It is politically incorrect for me to say this, but I think this British expert Malcom Grimston on CNN probably has it right:
http://www.cnn.com/2011/WORLD/asiapcf/03/13/japan.nuclear.reactors/ (Video at the top of the page.) He says "this may seem like a strange thing to say . . . but the explosion wasn't a terribly important event." I think he says they have flooded the entire control room with sea water, to remove heat. Adding sea water inside the reactor vessel probably wrote off the entire machine. This will corrode the machine. Since it has partially-melted fuel rods in it, and I expect the reactor was a write-off anyway, and I think that's what Grimston believes. It was close to end of its service life anyway. He thinks the experts handled the job well. Maybe they did -- I can't judge -- but they handled the job of informing the public and the government badly. P.M. Kan complained about the power company's confused and incomplete reports. My impression is that the reactor crisis has passed. There are severe shortages of electricity now. They are conducting scheduled black outs in Tokyo. Many of the electric trains are out of service. Traffic signals are off but police were deployed beforehand to direct traffic by hand. It seems strange to me. Don't they have separate circuits for traffic signals and railroads? They should have shut down big buildings and factories before disrupting transportation. Hundreds of thousands of people in Tokyo were caught in the transportation and communication shutdown the day of the earthquake. I have heard from two or three, including a mother who was downtown with a five-year-old. She says the railroad company and local officials were very responsive and helpful, bringing her and child to a temporary shelter, helping them contact the family and so on. Another person walked from downtown Tokyo to Musashi-koganei, which is quite a distance. It took him many hours. Many people were helpful along the way. - Jed