One of the most useful ways to overcome fear of the unknown is to gain knowledge about the source of the fear. There have been a lot of scary sounding reports recently about the state of the nuclear fuel cores inside the pressure vessels at Fukushima Daiichi units 1, 2, and 3. Many of them have breathlessly implied that there is still danger to the people who live within 20-50 miles of the plant boundaries.
Nothing could be farther from the truth. Those nuclear cores stopped producing fission heat about 80 days ago and their decay heat production has decreased rather dramatically.
The materials inside the pressure vessels melted and a few of the many radioactive isotopes escaped with some leaking water, but the vast majority of the material has solidified inside the reactor pressure vessels. No one outside of the plant boundaries is in any danger; the people working inside the boundaries need to take some protective measures, but they are at a higher risk from normal industrial accidents than from radiation.
Since it will still be many months before those vessels can be opened and inspected, I thought you might like to see what they probably look like inside.
Though core melts are rare, expensive and worth avoiding if at all possible, there is at least one documented case of a complete loss of coolant flow that resulted in substantially melting a large, light water reactor built to western regulatory standards. The Three Mile Island accident was not caused by an earthquake, tsunami or power outage, but the conditions inside the core were almost identical to those found at Fukushima Daiichi. There was a large core that had been operated a high power, the core was shut down, the coolant flow was stopped and the core ended up being uncovered for a number of hours before cooling was restored.
Here is a video that describes the decade long effort to inspect the results and remove the melted fuel. It was certainly not simple, but it was also not dangerous or scary. I have met a number of people who were involved; some are excitedly making plans to earn a large wad of cash by sharing their experience in Japan while knowing that they will not be putting their health at risk.
Part 1 of 2
Here is part 2 of 2
Note: The above videos were copied and loaded to YouTube with ex post facto permission from FirstEnergy, the current owner of Three Mile Island Unit 2 and the copyright holder for the archives that detail the clean up efforts. They have been available on YouTube for a couple of days, but I waited until receiving permission to leave them there before sharing them more widely.