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Brightness limitations in multi-kiloampere electron beam sources

Description: Heuristic relationships such as the Lawson-Penner criterion, used to scale Free Electron Laser (FEL) amplifier gain and efficiency over orders of magnitude in beam current and brightness, have no fundamental basis. The brightness of a given source is set by practical design choices such as peak voltage, cathode type, gun electrode geometry, and focusing field topology. The design of low emittance, high current electron guns has received considerable attention at Livermore over the past few years. The measured brightnesses of the Experimental Test Accelerator (ETA) and Advanced Test Accelerator (ATA) guns are less than predicted with the EBQ gun design code; this discrepancy is due to plasma effects from the present cold, plasma cathode in the code. The EBQ code is well suited to exploring the current limits of gridless relativistic Pierce columns with moderate current density (<50 A/cm/sup 2/) at the cathode. As EBQ uses a steady-state calculation it is not amenable for study of transient phenomena at the beam head. For this purpose, a Darwin approximation code, DPC, has been written. The main component in our experimental cathode development effort is a readily modified electron gun that will allow us to test many candidate cathode materials, types and electrode geometries at field stresses up to 1 MV/cm. 6 references, 6 figures.
Date: August 24, 1984
Creator: Barletta, W.A.; Boyd, J.K.; Paul, A.C. & Prono, D.S.
Partner: UNT Libraries Government Documents Department

FLOW ANALYSIS OF DIFFUSER-GETTER-DIFFUSER SYSTEMS

Description: Tritium clean-up systems typically deploy gas processing technologies between stages of palladium-silver (Pd/Ag) diffusers/permeators. The number of diffusers positioned before and after a gas clean-up process to obtain optimal system performance will vary with feed gas inert composition. A simple method to analyze optimal diffuser configuration is presented. The method assumes equilibrium across the Pd/Ag tubes and system flows are limited by diffuser vacuum pump speeds preceding or following the clean-up process. A plot of system feed as a function of inert feed gas composition for various diffuser configuration allows selection of a diffuser configuration for maximum throughput based on feed gas composition.
Date: July 24, 2007
Creator: Klein, J & Dave W. Howard, D
Partner: UNT Libraries Government Documents Department

An assessment of potential health impacts on Utrok Atoll from exposure to cesium-137 (137Cs) and plutonium

Description: Residual fallout contamination from the nuclear test program in the Marshall Islands is a concern to Marshall Islanders because of the potential health risks associated with exposure to residual fallout contamination in the environment. Scientists from Lawrence Livermore National Laboratory (LLNL) have been monitoring the amount of fallout radiation delivered to Utrok Atoll residents over the past 4 years. This briefing document gives an outline of our findings from the whole body counting and plutonium bioassay monitoring programs. Additional information can be found on the Marshall Islands web site (http://eed.lnl.gov/mi/). Cesium-137 is an important radioactive isotope produced in nuclear detonations and can be taken up from coral soils into locally grown food crop products that form an important part of the Marshallese diet. The Marshall Islands whole body counting program has clearly demonstrated that the majority of Utrok Atoll residents acquire a very small but measurable quantity of cesium-137 in their bodies (Hamilton et al., 2006; Hamilton et. al., 2007a; 2007b;). During 2006, a typical resident of Utrok Atoll received about 3 mrem of radiation from internally deposited cesium-137 (Hamilton et al., 2007a). The population-average dose contribution from cesium-137 is around 2% of the total radiation dose that people normally experience from naturally occurring radiation sources in the Marshall Islands and is thousands of times lower than the level where radiation exposure is known to produce measurable health effects. The existing dose estimates from the whole body counting and plutonium bioassay programs are also well below radiological protection standards for protection of the public as prescribed by U.S. regulators and international agencies including the Marshall Islands Nuclear Claim Tribunal (NCT). Similarly, the level of internally deposited plutonium found in Utrok Atoll residents is well within the range normally expected for people living in the Northern Hemisphere. In addition, the preliminary ...
Date: July 24, 2007
Creator: Hamilton, T
Partner: UNT Libraries Government Documents Department

