Within the operational characteristics of fast breeder reactors___________________?
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Answer: E. moderator is dispensed with
Explanation
Fast breeder reactors operate on fast neutrons and completely dispense with a moderating medium. Removing moderators prevents neutrons from slowing down, ensuring they retain the high energy needed for U-238 breeding. The absence of a moderator simplifies core physics design while requiring highly concentrated fissile fuel loading. Neutron moderators are materials like graphite or heavy water used in conventional reactors to slow down fast fission neutrons. Fast reactors utilize liquid metal coolants that provide minimal moderation, allowing high-energy neutron spectra to dominate. Dispensing with moderator structures increases core power density and improves the overall neutron economy of the breeder cycle.
Option A is incorrect because arbitrary moderators would slow down neutrons and disrupt the fast breeder reaction mechanism. Option B is wrong because graphite is a powerful moderator used in thermal reactors, not fast breeder reactors. Options C and D are incorrect because fast breeder reactors explicitly dispense with moderators rather than utilizing heavy water.
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- Engineering
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- Mechanical Engineering
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