1,720,983 research outputs found
The 1995 review and extension of the Nuclear Non-Proliferation Treaty
No full textnot peer reviewedMade available in DSpace on 2006-07-21T20:33:07Z (GMT). No. of bitstreams: 1
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Previous issue date: 1996unpublished"Includes bibliographical references. ""December 1996.""
The new nuclear arms control environment: Trip report and project conclusions
No full text"Includes bibliographical references. ""July 2002"""This paper reports the results of 9 conference, workshops and private meetings held on the current diplomatic and security problems associated with nuclear arms control, both before and after September 11. Appendixes include participants and questions.not peer reviewedMade available in DSpace on 2006-07-21T20:33:14Z (GMT). No. of bitstreams: 1
Singer_MacA_TripOPjul02.pdf: 316285 bytes, checksum: ca9626d80d965eb22ce1c33b49748f6e (MD5)
Previous issue date: 2002unpublishe
Systematic calibration of a theory-based transport model of tokamak plasmas
No full textA time-dependent theoretical model of flux-surface-averaged radial transport in tokamaks has been constructed and calibrated against a well documented set of temperature and density profiles from a pre-defined set of twelve discharges from seven different tokamaks. The transport theory includes neoclassical, \rm drift/\eta\sb{i}, circulating electron mode, kinetic ballooning, neoclassical magnetohydrodynamic (MHD), and resistive ballooning effects. An important feature of this study is a reproducible simulation methodology and a systematic statistical prescription for comparing theory against experiment. Optimization of the model is conducted using a simple maximum likelihood method to minimize quantitative differences between theoretical predictions and the experimental data. Simulations of a series of similar experiments where only certain dimensionless parameters were allowed to vary are also included. Here, a newly implemented and more complete drift wave theory from Sweden is tested and compared against results obtained from the theory previously used in the calibration study.Made available in DSpace on 2011-05-07T13:37:12Z (GMT). No. of bitstreams: 2
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9543629.pdf: 7932366 bytes, checksum: 85cdc51fd6e3010f2a32a73060c0c250 (MD5)
Previous issue date: 1995Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:57:03Z
Item is restricted indefinitely.Restriction data tranferred 2014-07-01T11:26:43-05:00
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Reason: ETDs are only available to UIUC Users without author permissionETDs are only available to UIUC Users without author permissionU of I Onl
Theoretical transport model for tokamaks
No full textIn the present thesis work a theoretical transport model is suggested to study the anomalous transport of plasma particles and energy across the axisymmetric equilibrium toroidal magnetic flux surfaces in tokamaks. The model suggests a linear combination of two transport mechanisms; drift waves, which dominate the transport in the core region, and resistive ballooning modes, which dominate the transport in the edge region. The resulting unified model has been used in a predictive transport code to simulate the plasma transport in different tokamak experiments operating in both the ohmic heating phase and the low confinement mode (L-mode).For ohmic plasma, the model was used to study the saturation of energy confinement time at high plasma density. The effect of the resistive ballooning mode as a possible cause of the saturation phenomena has been investigated together with the effect of the ion temperature gradient mode.For the low confinement mode plasmas, the study has emphasized on using the model to obtain a scaling law for the energy confinement time with the various plasma parameters compared to the scaling laws that are derived based on fitting the experimental data.Made available in DSpace on 2011-05-07T12:41:40Z (GMT). No. of bitstreams: 2
license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5)
9210813.pdf: 4211407 bytes, checksum: 5fdb0450d073ebd67321f8e35fea2708 (MD5)
Previous issue date: 1991Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:44:27Z
Item is restricted indefinitely.Restriction data tranferred 2014-07-01T11:19:34-05:00
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Spaceborne centrifugal relays for spacecraft propulsion
No full textAcceleration using centrifugal relays is a recently discovered method for the acceleration of spaceborne payloads to high velocity at high thrust. Centrifugal relays are moving rotors which progressively accelerate reaction mass to higher velocities. One important engineering problem consists of accurately tracking the position of the projectiles and rotors and guiding each projectile exactly onto the appropriate guide tracks on each rotor. The topics of this research are the system kinematics and dynamics and the computerized guidance system which will allow the projectile to approach each rotor with exact timing with respect to the rotor rotation period and with very small errors in lateral positions. Kinematics studies include analysis of rotor and projectile positions versus time and projectile/rotor interactions. Guidance studies include a detailed description of the tracking mechanism (interrupt of optical beams) and the aiming mechanism (electromagnetic focusing) including the design of electromagnetic deflection coils and the switching circuitry.Made available in DSpace on 2011-05-07T11:53:30Z (GMT). No. of bitstreams: 2
