I googled for the press release but didn't find it, but I'm pretty shure that they planned to expand in Yokohama, Shinagawa and Chiba. Certainly, Kanagawa is not part of Tokyo in any sense, but I think we both can agree that despite the political boundaries of the different prefectures, the build up area from Chiba to Yokohama at the other side of Tokyo bay is practically continuous.
On the other hand, TEPCO had so many chances, so many time to avoid this disaster that is amazing that their managers did't get charged for their criminal negligence. I expect such brazen, shameless display of impunity in my country, Mexico, or any third world place, but in a first world, supposedly democratic country like Japan is incredible. I work for the state owned electric company, and, despite the high level corruption cases that have happened in our company, we do our best to keep the safety of our installations. The energy business is not only that, we always have the safety and welfare of our customers in our hands, more so in the case of nuclear power plants; to do a sloppy job is not an option here.
Best Regards