KAKU: Even if the sea water successfully prevents this scenario, we are talking weeks to months to clean up this accident. The heat from the core will last for weeks, and cleanup operations are hampered by the chaos caused by the earthquake. Also, since these fission byproducts are water-soluble and would get into crops, this could also ruin the agricultural economy.
CRINCIONE: We have been talking about either a meltdown or shutdown but we have a third possibility that is emerging. That these reactors staying in a crisis state, venting radioactive steam for an extended period of time, maybe weeks — that means that the people who have evacuated, 200.000 and growing so far, can't return. You could be looking at hundreds, maybe thousands of [square] kilometers that would be uninhabitable for weeks, maybe months….
Tokyo is far away from these reactors that are in danger now, but we just had a U.S. carrier that is a hundred miles from this site redeployed to get even further away. A hundred miles is about Tokyo suburbs' distance. You've got to be a little worried if you are in Tokyo.
CIRINCIONE: We will be out of danger when the temperatures inside these reactors drop. Then we will know we have actually stabilized the reactions… The impact of a meltdown is almost immediate and it depends how strong the winds are, but people would be exposed immediately in the area and then within hours in nearby cities.