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Sandia National Laboratories participation in the National Ignition Facility project

Description: The National Ignition Facility is a $1.1B DOE Defense Programs Inertial Confinement Fusion facility supporting the Science Based Stockpile Stewardship Program. The goal of the facility is to achieve fusion ignition and modest gain in the laboratory. The NIF project is responsible for the design and construction of the 192 beam, 1.8 MJ laser necessary to meet that goal. - The project is a National project with participation by Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Sandia National Laboratory (SNL), the University of Rochester Laboratory for Laser Energetics (URLLE) and numerous industrial partners. The project is centered at LLNL which has extensive expertise in large solid state lasers. The other partners in the project have negotiated their participation based on the specific expertise they can bring to the project. In some cases, this negotiation resulted in the overall responsibility for a WBS element; in other cases, the participating laboratories have placed individuals in the project in areas that need their individual expertise. The main areas of Sandia`s participation are in the management of the conventional facility design and construction, the design of the power conditioning system, the target chamber system, target diagnostic instruments, data acquisition system and several smaller efforts in the areas of system integration and engineering analysis. Sandia is also contributing to the technology development necessary to support the project by developing the power conditioning system and several target diagnostics, exploring alternate target designs, and by conducting target experiments involving the ``foot`` region of the NIF power pulse. The project has just passed the mid-point of the Title I (preliminary) design phase. This paper will summarize Sandia`s role in supporting the National Ignition Facility and discuss the areas in which Sandia is contributing. 3 figs.
Date: August 1, 1996
Creator: Boyes, J.; Boyer, W.; Chael, J.; Cook, D.; Cook, W.; Downey, T. et al.
Partner: UNT Libraries Government Documents Department

Progress on the physics of ignition for radiation driven inertial confinement fusion (ICF) targets

Description: Extensive modeling of proposed National Ignition Facility (NIF) ignition targets has resulted in a variety of targets using different materials in the fuel shell, using driving temperatures which range from 250-300 eV, and requiring energies from < 1 MJ up to the full 1. 8 MJ design capability of NIF. Recent Nova experiments have shown that hohlraum walls composed of a mixture of high-z materials could result in targets which require about 20% less energy. Nova experiments are being used to quantify benefits of beam smoothing in reducing stimulated scattering processes and laser beam filamentation for proposed gas-filled hohlraum targets on NIF. Use of Smoothing by Spectral Dispersion with 2-3 {Angstrom}of bandwidth results in <4-5% of Stimulated Raman Scattering and less than about 1% Stimulated Brillouin Scattering for intensities less than about 2x10{sup 15}W/cm{sup 2} for this type of hohlraum. The symmetry in Nova gas- filled hohlraums is affected by the gas fill. A large body of evidence now exists which indicates that this effect is due to laser beam filamentation which can be largely controlled by beam smoothing. We present here the firs 3-D simulations of hydrodynamic instability for the NIF point design capsule. These simulations, with the HYDRA radiation hydrodynamics code, indicate that spikes can penetrate up to 10 {mu}m into the 30{mu}m radius hot spot before ignition is quenched. Using capsules whose surface is modified by laser ablation, Nova experiments have been used to quantify the degradation of implosions subject to near NIF levels of hydrodynamic instability.
Date: September 1, 1996
Creator: Lindl, J.D. & Marinak, M.M.
Partner: UNT Libraries Government Documents Department

SSD with generalized phase modulation

Description: Smoothing by spectral dispersion (SSD) with standard frequency modulation (FM), although simple to implement, has the disadvantage that low spatial frequencies present in the spectrum of the target illumination are not smoothed as effectively as with a more general smoothing method (eg, induced spatial incoherence method). The reduced smoothing performance of standard FM-SSD can result in spectral power of the speckle noise at these low spatial frequencies as much as one order of magnitude larger than that achieved with a more general method. In fact, at small integration times FM-SSD has no smoothing effect at all for a broad band of low spatial frequencies. This effect may have important implications for both direct and indirect drive ICF.
Date: January 9, 1996
Creator: Rothenberg, J.
Partner: UNT Libraries Government Documents Department

