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At least 829 records · Page 46

Grain Boundary Engineering the Mechanical Properties of Allvac 718Plus(Trademark) Superalloy

Grain Boundary Engineering can enhance the population of structurally-ordered "low S" Coincidence Site Lattice (CSL) grain boundaries in the microstructure. In some alloys, these "special" grain boundaries have been reported to improve overall resistance to corrosion, oxidation, and creep resistance. Such improvements could be quite beneficial for superalloys, especially in conditions which encourage damage and cracking at grain boundaries. Therefore, the effects of GBE processing on high-temperature mechanical properties of the cast and wrought superalloy Allvac 718Plus (Allvac ATI) were screened. Bar sections were subjected to varied GBE processing, and then consistently heat treated, machined, and tested at 650 C. Creep, tensile stress relaxation, and dwell fatigue crack growth tests were performed. The influences of GBE processing on microstructure, mechanical properties, and associated failure modes are discussed.

Gabb, Timothy P.↗

Radiological characterization of high Cs-137 waste items at LANL combining Cs-137 NDA results and acceptable process knowledge - 15592

Radiological characterization is an important component to disposition and disposal of radioactive waste at the Los Alamos National Laboratory. Gamma and neutron based non-destructive assay systems are available at LANL's TA-54 Area G for radiological characterization and are generally very effective in quantifying the transuranic radionuclide concentration required for a TRU or low level waste disposition determination. This is routinely performed by scaling some nuclides to direct assay results using acceptable process knowledge scaling from a directly measured key TRU nuclide, e.g., for gamma systems using a standard isotopic distribution to determine the amount of Pu-240 associated with a measured value of Pu-239. However, for two groups of LANL waste items that have high levels of Cs-137, these non-destructive assay systems were unable to make a standard TRU/LLW determination. Therefore, it was necessary to apply an extension of the typical scaling technique that keyed in on the direct Cs-137 gamma assay result to effectively characterize these waste items for TRU processing or LLW disposition. Two basic types of waste packages contained the high Cs-137 waste requiring special scaling: drums and boxes. The drums included 55-gallon, 85-gallon and 110-gallon volume sizes and the boxes included a corrugated metal box, a Standard Waste Box, and several overpack boxes containing oversized waste. All of these items contained radioactive waste generated from operations at the Chemistry and Metallurgical Research facility at LANL that included hot cell, metallographic sectioning and maintenance activities. All of the drums as well as the CMB, SWB and one oversized item in a plywood box were located above-ground at LANL's TA-54 Area G, while five of the oversized items were hot cell liners in metal boxes stored below-ground in shafts. All of the items were measured in the 2013-2014 time period at TA-54 Area G with LANL NDA systems. Most of the items were counted with LLW certified far-field gamma spectroscopy systems employing portable far-field HPGe detectors and carts and some of the items were counted on WIPP certified gamma only or gamma with neutron NDA systems. In all cases Cs-137 was quantified directly with a gamma measurement but the key TRU nuclides were not detectable. Thus, for each waste item AK/PK was studied and scaling factors to Cs-137 were established and applied to provide a comprehensive radiological characterization. A total of 49 waste items were successfully characterized as LLW based on this technique. The above ground waste items were dispositioned and disposed of at an offsite LLW repository and the below ground boxes were left in place as LLW in the TA-54 Area G shafts. This NDA with scaling application has proved effective and defensible in these high Cs-137 cases at LANL and will continue to be used as applicable and appropriate for future waste characterization at LANL. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Amphibian fertilization and development in microgravity

