Question

A reactor is developing energy at the rate of $32$MW. Calculate the required number of fissions per second of ${}_{92}{U}^{235}$. Assume that energy per fission is $200$MeV.

Answer 1

Rate at which energy is developed $\frac{E}{t}=32MW=32\times {10}^6\frac{J}{s}$
Energy generated per fission $E_f=200MeV=200MeV\times {10}^{6}eV/MeV\times 1.6\times {10}^{-19}J/eV$
$E_f=32\times {10}^{-12}J$
So, number of fissions required per second $N=\frac{32\times {10}^{6}J/s}{32\times {10}^{-12}J}$
$⟹N={10}^{18}$ fissions per second