At typical nuclear power plants refueling occurs every 19 mo

At typical nuclear power plants, refueling occurs every 19 months. Assuming that a plant has operated continuously since the last refueling and produces 1.9 GW of electrical power at an efficiency of 34%, how much less massive are the fuel rods at the end of the 19 months than at the start? (Assume 30-day months.)

Solution

Power = P*34/100 = E/t

=> E = 34Pt/100

=> E = 34*1.9*10^9*19*(2592000)/(100) ( no of second in one month = 2592000 sec )

=> mC^2 = E

=> m = 34*1.9*10^9*19*(2592000)/((3*10^8)^2*100) = 0.353 kg