The correct option is 2, which states that statement 2 and 3 are correct.
Let`s analyze each statement:
1. The statement claims that there is no chain reaction process in nuclear reactors, but it is incorrect. Nuclear reactors indeed utilize a controlled chain reaction process to produce energy. Alert - correct answer should be
2. This statement is correct. In a nuclear reactor, the reaction is controlled, meaning that the rate of the reaction can be adjusted by control rods to maintain a stable and safe operation. In contrast, in nuclear bombs, the reaction is uncontrolled, leading to a rapid and powerful release of energy.
3. This statement is correct. In a nuclear reactor, all operating reactors are `critical`, which means that the reaction is self-sustaining and balanced. On the other hand, in the case of a nuclear bomb, criticality is not a concern as the goal is to achieve a supercritical state.
4. This statement is incorrect. Nuclear reactors do use moderators to slow down the fast neutrons and increase the likelihood of fission reactions. In nuclear bombs, moderators are not used as the objective is to achieve a fast reaction for maximum energy release.