The ARC fusion reactor (affordable, robust compact reactor) is a theoretical design for a fusion reactor that is expected to produce the same amount of power as the most powerful fusion reactor currently under construction, ITER, at only half the size. The ARC design aims to produce 3x the energy required to operate it while being about half the diameter of the ITER reactor and cheaper to construct.
Contents
The design of the reactor is as proposed in a paper originally in arXiv and subsequently also distributed in the journal Fusion Engineering and Design, in 2015. No plans to build such a reactor exist at this time. The reactor design uses advances in other technologies, such as superconductor advances, to show that a smaller confinement theoretically feasible. The paper's authors include academics associated with the Alcator C-Mod reactor, the funding for which ends in 2016.
Design features
The ARC design has several major departures from traditional Tokamak style reactors. The changes occur in the design of the reactor components, whilst making use of the same D-T fusion reaction as current generation fusion devices.
Magnetic field
To achieve a near tenfold increase in fusion power density, the design makes use of rare-earth barium copper oxide superconducting tape for its toroidal field coils. The intense magnetic field allows sufficient confinement of superhot plasma in such a small device. In theory, the achievable fusion power density of a reactor is proportional to the fourth power of the magnetic field intensity.
ARC is a 270 MWe tokamak reactor with a major radius of 3.3 m, a minor radius of 1.1 m, and an on-axis magnetic field of 9.2 Teslas (T).
The design point has a plasma fusion gain of Qp ~13.6, yet is fully non-inductive, with a bootstrap fraction of ~63%.
The design is enabled by the ~23 T peak field on coil. External current drive is provided by two inboard RF launchers using 25 megawatts of lower hybrid and 13.6 MW of ion cyclotron fast wave power. The resulting current drive provides a steady state core plasma far from disruptive limits.
Removable core
The design includes a removable fusion power core that does not require dismantling the entire device. That makes it well-suited for research on other design changes.
Liquid blanket
Most of the solid blanket materials used to surround the fusion chamber in conventional designs are replaced by a fluorine lithium beryllium (FLiBe) molten salt that can easily be circulated/replaced, reducing maintenance costs.
The liquid blanket provides neutron moderation and shielding, heat removal, and a tritium breeding ratio ≥ 1.1. The large temperature range over which FLiBe is liquid permits blanket operation at 800 K with single phase fluid cooling and a Brayton cycle.