Answer:
The amount of nuclear fuel required is 1.24 kg.
Explanation:
From the principle of mass energy equivalence we know that energy generated by mass 'm' in an nuclear plant is

where
'c' is the speed of light in free space
Since the power plant operates at 1200 MW thus the total energy produced in 1 year equals

Thus using the energy produced in the energy equivalence we get

Now since the efficiency of conversion is 34% thus the fuel required equals