During the year before launch, female frogs will be tested every 3 months for the quantity and quality of eggs produced. Two weeks or more prior to launch, male and female frogs will be transported to the John F. Kennedy Space Center (KSC). During the few weeks before launch, groups will be periodically tested for egg quality to assure that the frogs have adapted to the KSC laboratory environment. About 27 hours before launch, four females will be placed in a damp foam-lined box, called the Adult Frog Box (AFB), through which 100 cc/min of air wil be circulated. The AFB will be lowered into the Spacelab and loaded into the Frog Environmental Unit (FEU) during the final pre-launch preparations. A sperm suspension, for use in flight to fertilize the eggs, will also be prepared and loaded during the pre-launch period. The sperm suspension, together with a kit of syringes containing Human Chorionic Gonadotropin (HCG), will be stored in a refrigerator aboard the shuttle until needed in flight. On the first day of flight, the AFB will be transferred from the FEU to the General Purpose Work Station (GPWS), which is a type of glove box specially designed to allow the crew to use chemicals and biological materials during the flight without contaminating the shuttle/Spacelab environment. Inside the GPWS the four adult frogs will be injected with the HCG hormone and returned to the FEU. Approximately 16 hours after injection, ovulation should have taken place and 15 to 20 eggs from each frog will be placed on each of two egg baskets and covered with sperm for 10 minutes. The egg baskets are inserted into acrylic egg chambers and 50 ml of 'pond water' (20 percent strength Modified Ringers solution (is added. One of the chambers from each frog will be placed on a centrifuge within the FEU and rotated to simulate normal terrestrial gravity (1 g). The remaining chambers are incubated under microgravity conditions within the FEU. Forty minutes after fertilization, the four chambers exposed to 1 g will be removed and observed within the GPWS using a dissecting microscope and camera system. On the basis of egg rotation and egg appearance, the 'best' and 'second best' frogs will be selected to contribute additional eggs. Using the two best frogs, 22 egg chambers will be loaded with eggs and fertilized. Eleven chambers wil be incubated at microgravity and eleven will be incubated on the centrifuge. At various times during the flight, chambers will be removed from the FEU and transferred to the GPWS where a formaldehyde-based fixative will be injected in order to preserve important developmental stages for in depth study following the flight. Five of the 22 chambers plus the eight fertilization test chambers will be returned to Earth with live tadpoles. The swimming behavior of these free swimming tadpoles will be examined within several hours of landing and some will be fixed for a detailed analysis of their inner ear, the otolity, the animals 'balance system.' Lychakov and Vinikov reported an increase in otolith size in tadpoles that developed (but were not fertilized) in space. Live tadpoles from the SL-J flight will be raised through metamorphsis for studies of maturation including an analysis of the effects of space flight on their ability to produce normal progency. Following the flight, the fixed embryos will be serially sectioned and stained using procedures that were developed for this experiment. The embroys fixed at the 2-4 cell stage will be examined for the distribution of cytoplasmic contents, including the various classes of yolk platelets, and the location and shape of the cleavage furrows. The gastrulae will be assessed for the normality of the complex cellular rearrangements that constitute blastopore formation and involution, i.e., the differentiation of the embryo into its specialized body parts. Using a new procedure, the gastrulae will be bleached which will enable the initial sperm entry point (SEP) to be located. The correlation between the SEP and the dorsal lip of the blastopore will be determined. Under normal terrestrial conditions it was shown that the SEP typically is located on the side of the egg opposite the future dorsal side of the embryo. The neurulae will be examined for the normality and completeness of the neural plate and archenteron expansion. The tadpole stages will be used to study the allometry and morphology of the various organ systems.

Souza, Kenneth A.↗

Investigation in the 7-By-10 Foot Wind Tunnel of Ducts for Cooling Radiators Within an Airplane Wing, Special Report

An investigation was made in the NACA 7- by 10-foot wind tunnel of a large-chord wing model with a duct to house a simulated radiator suitable for a liquid-cooled engine. The duct was expanded to reduce the radiator losses, and the installation of the duct and radiator was made entirely within the wing to reduce form and interference drag. The tests were made using a two-dimensional flow set-up with a full-span duct and radiator. Section aerodynamic characteristics of the basic airfoil are given and also curves showing the characteristics of the various duct-radiator combinations. An expression for efficiency, the primary criterion of merit of any duct, and the effect of the several design parameters of the duct-radiator arrangement are discussed. The problem of throttling is considered and a discussion of the power required for cooling is included. It was found that radiators could be mounted in the wing and efficiently pass enough air for cooling with duct outlets located at any point from 0.25c to 0.70c from the wing leading edge on the upper surface. The duct-inlet position was found to be critical and, for maximum efficiency, had to be at the stagnation point of the airfoil and to change with flight attitude. The flow could be efficiently throttled only by a simultaneous variation of duct inlet and outlet sizes and of inlet position. It was desirable to round both inlet and outlet lips. With certain arrangements of duct, the power required for cooling at high speed was a very low percentage of the engine power.

