A. Hagnestål

KTH Royal Institute of Technology | KTH · Division of Electric Power and Energy Systems

Metabolism within the tumor microenvironment, where a complex mixture of different cell types resides in a nutrient-deprived surrounding, is not fully understood due to difficulties in measuring metabolic fluxes and exchange of metabolites between different cell types in vivo. Genome-scale metabolic modeling enables estimation of such exchange flux...

Variable reluctance machines such as transverse flux machines (TFM) have very suitable properties for slow speed renewable energy conversion applications such as wave power. The double-sided TFM variant with flux-concentrating magnet setup has generally better performance than other variants, but is considerably more challenging to build. One of th...

Ocean wave power is a promising renewable energy source. It has, however, been difficult to find a cost-effective solution to convert wave energy into electricity. The harsh marine environment and the fact that wave power is delivered with large forces at low speed make design of durable mechanical structures and efficient energy conversion challen...

Ocean wave power is a promising renewable energy source for future energy production. It has however been difficult to find a cost-effective solution to convert the wave energy into electricity. The harsh marine environment and the fact that wave power is delivered with high forces at low speeds makes design of durable mechanical structures and eff...

In this work, ferrite magnet linear generators for wave power applications are considered. These machines operate at unusually low speeds, around and even below 1 m/s, at which the optimal geometry differs from standard machines, since the copper loss and the force density become considerably more important. The focus is on translator design, and a...

A force-dense, low-cost and very efficient direct drive transverse flux generator aimed for wave power applications is being developed at the Royal Institute of Technology in Sweden, and a linear version is currently being built. The machine is specialized for low speeds, and the project is presented in this paper, where we focus on why TFMs are ve...

Wave power could give a significant contribution to a future sustainable energy system if the Levelized Cost Of Energy can be reduced to a competitive level. Winch-based point absorbers could potentially accomplish this if a key component-a low-cost, durable and efficient winch that can deal with high loads-can be developed. In this article the pos...

A force-dense and very efficient direct drive transverse flux generator aimed for wave power applications is being developed at the Royal Institute of Technology in Sweden. The machine is specialized for low speeds, and the design of a linear version is presented in this paper. The basic electromagnetic design is given as well as an overview of the...

The development of a stellarator–mirror fission–fusion hybrid concept is reviewed. The hybrid comprises of a fusion neutron source and a powerful sub-critical fast fission reactor core. The aim is the transmutation of spent nuclear fuel and safe fission energy production. In its fusion part, neutrons are generated in deuterium–tritium (D–T) plasma,...

point absorbing wave energy converter (WEC) is a complicated dynamical system. A semi-submerged buoy drives a power take-off device (PTO), which acts as a linear or non-linear damper of the WEC system. The buoy motion depends on the buoy geometry and dimensions, the mass of the moving parts of the system and on the damping force from the generator....

The power amplification factor PAF of a driven subcritical system is defined as the ratio of the fission power output of the blanket to the power which the driver must deliver to sustain its neutron source intensity. This parameter decisively determines the effectiveness of the whole system independent of its special purpose as energy amplifier or...

The output voltage from a direct-driven permanent magnet linear generator installed in a wave power plant varies both in amplitude and frequency. Electrical conversion is therefore necessary before grid connection can be achieved. The aim of this paper is to present an electrical conversion system based on the electric resonance phenomena. As one o...

The straight field line mirror (SFLM) hybrid reactor studies aim to identify a concept where the safety of fission power production could be enhanced. A fusion neutron source could become a mean to achieve this. The SFLM studies address critical issues such as reactor safety, natural circulation of coolants, steady state operation for a year or mor...

The straight field line mirror (SFLM) hybrid reactor studies aim to identify a concept where the safety of fission power production could be enhanced. A fusion neutron source could become a mean to achieve this. The SFLM studies address critical issues such as reactor safety, natural circulation of coolants, steady state operation for a year or mor...

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 BðzÞ¼�BðzÞ 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...

The straight field line mirror (SFLM) concept is aiming towards a steady-state compact fusion neutron source. Besides the possibility for steady state operation for a year or more, the geometry is chosen to avoid high loads on materials and plasma facing components. A comparatively small fusion hybrid device with 'semi-poor' plasma confinement (wit...

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 keff does not exceed 0.95. The model can...

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 semiplanar coils in two layers. The alternative coil system is for a downscaled magneti...

In omnigenous systems, the guiding centers are constrained to move on magnetic surfaces. Since a magnetic surface is determined by a constant radial Clebsch coordinate, omnigenuity implies that the guiding center radial coordinate (the Clebsch coordinate) is constant. Near omnigenuity is probably a requirement for high quality confinement and in su...

The vacuum field flux tube ellipticity depen- dence 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...

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 assumpt...

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 o...

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...

A comparatively small mirror fusion hybrid device may be developed for industrial transmutation and energy production from spent nuclear waste. This opportunity ensues from the large fission to fusion energy multiplication ratio, Q r =P fis /P fus  150, in a subcritical fusion device surrounded by a fission mantle with the neutron multiplicity k e...

A hybrid reactor based on the straight field line mirror (SFLM) with magnetic expanders at the ends is proposed as a compact device for transmutation of nuclear waste and power production. Compared to a fusion reactor, plasma confinement demands can be relaxed if there is a strong energy multiplication by the fission reactions, i.e. Qr=Pfission/Pfu...

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...

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...

A comparatively simple fusion driven fission device may be developed for industrial transmutation and energy production from spent nuclear waste [1-2]. This opportunity stems from the large fission to fusion power production ratio, Pfis/Pfus 150, in a subcritical fusion device surrounded by a fission mantle with the neutron multiplicity keff =0.96....

A pure fusion mirror device suffers from the predicted low values of the Q factor (energy gain factor). A much higher energy production may be achieved in a fusion-fission reactor, where the fusion plasma neutron source is surrounded by a fission mantle. The fusion neutrons are capable of initiating energy producing fission reactions in the surroun...

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 fo...

The straight field line mirror field is a marginal minimum B field with straight nonparallel field lines. This field gives optimal ellipticity, the drift surfaces lie on a magnetic surface, radiofrequency heating of the plasma is predicted to be efficient and MHD stability is provided by the minimum B property. One intended application of the magne...