Question

A reactor is generating energy at the rate of $1500kW$. How many atoms of $U_{235}$ undergo fission per second, if $180MeV$ energy is released per fission?

• A. $6.5\times {10}^{2}2$
• B. $5.2\times {10}^{16}$
• C. $1.3\times {10}^{21}$
• D. $2.6\times {10}^{16}$

Answer 1

The correct option is B $5.2\times {10}^{16}$

Rate of generation of energy by the reactor $=1500kW=1.5\times {10}^{6}J{s}^{-1}$

Energy released per fission = $180MeV=180\times {10}^{6}eV=180\times {10}^6\times 1.6\times {10}^{-19}J/atom=2.88\times {10}^{-11}J/atom$

Number of atoms undergoing fission per second = $\frac{1.5\times {10}^{6}J{s}^{-1}}{2.88\times {10}^{-11}J/atom}$
$=0.521\times {10}^{17}atoms/sec$
$=5.21\times {10}^{16}atoms/sec$