Harris, Thomas A.↗

Geant4 Event Biasing and Fast Simulation

Geant4 offers advanced event biasing techniques to significantly accelerate simulations involving rare events. Various biasing methods, such as leading particle selection, cross-section biasing, radioactive decay enhancement, and bremsstrahlung splitting, enable efficient event sampling, though they require careful handling. Additionally, Geant4 provides a Fast Simulation Interface, allowing the replacement of standard processes in specific region and for selected particles, enabling faster execution or external code integration. Applications of fast simulation include electromagnetic shower modeling in calorimeters, machine learning inference, and offloading tasks to specialized hardware like GPUs, making Geant4 a powerful tool for computationally demanding simulations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

X-Ray Computed Tomography During Preliminary Examination of Apollo Drive Tube 73001

Introduction: Starting in 2019, the Apollo Next Generation Sample Analysis (ANGSA) Program has enabled consortium studies of specially curated Apollo samples that were previously unstudied (or under studied). This began with unsealed core tube 73002 [1,2] that is the upper part of a station 3 double drive tube. More recently the pro-gram extended to the study of a variety of frozen Apollo 17 samples [3], as well as the gas extraction [4] and dis-section [5] of 73001, the lower half of the station 3 double drive tube, that was sealed under vacuum on the Moon. In this abstract we will examine the role of X-ray Computed Tomography (XCT) during the preliminary examination process for sealed core 73001, including: (1) engineering scans to aid in understanding the gas extraction process, whole-core scanning prior to opening to inform extrusion and dissection work, and (3) individual particle scanning to characterize rock fragment lithologies for follow on studies. Methodology: Sample 73001 is a 33 cm long, 4 cm diameter regolith sample collected inside a drive tube (~1 mm aluminum walls). That drive tube was sealed inside a 0.5 mm thick stainless steel (SS) Core Sample Vacuum Container (CSVC). XCT scans for engineering purposes were done on the Nikon XTH 320 system at Johnson Space Center using the 225 kV multi-metal reflection source at 215 kV, 179 A, and a 38.49 m voxel size. Individual >4 mm particles separated from the core during processing (then triply sealed in Teflon bags) were also scanned at JSC using the 180 kV source at 90 kV, 33 A, and a 2.98 – 10.65 m voxel size. Whole-core scans were done at the University of Texas High-Resolution X-ray Computed Tomography Facility (UTCT) on the 225 kV reflection source on the North Star Imaging cabinet XCT system. These scans included: (1) a series of 9 overlapping super-resolution scans each covering a ~4 cm length of the tube at 190 kV, 180 µA, and a 12.9 µm voxel size and (2) a lower resolution continuous helical scan of the entire core at 190 kV, 180 µA, and a 51.8 µm voxel size. Progress and Results: Before piercing and extracting the gas from sample 73001, an XCT scan of the bottom portion of the CSVC was used to confirm the location of the Teflon cap on the inner drive tube, to ensure it was not accidentally pierced during gas extraction. Similarly, after piercing, the bottom and top portions of the CSVC were scanned in order to capture engineering knowledge about the results of the piercing process, as well as the metal knife edge vacuum seal (SS into In-Ag alloy). Both scans will provide constraints on future work of this type, particularly for samples collected during the Artemis mission. Another finding from these "engineering" scans was that the device in the drive tube that immobilizes the regolith (the keeper) was not seated in the tube properly. This meant that (1) the drive tube could not be removed from the CSVC for the trip to UTCT, and (2) the procedure for opening and extruding the drive tube had to be modified. Had either of these things not been known prior to opening the CSVC, it could have led to an inability to XCT scan the whole core at high resolution and/or potential disruption of the core stratigraphy during extrusion. At UTCT, the entire length of the core was scanned at high resolution (12.9 microns per voxel). This scan serves multiple purposes: (1) A lower resolution (and uncorrected) version of these scans stitched together was used to help inform the processors of potential pitfalls during extrusion and dissection; and (2) the full resolution corrected data will serve as the permanent in situ record of the stratigraphy of the sample and will enable future researchers to perform a variety of analyses. So far, 92 of the 121 >4 mm particles separated during dissection pass 1 of sample 73001 have been individually scanned. These scans clearly show the lithology of each particle while keeping the particles in pristine condition. Because of the dust adhering to particle exteriors it would otherwise be impossible to determine lithologies in a non-contaminating way. Thus far the types of lithologies seen in sample 73001 (e.g., regolith breccias, impact-melt breccias, agglutinates, and basalts) are similar to those previously identified in sample 73002 [2]. By the time of the meeting, all particles from all 3 dissection passes will have been scanned and statistics on the different lithologies in 73001 compiled. References: [1] Shearer et al. (2020) 51st LPSC, abstract 1181. [2] Zeigler et al. (2020) 51st LPSC, abstract 3023. [3] Kent et al. (2022) This Volume. [4] McDonald et al. (2022) European Lunar Symposium. [5] Gross et al (2022) This volume.

