Say your reactor has a neutron injector on a rotor. The fission fuel has started vibrating, creating a feedback loop that could cause the reaction to become unstable. Running the rotor in reverse would change the pattern of incident neutrons just enough to stop the vibration. And the way you make a rotor go the other way is by reversing the polarity of its drive current.
That's the best that I could ground this technobabble off the top of my head.
especially with how tepid the results are for the money poured in, it seems much more the case that we are seeing a lot of nakedly cynical playing of the 'give us what we want, lest the chinese win' by people who are otherwise on deeply shaky ground
I'm ok with it as long as I don't have to bail it out if it fails.
Never underestimate the bandwidth of a station wagon full of tapes. -- Dr. Warren Jackson, Director, UTCS