fukushima. this is reactor number 3, the worst explosion took place here, and this is one of the reactors where concerns about overheating nuclear fuel are growing. >> footage from itn news. i will tell you in the midst of all of this seriousness that my teleprompter has now just gone to footage of a live basketball game, which feels to me like some sort of message from god that i'm doing something wrong. joining us now is a physicist named dr. james acton, who joins us in order to help understand the course of events at fukushima. dr. acton, thanks very much for joining us. really appreciate your time. >> my pleasure, rachel. >> engineers were able to connect an external grid power line cable to unit 2 today. how important is that? how will connecting power to the unit 2 reactor help the overall safety situation at daiichi? >> well, rachel, you focused in your introduction on this issue of the spent fuel pools. and that's one thing we're worried about. but if you remember, this crisis started off and continued with the issue of these rods in the