Consider the following statements:

1. The chain reaction process is used in nuclear bombs to release a vast amount of energy, but in nuclear reactors, there is no chain reaction.
2. In a nuclear reactor, the reaction is controlled, while in nuclear bombs, the reaction is uncontrolled.
3. In a nuclear reactor, all operating reactors are ‘critical’, while there is no question of ‘criticality’ in case of a nuclear bomb.
4. Nuclear reactors do not use moderators, while nuclear bombs use them.

Which of the above statements about operational principles of a nuclear reactor and a nuclear bomb is/are correct?