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THE PERFORMANCE OF THE 8.4 MW MODULATOR/REGULATOR POWE SYSTEMS FOR THE ELECTRON CYCLOTRON HEATING FACILITY UPGRADE AT DIII-D

Description: The DIII-D National Fusion Facility at General Atomics is completing the upgrade of its electron cyclotron heating (ECH) capability from the previous 3 MW at 110 GHz to 6 MW of generated microwave power. An 8.4 MW modulator/regulator (M/R) power system has been designed and constructed. Surplus hardware that was acquired from the Lawrence Livermore National Laboratory (LLNL) Mirror Fusion Test Facility (MFTF program) was used as part of the design foundation. The power system, with a nominal output of -80 kV and 80 A, can supply a pair of gyrotrons with up to 10 second long pulses that may or may not be modulated. The modulator/regulator was designed about the BBC CKQ200-4 tetrode, which was the key component acquired from the LLNL program. In order to meet the performance goals of the program, substantial design modifications were needed to be made on the grid driver amplifier and the closed-loop feedback regulator circuits. Also, a newly designed crowbar switch system, featuring a high speed, thyratron-like triggered gas switch, was implemented. The modulator/regulator performance to date has been demonstrated as having <0.06% peak-to-peak ripple and square wave modulation of 50% amplitude at 2 kHz. The key features of the design of the power system and its performance will be presented in this paper.
Date: November 1, 2000
Creator: PRONKO, S.G.E.; DELAWARE, S.W.; HARRIS, T.E.; HOYT, D.; KELLMAN, D.H.; LEGG, R.A. et al.
Partner: UNT Libraries Government Documents Department

Vacuum vessel for the tandem Mirror Fusion Test Facility

Description: In 1980, the US Department of Energy gave the Lawrence Livermore National Laboratory approval to design and build a tandem Mirror Fusion Test Facility (MFTF-B) to support the goals of the National Mirror Program. We designed the MFTF-B vacuum vessel both to maintain the required ultrahigh vacuum environment and to structurally support the 42 superconducting magnets plus auxiliary internal and external equipment. During our design work, we made extensive use of both simple and complex computer models to arrive at a cost-effective final configuration. As part of this work, we conducted a unique dynamic analysis to study the interaction of the 32,000-tonne concrete-shielding vault with the 2850-tonne vacuum vessel system. To maintain a vacuum of 2 x 10/sup -8/ torr during the physics experiments inside the vessel, we designed a vacuum pumping system of enormous capacity. The vacuum vessel (4200-m/sup 3/ internal volume) has been fabricated and erected, and acceptance tests have been completed at the Livermore site. The rest of the machine has been assembled, and individual systems have been successfully checked. On October 1, 1985, we began a series of integrated engineering tests to verify the operation of all components as a complete system.
Date: March 10, 1986
Creator: Gerich, J.W.
Partner: UNT Libraries Government Documents Department

Mechanical considerations for MFTF-B plasma-diagnostic system

Description: The reconfiguration of MFTF to a tandem mirror machine with thermal barriers has caused a significant expansion in the physical scope of plasma diagnostics. From a mechanical perspective, it complicates the plasma access, system interfaces, growth and environmental considerations. Conceptual designs characterize the general scope of the design and fabrication which remains to be done.
Date: October 19, 1981
Creator: Thomas, S.R. Jr. & Wells, C.W.
Partner: UNT Libraries Government Documents Department

Integrated operations plan for the MFTF-B Mirror Fusion Test Facility. Volume I. Organization plan

Description: This plan and the accompanying MFTF-B Integrated Operations Plan are submitted in response to UC/LLNL Purchase Order 3883801, dated July 1981. The organization plan also addresses the specific tasks and trade studies directed by the scope of work. The Integrated Operations Plan, which includes a reliability, quality assurance, and safety plan and an integrated logistics plan, comprises the burden of the report. In the first section of this volume, certain underlying assumptions and observations are discussed setting the requirements and limits for organization. Section B presents the recommended structure itself. Section C Device Availability vs Maintenance and Support Efforts and Section D Staffing Levels and Skills provide backup detail and justification. Section E is a trade study on maintenance and support by LLNL staff vs subcontract and Section F is a plan for transitioning from the construction phase into operation. A brief summary of schedules and estimated costs concludes the volume.
Date: December 1, 1981
Partner: UNT Libraries Government Documents Department

