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Coil Design and Related Studies for the Fusion-Fission Reactor Concept SFLM Hybrid
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A fusion-fission (hybrid) reactor is a combination of a fusion device and a subcritical fission reactor, where the fusion device acts as a neutron source and the power is mainly produced in the fission core. Hybrid reactors may be suitable for transmutation of transuranic isotopes in the spent nuclear fuel, due to the safety margin on criticality imposed by the subcritical fission core. The SFLM Hybrid project is a theoretical project that aims to point out the possibilities with steady-state mirror-based hybrid reactors. The quadrupolar magnetic mirror vacuum field is based on the Straight Field Line Mirror field and the central cell is 25 m long. A fission mantle surrounds the mirror cell. The fission to fusion power ratio is about 150 with keff = 0.97, implying that almost all the produced energy comes from fission. Beyond each mirror end magnetic expanders are located, which increase the plasma receiving “divertor” area and provide tolerable heat load on wall materials. The plasma is heated with ion cyclotron radio frequency heating and the fission mantle is cooled using a liquid lead-bismuth eutectic. The device is self-sufficient in tritium, and does not seem to suffer from severe material problems. A remaining issue may be the plasma electron temperature, which need to reach about 500 eV for efficient power production.  In this doctoral thesis, theoretical work has been done with the magnetic coil system of such a device and also with the overall concept. A new coil type, the fishbone coil, suitable for single cell quadrupolar mirrors, has been invented. Two vacuum field coil sets with satisfying properties have been found, where the most recent coil set consists of fishbone coils. Finite ß effects on the magnetic field have been investigated, showing that the flux tube ellipticity increases with ß. The ellipticity of the vacuum field increases slightly with radius, but with finite ß it decreases with radius. The maximum flux surface radial extensions decrease with ß, which is an unexpected and beneficial result. A radial invariant has also been identified, and particle simulations have been made to emphasize that quadrupolar mirrors must be symmetric or confinement may be lost.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. , 138 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 991
Keyword [en]
Fusion, Fission, Hybrid reactor, Actinides, Mirror Machine, Quadrupolar mirror, Coils
National Category
Fusion, Plasma and Space Physics
Research subject
Physics
Identifiers
URN: urn:nbn:se:uu:diva-183362ISBN: 978-91-554-8521-4 (print)OAI: oai:DiVA.org:uu-183362DiVA: diva2:562517
Public defence
2012-12-10, Polhemssalen, Ångströmslaboratoriet, Lägerhyddsv. 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2012-11-19 Created: 2012-10-24 Last updated: 2013-01-23Bibliographically approved
List of papers
1. Field and Coil Design for a Quadrupolar Mirror Hybrid Reactor
Open this publication in new window or tab >>Field and Coil Design for a Quadrupolar Mirror Hybrid Reactor
2011 (English)In: Journal of fusion energy, ISSN 0164-0313, E-ISSN 1572-9591, Vol. 30, no 2, 144-156 p.Article in journal (Refereed) Published
Abstract [en]

A vacuum magnetic field from a superconducting coil set for a single cell minimum B fusion-fission mirror machine reactor is computed. The magnetic field is first optimized for MHD flute stability, ellipticity and field smoothness in a long-thin approximation. Recirculation regions and magnetic expanders are added to the mirror machine without an optimizing procedure. The optimized field is thereafter reproduced by a set of circular and quadrupolar coils. The coils are modelled using filamentary line current distributions. Basic scaling assumptions are implemented for the coil design, with a maximum allowed current density of 1.5 kA/cm(2). The coils are optimized using a local optimization method and the resulting field is checked for MHD flute stability and maximum ellipticity.

