transition. Hot spot deflagration rates are found to be fast enough to consume explosive particles less than 10 mm in diameter during typical shock duration times, but larger particles must fragment and create more reactive surface area in order to be rapidly consumed.
Date: August 26, 1998
Creator: Nicholls, A. L., III & Tarver, C. M.
Partner: UNT Libraries Government Documents Department