Integrated operations plan for the MFTF-B Mirror Fusion Test Facility. Volume II. Integrated operations plan

Description: This document defines an integrated plan for the operation of the Lawrence Livermore National Laboratory (LLNL) Mirror Fusion Test Facility (MFTF-B). The plan fulfills and further delineates LLNL policies and provides for accomplishing the functions required by the program. This plan specifies the management, operations, maintenance, and engineering support responsibilities. It covers phasing into sustained operations as well as the sustained operations themselves. Administrative and Plant Engineering support, which are now being performed satisfactorily, are not part of this plan unless there are unique needs.
Date: December 1, 1981
Partner: UNT Libraries Government Documents Department

Control and diagnostic data structures for the MFTF

Description: A Data Base Management System (DBMS) is being written as an integral part of the Supervisory Control and Diagnostics System (SCDS) of programs for control of the Mirror Fusion Test Facility (MFTF). The data upon which the DBMS operates consist of control values and evaluative information required for facilities control, along with control values and disgnostic data acquired as a result of each MFTF shot. The user interface to the DBMS essentially consists of two views: a computer program interface called the Program Level Interface (PLI) and a stand-alone interactive program called the Query Level Interface to support terminal-based queries. This paper deals specifically with the data structure capabilities from the viewpoint of the PLI user.
Date: November 12, 1979
Creator: Wade, J.A. & Choy, J.H.
Partner: UNT Libraries Government Documents Department

MFTF exception handling system

Description: In the design of large experimental control systems, a major concern is ensuring that operators are quickly alerted to emergency or other exceptional conditions and that they are provided with sufficient information to respond adequately. This paper describes how the MFTF exception handling system satisfies these requirements. Conceptually exceptions are divided into one of two classes. Those which affect command status by producing an abort or suspend condition and those which fall into a softer notification category of report only or operator acknowledgement requirement. Additionally, an operator may choose to accept an exception condition as operational, or turn off monitoring for sensors determined to be malfunctioning. Control panels and displays used in operator response to exceptions are described.
Date: November 12, 1979
Creator: Nowell, D.M. & Bridgeman, G.D.
Partner: UNT Libraries Government Documents Department

Design lessons from using programmable controllers in the MFTF-B personnel safety and interlocks system

Description: Applying programmable controllers in critical applications such as personnel safety and interlocks systems requires special considerations in the design of both hardware and software. All modern programmable controller systems feature extensive internal diagnostic capabilities to protect against problems such as program memory errors; however most, if not all present designs lack an intrinsic capability for detecting and countering failures on the field-side of their I/O modules. Many of the most common styles of I/O modules can also introduce potentially dangerous sneak circuits, even without component failure. This paper presents the most significant lessons learned to date in the design of the MFTF-B Personnel Safety and Interlocks System, which utilizes two non-redundant programmable controllers with over 800 I/O points each. Specific problems recognized during the design process as well as those discovered during initial testing and operation are discussed along with their specific solutions in hardware and software.
Date: November 29, 1983
Creator: Branum, J.D.
Partner: UNT Libraries Government Documents Department

Mirror Fusion Test Facility data compression study. Final report

Description: This report is organized as follows. Discussions are given of three of the most important data compression methods that have been developed and studied over the years: coding, transforms, and redundancy reduction. (A brief discussion of how to combine and synthesize these ideas, and others, into a system is given). Specific ideas for compressing MFTF diagnostics and control data are developed. Listings and instructions for using FORTRAN programs that were compiled on the Livermore MFTF computers during the course of the study are also given.
Date: November 1, 1979
Partner: UNT Libraries Government Documents Department