Moon↗

Covariance generation for the prompt neutron multiplicity of 239 Pu including the (n, γ f) process

Fission cross section of 239 Pu can be seen as a sum of the “immediate" fission and “two-step" (n,γf) reactions. In the Resolved Resonance Range of the reaction cross sections, the contribution of the (n,γf) process has an impact on the determination of the partial widths magnitude involved in the Reich-Moore approximation of the R-matrix theory. The present work aims to investigate this impact by using the CONRAD code and the partial width Γ γf for the (n,γf) reaction calculated by Lynn et al. A special attention will be paid to the covariance matrix obtained on ν p .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Electron density profile measurements at a self-focusing ion beam with high current density and low energy extracted through concave electrodes

The self-focusing phenomenon has been observed in a high current density and low energy ion beam. In order to study the mechanism of this phenomenon, a special designed double probe to measure the electron density and temperature is installed into the chamber where the high current density ion beam is injected. Electron density profile is successfully measured without the influence of the ion beam components. Estimated electron temperature and density are ∼0.9 eV and ∼8 × 10{sup 8} cm{sup −3} at the center of ion beam cross section, respectively. It was found that a large amount of electrons are spontaneously accumulated in the ion beam line in the case of self-forcing state.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Radiation of a Charge Intersecting a Boundary Between a Bilayer Area and a Homogeneous One in a Circular Waveguide

This paper is devoted to the analysis of electromagnetic field excited by a charge moving in a circular waveguide, which consists of two semi-infinite parts. The charge moves with a constant velocity along the waveguide axis from the partially dielectric section into the homogeneous one. It is assumed that Cherenkov radiation is generated in the bilayer section. The total field is represented as a sum of a known forced field that is the field of the charge in the infinite regular waveguide and a free field resulting from the presence of the transverse boundary. The infinite system of algebraic equations for amplitudes of the free-field modes is derived. The further analysis is conducted using numerical calculations. Special attention is given to the study of the so-called Cherenkov-transition radiation (CTR) within the homogeneous part of the waveguide volume. Typical distributions of CTR over frequencies and modes are presented for the case when the channel and the homogeneous area are free of medium. Analytical results obtained for the point charge are generalized for the charged bunch with an arbitrary profile and verified using direct simulations for the case of Gaussian bunch.

Cherenkov-transition radiation (CTR)↗

Swirling jets for the mitigation of hot spots and thermal stratification in the VHTR lower plenum

The Department of Energy (DOE) has a special interest in the development of Generation IV next generation nuclear plants (NGNPs) in the form of very high (gas cooled) temperature reactors (VHTRs) for the production of electricity, hydrogen, and process heat. As of 2010, the prismatic and pebble bed reactors are the top VHTR candidates [ORNL, 2010; Wikipedia, 2010a; World Nuclear News, 2010; Kinsey, 2010]. However, for reasons elucidated in Section 2, this research will concentrate on the prismatic core VHTR.

Rodriguez, Salvador B.↗

Acquisition of quantitative physiological data and computerized image reconstruction using a single scan TV system

Single scan operation of television X-ray fluoroscopic systems allow both analog and digital reconstruction of tomographic sections from single plan images. This type of system combined with a minimum of statistical processing showed excellent capabilities for delineating small changes in differential X-ray attenuation. Patient dose reduction is significant when compared to normal operation or film recording. Flat screen, low light level systems were both rugged and light in weight, making them applicable for a variety of special purposes. Three dimensional information was available from the tomographic methods and the recorded data was sufficient when used with appropriate computer display devices to give representative 3D images.

Baily, N. A.↗

Component-Level Electronic-Assembly Repair (CLEAR) Synthetic Instrument Capabilities Assessment and Test Report

The role of synthetic instruments (SIs) for Component-Level Electronic-Assembly Repair (CLEAR) is to provide an external lower-level diagnostic and functional test capability beyond the built-in-test capabilities of spacecraft electronics. Built-in diagnostics can report faults and symptoms, but isolating the root cause and performing corrective action requires specialized instruments. Often a fault can be revealed by emulating the operation of external hardware. This implies complex hardware that is too massive to be accommodated in spacecraft. The SI strategy is aimed at minimizing complexity and mass by employing highly reconfigurable instruments that perform diagnostics and emulate external functions. In effect, SI can synthesize an instrument on demand. The SI architecture section of this document summarizes the result of a recent program diagnostic and test needs assessment based on the International Space Station. The SI architecture addresses operational issues such as minimizing crew time and crew skill level, and the SI data transactions between the crew and supporting ground engineering searching for the root cause and formulating corrective actions. SI technology is described within a teleoperations framework. The remaining sections describe a lab demonstration intended to show that a single SI circuit could synthesize an instrument in hardware and subsequently clear the hardware and synthesize a completely different instrument on demand. An analysis of the capabilities and limitations of commercially available SI hardware and programming tools is included. Future work in SI technology is also described.