Chamber technology concepts for inertial fusion energy: Three recent examples

Description: The most serious challenges in the design of chambers for inertial fusion energy (IFE) are 1) protecting the first wall from fusion energy pulses on the order of several hundred megajoules released in the form of x rays, target debris, and high energy neutrons, and 2) operating the chamber at a pulse repetition rate of 5-10 Hz (i.e., re-establishing, the wall protection and chamber conditions needed for beam propagation to the target between pulses). In meeting these challenges, designers have capitalized on the ability to separate the fusion burn physics from the geometry and environment of the fusion chamber. Most recent conceptual designs use gases or flowing liquids inside the chamber. Thin liquid layers of molten salt or metal and low pressure, high-Z gases can protect the first wall from x rays and target debris, while thick liquid layers have the added benefit of protecting structures from fusion neutrons thereby significantly reducing the radiation damage and activation. The use of thick liquid walls is predicted to 1) reduce the cost of electricity by avoiding the cost and down time of changing damaged structures, and 2) reduce the cost of development by avoiding the cost of developing a new, low-activation material. Various schemes have been proposed to assure chamber clearing and renewal of the protective features at the required pulse rate. Representative chamber concepts are described, and key technical feasibility issues are identified for each class of chamber. Experimental activities (past, current, and proposed) to address these issues and technology research and development needs are discussed.
Date: February 27, 1997
Creator: Meier, W.R.; Moir, R.W. & Abdou, M.A.
Partner: UNT Libraries Government Documents Department

Current progress in NIF target concepts

Description: Target concepts for the National Ignition Facility (NIF) require progress in the art and science of target fabrication. Three distinct issues are addressed: beryllium fuel capsules, foam-buffered direct drive, and high-density gas-filled hohlraums. In all cases experiments on the existing Nova laser at LLNL are either in progress or planned for the near future to test the various concepts. Consequently, target fabrication must be able to deliver targets appropriate for each.
Date: October 1, 1996
Creator: Gobby, P.L.; Foreman, L.R.; Thoma, D.J.; Jacobson, L.A.; Hollis, R.V.; Barrera, J. et al.
Partner: UNT Libraries Government Documents Department

Complexity versus availability for fusion: The potential advantages of inertial fusion energy

Description: Probably the single largest advantage of the inertial route to fusion energy (IFE) is the perception that its power plant embodiments could achieve acceptable capacity factors. This is a result of its relative simplicity, the decoupling of the driver and reactor chamber, and the potential to employ thick liquid walls. We examine these issues in terms of the complexity, reliability, maintainability and, therefore, availability of both magnetic and inertial fusion power plants and compare these factors with corresponding scheduled and unscheduled outage data from present day fission experience. We stress that, given the simple nature of a fission core, the vast majority of unplanned outages in fission plants are due to failures outside the reactor vessel itself Given we must be prepared for similar outages in the analogous plant external to a fusion power core, this puts severe demands on the reliability required of the fusion core itself. We indicate that such requirements can probably be met for IFE plants. We recommend that this advantage be promoted by performing a quantitative reliability and availability study for a representative IFE power plant and suggest that databases are probably adequate for this task.
Date: September 5, 1996
Creator: Perkins, L.J.,
Partner: UNT Libraries Government Documents Department

Scoping the parameter space for demo and the engineering test facility (ETF)

Description: In our IFE development plan, we have set a goal of building an Engineering Test Facility (ETF) for a total cost of $2B and a Demo for $3B. In Mike Campbell� s presentation at Madison, we included a viewgraph with an example Demo that had 80 to � 250 MWe of net power and showed a plausible argument that it could cost less than $3B. In this memo, I examine the design space for the Demo and then briefly for the ETF. Instead of attempting to estimate the costs of the drivers, I pose the question in a way to define R&D goals: As a function of key design and performance parameters, how much can the driver cost if the total facility cost is limited to the specified goal? The design parameters examined for the Demo included target gain, driver energy, driver efficiency, and net power output. For the ETF; the design parameters are target gain, driver energy, and target yield. The resulting graphs of allowable driver cost determine the goals that the driver R&D programs must seek to meet.
Date: January 19, 1999
Creator: Meier, W. R.
Partner: UNT Libraries Government Documents Department

Design and Use of a Novel Apparatus for Measuring Capsule Fill Hole Conductance

Description: Description and results of a novel apparatus for determining the flow conductance through a laser drilled hole in a spherical shell for inertial confinement fusion experiments are described. The instrument monitors the pressure of an enclosed volume containing the laser pressure drilled capsule as air bleeds through the hole into the shell. From these measurements one obtains the conductance of the fill hole. This system has proven to be a valuable tool for verifying the conduct conductance into the capsule in a timely and nondestructive manner.
Date: November 27, 2006
Creator: Seugling, R M; Nederbragt, W W; Klingmann, J L; Edson, S; Reynolds, J & Cook, R
Partner: UNT Libraries Government Documents Department

