A town has a population of 1 million. The average electric power needed per person is 300 W. A reactor is to be designed to supply power to this town. The efficiency with which thermal power is converted into electric power is aimed at 25 %. (a) Assuming 200 MeV of thermal energy to come from each fission event on an average, find the number of events that should take place every day. (b) Assuming the fission to take place largely through 235U, at what rate will the amount of 235U decrease ? Express your answer in kg per day. (c) Assuming that uranium enriched to 3% in 235U will be used, how much uranium is needed per month (30 days) ?
(a) Total power used by town in one day
= 300×106×60×60×24 Joule
Energy generated in one fission
= 3.2×10−11 Joule
Let no of fission be N
So, N×8×10−12 Joule
N = 3.24×1024
(b) Number of moles required per day
= 3.24×10246.023×1023=5.38 mole
So number of moles not required per day
= 1264.3 gm = 1.2643 kg.
(c) Total uranium needed per month
= 1.264×30 kg
Let xgm of uranium enriched 803 % is used
So, x ×3100=1.264×30
x = 1264 kg.