Calculate the energy content of 1 kg of natural uranium assuming complete fission. Estimate an average energy per fission. Compare this to the energy in 1 kg of coal (reference all values assumed). Why is this estimate of the energy content of 1 kg of uranium somewhat misleading when we consider the current "once through" fuel cycle that exists in the US? What is the energy content in the roughly 64,000 tonne of used fuel in the US and the roughly 800,000 tonne of depleted uranium in the US (again assuming complete fission of each of these)?