Nuclear power plants as well as power plants in general are not self-sufficient in terms of electricity. If a nuclear power plant loses outside electrical power, the plant must then be powered with emergency diesel generators which typically have about 10-12 hours worth of fuel, and then emergency batteries. When the batteries lose power, and they still haven't gotten electricity going back to the plant, the cooling systems for the reactors won't work because of no electricity, and then the reactors will overheat and melt. Inevitably resulting in a total meltdown. This is precisely what happened at the Fukashima NPP in Japan. The earthquake knocked out power, and then precisely what I described in the above paragraph occurred. But also many of the important systems at the plant were flooded, destroyed, or severely damaged by the tsunami. This is a very real danger facing nuclear power facilities. Have electrical engineers figured out a fool-proof way designing the electric grid in a manner where nuclear power stations will have electricity regardless of power outages/damage to the local grid from things like severe storms, earthquakes, tornadoes, and other natural disasters?