Sequential charged-particle and neutron activation of Flibe in the HYLIFE-II inertial fusion energy power plant design

Description: Most radionuclide generation/depletion codes consider only neutron reactions and assume that charged particles, which may be generated in these reactions, deposit their energy locally without undergoing further nuclear interactions. Neglect of sequential charged-particle (x,n) reactions can lead to large underestimation in the inventories of radionuclides. PCROSS code was adopted for use with the ACAB activation code to enable calculation of the effects of (x,n) reactions upon radionuclide inventories and inventory-related indices. Activation calculations were made for Flibe (2LiF + BeF{sub 2}) coolant in the HYLIFE-II inertial fusion energy (IFE) power plant design. For pure Flibe coolant, it was found that (x,n) reactions dominate the residual contact dose rate at times of interest for maintenance and decommissioning. For impure Flibe, however, radionuclides produced directly in neutron reaction dominate the contact dose rate and (x,n) reactions do not make a significant contribution. Results demonstrate potential importance of (x,n) reactions and that the relative importance of (x,n) reactions varies strongly with the composition of the material considered. Future activation calculations should consider (x,n) reactions until a method for pre-determining their importance is established.
Date: June 14, 1996
Creator: Latkowski, J.F.; Tobin, M.T.; Vujic, J.L. & Sanz, J.
Partner: UNT Libraries Government Documents Department

Target area design issues for implementing direct drive on the National Ignition Facility

Description: NIF will be configured in its baseline design to achieve ignition and gain using the indirect drive approach. However, the requirements require the design to not preclude the conduct of inertial confinement fusion experiments using direct drive. This involves symmetrical illumination of an ICF capsule, where each beam fully subtends the capsule. The re-directing of 24 of the 48 NIF beamlines (2x2 beamlet group each) from 30 and 50{degree} cone angles to 75{degree} cone angles near the chamber `equator` is required. This would be done by adjusting intermediate transport mirrors so that the beams intercept different final mirrors in the Target Bay and be directed into final optics assemblies attached to chamber ports positioned at the new port locations. Space for converting from one irradiation scheme to another is a problem; also NIF user needs cannot be compromised by direct drive needs. Target for direct drive, absent a hohlraum, emits much fewer cold x rays than for indirect drive. Further, the irradiation scheme may not result in the absorption of all the 3{omega} light and this may create a hazard to the NIF chamber first wall. This paper describes possible design features of the NIF Target Area to allow conversion to direct drive and discusses some differences in post-shot conditions created compared to indirect drive.
Date: June 14, 1996
Creator: Tobin, M.; Karpenko, V.; Burnham, A. & Peterson, R.
Partner: UNT Libraries Government Documents Department

Lifetime survivability of contaminated target-chamber optics

Description: Target chambers used for Inertial Confinement Fusion (ICF) expose laser optics to a very hostile environment, not only from high-fluence laser irradiation but also x-ray irradiation and particulate debris from targets and chamber wall materials. Expendable debris shields provide the first line of defense to more costly optics upstream in the laser beam path to contaminants generated within the target chamber. However, the replacement of a large number of debris shields is also an expensive proposition so that extending their usable lifetime within the chamber is important. We have conducted tests to show that optics can both be cleaned and damaged by laser irradiation at 355 nm after being contaminated with potential chamber-wall materials such as B{sub 4}C and Al{sub 2}O{sub 3}. Such optics can survive from one to hundreds of laser shots, depending on degree of contamination and laser fluence levels. Similarly, we have studied the survivability of optics that have been exposed to direct contamination from representative target materials irradiated in the target chamber. We have also studied the effects on optics that were not directly exposed to targets, yet received secondary exposure from the above directly-exposed samples.
Date: November 1, 1996
Creator: Rainer, F.; Anderson, A.; Burnham, A.; Milam, D. & Turner, R.
Partner: UNT Libraries Government Documents Department

