1 kg of  $1^{{\text{H}}^2}$  is used in fusion reactor to produce electric power. The nuclear reaction is
$1^{{\text{H}}^2}+1^{{\text{H}}^2}\to 2^{{\text{He}}^4}$ 
It is given that mass of  $1^{{\text{H}}^2}$  is 2.014 u and mass of  $2^{{\text{He}}^4}$  is 4.0026 u 
The energy liberated is  $P\times {10}^{14}\text{J}$
To convert this nuclear energy into electrical energy. The water at 300 K is heated to convert into stream at temperature 800 K. The left-over steam is at 400 K. The energy supplied to electric grid is   $Q\times {10}^{14}\text{J}$
Specific heat capacity of water $=4.2\times {10}^3\text{\hspace{0.17em}J/kg}-\text{k}$
Specific heat capacity of steam  $=2\times {10}^3\text{\hspace{0.17em}J/kg}-\text{k}$
Latent heat of vaporization of water  $=2.25\times {10}^6\text{\hspace{0.17em}J/kg}$
1 amu = $931{\text{\hspace{0.17em}MeV/c}}^{\text{2}}$