Keyword
Fusion-fission reactor, Hybrid reactor, Magnetic coils, Mirror machine
National Category
Physical Sciences Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-149593 (URN)10.1007/s10894-010-9353-4 (DOI)000287927500009 ()
Available from: 2011-03-21 Created: 2011-03-21 Last updated: 2017-12-11Bibliographically approved
2. A Compact Non-Planar Coil Design for the SFLM Hybrid
Open this publication in new window or tab >>A Compact Non-Planar Coil Design for the SFLM Hybrid
2012 (English)In: Journal of fusion energy, ISSN 0164-0313, E-ISSN 1572-9591, Vol. 31, no 4, 379-388 p.Article in journal (Refereed) Published
Abstract [en]

A non-planar single layer semiconductor coil set for a version of the Straight Field Line Mirror Hybrid concept with reduced magnetic field has been computed. The coil set consists of 30 coils that are somewhat similar to baseball coils with skewed sides. The coil set has been modeled with filamentary current distributions and basic scaling assumptions have been made regarding the coil widths. This coil set is expected to be considerably cheaper than a previous computed coil set. The coils can probably be produced with technologies known today.

Keyword
Engineering
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-164207 (URN)10.1007/s10894-011-9479-z (DOI)000305524000010 ()
Available from: 2011-12-16 Created: 2011-12-16 Last updated: 2017-12-08Bibliographically approved
3. Vacuum Field Ellipticity Dependence on Radius in Quadrupolar Mirror Machines
Open this publication in new window or tab >>Vacuum Field Ellipticity Dependence on Radius in Quadrupolar Mirror Machines
2012 (English)In: Journal of fusion energy, ISSN 0164-0313, E-ISSN 1572-9591, Vol. 31, no 5, 448-454 p.Article in journal (Refereed) Published
Abstract [en]

The vacuum field flux tube ellipticity dependence on radius for quadrupolar mirror machines has been investigated. A third order expression in the paraxial approximation has been derived for the vacuum field ellipticity. The dependence of ellipticity on midplane radius has been examined in the SFLM Hybrid and the outermost plasma flux tube is 3.5 cm wider than predicted by the first order paraxial approximation, which is within boundaries set by the first wall. The third order approximation has a high accuracy for the ellipticity for long-thin mirrors such as the SFLM Hybrid, and even the first order approximation that is independent of radius is sufficient in many applications. The ellipticity dependence on midplane radius for mirrors with more strongly localized quadrupolar fields than the SFLM Hybrid is also shown to be minor.

Place, publisher, year, edition, pages
Springer Netherlands, 2012
Keyword
Engineering
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-164206 (URN)10.1007/s10894-011-9493-1 (DOI)000308113200007 ()
Available from: 2011-12-16 Created: 2011-12-16 Last updated: 2017-12-08Bibliographically approved
4. Radial Confinement in Non-Symmetric Quadrupolar Mirrors
Open this publication in new window or tab >>Radial Confinement in Non-Symmetric Quadrupolar Mirrors
2013 (English)In: Journal of fusion energy, ISSN 0164-0313, E-ISSN 1572-9591, Vol. 32, no 3, 327-335 p.Article in journal (Refereed) Published
Abstract [en]

Charged particles in symmetric quadrupolar mirrors are radially confined and have an associated radial invariant. In a symmetric quadrupolar field the magnetic field modulus satisfies B(z)=−B(z) along the axis if z = 0 defines the field minimum of the mirror, and the quadrupolar field has a corresponding symmetry. The field in the anchor cells of a tandem mirror need not obey a corresponding symmetry. In this paper, the radial confinement of non-symmetric mirrors is examined by tracing sample ions in the magnetic field. It is found that for non-symmetric mirrors, particles are typically not confined, and no radial invariant exists for such devices. Without attention to this effect in the field and coil design, radial confinement of trapped particles may be lost.