Neutronics issues and inertial fusion energy: a summary of findings

Description: We have analyzed and compared five major inertial fusion energy (IFE) and two representative magnetic fusion energy (MFE) power plant designs for their environment, safety, and health (ES&H) characteristics. Our work has focussed upon the neutronics of each of the designs and the resulting radiological hazard indices. The calculation of a consistent set of hazard indices allows comparisons to be made between the designs. Such comparisons enable identification of trends in fusion ES&H characteristics and may be used to increase the likelihood of fusion achieving its full potential with respect to ES&H characteristics. The present work summarizes our findings and conclusions. This work emphasizes the need for more research in low-activation materials and for the experimental measurement of radionuclide release fractions under accident conditions.
Date: May 29, 1998
Creator: Latkowski, J. F.
Partner: UNT Libraries Government Documents Department

Inertial Fusion Energy Development: What is Needed and What will be Learned at the National Ignition Facility

Description: Successful development of inertial fusion energy (IFE) requires that many technical issues be resolved. Separability of drivers, targets, chambers and other IFE power plant subsystems allows resolution of many of these issues in off-line facilities and programs. Periodically, major integrated facilities give a snapshot of the rate of progress toward the ultimate solutions. The National Ignition Facility (NIF) and Laser Megajoule (LMJ) are just such integrating facilities. This paper reviews the status of IFE development and projects what will be learned from the NIF and LMJ.
Date: October 21, 1999
Creator: Hogan, W.J.
Partner: UNT Libraries Government Documents Department

Developing inertial fusion energy - Where do we go from here?

Description: Development of inertial fusion energy (IFE) will require continued R&D in target physics, driver technology, target production and delivery systems, and chamber technologies. It will also require the integration of these technologies in tests and engineering demonstrations of increasing capability and complexity. Development needs in each of these areas are discussed. It is shown how IFE development will leverage off the DOE Defense Programs funded inertial confinement fusion (ICF) work.
Date: June 11, 1996
Creator: Meier, W.R. & Logan, G.
Partner: UNT Libraries Government Documents Department

The status of the ICF target physics program at Lawrence Livermore National Laboratory

Description: Calculations of x-ray driven igniting implosions require several critical parameters which have been separately tested on Nova, viz., acceptable levels of SBS and SRS from plasmas equivalent to the plasmas in igniting hohlraums, quantitative understanding of radiation temperature in gas-filled hohlraums, demonstration of control of drive symmetry in gas-filled hohlraums, low levels of seeding of hydrodynamic instabilities from surfaces, especially cryogenic deuterium tritium ice, and quantitative understanding of the mix of cold fuel into a hot spot in high growth factor implosions. 14 refs.
Date: June 14, 1996
Creator: Kilkenny, J.D.; Bernat, t.P. & Hammel, B.A.
Partner: UNT Libraries Government Documents Department

Inertial fusion energy development approaches for direct and indirect-drive

Description: Consideration of different driver and target requirements for inertial fusion energy (IFE) power plants together with the potential energy gains of direct and indirect-drive targets leads to different optimal combinations of driver and target options for each type of target. In addition, different fusion chamber concepts are likely to be most compatible with these different driver and target combinations. For example, heavy-ion drivers appear to be well matched to indirect=drive targets with all-liquid-protected-wall chambers requiring two-sided illuminations, while diode-pumped, solid- state laser drivers are better matched to direct-drive targets with chambers using solid walls or flow-guiding structures to allow spherically symmetric illuminations. R&D on the critical issues of drivers, targets, and chambers for both direct and indirect-drive options should be pursued until the ultimate gain of either type of target for IFE is better understood.
Date: August 20, 1996
Creator: Logan, B.G.; Lindl, J.D. & Meier, W.R.
Partner: UNT Libraries Government Documents Department

Inertial fusion energy: A clearer view of the environmental and safety perspectives

Description: If fusion energy is to achieve its full potential for safety and environmental (S&E) advantages, the S&E characteristics of fusion power plant designs must be quantified and understood, and the resulting insights must be embodied in the ongoing process of development of fusion energy. As part of this task, the present work compares S&E characteristics of five inertial and two magnetic fusion power plant designs. For each design, a set of radiological hazard indices has been calculated with a system of computer codes and data libraries assembled for this purpose. These indices quantify the radiological hazards associated with the operation of fusion power plants with respect to three classes of hazard: accidents, occupational exposure, and waste disposal. The three classes of hazard have been qualitatively integrated to rank the best and worst fusion power plant designs with respect to S&E characteristics. From these rankings, the specific designs, and other S&E trends, design features that result in S&E advantages have been identified. Additionally, key areas for future fusion research have been identified. Specific experiments needed include the investigation of elemental release rates (expanded to include many more materials) and the verification of sequential charged-particle reactions. Improvements to the calculational methodology are recommended to enable future comparative analyses to represent more accurately the radiological hazards presented by fusion power plants. Finally, future work must consider economic effects. Trade-offs among design features will be decided not by S&E characteristics alone, but also by cost-benefit analyses. 118 refs., 35 figs., 35 tabs.
Date: November 1, 1996
Creator: Latkowski, J.F.
Partner: UNT Libraries Government Documents Department

