Science
MediumQ. No. which-particle-is-used-to-initiate-nuclear-fission-in-a-reactor
Which particle is used to initiate nuclear fission in a reactor?
Last Updated:
AProton
BAlpha particle
CSlow neutron
DBeta particle
Correct Answer: Slow neutron
In a nuclear reactor, slow neutrons (also called thermal neutrons) are used to initiate and sustain nuclear fission. Option C is correct: Slow neutrons have the right energy level to be captured efficiently by U-235 nuclei, making them unstable and causing fission. Fast neutrons are less efficient because they pass through without being captured. Option A is incorrect: Protons carry positive charge and are repelled by the positively charged nucleus due to electrostatic repulsion, making them ineffective for initiating fission. Option B is incorrect: Alpha particles are helium nuclei with +2 charge and are also repelled by the nucleus due to Coulomb repulsion, making them unsuitable. Option D is incorrect: Beta particles are fast-moving electrons emitted during radioactive decay; they do not initiate nuclear fission. A moderator (heavy water or graphite) is used in reactors to slow down fast neutrons to thermal speeds required for sustained fission.
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