Development of a Plasma Streaming System for the Mirror Fusion Test Facility

Description: The Plasma Streaming System (PSS) is an essential portion of the Mirror Fusion Test Facility (MFTF), scheduled for completion in October 1981. The PSS will develop a plasma density of at least 2 x 10/sup 12/ particles/cm/sup 3/ at the MFTF magnet centerline by injecting particles along the field lines. The plasma will have a midplane plasma radius as large as 40 cm with variable plasma particle energy and beam geometry. Minimum amounts of impurities will be injected, with emphasis on minimizing high Z materials. Each of the 60 PSS units will consist of a gun magnet assembly (GMA) and a power supply. Each GMA consists of a plasma streaming gun, a pulse magnet that provides variable beam shaping, and a fast reaction pulse gas valve.
Date: November 12, 1979
Creator: Holdsworth, T.; Clark, R.N.; McCotter, R.E.; Rossow, T.L. & Cruz, G.E.
Partner: UNT Libraries Government Documents Department

Fabrication of ion source components by electroforming

Description: Several components of the Oak Ridge National Laboratory (ORNL)/Magnetic Fusion Test Facility (MFTF-B) ion source have been fabricated utilizing an electroforming process. A procedure has been developed for enclosing coolant passages in copper components by electrodepositing a thick (greater than or equal to 0.75-mm) layer of copper (electroforming) over the top of grooves machined into the copper component base. Details of the procedure to fabricate acceleration grids and other ion source components are presented.
Date: January 1, 1983
Creator: Schechter, D.E. & Sluss, F.
Partner: UNT Libraries Government Documents Department

Maintenance and availability considerations for MFTF-B upgrade

Description: The upgrade of the Mirror Fusion Test Facility (MFTF-B) tandem mirror device incorporates the operation of advanced systems plus the requirement for remote maintenance. To determine if the operating availability goal of this device is achievable, an assessment of component lifetimes was made, along with estimates of device downtime. Key subsystem components were considered from the magnet, heating, impurity control, pumping, and test module systems. Component replacements were grouped into three categories, and a lifetime operating plan, including component replacements, was developed. It was determined that this device could achieve a 10% operating availability.
Date: January 1, 1983
Creator: Spampinato, P.T.
Partner: UNT Libraries Government Documents Department

Options for axisymmetric operation of MFTF-B

Description: The flexibility of MFTF-B for axisymmetric experiments has been investigated. Interhcanging the axicell coils and increasing their separation results in an axisymmetric plug cell with 12:1 and 6:1 inner and outer mirror ratios, respectively. For axisymmetric operation, the sloshing-ion neutral beams, ECRH gyrotrons, and the pumping system would be moved to the axicell. Stabilization by E-rings could be explored in this configuration. With the addition of octopole magnets, off-axis multipole stabilization could also be tested. Operating points for octopole and E-ring-stabilized configurations with properties similar to those of the quadrupole MFTF-B, namely T/sub ic/ = 10 - 15 keV and n/sub c/ approx. = 3 x 10/sup 13/ cm/sup -3/, have been obtained. Because of the negligible radial transport of central-cell ions, the required neutral-beam power in the central cell has been dramatically reduced. In addition, because MHD stabilization is achieved by off-axis hot electrons in both cases, much lower barrier beta is possible, which aids in reducing the barrier ECRH power. Total ECRH power in the end cell is projected to be approx. =1 MW. Possible operating points for both octopole and E-ring configurations are described along with the stability considerations involved.
Date: March 30, 1986
Creator: Fenstermacher, M.E.; Devoto, R.S. & Thomassen, K.I.
Partner: UNT Libraries Government Documents Department

MFTFB+T magnetostatic and circuit fault-induced forces

Description: This report presents the results of work performed on the estimation of the Lorentz forces acting on the various coils in the MFTFB+T mirror machine. The analyses incude: (1) static loading under normal operating conditions; (2) transient loading during a normal discharge; and (3) transient loading for one coil short circuits with all coils discharging. For the purpose of this memo, normal operation is defined as any possible combination of circuits fully charged to their operating current level or at zero current. This definition would then include any possible scenario for the entire system or partial system at full operating current.
Date: August 1, 1983
Creator: Pillsbury, Jr., R. D.; Thome, R. J.; Mann, W. R. & Langton, W. G.
Partner: UNT Libraries Government Documents Department