Inertial Confinement Fusion: Quarterly report, April-June 1996

Description: The lead article, `Ion-beam propagation in a low-density reactor chamber for heavy-ion inertial fusion` (p. 89), explores the ability of heavy-ion beams to be adequately transported and focused in an IFE reactor. The next article, `Efficient production and applications of 2- to 10-keV x rays by laser-heated underdense radiators` (p. 96), explores the ability of the NIF to produce sufficient high-energy x rays for diagnostic backlighting, target preheating, or uniform irradiation of large test objects for Nuclear Weapons Effects Testing. For capsule implosion experiments, the increasing energies and distances involved in the NIF compared to Nova require the development of new diagnostics methods. The article `Fusion reaction-rate measurements--Nova and NIF` (p. 115) first reviews the use of time-resolved neutron measurements on Nova to monitor fusion burn histories and then explores the limitations of that technique, principally Doppler broadening, for the proposed NIF. It also explores the use of gamma rays on Nova, thereby providing a proof-of-principle for using gamma rays for monitoring fusion burn histories on the NIF. The articles `The energetics of gas-filled hohlraums` (p. 110) and `Measurements of laser- speckle-induced perturbations in laser-driven foils` (p. 123) report measurements on Nova of two important aspects of implosion experiments. The first characterizes the amount of energy lost from a hohlraum by stimulated Brillouin and Raman scattering as a function of gas fill and laser-beam uniformity. The second of these articles shows that the growth of density nonuniformities implanted on smooth capsule surfaces by laser speckle can be correlated with the effects of physical surface roughness. The article `Laser-tissue interaction modeling with the LATIS computer program` (p. 103) explores the use of modeling to enhance the effectiveness--maximize desired effects and minimize collateral damage--of lasers for medical purposes.
Date: June 1, 1996
Creator: Correll, D.
Partner: UNT Libraries Government Documents Department

Spectroscopic diagnostics on high-density, strongly-coupled ICF plasmas. Semi-annual report, February 1, 1995--July 31, 1995

Description: In our research for the period of February 1, 1995 through July 31, 1995, we have upgraded our equipment in anticipation of the restart of the Omega-Upgrade laser at the University of Rochester Laboratory for Laser Energetics/National Laser User Facility (LLE/NLUF). During this period we also have carried out some exploratory experiments on aluminum targets related to both continuum and line emissions near series limits where lines blend into the continuum. This work was performed using the Trident glass laser at Los Alamos National Laboratory. The layout of this experiment showing the diagnostics deployed is presented in this report. We had almost 60 shots at full power [175 J at 2{omega} in 1 ns pulses focused to a 0.5-mm diameter spot for an irradiance per beam of 8{times}10{sup 13} W/cm{sup 2}]. The targets were mainly 1 mm {times} 1 mm square aluminum foils of thickness varying from 2.5 to 25 {mu}m. Most were coated with 1 {mu}m of CH on both sides as a tamper to increase the compressed plasma density prior to expansion. Also, most targets were illuminated from both sides.
Date: February 1, 1996
Creator: Griem, H.R.; Elton, R.C. & Welch, B.L.
Partner: UNT Libraries Government Documents Department

Spectroscopic diagnostics on high-density, strongly-coupled ice plasmas. Revision. Final report, February 1, 1995--November 30, 1995

Description: In our research for the period of February 1, 1995 through November 30, 1995, we have upgraded our equipment in anticipation of the restart of the Omega-Upgrade laser at the University of Rochester Laboratory for Laser Energetics/National Laser User Facility (LLE/NLUF). During the period of this grant we also have completed exploratory experiments on aluminum targets related to both continuum and line emissions near series limits where lines blend into the continuum. This work was performed using the Trident glass laser at Los Alamos National Laboratory.
Date: February 1, 1996
Creator: Griem, H.R.; Elton, R.C. & Welch, B.L.
Partner: UNT Libraries Government Documents Department