license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5)
9411740.pdf: 4605920 bytes, checksum: ea345ee8f5b77afcd5f664a6a8b96283 (MD5)
Previous issue date: 1993Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:33:53Z
Item is restricted indefinitely.Restriction data tranferred 2014-07-01T11:12:43-05:00
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Preliminary design and analysis for selected problems in deep borehole disposal of spent nuclear fuel
Get PDFMultiple reports by the Used Fuel Disposition Campaign centered at Sandia National Laboratories, Dr. Michael Driscoll and collaborators at MIT, and Dr. Fergus Gibb and collaborators at the University of Sheffield have generated interest in deep boreholes as a nuclear waste disposal option for all or part of the U.S. high-level waste inventory. Many design elements of deep borehole disposal have not yet been solidified, and there has not yet been a systematic analysis of the logistics necessary to implement deep boreholes for the storage of commercial spent nuclear fuel. This thesis contains preliminary analysis on a variety of unanswered or incomplete elements of the deep borehole approach, including emplacement method, disposal region design, canister loading method, transportation and logistics scheduling and cost, and risk analysis for borehole-specific issues. Additionally, the thesis presents an analytical heat transport model which can be used to validate more detailed numerical solutions. The logistics analysis, performed using the TSL-CALVIN fuel cycle logistics simulator, demonstrates that a deep borehole repository can be cost-competitive with a more traditional mined repository approach, but that the differences between mined repositories and a deep borehole repository are large enough that other system-level cost estimates performed for the Yucca Mountain repository might not transfer to a deep borehole repository.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2016-07-07 without embargo termsThe student, Robert Geringer, accepted the attached license on 2016-04-27 at 13:03.The student, Robert Geringer, submitted this Thesis for approval on 2016-04-27 at 13:06.This Thesis was approved for publication on 2016-04-28 at 13:36.DSpace SAF Submission Ingestion Package generated from Vireo submission #9549 on 2016-07-07 at 13:33:43Made available in DSpace on 2016-07-07T19:58:18Z (GMT). No. of bitstreams: 2
GERINGER-THESIS-2016.pdf: 1305988 bytes, checksum: 332764d3c06f322f12bebefa8b08ae42 (MD5)
LICENSE.txt: 4212 bytes, checksum: 227d4a3e8dd4ee2b8c28263b6147e58f (MD5)
Previous issue date: 2016-04-2
Thermal helium buildup and control in a fusing tokamak
No full text"The effect of thermal helium ""ash"" accumulation on the ignition burn parameter has been examined using a global model. The sensitivity of ash build-up to changes in transport coefficients was explored using a 1-1/2-D transport code for an ARIES-I type plasma. The effect of helium edge recycling was also examined using the code. In addition, the influence of controlled sawteeth on helium exhaust was explored. It is shown that ash accumulation potentially stops ignition of tokamaks, such as TIBER II/ETR-type, if ash concentration exceeds 10%. It is also shown that ash buildup is sensitive to the ratio of helium to fuel ion transport coefficient, and to the magnitude of the helium inward pinch velocity. Sawteeth are useful for removing the ash from the center of the plasma to the outer region. Outer region transport enhancement is found essential to help in removing the ash from there. It is found that the optimal sawtooth period to give minimum ash level (or maximum fusion power) is several times larger than the fast alpha slowing down time for the ARIES-I type driven plasma. With sawtooth period 5 seconds and helium transport selectively enhanced by an order of magnitude, the fusion power increases 30% compared to the case without sawteeth/without enhancement. It is shown that ash buildup effect can seriously degrade the plasma performance, and sawteeth combined with outer region transport enhancement have the potential to advantageously reduce the helium concentration."Made available in DSpace on 2011-05-07T14:07:49Z (GMT). No. of bitstreams: 2
license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5)
9215827.pdf: 5694817 bytes, checksum: ebdfb382c64afd82d6cc9c9d5b31b092 (MD5)
Previous issue date: 1992Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T15:03:16Z
Item is restricted indefinitely.Restriction data tranferred 2014-07-01T11:30:09-05:00
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Reason: ETDs are only available to UIUC Users without author permissionETDs are only available to UIUC Users without author permissionU of I Onl
Methods for Testing Transport Theories