Place, publisher, year, edition, pages
Springer, 2013
Keyword
Quadrupolar mirror machine, radial transport
National Category
Physical Sciences Engineering and Technology
Research subject
Physics with specialization in Space and Plasma Physics; Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-183354 (URN)10.1007/s10894-012-9573-x (DOI)000317973500003 ()
Available from: 2012-10-24 Created: 2012-10-24 Last updated: 2017-12-07Bibliographically approved
5. Finite ß corrections to the magnetic field in the SFLM Hybrid
Open this publication in new window or tab >>Finite ß corrections to the magnetic field in the SFLM Hybrid
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Finite  effects for the magnetic field in the SFLM Hybrid reactor concept have been studied numerically. The parallel current has been calculated, and it is found to be negligible. The constant pressure surfaces at the midplane are not significantly affected by the parallel current, and have a square-like octupolar distortion near the plasma edge. In most of the plasma region, their cross sections are nearly circular. The flux tube ellipticity is found to increase by the finite  effects, but the increase is considerably more pronounced near the z axis where the pressure is high. At the plasma edge, the increase in ellipticity by finite  effects is only moderate and the maximum radial extensions of the flux tube are even slightly decreased compared to the vacuum case.

Keyword
finite beta, quadrupolar mirror, ellipticity
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-183359 (URN)
Available from: 2012-10-24 Created: 2012-10-24 Last updated: 2013-01-23
6. Studies of a Straight Field Line Mirror with emphasis on fusion-fission hybrids
Open this publication in new window or tab >>Studies of a Straight Field Line Mirror with emphasis on fusion-fission hybrids
2010 (English)In: Fusion science and technology, ISSN 1536-1055, E-ISSN 1943-7641, Vol. 57, no 4, 326-334 p.Article in journal (Refereed) Published
Abstract [en]

The straight field line mirror (SFLM) field with magnetic expanders beyond the confinement region is proposed as a compact device for transmutation of nuclear waste and power production. A design with reactor safety and a large fission-to-fusion energy multiplication is analyzed. Power production is predicted with a fusion Q = 0.15 and an electron temperature of [approximately]500 eV. A fusion power of 10 MW may be amplified to 1.5 GW of fission power in a compact hybrid mirror machine. In the SFLM proposal, quadrupolar coils provide stabilization of the interchange mode, radio-frequency heating is aimed to produce a hot sloshing ion plasma, and magnetic coils are computed with an emphasis on minimizing holes in the fission blanket through which fusion neutrons could escape. Neutron calculations for the fission mantle show that nearly all fusion neutrons penetrate into the fission mantle. A scenario to increase the electron temperature with a strong ambipolar potential suggests that an electron temperature exceeding 1 keV could be reached with a modest density depletion by two orders in the expander. Such a density depletion is consistent with stabilization of the drift cyclotron loss cone mode.

Keyword
hybrid reactor, fusion-fission reactor, mirror machine
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-122199 (URN)000277533900004 ()
Available from: 2010-04-07 Created: 2010-04-07 Last updated: 2017-12-12Bibliographically approved
7. Radial Drift Invariant in Long-Thin Mirrors
Open this publication in new window or tab >>Radial Drift Invariant in Long-Thin Mirrors
2012 (English)In: European Physical Journal D: Atomic, Molecular and Optical Physics, ISSN 1434-6060, E-ISSN 1434-6079, Vol. 66, no 28Article in journal (Refereed) Published
Abstract [en]

In omnigenous systems, guiding centers are constrained to move on magnetic surfaces. Sincea magnetic surface is determined by a constant radial Clebsch coordinate, omnigeneity implies that theguiding center radial coordinate (the Clebsch coordinate) is a constant of motion. Near omnigeneity isprobably a requirement for high quality confinement and in such systems only small oscillatory radialbanana guiding center excursions from the average drift surface occur. The guiding center radial coordinateis then the leading term for a more precise radial drift invariant Ir, corrected by oscillatory “bananaripple” terms. An analytical expression for the radial invariant is derived for long-thin quadrupolar mirrorequilibria. The formula for the invariant is then used in a Vlasov distribution function. Comparisons arefirst made with Vlasov equilibria using the adiabatic parallel invariant. To model radial density profiles, itis necessary to use the radial invariant (the parallel invariant is insufficient for this). The results are alsocompared with a fluid approach. In several aspects, the fluid and Vlasov system with the radial invariantgive analogous predictions. One difference is that the parallel current associated with finite banana widths could be derived from the radial invariant.

