Safety Issues for Superconducting Fusion Magnets

Safety Issues for Superconducting Fusion Magnets
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Release: 1978
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Safety issues for future superconducting fusion magnet systems are examined. It is found that safety and failure experience with existing superconducting magnets is not very applicable to predictions as to the safety and reliability of fusion magnets. Such predictions will have to depend on analysis and judgement for many years to come, rather than on accumulated experience. A number of generic potential structural, thermal-hydraulic, and electrical safety problems are identified and analyzed. Prevention of quenches and non-uniform temperature distributions, if quenches should occur, is of great importance, since such events can trigger processes which lead to magnet damage or failure. Engineered safety features will be necessary for fusion magnets. Two of these, an energy dispersion system and external coil containment, appear capable of reducing the probability of coil disruption to very low levels. However, they do not prevent loss of function accidents which are of economic concern. Elaborate detector, temperature equalization, and energy removal systems will be required to minimize the chances of loss of function accidents.

Safety Systems and Structural Aspects of Superconducting Magnets for Fusion Power Reactors

Safety Systems and Structural Aspects of Superconducting Magnets for Fusion Power Reactors
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Release: 1976
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Potential safety systems are examined for superconducting magnets in fusion power reactors. Because of current and voltage limitations, energy removal systems do not appear practical for dumping significant amounts of energy external to the magnet for designs currently envisioned. Some type of Temperature Equalization System appears necessary to minimize temperature inhomogeneities if energy is dumped internally during a quench or other accident situation since inhomogeneities may cause electrical breakdown and/or structural damage. Large detection nets appear necessary to detect potential ''hot spots'' before they can damage the magnet. Qualitative fault/event trees have been developed for some potential accident pathways; however, many years will be required before quantitative risk assessment studies can be made.

Safety of Superconducting Fusion Magnets

Safety of Superconducting Fusion Magnets
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Release: 1979
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Twelve problem areas of superconducting magnets for fusion reaction are described. These are: Quench Detection and Energy Dump, Stationary Normal Region of Conductor, Current Leads, Electrical Arcing, Electrical Shorts, Conductor Joints, Forces from Unequal Currents, Eddy Current Effects, Cryostat Rupture, Vacuum Failure, Fringing Field and Instrumentation for Safety. Each is described under the five categories: Identification and Definition, Possible Safety Effects, Current Practice, Adequacy of Current Practice for Fusion Magnets and Areas Requiring Further Analytical and Experimental Study. Priorities among these areas are suggested; application is made to the Large Coil Project at Oak Ridge National Laboratory.

Aspects of Safety and Reliability of Superconducting Magnet Systems for Fusion Power Reactors

Aspects of Safety and Reliability of Superconducting Magnet Systems for Fusion Power Reactors
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Release: 1976
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Existing superconducting (SC) systems are shown to be inadequate for predicting successful performance of fusion magnets, since they have simpler geometry, much smaller size and simpler safety systems, less complex loading conditions and cyclical variations in loads, and are not exposed to radiation. Even so, a number of mechanical and electrical failures have occurred in existing magnet systems. Using the UWMAK and various EPR SC magnet designs as starting points, a number of potential safety and reliability problems are analyzed for future Tokamak TF coil systems. The voltage withstand capability of TF coils appears to be only a few hundred volts during quenches because of release of H2 from organic glues and insulators to form Penning mixtures with helium, ionization of He by gamma rays, and use of equipotential magnet structures.

Aspects of Safety and Reliability for Fusion Magnet Systems First Annual Report

Aspects of Safety and Reliability for Fusion Magnet Systems First Annual Report
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Release: 1976
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General systems aspects of fusion magnet safety are examined first, followed by specific detailed analyses covering structural, thermal, electrical, and other aspects of fusion magnet safety. The design examples chosen for analysis are illustrative and are not intended to be definitive, since fusion magnet designs are rapidly evolving. Included is a comprehensive collection of design and operating data relating to the safety of existing superconducting magnet systems. The remainder of the overview lists the main conclusions developed from the work to date. These should be regarded as initial steps. Since this study has concentrated on examining potential safety concerns, it may tend to overemphasize the problems of fusion magnets. In fact, many aspects of fusion magnets are well developed and are consistent with good safety practice. A short summary of the findings of this study is given.

Safety and Reliability in Superconducting MHD Magnets

Safety and Reliability in Superconducting MHD Magnets
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Release: 1979
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This compilation adapts studies on safety and reliability in fusion magnets to similar problems in superconducting MHD magnets. MHD base load magnet requirements have been identified from recent Francis Bitter National Laboratory reports and that of other contracts. Information relevant to this subject in recent base load magnet design reports for AVCO - Everett Research Laboratories and Magnetic Corporation of America is included together with some viewpoints from a BNL workshop on structural analysis needed for superconducting coils in magnetic fusion energy. A summary of design codes used in large bubble chamber magnet design is also included.

Structural Safety Features for Superconducting Magnets

Structural Safety Features for Superconducting Magnets
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Release: 1975
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A survey has been carried out for various potential structural safety problems of superconducting fusion magnets. These areas include: (1) Stresses due to inhomogeneous temperature distributions in magnets where normal regions have been initiated. (2) Stress distributions and yield forces due to cracks and failed regions. (3) Superconducting magnet response due to seismic excitation. These analyses have been carried out using a variety of large capacity finite element computer codes that allow for the evaluation of stresses in elastic or elastic-plastic zones and around singularities in the magnet structure. Thus far, these analyses have been carried out on UWMAK-I type magnet systems. (auth).