No full textClassical transport based on simple particle collisions theory underestimates the rates of energy losses. The main sources of energy transport are instabilities due to fluctuations in magnetic fields, electric fields, and plasma density and/or temperature gradient. Although many theoretical models have been introduced to describe anomalous transport mechanisms, none of the proposed models, alone, provides a satisfying description of the experimental data. In recent years, there has been a great interest in the theoretical multiple mode tokamak transport model. In this study, we develop methods for testing models which contain a linear combination of several theoretical transport fluxes, namely, drift waves, resistive ballooning, and rippling modes added to a fixed level of neoclassical transport. The purpose of this work is to calibrate the proposed model against existing L-mode energy confinement time data.Made available in DSpace on 2014-12-17T22:36:15Z (GMT). No. of bitstreams: 1
9305508.pdf: 4893853 bytes, checksum: 1df086bd304c0efa8f1546b9cb582e36 (MD5)
Previous issue date: 1992Embargo set by: Seth Robbins for item 72615
Lift date: Forever
Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDsRestricted to the U of I community idenfinitely during batch ingest of legacy ETDsU of I Only190 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1992
Mathematical Modeling Plasma Transport in Tokamaks
No full text167 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998.In this work, we have applied a systematic calibration, validation and application procedure based on the methodology of mathematical modeling to international thermonuclear experimental reactor (ITER) ignition studies. The multi-mode plasma transport model used here includes a linear combination of drift wave branch and ballooning branch instabilities with two a priori uncertain constants to account for anomalous plasma transport in tokamaks. A Bayesian parameter estimation method is used including experimental calibration error/model offsets and error bar rescaling factors to determine the two uncertain constants in the transport model with quantitative confidence level estimates for the calibrated parameters, which gives two saturation levels of instabilities. This method is first tested using a gyroBohm multi-mode transport model with a pair of DIII-D discharge experimental data, and then applied to calibrating a nominal multi-mode transport model against a broad database using twelve discharges from seven different tokamaks. The calibrated transport model is then validated on five discharges from JT-60 with no adjustable constants. The results are in a good agreement with experimental data. Finally, the resulting class of multi-mode tokamak plasma transport models is applied to the transport analysis of the ignition probability in the next generation machine, ITER. The ignition probability of ITER for engineering design activity (EDA) parameters can be formally as high as 99.9% in the present context. The same probability for conceptual design activity (CDA) parameters of ITER, which has smaller size and lower current, is only 62.6%. This suggests that EDA parameters for ITER tokamak are very likely to achieve the self-sustained thermonuclear reaction, but CDA parameters are risky for the realization of ignition.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD
Energy Economic Modeling and Optimization
No full textIn this work, we have established a multisector utility optimization model to study energy futures. This model can be used to study energy evolution within a particular geographical region or in a number of such regions. To construct a general solution method, a one-sector economic model serves as a starting point. Population growth, labor force participation and labor productivity are assumed as exogenous inputs to a utility optimization calculation. A one-group dynamic population model is used to project population growth. With these preliminaries in hand, several computational tools are developed for the underlying model of overall economic growth. A completely numerical shooting method is developed. The computational results are extended with power series expansion methods. The effects of varying input parameters on simulation of Indian population and economic growth are examined. A maximum likelihood method is developed for calibrating parameters upon which the results depend most sensitively. In order to examine overall energy use, a two-sector model has been established to compute energy production coupled with the rest of economy. The numerical method developed for one-sector model has also been tested for the two-sector model. A multisector model suitable for examining the economic competitiveness of nuclear energy and fossil fuel is also defined to motivate this work and for possible use in future studies. This work also focuses on the development of accurate and efficient analytic and computational methods to provide a sound basis for solving multisector energy economics optimization.Made available in DSpace on 2015-09-28T14:51:32Z (GMT). No. of bitstreams: 2
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9955686.pdf: 9453817 bytes, checksum: 5d6d1d4d31c3f69689a4d15992575530 (MD5)
Previous issue date: 2000Embargo set by: Seth Robbins for item 87233
Lift date: Forever
Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDsRestricted to the U of I community idenfinitely during batch ingest of legacy ETDsU of I Only258 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2000
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