Cryogen system analysis for the Mirror Fusion Test Facility. Final report

Description: The Mirror Fusion Test Facility being designed and constructed at the Lawrence Livermore Laboratory requires a liquid helium liquefaction, storage, distribution, and recovery system and a liquid nitrogen storage and distribution system. To provide a powerful analytical tool to aid in the design evolution of this system through hardware, a thermodynamic fluid flow model was developed. This final report defines the cryogen system that was analyzed (consisting of the LHe subsystem, the GHe recovery subsystem and the LN/sub 2/ subsystem). It details the program assumptions, the theoretical basis for the analysis and limitations of the output. Several parametric runs were performed to illustrate the use of the program. Special detailed analyses were also performed on components such as the recuperator in the helium gas recovery system.
Date: June 1, 1979
Creator: Parmley, R.T.; Hausman, R.F. & Naes, L.G.
Partner: UNT Libraries Government Documents Department

Compact 80-keV neutral-beam module

Description: A compact and maintainable source of 80-keV neutral beams that focus to a high power density is required for the Mirror Fusion Test Facility (MFTF). In the new source being designed and built to meet these requirements, the cross-sectional area is reduced in two ways: by immersing the source in a vacuum where high voltage can be held over smaller distances and by redesigning grid supporting structures. Reliability is increased by reducing the electric fields everywhere else below those present between grids and by design innovations. The latter include techniques to reduce stray magnetic field and disperse gas uniformly, all metal-ceramic construction, and a 60-kV shield enclosing all 80-kV electrodes. Wherever possible, we have attempted to simplify the construction. We expect to solve problems that arise during testing either with add-on fixes or with the techniques already tested successfully on the Lawrence Berkeley Laboratory (LBL) 120-keV source. Easy maintenance is obtained by a compact isolation valve and by modular construction. Curving both the grid wires and their holders provides focusing in two planes.
Date: September 29, 1977
Creator: Molvik, A.W.; Baird, E.D.; Berkner, K.H.; Cooper, W.S.; Duffy, T.J.; Ehlers, K.W. et al.
Partner: UNT Libraries Government Documents Department

Axicell design for the end plugs of MFTF-B

Description: Certain changes in the end-plug design in the Mirror Fusion Test Facility (MFTF-B) are described. The Laboratory (LLNL) proposes to implement these changes as soon as possible in order to construct the machine in an axicell configuration. The present physics and technology goals as well as the project cost and schedule will not be affected by these changes.
Date: April 23, 1982
Creator: Thomassen, K.I. & Karpenko, V.N.
Partner: UNT Libraries Government Documents Department

Static and dynamic analyses on the MFTF-B vacuum vessel. Revision 1

Description: The Mirror Fusion Test Facility is a major magnetic fusion energy project at the Lawrence Livermore National Laboratory. An important component of this facility is the vacuum vessel, which forms the vacuum chamber. The vessel is supported on twenty-two pairs of legs that rest on reinforced concrete piers. In performing static and dynamic analyses on the vacuum vessel, we separately investigated the load distribution under gravity loads, pressure loads, electromagnetic loads, and thermal loads. We also performed sophisticated dynamic analyses to predict the structural behavior under a postulated earthquake. The modeling assumptions and analytic procedures are highlighted in this paper.
Date: January 15, 1984
Creator: Ng, D.S.
Partner: UNT Libraries Government Documents Department

Stress analysis of MFTF-B getter system bellows. Final report

Description: The MFTF-B design includes a retractable getter system. Eight getter assemblies are planned (4 in each end plug). Electrically heated Ti wires are mounted on a telescoping insertion mechanism and, between machine shots (pulses), are extended into the chamber in the vicinity of inward-facing water-cooled magnet liners. During the shots, the sublimators must be withdrawn because they will intrude into plasma and diagnostic space. Each of the getter assemblies will be mounted on the exterior of the vacuum vessel. Bellows are used to keep essentially all of the mechanism isolated from the vessel vacuum. The bellows come in two sizes (8.25'' O.D. and 14'' O.D.). The smaller of the two bellows has been qualified by testing up to 94,000 cycles by empirically adjusting details of the bellow design (geometry and thickness). The process required 12 different test samples and took over a one-year period to accomplish. The bellows consistently failed in the inside diameter weld heat-affected zone. Results from stress analysis studies are presented.
Date: April 1, 1982
Creator: Tokarz, F.J.; Johnson, J.J.; Mukherjee, A.N. & Dalder, E.N.
Partner: UNT Libraries Government Documents Department

