2017 · Q60
Consider the following statements :
- 1The chain reaction process is used in nuclear bombs to release a vast amount of energy, but in nuclear reactors, there is no chain reaction.
- 2In a nuclear reactor, the reaction is controlled, while in nuclear bombs, the reaction is uncontrolled.
- 3In a nuclear reactor, all operating reactions are ‘critical’, while there is no question of ‘criticality’ in case of a nuclear bomb.
- 4Nuclear 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 ?
General KnowledgePhysics
- A1 and 3
- B2 and 3
- C4 only
- D1 and 4
Explanation
Statement 1 is false: a nuclear reactor does sustain a controlled nuclear chain reaction. Statement 2 is true: the reactor's reaction is controlled (via control rods and moderators), whereas a bomb's chain reaction is uncontrolled. Statement 3 is true: reactors are maintained in a critical state (neutron multiplication factor k = 1), while criticality is a concept inapplicable to a bomb's supercritical explosion. Statement 4 is false: reactors use moderators (water, graphite) to slow neutrons; atom bombs do not. Hence statements 2 and 3 only are correct.