So my basic argument was ... even if the risk of accident was 0.0001% ... the magnitude and scale of damage made it not worth the risk.

I don't think we know the full story of what's going on at Japan. There's already been an explosion inside Reactor #1. They resorted to flooding some of the reactors with seawater, essentially destroying them, which means they were on the verge of meltdown.

They are presently unable to determine whether reactors #1 and/or #3 have in fact already at least partially melted down. This would be the most serious high profile nuclear incident since three mile island.

Moreover, nuclear reaction trace elements like cesium are already being detected in abnormally high levels around the reactor. Radiation at the facility is already above normal year-long safe exposure levels.