SUBURFACE SHIELDING-SPECIFIC SOURCE TERM EVALUATION

Description: The purpose of this work is to provide supporting calculations for determination of the radiation source terms specific to subsurface shielding design and analysis. These calculations are not intended to provide the absolute values of the source terms, which are under the charter of the Waste Package Operations (WPO) Group. Rather, the calculations focus on evaluation of the various combinations of fuel enrichment, burnup and cooling time for a given decay heat output, consistent with the waste package (WP) thermal design basis. The objective is to determine the worst-case combination of the fuel characteristics (enrichment, burnup and cooling time) which would give the maximum radiation fields for subsurface shielding considerations. The calculations are limited to PWR fuel only, since the WP design is currently evolving with thinner walls and a reduced heat load as compared to the viability assessment (VA) reference design. The results for PWR fuel will provide a comparable indication of the trend for BWR fuel, as their characteristics are similar. The source term development for defense high-level waste and other spent nuclear fuel (SNF) is the responsibility of the WPO Group, and therefore, is not included this work. This work includes the following items responsive to the stated purpose and objective: (1) Determine the possible fuel parameters (initial enrichment, burnup and cooling time), that give the same decay heat value as specified for the waste package thermal design; (2) Obtain the neutron and gamma source terms for the various combinations of the fuel parameters for use in radiation field calculations; and (3) Calculate radiation fields on the surfaces of the waste package and its transporter to quantify the effects of the fuel parameters with the same decay heat value for use in identifying the worst-case combination of the fuel parameters.
Date: August 24, 1999
Creator: Su, S.
Partner: UNT Libraries Government Documents Department

Nitrate Biogeochemistry and Reactive Transport in California Groundwater: LDRD Final Report

Description: Nitrate is the number one drinking water contaminant in the United States. It is pervasive in surface and groundwater systems,and its principal anthropogenic sources have increased dramatically in the last 50 years. In California alone, one third of the public drinking-water wells has been lost since 1988 and nitrate contamination is the most common reason for abandonment. Effective nitrate management in groundwater is complicated by uncertainties related to multiple point and non-point sources, hydrogeologic complexity, geochemical reactivity, and quantification of denitrification processes. In this paper, we review an integrated experimental and simulation-based framework being developed to study the fate of nitrate in a 25 km-long groundwater subbasin south of San Jose, California, a historically agricultural area now undergoing rapid urbanization with increasing demands for groundwater. The modeling approach is driven by a need to integrate new and archival data that support the hypothesis that nitrate fate and transport at the basin scale is intricately related to hydrostratigraphic complexity, variability of flow paths and groundwater residence times, microbial activity, and multiple geochemical reaction mechanisms. This study synthesizes these disparate and multi-scale data into a three-dimensional and highly resolved reactive transport modeling framework.
Date: February 24, 2006
Creator: Esser, B K; Beller, H; Carle, S; Cey, B; Hudson, G B; Leif, R et al.
Partner: UNT Libraries Government Documents Department

STAR: The Secure Tranportable Autonomous Reactor system, Encapsulated Fission Heat Source. Progress report for period terminating March 31, 2000

Description: Significant progress has been made since the beginning of this project, in September 1999. Part of the project findings are described in References 1 and 2. So far we have found no ''show-stopper''. In fact, based on the findings accumulated so far it appears to us that the Encapsulated Nuclear Heat Source (ENHS) is technologically feasible and looks even more attractive than initially conceived.
Date: April 24, 2000
Creator: Greenspan, Ehud
Partner: UNT Libraries Government Documents Department

DEGRADATION OF MAGNET EPOXY AT NSLS X-RAY RING.

