I checked two supermarkets in my area today. There are toilet rolls, tissue boxes, milk, eggs, rice and all other products except for mineral water. I have some bottles @ home, so just bought a bottle of Perrier.
Also, studied current situation of nuke plant and found some practical information @ some professor's site. I don't have time to translate all those, ( Hoping I can do some points in the near future FYI )but in Tokyo area, at the moment, no worries to live. Wearing mask and long sleeves would be recommended. He says for now, it's better to drink bottled water and avoid veggies from those areas and see how it goes. In Tokyo, it's suggested. His theory is while you are not sure, it's good idea to take precautions. After a month or so, you can be more relaxed. There is some shipping restriction by the government on spinach and some other veggies and milk, but these are about products from Fukushima , Northern Kanto region.
I read various articles of different sources. At the moment, this professor's tone is well balanced ( not just accusing somebody ) and most practical. Good reference for me to consider how to stay safe.