Oeftering, Richard C.↗

F-Tank Farm Performance Assessment Updates through the Special Analysis Process at Savannah River Site - 12169

The F-Area Tank Farm (FTF) is owned by the U.S. Department of Energy and operated by Savannah River Remediation, LLC (SRR), Liquid Waste Operations contractor at DOE's Savannah River Site (SRS). The FTF is in the north-central portion of the SRS and occupies approximately 22 acres within F-Area. The FTF is an active radioactive waste storage facility consisting of 22 carbon steel waste tanks and ancillary equipment such as transfer lines, evaporators and pump tanks. An FTF Performance Assessment (PA) was prepared to support the eventual closure of the FTF underground radioactive waste tanks and ancillary equipment. The PA provides the technical basis and results to be used in subsequent documents to demonstrate compliance with the pertinent requirements identified below for final closure of FTF. The FTank Farm is subject to a state industrial waste water permit and Federal Facility Agreement. Closure documentation will include an F-Tank Farm Closure Plan and tank-specific closure modules utilizing information from the performance assessment. For this reason, the State of South Carolina and the Environmental Protection Agency must be involved in the performance assessment review process. The residual material remaining after tank cleaning is also subject to reclassification prior to closure via a waste determination pursuant to Section 3116 of the Ronald W. Reagan National Defense Authorization Act of Fiscal Year 2005. The projected waste tank inventories in the FTF PA provide reasonably bounding FTF inventory projections while taking into account uncertainties in the effectiveness of future tank cleaning technologies. As waste is removed from the FTF waste tanks, the residual contaminants will be sampled and the remaining residual inventory is characterized. In this manner, tank specific data for the tank inventories at closure will be available to supplement the waste tank inventory projections currently used in the FTF PA. For FTF, the new tank specific data will be evaluated through the Special Analysis process. The FTF Special Analyses process will be utilized to evaluate information regarding the final residual waste that will be grouted in place in the FTF Tanks and assess the potential impact the new inventory information has on the FTF PA assumptions and results. The Special Analysis can then be used to inform decisions regarding FTF tank closure documents. The purpose of this paper is to discuss the Special Analysis process and share insights gained while implementing this process. An example of an area of interest in the revision process is balancing continuous improvement versus configuration control of agreed upon methodologies. Other subjects to be covered include: 1) defining the scope of the revisions included in the Special Analysis, 2) determining which PA results should be addressed in the Special Analysis, and 3) deciding whether the Special Analysis should utilize more qualitative or quantitative assessments. For the SRS FTF, an FTF PA has been prepared to provide the technical basis and results to be used in subsequent documents to demonstrate compliance with the pertinent requirements for final closure of FTF. The FTF Special Analyses process will be utilized to evaluate the impact new information has on the FTF PA assumptions and results. The Special Analysis can then be used to inform decisions regarding FTF tank closure documents. In preparing SAs, it is crucial that the scope of the SA be well defined within the SA, since the specific scope will vary from SA to SA. Since the SAs are essentially addendums to the PA, the SA scope should utilize the PA as the baseline from which the SA scope is defined. The SA needs to focus on evaluating the change associated with the scope, and not let other changes interfere with the ability to perform that evaluation by masking the impact of the change. In preparing the SA, it is also important to let the scope determine whether the Special Analysis should utilize more qualitative or quantitative assessments and also which results from the PA should be addressed in the Special Analysis. These decisions can vary from SA and should not be predetermined. (author)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Reducing Airborne Debris In Wind Tunnels

In proposed technique to trap airborne particles during normal wind-tunnel testing, large sections of single-backed adhesive paper or cloth mounted with adhesive side exposed to flow. Adhesive material securely installed on flow vanes, walls, or other surfaces of wind tunnel in manner facilitating replacement. Installed or replaced anytime permissible to enter tunnel. Provides safe, inexpensive, rugged, passive, continuous, and otherwise inert cleansing action suitable for wind tunnel of any size. Also applied to specialized clean-room environments and to air-conditioning systems in general.