Description: Epoxy resin degradation was analyzed for NSLS X-ring magnets after two decades of 2.58-2.8 GeV continuous electron-beam operation, based on results obtained from thermoluminescent dosimeters irradiated along the NSLS ring and epoxy samples irradiated at the beamline target location. A Monte Carlo-based particle transport code, MCNP, was utilized to verify the dose from synchrotron radiation distributed along the axial- and transverse-direction in a ring model, which simulates the geometry of a ring quadrupole magnet and its central vacuum chamber downstream of the bending-magnet photon ports. The actual life expectancy of thoroughly vacuum baked-and-cured epoxy resin was estimated from radiation tests on similar polymeric materials using a radiation source developed for electrical insulation and mechanical structure studies.
Date: May 24, 2004
Creator: HU,J. P.; ZHONG,Z.; HAAS,E.; HULBERT,S. & HUBBARD,R.
Partner: UNT Libraries Government Documents Department

Carbon-14 extraction from reactor gas, Progress report. Production test authorization {number_sign}124

Description: Carbon-14 is by far the most popular of the labeled isotopes because of its adaptability to so many chemical compounds and its relatively harmless characteristic beta radiation. Because the inert gas atmosphere contains up to 30% nitrogen, carbon-14 is generated within the K Reactors by the conversion of nitrogen-14, and if not immediately oxidized, carbon-14 may remain in the reactor core for some time. It is eventually oxidized and escapes when the outward gas leakage from the reactor is vented to the stack. Production Test 124 was authorized to determine if carbon-14 could be extracted from the K gas as a profitable by-product. It was concluded that as much as 500--600 curies per year of carbon-14 could be recovered if both K Reactors were provided with relatively simple extraction facilities. This is about twice the amount of this product for which there is a current market at the present price level of approximately $3,000/curie. The grade (as specific activity) of the product recovered in the production test was low -- ranging from 3 to 26 millicuries per mol. Substantial upgrading (perhaps by a factor of 10X to 100X) is possible by skimming techniques and reduced oxidation of normal carbon at Hanford, but economic parameters of upgrading vs total production rates will require additional market volume and price data. Two further methods of upgrading the product after it leaves Hanford are discussed briefly.
Date: January 24, 1969
Creator: Cooke, J. P.
Partner: UNT Libraries Government Documents Department

Mercury control in the RTF

Description: Engineering controls, described in this report, limit the amount of mercury and moisture introduced to the RTF (233-H). These controls include liquid nitrogen chilled gold traps for mercury and zeolite beds for moisture which are installed in-line. All gas transfers between 232-H or 236-H to 233-H will pass through these traps. Barring unforeseen catastrophic failure of the traps, no detectable amounts of mercury will be introduced via this route. However, a small amount of mercury (near detection limits) will be introduced via the reservoir recycle stream. This amount is conservatively calculated to be 7 milligrams per year and will have negligible impact on hydride bed performance. In no case will the design agency limits for mercury (0.3 {mu}g/liter) be approached, because the reservoir recycle gas is much lower than those limits already, and the hydride beds will amalgamate with any free mercury.
Date: March 24, 1993
Creator: Malstrom, R. A.
Partner: UNT Libraries Government Documents Department

GPHS-RTGs in support of the Cassini Mission. Semiannual technical progress report, 27 September 1993--27 March 1994

Description: This report is organized by the program task structure as follows: (1) spacecraft integration and liaison; (2) engineering support; (3) safety; (4) qualified unicouple fabrication; (5) ETG fabrication, assembly, and test; (6) ground support equipment (GSE); (7) RTG shipping and launch support; (8) designs, reviews, and mission applications; (9) project management, quality assurance and reliability, contract changes, non-capital CAGO acquisition, and CAGO maintenance; and (H) contractor acquired government owned property (CAGO) acquisition.
Date: April 24, 1994
Partner: UNT Libraries Government Documents Department

X-Ray Optics Research for the Linac Coherent Light Source: Interaction of Ultra-Short X-Ray Laser Pulses with Optical Materials

