Historical research guide · 0940 · 2002
Nonelectric Applications of Fusion
Kathryn McCarthy · Charles Baker · Edward Cheng · Gerald Kulcinski · Grant Logan · George Miley · John Perkins · Dave Petti · John Sheffield · Don Steiner · Weston Stacey · Lester Waganer
In one minute
In 2003 the United States Department of Energy put a direct question to its Fusion Energy Sciences Advisory Committee: should the fusion programme widen its aim beyond electricity? A twelve-person panel chaired by Kathryn McCarthy of the Idaho National Engineering and Environmental Laboratory — with Gerald Kulcinski of Wisconsin, George Miley of Illinois, John Sheffield of Tennessee, Weston Stacey of Georgia Tech, Grant Logan of Berkeley and others — answered by naming four things fusion could sell before it ever sells a kilowatt-hour: near-term products from small devices, transmutation of nuclear waste, hydrogen, and space propulsion. Each was judged against three plain criteria — does it solve a national problem, what does it demand of fusion compared with making electricity, and can fusion beat the competition. The near-term list is striking for how modest the machines are: low-gain devices already making PET isotopes for hospitals and neutrons for finding concealed materials. The propulsion chapter, built on material supplied by Francis Thio, concludes that fusion is the only near-term process that can deliver what deep-space missions need.
Connection
Chapter 12 keeps the ledger of what fusion is actually for, and this is the United States government’s own answer, on the record: four missions, three tests, named recommendations. Chapter 9 gets the near-term half — small, low-gain plasma devices already selling neutrons and medical isotopes — and the propulsion chapter is where a federal advisory panel writes down that compact, pulsed, plasma-liner fusion is the architecture propulsion actually wants.
From the source
The panel’s answer to the charge is that the most promising non-electric applications of fusion fall into four categories — near-term applications, transmutation, hydrogen production and space propulsion — listed in no order of priority, and none of them to be pursued at the expense of existing programmes.Executive Summary, opening; Section VI, Findings and Recommendations
The near-term case does not wait on breakeven. Small, low-gain fusion devices have already produced PET isotopes for medical diagnosis and deuterium-deuterium neutrons for the detection of clandestine explosives, chemical and biological weapons and drugs; the panel puts the latter at proof-of-principle stage already and says scale-up and miniaturisation need only modest plasma-physics investment, with impact possible in a five to ten year time frame.Executive Summary, Near-Term Applications; Section VI, Near-Term Applications
For transmutation the physics bar is lower than for a power station: a tokamak fusion neutron source built on the existing ITER physics and technology database would meet most of the needs of the mission of destroying long-lived radioisotopes in spent fuel, disposing of surplus weapons-grade plutonium and breeding fissile fuel. What is missing is not plasma performance but component reliability and quasi steady-state operation.Executive Summary, Transmutation; Section VI, Transmutation
The propulsion requirement is stated in numbers rather than adjectives. A five-month outbound leg to a moon of Jupiter needs a mean cruising speed near fifty kilometres per second and a velocity increment of at least a hundred; with a payload fraction of 0.75 the rocket equation then demands a propellant exhaust velocity of 350 kilometres per second and a mean specific jet power above four kilowatts per kilogram — where a fission-electric rocket is generally limited to under a tenth of a kilowatt per kilogram.Section V, The Rationale for Fusion Propulsion
The mass budget rules out the mainstream machines. Taking an initial-orbit cost of five to ten billion dollars as politically sustainable and fifty thousand dollars per kilogram to build space-qualified hardware, the whole propulsion unit must come in under five hundred tonnes — which a conventional tokamak or conventional inertial fusion reactor will not do, so the compact concepts of the Innovative Confinement Concepts programme are required, and of those only the plasma-jet or plasma-liner driven magnetized target fusion was formulated for propulsion in the first place.Section V, Critical Issues for Fusion Propulsion
What to watch: the panel’s formal recommendation is that the Office of Fusion Energy Sciences respond to any NASA request, and that as a first step DOE contact NASA about a joint task force, NASA-led, to evaluate the feasibility of fusion for space propulsion at the conceptual level. The panel also states the physics constraint that shapes any such design — because waste heat can only leave a spacecraft as radiation, neutrons are worse than useless for propulsion unless the fusing plasma absorbs their energy directly, which favours advanced low-neutron fuels such as deuterium-helium-3.Section V, Critical Issues and Summary and Recommendations; Section VI, Space Propulsion
The way in
https://doi.org/10.1023/a:1026281007353How to cite it
Kathryn McCarthy, Charles Baker, Edward Cheng, Gerald Kulcinski, Grant Logan, George Miley, John Perkins, Dave Petti, John Sheffield, Don Steiner, Weston Stacey, Lester Waganer (2002) Nonelectric Applications of Fusion doi:10.1023/a:1026281007353