ARC fusion reactor
The ARC fusion reactor (affordable, robust, compact) is a theoretical design for a compact fusion reactor developed by the Massachusetts Institute of Technology (MIT) Plasma Science and Fusion Center (PSFC). The ARC design aims to achieve an engineering gain of three (to produce three times the electricity required to operate the machine) while being about half the diameter of the ITER reactor and cheaper to construct.
The design of the reactor was proposed in an article originally on arXiv and subsequently also distributed in the journal Fusion Engineering and Design, in 2015. The reactor design uses advances in other technologies, such as superconductor materials, to show that a smaller confinement is theoretically feasible. The article authors include academics associated with the Alcator C-Mod reactor. There is a plan to build a scaled-down demonstration version of the reactor, named SPARC, by the company Commonwealth Fusion Systems, with backing from Eni.
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 (deuterium - tritium) fusion reaction as current-generation fusion devices.
To achieve a near tenfold increase in fusion power density, the design makes use of rare-earth barium-copper-oxide (REBCO) 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.
The design point has a fusion energy gain factor Qp ≈ 13.6 (the plasma produces 13 times more fusion energy than is required to heat it), 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 vacuum vessel
The design includes a removable vacuum vessel (the solid component that separates the plasma and the surrounding vacuum from the liquid blanket) that does not require dismantling the entire device. That makes it well-suited for research on other design changes.
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.
- Commonwealth Fusion Systems, a company aiming to build the reactor
- Yttrium barium copper oxide, the most studied/useful rare-earth barium copper oxide
- "Advances in magnet technology could bring cheaper, modular fusion reactors from sci-fi to sci-reality in less than a decade". Retrieved 2015-08-12.
- Sorbom, B. N.; Ball, J.; Palmer, T. R.; Mangiarotti, F. J.; Sierchio, J. M.; Bonoli, P.; Kasten, C.; Sutherland, D. A.; Barnard, H. S. (2014-09-10). "ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets". Fusion Engineering and Design. 100: 378. arXiv: . doi:10.1016/j.fusengdes.2015.07.008.
- Sorbom, B. N.; Ball, J.; Palmer, T. R.; Mangiarotti, F. J.; Sierchio, J. M.; Bonoli, P.; Kasten, C.; Sutherland, D. A.; Barnard, H.S.; Haakonsen, C. B.; Goh, J.; Sung, C.; Whyte, D. G. (2015). "ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets". Fusion Engineering and Design. 100: 378. arXiv: . doi:10.1016/j.fusengdes.2015.07.008.
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