Reply To: Richard Branson – Virgin Pledge

[Jolly Roger]

Lerner wrote: Reactor plus shielding is 2 meters across but whole thing, including capacitor bank may be more like 3x2x2 meters.

Duke Leto wrote: So barring some miracle discovery in radiation containment, there’s an asymptotal lower limit on unit size of about a cubic meter. Ergo no fusion-electric car or propellor airplane…

It may be possible to design a semi-tractor or bus around a Focus Fusion reactor, but I wouldn’t be too comfortable being stuck in rush hour traffic next to an active gamma and x-ray source. But then again, I have been involved in shipping low-level fission waste down the road, so there is not much difference.

Trains and ships will not be a problem fitting an FF reactor aboard. A large plane could carry one under each wing or in its belly to power electric ducted fans.

1 Watt = 1 Newton-meter/second, therefore 5 MW = 5,000 kN-m/s. The engines of a Boeing 747 develop ~280 kN of thrust. (The units aren’t quite right, so this might be mixing “apples-and-oranges”.)

Does this mean that if a reactor/engine system had an efficiency higher than ~6% a Focus-Fusion-powered 747 could fly? If not, why not?