Fusion scientist suggests new direction for the field

In an era when many critics of the scientific “establishment” claim that scientists are mostly concerned about circling the wagons to protect funding of their existing pet projects, and in the wake of the battle brewing in the U.S. over the funding of nuclear fusion research in particular, it is interesting to read comments by Robert Hirsch, a senior researcher in the fusion science field, in a speech he recently gave at a fusion workshop.

Here is a brief summary:

  1. After decades of effort, and although a great deal has been learned and accomplished, the stark fact is no one has yet developed or demonstrated a practical fusion power system (even if we set aside the task of engineering an industrial-scale system).
  2. “Practical” fusion power must compete against a variety of other options, including oil, gas, conventional nuclear, solar and wind.
  3. In particular, to compensate for the higher economic risks of such a new system, fusion plants must have lower lifecycle costs when they are first commercialized.
  4. A Tokamak-based system (like the International Thermonuclear Experimental Reactor prototype now in development in France), because of its huge size and its need for even larger containment vessel, does not appear to be viable — it would be much more expensive than a comparable fission reactor.
  5. Tokamak-based systems inevitably generate neutrons, so measures must be taken to control neutron flux; also, materials subjected to neutron flux will inevitably degrade.
  6. Measures must be taken to guard against the potential breakdown of superconducting magnets.
  7. We need to look at new possibilities — a new concept that is inherently small in size, and which can be based on zero or very low neutron emanations.
  8. One promising example is the proton-boron fusion reaction. But it requires much higher temperatures than the deuterium-tritum reaction, and must be not based on plasma, since a plasma would kill the concept.
  9. Another example is inertial electrostatic confinement (IEC) fusion, which potentially could be very high in density and very small, thus simplifying the plasma problem.
  10. Especially in the wake of global warming, everyone wants “clean” fusion energy systems to succeed. But only a more sober approach will yield a practical solution.

Hirsch acknowledged that these thoughts were “painful” to formulate. He himself played a key role in establishing tokamak research in the U.S., and for many years had high hopes for its success. But “realities have emerged to dash those hopes.”

The full text of Hirsch’s comments is available here.

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