The news from Japan sounds like what many in the survivalist community are trying to plan for. Natural disaster combined with man made hazards. The earthquake shook the land which caused tsunamis in the area and practically destroyed the nuclear facilities there. The Japanese don't seem to be worried but they sure are risking alot trying to stop what could happen. They've decided to send men in to re-enact Chernobal. Men are trying to keep the nuclear rods wet and repair as much damage as they can to keep a meltdown from happening.
We can not prepare for everything but those outside the radius of initial blast and heaviest radiation concentration may survive with an underground bunker, food, and water stores. Most of us are not able to build an underground bunker so we need to make do. Such as thick plastic sheeting and duct tape. Find a place in your dwelling with as few openings as possible. Load all the water and food you can in there along with a way to hold waste and control the odor. Remember that for this to work you have to use the plastic sheeting to cover all openings in the room so oxygen will be limited. Use in emergency situation only. If time permits shut off electricity, water, and gas to the dwelling before entering into the emergency room. This will prevent the circulation of radioactive material in the home and reduce fires. One of the main reasons people get radiation poisoning is the radiactive dust they breath after the explosion.
Use precaution and prepare. Its the safest way to survive another day.