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arXiv:1409.3540physics.plasm-ph

ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets

B. N. Sorbom, J. Ball, T. R. Palmer, F. J. Mangiarotti, J. M. Sierchio, P. Bonoli, C. Kasten, D. A. Sutherland, H. S. Barnard, C. B. Haakonsen, J. Goh, C. Sung, D. G. Whyte

Abstract

The affordable, robust, compact (ARC) reactor conceptual design study aims to reduce the size, cost, and complexity of a combined fusion nuclear science facility (FNSF) and demonstration fusion Pilot power plant. ARC is a 200-250 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 T. ARC has rare earth barium copper oxide (REBCO) superconducting toroidal field coils, which have joints to enable disassembly. This allows the vacuum vessel to be replaced quickly, mitigating first wall survivability concerns, and permits a single device to test many vacuum vessel designs and divertor materials. The design point has a plasma fusion gain of Q_p~13.6, yet is fully non-inductive, with a modest bootstrap fraction of only ~63%. Thus ARC offers a high power gain with relatively large external control of the current profile. This highly attractive combination is enabled by the ~23 T peak field on coil with newly available REBCO superconductor technology. External current drive is provided by two innovative inboard RF launchers using 25 MW of lower hybrid and 13.6 MW of ion cyclotron fast wave power. The resulting efficient current drive provides a robust, steady state core plasma far from disruptive limits. ARC uses an all-liquid blanket, consisting of low pressure, slowly flowing fluorine lithium beryllium (FLiBe) molten salt. The liquid blanket is low-risk technology and provides effective neutron moderation and shielding, excellent heat removal, and a tritium breeding ratio >= 1.1. The large temperature range over which FLiBe is liquid permits blanket operation at 900 K with single phase fluid cooling and a high-efficiency Brayton cycle, allowing for net electricity generation when operating ARC as a Pilot power plant.

arXiv comments
35 pages, 32 figures
Journal reference
DOI
doi:10.1016/j.fusengdes.2015.07.008
Subjects
physics.plasm-phPlasma Physics physics.ins-detInstrumentation and Detectors

On Hacker News

Linked by 10 identifiable commenters in 19 comments across 16 threads, from Aug 2015 to Feb 2025.

Comments linking this paper, per year.

Discussed in comments16 threads

  1. Nuclear fusion: WEST beats the world record for plasma duration 1 comment
  2. Largest nuclear fusion reactor is finally completed 1 comment

    • > Their problem is all the rare earths The fraction of mass in a HTS magnet that is rare earth is surprisingly small. Most of the mass is mechanical support, or substrate on which the thin HTS film is deposited. The entire ARC reactor might contain 10 kilograms of REBCO (2015…

      pfdietzView on HNParent context

  3. Progress toward fusion energy breakeven measured against Lawson criterion 1 comment

    • SPARC is in fact a heavily marketed continuation of ARC, which has been around since 2014 (https://arxiv.org/abs/1409.3540 - note the same authors). So the commercialization ideas would have started way earlier. But a project lead believing in the project shouldn't matter in any…

      sigmoid10View on HNParent context

  4. White House: Developing a Bold Decadal Vision for Commercial Fusion Energy 1 comment

    • You can construct any narrative you want if you have selective perception and decide to not actually research or learn anything. https://arxiv.org/pdf/1409.3540v1.pdf

      willis936View on HNParent context

  5. Tokamak Energy sets a temperature record among commercial fusion companies 1 comment

    • 20m may be an overestimate, but 15m looks quite reasonable. Look at figure 1 in https://arxiv.org/pdf/1409.3540.pdf

      pfdietzView on HNParent context

  6. Nothing like this will be built again (2002) 1 comment

    • ARC has a mass of 7,190 tonnes (not including generators or radiators). This is about the mass of three US WW2 destroyers. It's not room sized; the thing is something like 20m tall (once you include the support structure). https://arxiv.org/pdf/1409.3540.pdf A 190MW(e) fission…

      pfdietzView on HNParent context

  7. The Truth About Nuclear Fusion Q Factors 2 comments

    • SPARC will not generate electricity[0]. It's intended to show that the ARC concept, which should be able to generate net electricity[1], is viable. If SPARC works, ARC might be built as early as 2030. 'As early as' being the keywords here. Showing that the difficult physics work…

      gene-hView on HNParent context

    • The ARC design (see https://arxiv.org/abs/1409.3540 for details) uses surprisingly little yttrium. The superconductor is only about 1% of the tapes, and the tapes are only a faction of the coils, and the coils mass is just a fraction of the mass of the coil support structure. I…

      pfdietzView on HNParent context

  8. Fusion startup plans reactor with small but powerful superconducting magnets 1 comment
  9. South Korea's fusion device KSTAR runs for 20 seconds at 100M degrees Celsius 2 comments