Place, publisher, year, edition, pages
Springer, 2012
Keyword
Radial invariant, quadrupolar mirror
National Category
Physical Sciences Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-183360 (URN)10.1140/epjd/e2011-20477-4 (DOI)000300852900016 ()
Available from: 2012-10-24 Created: 2012-10-24 Last updated: 2017-12-07Bibliographically approved
8. Neutronic model of a mirror based fusion-fission hybrid for the incineration of the transuranic elements from spent nuclear fuel and energy amplification
Open this publication in new window or tab >>Neutronic model of a mirror based fusion-fission hybrid for the incineration of the transuranic elements from spent nuclear fuel and energy amplification
2011 (English)In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 38, no 2-3, 578-589 p.Article in journal (Refereed) Published
Abstract [en]

The Georgia Institute of Technology has developed several design concepts of tokamak based fusion-fission hybrids for the incineration of the transuranic elements of spent nuclear fuel from Light-Water-Reactors. The present paper presents a model of a mirror hybrid. Concerning its main operation parameters it is in several aspects analogous to the first tokamak based version of a "fusion transmutation of waste reactor". It was designed for a criticality keff <= 0.95 in normal operation state. Results of neutron transport calculations carried out with the MCNP5 code and with the JEFF-3.1 nuclear data library show that the hybrid generates a fission power of 3 GWth requiring a fusion power between 35 and 75 MW, has a tritium breeding ratio per cycle of TBRcycle = 1.9 and a first wall lifetime of 12-16 cycles of 311 effective full power days. Its total energy amplification factor was roughly estimated at 2.1. Special calculations showed that the blanket remains in a deep subcritical state in case of accidents causing partial or total voiding of the lead-bismuth eutectic coolant. Aiming at the reduction of the required fusion power, a near-term hybrid option was identified which is operated at higher criticality keff <= 0.97 and produces less fission power of 1.5 GWth. Its main performance parameters turn out substantially better.

Keyword
Energy amplification, Fusion-fission hybrid, MCNP5 calculations, Mirror plasma device, Spent nuclear fuel
National Category
Physical Sciences Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-140347 (URN)10.1016/j.anucene.2010.09.031 (DOI)000287571100046 ()
Available from: 2011-01-05 Created: 2011-01-05 Last updated: 2017-12-11Bibliographically approved
9. Coil design for the straight field line mirror
Open this publication in new window or tab >>Coil design for the straight field line mirror
2009 (English)In: Fusion science and technology, ISSN 1536-1055, E-ISSN 1943-7641, Vol. 55, no 2T, 127-130 p.Article in journal (Refereed) Published
Abstract [en]

Coil systems for producing the Straight Field Line Mirror field using axisymmetric and quadrupolar coils are calculated. Two applications are intended, a fusion-fission nuclear waste transmutation device and a small plasma deposition device. Position, size and current for the axisymmetric coils are optimized as well as radial profile and current for the quadrupolar coils for the two applications. Calculations show that such a coil system can produce the Straight Field Line Mirror field for long-thin mirrors with moderate mirror ratio, but some other coil configuration needs to be found for mirrors where the coils cannot reside close to the plasma edge. In this work, the material science experiment mirror can be produced with about 1% error but the fusion-fission device field has not at this moment been reproduced with acceptable errors.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-148887 (URN)000265186400026 ()
Available from: 2011-03-11 Created: 2011-03-11 Last updated: 2017-12-11Bibliographically approved
10. Theoretical field and coil design for a single cell minimum-B mirror hybrid reactor
Open this publication in new window or tab >>Theoretical field and coil design for a single cell minimum-B mirror hybrid reactor
2011 (English)In: Fusion science and technology, ISSN 1536-1055, E-ISSN 1943-7641, Vol. 59, no 1T, 217-219 p.Article in journal (Refereed) Published
Abstract [en]

A vacuum magnetic field from a superconducting coil set for a single cell minimum-B mirror-based,fission-fusion reactor is computed. The magnetic field is optimized for MHD stability, ellipticity and field smoothness. A recirculation region and wide magnetic expanders on both sides are provided to the central mirror cell. A coil set producing this field is computed which consists of circular and quadrupolar coils. Basic scaling assumptions are made for the coil dimensions, based on a maximum allowed current density of 1.5 kA/cm(2) for superconducting coils. Sufficient space is available for a fission mantle. The field produced by the coils is checked for MHD plasma stability and maximum ellipticity. The resulting confinement region is 25 in long with a 40 cm midplane plasma radius.