Sleeper, Robert K.↗

A special method for finding body distortions that reduce the wave drag of wing and body combinations at supersonic speeds

For a given wing and supersonic Mach number, the problem of shaping an adjoining fuselage so that the combination will have a low wave drag is considered. Only fuselages that can be simulated by singularities (multipoles) distributed along the body axis are studied. However, the optimum variations of such singularities are completely specified in terms of the given wing geometry. An application is made to an elliptic wing having a biconvex section, a thickness-chord ratio equal to 0.05 at the root, and an aspect ratio equal to 3. A comparison of the theoretical results with a wind-tunnel experiment is also presented.

Lomax, Harvard↗

Aerospace Safety Advisory Panel

The Aerospace Safety Advisory Panel (ASAP) provided oversight on the safety aspects of many NASA programs. In addition, ASAP undertook three special studies. At the request of the Administrator, the panel assessed the requirements for an assured crew return vehicle (ACRV) for the space station and reviewed the organization of the safety and mission quality function within NASA. At the behest of Congress, the panel formed an independent, ad hoc working group to examine the safety and reliability of the space shuttle main engine. Section 2 presents findings and recommendations. Section 3 consists of information in support of these findings and recommendations. Appendices A, B, C, and D, respectively, cover the panel membership, the NASA response to the findings and recommendations in the March 1992 report, a chronology of the panel's activities during the reporting period, and the entire ACRV study report.

Source record↗

INFORMS Section on Location Analysis Dissertation Award Submission

This research effort can be summarized by two main thrusts, each of which has a chapter of the dissertation dedicated to it. First, I pose a novel polyhedral approach for identifying polynomially solvable in- stances of the QAP based on an application of the reformulation-linearization technique (RLT), a general procedure for constructing mixed 0-1 linear reformulations of 0-1 pro- grams. The feasible region to the continuous relaxation of the level-1 RLT form is a polytope having a highly specialized structure. Every binary solution to the QAP is associated with an extreme point of this polytope, and the objective function value is preserved at each such point. However, there exist extreme points that do not correspond to binary solutions. The key insight is a previously unnoticed and unexpected relationship between the polyhedral structure of the continuous relaxation of the level-1 RLT representation and various classes of readily solvable instances. Specifically, we show that a variety of apparently unrelated solvable cases of the QAP can all be categorized in the following sense: each such case has an objective function which ensures that an optimal solution to the continuous relaxation of the level-1 RLT form occurs at a binary extreme point. Interestingly, there exist instances that are solvable by the level-1 RLT form which do not satisfy the conditions of these cases, so that the level-1 form theoretically identifies a richer family of solvable instances. Second, I focus on instances of the QAP known in the literature as linearizable. An instance of the QAP is defined to be linearizable if and only if the problem can be equivalently written as a linear assignment problem that preserves the objective function value at all feasible solutions. I provide an entirely new polyheral-based perspective on the concept of linearizable by showing that an instance of the QAP is linearizable if and only if a relaxed version of the continuous relaxation of the level-1 RLT form is bounded. We also shows that the level-1 RLT form can identify a richer family of solvable instances than those deemed linearizable by demonstrating that the continuous relaxation of the level-1 RLT form can have an optimal binary solution for instances that are not linearizable. As a byproduct, I use this theoretical framework to explicity, in closed form, characterize the dimensions of the level-1 RLT form and various other problem relaxations.

97 MATHEMATICS AND COMPUTING↗

Special Analysis for the Disposal of U.S. Department of Energy High Activity Cesium Sources Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

This special analysis evaluates whether the Lawrence Livermore National Laboratory (LLNL) U.S. Department of Energy (DOE) High Activity Cesium (Cs) Sources waste stream is suitable for shallow land burial at the Area 5 Radioactive Waste Management Site on the Nevada National Security Site. Disposal of the LLNL DOE High Activity Cs Sources waste meets all DOE M 435.1-1, “Radioactive Waste Management Manual,” Chapter IV, Section P performance objectives (DOE 1999). The LLNL DOE High Activity Cs Sources waste stream is recommended for acceptance with the conditions that 1) the total waste stream cesium-137 activity be limited to 1.7E16 Bq and 2) the waste be disposed 4.4 m (10 ft) below existing grade.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