Advanced physics

In a given year, the entirety of China consumes about 8000 TWh of electrical energy. If Chinese power plants wanted to provide all of this energy purely by using 258U nuclear reactors, how much uranium would they need each year? Take the energy density of 238U to be 8.1 1010 kJ/kg, and assume that the power plants are 30% efficient. Some helpful unit conversions: 1 TWh = 3.6*1015 J O 1.2E+6 kg O 3.6E+8 kg O 2.5E+10 kg O 1.2E+9 kg O 3.6E+6 kg