National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-152643 (URN)000288974200053 ()
Available from: 2011-04-29 Created: 2011-04-29 Last updated: 2017-12-11Bibliographically approved
11. Coil System For a Mirror-Based Hybrid Reactor
Open this publication in new window or tab >>Coil System For a Mirror-Based Hybrid Reactor
2012 (English)In: Fusion for Neutrons and Subcritical Nuclear Fission: Proceedings of the International Conference / [ed] Jan Källne, Dimitri Ryutov, Giuseppe Gorini, Carlo Sozzi, Marco Tardocchi, 2012, 217-223 p.Conference paper, Published paper (Refereed)
Abstract [en]

Two different superconducting coil systems for the SFLM Hybrid study - a quadrupolar mirror based fusion-fission reactor study - are presented. One coil system is for a magnetic field with 2 T at the midplane and a mirror ratio of four. This coil set consists of semi-planar coils in two layers. The alternative coil system is for a downscaled magnetic field of 1.25 T at the midplane and a mirror ratio of four, where a higher beta is required to achieve sufficient the neutron production. This coil set has one layer of twisted 3D coils. The 3D coils are expected to be considerably cheaper than the semiplanar, since NbTi superconductors can be used for most coils instead of Nb3Sn due to the lower magnetic field.

Series
AIP Conference Proceedings, ISSN 0094-243X ; 1442
Keyword
Hybrid reactor, fusion, fission, superconducting coils, minimum B, magnetic mirror
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-181210 (URN)10.1063/1.4706871 (DOI)000306895100024 ()978-0-7354-1038-1 (ISBN)
Conference
International Workshop on Fusion Neutrons and Subcritical Nuclear Fission (FUNFI), SEP 12-15, 2011, Varenna, ITALY
Available from: 2012-09-24 Created: 2012-09-19 Last updated: 2013-03-04Bibliographically approved
12. Safety And Power Multiplication Aspects Of Mirror Fusion-Fission Hybrids
Open this publication in new window or tab >>Safety And Power Multiplication Aspects Of Mirror Fusion-Fission Hybrids
Show others...
2012 (English)In: Fusion for Neutrons and Subcritical Nuclear Fission: Proceedings of the International Conference / [ed] Jan Källne, Dimitri Ryutov, Giuseppe Gorini, Carlo Sozzi, Marco Tardocchi, 2012, 186-198 p.Conference paper, Published paper (Refereed)
Abstract [en]

Recently, in a research project at Uppsala University a simplified neutronic model for a straight field line mirror hybrid has been devised and its most important operation parameters have been calculated under the constraints of a fission power production of 3 GW and that the effective multiplication factor k(eff) does not exceed 0.95. The model can be considered as representative for hybrids driven by other types of mirrors too. In order to reduce the demand on the fusion power of the mirror, a modified option of the hybrid has been considered that generates a reduced fission power of 1.5 GW with an increased maximal value k(eff) = 0.97. The present paper deals with nuclear safety aspects of this type of hybrids. It presents and discusses calculation results of reactivity effects as well as of driver effects.

Series
AIP Conference Proceedings, ISSN 0094-243X ; 1442
Keyword
Fusion-fission hybrid, Mirror plasma device, Spent nuclear fuel, Nuclear safety, MCNP5 calculations
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-181209 (URN)10.1063/1.4706868 (DOI)000306895100021 ()978-0-7354-1038-1 (ISBN)
Conference
International Workshop on Fusion Neutrons and Subcritical Nuclear Fission (FUNFI), SEP 12-15, 2011, Varenna, ITALY
Available from: 2012-09-24 Created: 2012-09-19 Last updated: 2016-04-21Bibliographically approved

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