Description: Free electron lasers operating in the 0.1 to 1.5 nm wavelength have been proposed for the Stanford Linear Accelerator Center and DESY (Germany). The unprecedented brightness and associated fluence predicted for pulses &lt;300 fs pose new challenges for optical components. A criterion for optical component design is required, implying an understanding of x-ray-matter interactions at these extreme conditions. In our experimental effort, the extreme conditions are simulated by currently available sources ranging from optical lasers, through x-ray lasers (at 14.7 nm) down to K-alpha sources ({approx}0.15 nm). In this paper we present an overview of our research program, including (a) Results from the experimental campaign at a short pulse (100 fs-5 ps) power laser at 800 nm, (b) K-a experiments, and (c) Computer modeling and experimental project using a tabletop high brightness ps x-ray laser at the Lawrence Livermore National Laboratory.
Date: July 24, 2002
Creator: Kuba, J; Wootton, A; Bionta, R M; Shepherd, R; Dunn, J; Smith, R F et al.
Partner: UNT Libraries Government Documents Department

Thulium oxide fuel characterization study: Thulium-170 fueled capsule parametric design

Description: An analytical parametric study was made of an infinitely long, cylindrical fuel capsule containing thulia (Tm/sub 2//sup 170/O/sub 3/) encapsulated in two different physical forms and in two different liner configurations. Diameters of wafers maintained at 0.060 inch thickness were varied between 0.6 and 3.0 inches. Radial temperature profiles were determined for thulia power densities ranging from 8 to 24 W/cc and fuel capsule surface temperatures ranging from 1000 to 2732/sup 0/F. Hastelloy-X, Haynes-25, T-222, tungsten, platinum and molybdenum are the liner materials investigated. Methods of calculation, (including computer codes), assumptions used, error analyses and results are presented and discussed.
Date: June 24, 1970
Creator: DesChamps, N.H.; Fink, C.R. & Nelson, C.A.
Partner: UNT Libraries Government Documents Department

The Ghanaian Approach to the Development of an Effective Waste Management Regime

Description: In Ghana, radioactive waste is generated mainly from spent sealed sources, various nuclear applications--diagnostic and therapeutic procedures in medicine and measurement and processing techniques in industry. The radionuclide composition in the waste arising from industry, research and teaching includes 14C, 137Cs, 60Co, 241Am, 3H, 32P, 125I, 192Ir, 131I, 99m Tc, 35S and 90Sr. Ghana is strengthening its radioactive waste management infrastructure, which include the development of a legal framework by providing laws, regulations and guidelines and allocating responsibilities of waste generators, the National Radioactive Waste Management Centre (NRWMC), and the Radiation Protection Board (RPB). The radioactive waste management regulations which is in it's final stage of promulgation set up the basic technical and organizational requirements to be complied with by waste generators and operators of waste management facilities and make provisions for penalties for non-compliance with the regulations. With the installation of a 30 kW Research Reactor for neutron activation analysis, 185 TBq 60Co facility for the treatment of cancer at the Korle-bu teaching hospital, 1850 TBq 60Co facility for irradiation of medical and agricultural products and 192Ir sources for industrial radiography, radioactive waste is expected to increase in the near future. At present, waste management is limited exclusively to decay, storage and permissible discharge for liquid waste. Radiation sources and radioactive waste inventory have also been established using the Regulatory Authority Information System (RAIS) and the Sealed Radiation Sources Registry System (SRS). Considering the gradual increase in the generation of radioactive waste, there the need to strengthen the infrastructure for the management of radioactive waste in Ghana. A new working group made up of scientists and technicians with experience in working with ionizing radiation has been formed. This paper will outline the measures being put in place by the NRWMC and the new working group in establishing the appropriate ...
Date: February 24, 2003
Creator: Adu, P. S.; Gbadago, J. K. & Glover, E. T.
Partner: UNT Libraries Government Documents Department

Toward Control of Matter: Basic Energy Science Needs for a New Class of X-Ray Light Sources

