these systems could be compromised, and then we really have to worry that -- that there could be a serious accident. >> right. and -- and to that point, how can a scenario like this be perhaps better mitigated? i think only one reactor of the six was running. if the reactors aren't running, are they safe or safer? or -- or not? >> well, even as a controlled shutdown of the reactor, it's not like you just click a switch and it's off. the fuel remains in the core for some time, for several weeks actually, until it's cool enough to take out and transport to a spent-fuel pool that's normally outside of the reactor building. and actually, spent fuel pools are underestimated. there are points of vulnerability in -- in the safety and security of a nuclear power plant. um, there -- the fuel there is