Answer with Explanation:
The relation between power and energy is
![Energy=Power* Time](https://img.qammunity.org/2020/formulas/physics/high-school/1qt8q3arlkuodux4pysbi83zej0s96zd51.png)
Since the nuclear reactor operates at 1200 MW throughout the year thus the energy produced in 1 year equals
![E=1200* 10^(6)* 3600* 24* 365=3.784* 10^(16)](https://img.qammunity.org/2020/formulas/engineering/college/og2nebyobcwfj2yn7zkstp9m3p3atayub8.png)
Now from the energy mass equivalence we have
![E=mass* c^2](https://img.qammunity.org/2020/formulas/engineering/college/m13xyxglxn8ie0czkngwjts2p320k4t9ig.png)
where
'c' is the speed of light in free space
Thus equating both the above values we get
![3.784* 10^(16)=mass* (3* 10^(8))^(2)\\\\\therefore mass=(3.784* 10^(16))/(9* 10^(16))=0.42kg](https://img.qammunity.org/2020/formulas/engineering/college/uveln3y3z3pfvyghdqvbjzmlko2yoj8nk3.png)
Since it is given that 1 kg of mass is 34% effective thus the mass reuired for the reactor is
![mass_(req)=(mass)/(\eta )=(0.43)/(0.34)=1.235](https://img.qammunity.org/2020/formulas/engineering/college/8j0mvyl7lpzz0i3ikvbb1ck09nfxsvwupu.png)
Thus 1.235 kg of nuclear fuel is reuired for operation.