Description: Over the past quarter century, light-source user facilities have transformed research in areas ranging from gas-phase chemical dynamics to materials characterization. The ever-improving capabilities of these facilities have revolutionized our ability to study the electronic structure and dynamics of atoms, molecules, and even the most complex new materials, to understand catalytic reactions, to visualize magnetic domains, and to solve protein structures. Yet these outstanding facilities still have limitations well understood by their thousands of users. Accordingly, over the past several years, many proposals and conceptual designs for&quot;next-generation&quot; x-ray light sources have been developed around the world. In order to survey the scientific problems that might be addressed specifically by those new light sources operating below a photon energy of about 3 keV and to identify the scientific requirements that should drive the design of such facilities, a workshop&quot;Science for a New Class of Soft X-Ray Light Sources&quot; was held in Berkeley in October 2007. From an analysisof the most compelling scientific questions that could be identified and the experimental requirements for answering them, we set out to define, without regard to the specific technologies upon which they might be based, the capabilities such light sources would have to deliver in order to dramatically advance the state of research in the areas represented in the programs of the Department of Energy's Office of Basic Energy Sciences (BES). This report is based on the workshop presentations and discussions.
Date: September 24, 2008
Creator: Arenholz, Elke; Belkacem, Ali; Cocke, Lew; Corlett, John; Falcone, Roger; Fischer, Peter et al.
Partner: UNT Libraries Government Documents Department

Resonances in near-threshold x-ray photoabsorption of inner shells

Description: Synchrotron radiation measurements of near-threshold and broad-range (20 eV - 3 keV) absolute photoabsorption cross sections were made at the Brookhaven National Laboratory (NSLS) and at Stanford (SSRL). Transmission data for well-characterized multilayer foils provided absolute cross sections with 10% overall uncertainties and better than 0.2% energy resolution. Several examples of our results are presented.
Date: August 24, 1987
Creator: Del Grande, N.K.; Tirsell, K.G.; Schneider, M.B.; Garrett, R.F.; Kneedler, E.M. & Manson, S.T.
Partner: UNT Libraries Government Documents Department

GPHS-RTGs in support of the Cassini mission. Semi-annual technical report, 29 March 1993--26 September 1993

Description: The following tasks were reported on: Spacecraft integration and liaison, engineering support, safety, qualified unicouple fabrication, ETG fabrication/assembly/test, ground support equipment, RTG shipping and launch support, designs/reviews/mission applications, project management/quality assurance/contract changes.
Date: October 24, 1993
Partner: UNT Libraries Government Documents Department

Development of ultrafiltration and inorganic adsorbents: January--March 1977. [Beta and. gamma. rays]

Description: Ultrafiltration media with and without the assistance of bone char filters were evaluated to determine their effectiveness in removing radionuclides from contaminated solutions. Precipitants, resin, adsorbents, and inorganic adsorbents were studied to determine their effectiveness in decontaminating solutions. A study of the effects of radiation on ultrafiltration media was initiated. An ultrafiltration media pilot plant was ordered and is being installed.
Date: June 24, 1977
Creator: Koenst, J. W. Jr.
Partner: UNT Libraries Government Documents Department

GPHS (General Purpose Heat Source) uranium oxide encapsulations supporting satellite safety tests

Description: General Purpose Heat Source (GPHS) simulant-fueled capsules were assembled, welded, nondestructively examined, and shipped to Los Alamos National Laboratory (LANL) for satellite safety tests. Simulant-fueled iridium capsules contain depleted uranium oxide pellets that serve as a stand-in for plutonium-238 oxide pellets. Information on forty seven capsules prepared during 1987 and 1988 is recorded in this memorandum along with a description of the processes used for encapsulation and evaluation. LANL expects to use all capsules for destructive safety tests, which are under way. Test results so far have demonstrated excellent integrity of the Savannah River capsule welds. 10 refs., 5 figs., 3 tabs.
Date: April 24, 1989
Creator: Kanne, W. R.
Partner: UNT Libraries Government Documents Department