Please do not believe all the Hell & Death stories in the UK and American media. At the moment a criticality event is highly unlikely. The main threat now is radiation in the form of air pollution. Things could get very ugly very soon, depending on the direction of winds and also whether or not it will rain in the coming days. The government and electric power company have the appearance of being close with the news, reeking of cover-up and deliberate news blackout to prevent mass panic – already in my neighbourhood there is panic-buying of food and supplies – but also more likely because they do not know the full extent of the danger at the moment. There is no question that Tokyo Denryoku employees are risking their lives round the clock in a dangerous and radioactive environment doing their utmost to control the heat of the reactors; and Kasumigaseki will be just as affected as the rest of Tokyo if things go pear-shaped, so it is important to stay informed and keep listening to the radio or television. A lot of expats here seem to be scared because there is a paucity of English information available, and some have bent their ears to some of the more ludicrous rumours doing the rounds at the moment. My advice would be to keep an eye on NHK, the Japanese public broadcasters, who have a good rolling news site in English:
The BBC also has a pretty good explanation of what has happened and is ongoing, including a diagram explaining the process:
And shame and a pox on those news providers broadcasting sensational, wild headlines and often very clearly wrong information about current events.