    • That weight figure (7190 tonnes, not 4000) for ARC is just for the reactor. https://arxiv.org/pdf/1409.3540.pdf (page 30) The net output of ARC in that design is 190 MW(e), which comes to 26 kW(e)/tonne. It doesn't include anything outside the reactor, which would likely…

      pfdietzView on HNParent context

    • > That weight figure (7190 tonnes, not 4000) for ARC is just for the reactor. https://arxiv.org/pdf/1409.3540.pdf (page 30) Thanks. As I hadn't seen that paper, I used the Fletcher class destroyer, which was the most numerous class the US built, and it was slightly on the larger…

      jablView on HNParent context

  10. Compact nuclear fusion reactor is 'very likely to work,' studies suggest 1 comment

    • The arxiv paper describing the design concept is here: https://arxiv.org/abs/1409.3540 Some additional features (besides the magnets) that jump out at me: The reactor vessel has joints to allow it to open up for maintenance access (previous tokamak designs have a reactor vessel…

      pdonisView on HNParent context

  11. The Trouble with Fusion (1983) [pdf] 1 comment

    • The volume is the volume of the reactor, including blanket, magnets, and the structure needed to support the JxB forces on the magnets, not the volume of the plasma. See table 11, page 30, in the ARC paper: https://arxiv.org/pdf/1409.3540.pdf For PWRs…

      pfdietzView on HNParent context

  12. A faster, cheaper path to fusion energy 1 comment

    • The ARC paper proposes that the lithium in the salt should be enriched to 90% lithium 6 to reach a tritium breeding ratio of 1.1. See section 5.3, "Tritium breeding." https://arxiv.org/pdf/1409.3540.pdf I presume that the breeding ratio would fall below 1.0 with natural lithium.

      philipkglassView on HNParent context

  13. MIT and newly formed company launch effort to build compact tokamak pilot plant 1 comment

    • According to the 2014 arxiv.org paper on the ARC reactor https://arxiv.org/pdf/1409.3540.pdf the concept (which would produce 190MW(e)) uses 90 tonnes of beryllium. According to the USGS, the current total world annual production of Be is 220 tonnes, and total global resource is…

      pfdietzView on HNParent context

  14. Nuclear fusion on brink of being realised, say MIT scientists 1 comment

    • According to the 2014 arxiv.org paper on the ARC reactor https://arxiv.org/pdf/1409.3540.pdf the concept (which would produce 190MW(e)) uses 90 tonnes of beryllium. According to the USGS, the current total world annual production of Be is 220 tonnes, and total global resource is…

      pfdietzView on HNParent context

  15. Is nuclear fusion poised to deliver? 1 comment

    • I'm finding it difficult to Google how efficiency scales with magnetic flux. I've ended up at a thirty five page pdf https://arxiv.org/pdf/1409.3540. Equation 1 on page 5 states the fourth power dependency. So using REBCO magnets, instead of Niobium-Tin, to get twice the…

      alan-croweView on HNParent context

  16. New design could finally help to bring fusion power closer to reality 2 comments

    • Here's the paper (no paywall): http://arxiv.org/abs/1409.3540 Interesting that the liquid blanket is the same as in the molten-salt thorium reactors (lithium beryllium fluoride (FLiBe)).

      throwaway_yy2DiView on HNParent context

    • According to their paper [0], the entire vaccum vessel is considered disposable and might survive only a few months. (It's also explicitly an experimental reactor meant to study neutron radiation damage, so they're hardly claiming it's a practical commercial design. But I think…

      throwaway_yy2DiView on HNParent context

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