Reply To: Investment risk

[Ivy Matt]

On January 22, Dr. Park delivered a Microsoft Research talk, titled Polywell Fusion: Electrostatic Fusion in a Magnetic Cusp. It’s an hour and half long, but well worth watching in my opinion.

The upshot: the Polywell appears to be a viable and attractive fusion reactor. However, it will take time and money to produce a power-generating fusion reactor, but not nearly as much as will be required for a tokamak DEMO reactor. Dr. Park envisions a three-year proof-of-principle research effort to see how the device scales, followed by a $300 million net-power reactor to demonstrate scientific feasibility within a few years. Right now Dr. Park envisions using D-T fuel for the net-power device, but the actual fuel used will be affected by results obtained on the proof-of-principle device. If ion heating efficiency is sufficient (~90%), then he will strongly consider using p-B11 fuel in the net-power device.

Phase +1: Proof-of-Principle Reactor
~3 years
~5 ms high-beta operation
>10-kV ion heating by electron beam injection
~$35 million (?)
Success defined by 1) high-energy electron confinement within a factor of 10 of Harold Grad’s conjecture and 2) minimum (for D-T fuel) 30% ion-heating efficiency via electron beam.

Phase +2: Net Power Reactor
a few years
2m coil radius
5T magnetic field
80-kV electron beam
185 MW plasma heating power
1.1 GW fusion power (D-T fuel)
~$300 million
Success defined by net fusion power output.

The presentation slides can be downloaded here. The video of the talk can also be downloaded.

A thought that occurred to me while watching Dr. Park’s talk is that the Polywell is almost the opposite of the DPF in that it tries to achieve maximum plasma stability (using convex magnetic fields and high-beta cusp confinement) whereas the DPF uses plasma [em]instability[/em] to achieve fusion conditions.