Question

Why can't nuclear fusion be used in nuclear power plants?

Answer 1

See below

Explanation:

Nuclear fusion cannot be used in nuclear power plants because it cannot be controlled. Once it is started, it cannot be stopped till the reactants are finished.
Moreover, tremendous amount of energy is released during the nuclear fusion and it is very difficult to use the energy efficiently.
If in the future, it may be controlled then it could be used in nuclear power plants.