Gyrokinetic equilibrium and stability in quadrupole tandem mirrors

Description: This paper discusses recent theoretical work on the equilibrium and stability of quadrupole tandem mirrors in the paraxial limit. It reviews calculations of three-dimensional equilibria by means of a ..beta..-expansion technique which lead to an understanding of the important role played by parallel currents and the corollary importance of careful design of the structure of the vacuum geodesic curvature. The previously predicted scaling with central-cell length of the finite-..beta.. distortion of vacuum flux surfaces is shown to saturate because of finite orbit effects. An adaptation to tandem geometries of the reduced MHD technique for calculating high-..beta.. three-dimensional equilibria is described. This approach uses the paraxial expansion to resolve the time-dependent relaxation to equilibrium into three distinct timescales on which the motion can be followed independently. Regarding stability, it is shown that kinetic effects suppress ballooning modes of short-to-moderate perpendicular wavelength; in the limit that such effects are dominant only rigid modes are possible. The stability of the latter modes is investigated within the context of the energy principle. Results of equilibrium and stability calculations for the TMX-U and MFTF-B experiments at Livermore are presented.
Date: August 2, 1982
Creator: Bulmer, R.H.; Kaiser, T.B.; Nevins, W.M.; Newcomb, W.A.; Pearlstein, L.D.; Strauss, H.R. et al.
Partner: UNT Libraries Government Documents Department

Construction and testing of the Mirror Fusion Test Facility magnets

Description: This paper describes the construction and testing of the Mirror Fusion Test Facility superconducting magnet set. Construction of the first Yin Yang magnet was started in 1978. And although this particular magnet was later modified, the final construction of these magnets was not completed until 1985. When completed these 42 magnets weighed over 1200 tonnes and had a maximum stored energy of approximately 1200 MJ at full field. Together with power supplies, controls and liquid nitrogen radiation shields the cost of the fabrication of this system was over $100M. General Dynamics/Convair Division was responsible for the system design and the fabrication of 20 of the magnets. This contract was the largest single procurement action at the Lawrence Livermore National Laboratory. During the PACE acceptance tests, the 26 major magnets were operated at full field for more than 24 hours while other MFTF subsystems were tested. From all of the data, the magnets operated to the performance specifications. For physics operation in the future, additional helium and nitrogen leak checking and repair will be necessary. In this report we will discuss the operation and testing of the MFTF Magnet System, the world's largest superconducting magnet set built to date. The topics covered include a schedule of the major events, summary of the fabrication work, summary of the installation work, summary of testing and test results, and lessons learned.
Date: August 1, 1986
Creator: Kozman, T.; Shimer, D.; VanSant, J. & Zbasnik, J.
Partner: UNT Libraries Government Documents Department

Technology for large tandem mirror experiments

Description: Construction of a large tandem mirror (MFTF-B) will soon begin at Lawrence Livermore National Laboratory (LLNL). Designed to reach break-even plasma conditions, the facility will significantly advance the physics and technology of magnetic-mirror-based fusion reactors. This paper describes the objectives and the design of the facility.
Date: September 4, 1980
Creator: Thomassen, K.I.
Partner: UNT Libraries Government Documents Department

Overview of the MFTF electrical systems

Description: The Mirror Fusion Test Facility, scheduled for completion in October 1981, will contain a complex, state-of-the-art array of electrical and electronics equipment valued at over 60 M$. Three injector systems will be employed to initiate and sustain the MFTF deuterium plasma. A plasma streaming system and a startup neutron beam system will be used to establish a target plasma. A sustaining neutral beam system will be used to fuel and sustain the MFTF plasma for 0.5 s. Additional power supply systems required on MFTF include two magnet power supplies with quench protection circuitry for powering the superconducting YIN/YANG magnet pair and eight 10 KHz power supplies for powering the Ti gettering system. Due to the complexity, physical size, and multiple systems of MFTF, a distributed, hierarchial, computer control and instrumentation system will be used. Color graphic, touch-panel, control consoles will provide the man-machine interface. The MFTF will have the capability of conducting an experiment every five minutes.
Date: November 12, 1979
Creator: Lindquist, W.B.; Eckard, R.D.; Holdsworth, T.; Mooney, L.J.; Moyer, D.R.; Peterson, R.L. et al.
Partner: UNT Libraries Government Documents Department