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18 Cards in this Set
- Front
- Back
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Delayed neutrons are fission neutrons that... A. have reached thermal equilibrium with the surrounding medium. B. are expelled as thermal neutrons. C. are expelled at a lower average kinetic energy than most other fission neutrons. D. are responsible for the majority of U-235 fissions.
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C.
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Delayed neutrons are the neutrons that... A. have reached thermal equilibrium with the surrounding medium. B. are expelled within 10-14 seconds of the fission event. C. are produced from the radioactive decay of certain fission fragments. D. are responsible for the majority of U-235 fissions.
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C.
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Which one of the following is a characteristic of a prompt neutron? A. Expelled with an average kinetic energy of 0.5 MeV. B. Usually emitted by the excited nucleus of a fission product. C. Accounts for more than 99 percent of fission neutrons. D. Released an average of 13 seconds after the fission event.
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C.
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A neutron that is expelled 1.0 x 10-2 seconds after the associated fission event is a ____________ neutron. A. thermal B. delayed C. prompt D. capture
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B.
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A neutron that is expelled 1.0 x 10-6 seconds after the associated fission event is a ____________ neutron. A. thermal B. delayed C. prompt D. capture
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B.
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Which one of the following types of neutrons has an average neutron generation lifetime of 12.5 seconds? A. Prompt B. Delayed C. Fast D. Thermal
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B.
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In a comparison between a delayed neutron and a prompt neutron produced from the same fission event, the prompt neutron is more likely to... A. require a greater number of collisions to become a thermal neutron. B. be captured by U-238 at a resonance energy peak between 1 eV and 1000 eV. C. be expelled with a lower kinetic energy. D. cause thermal fission of a U-235 nucleus.
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A.
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In a comparison between a delayed neutron and a prompt neutron produced from the same fission event, the prompt neutron is more likely to... A. cause fast fission of a U-238 nucleus. B. be captured by a U-238 nucleus at a resonance energy between 1 eV and 1000 eV. C. be captured by a Xe-135 nucleus. D. cause thermal fission of a U-235 nucleus.
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A.
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A neutron that is released 1.0 x 10-10 seconds after the associated fission event is classified as a ____________ fission neutron. A. delayed B. prompt C. thermal D. spontaneous
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A.
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As compared to a prompt neutron, a delayed neutron, produced from the same fission event, requires _______ collisions in the moderator to become thermal and is _______ likely to cause fission of a U-238 nucleus. (Neglect the effects of neutron leakage.) A. more; more B. more; less C. fewer; more D. fewer; less
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D.
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In a comparison between a delayed neutron and a prompt neutron produced from the same fission event, the prompt neutron is more likely to... A. leak out of the core while slowing down. B. be captured by a U-238 nucleus at a resonance energy. C. be captured by a Xe-135 nucleus. D. cause thermal fission of a U-235 nucleus.
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A.
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In a comparison between a delayed neutron and a prompt neutron produced from the same fission event, the delayed neutron is more likely to... A. leak out of the core. B. cause fission of a U-238 nucleus. C. become a thermal neutron. D. cause fission of a Pu-240 nucleus.
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C.
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During a brief time interval in a typical commercial nuclear reactor operating near the beginning of a fuel cycle, 1.0 x 103 delayed neutrons were emitted. Approximately how many prompt neutrons were emitted during this same time interval? A. 1.5 x 105 B. 6.5 x 106 C. 1.5 x 107 D. 6.5 x 108
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A.
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Which one of the following types of neutrons in a nuclear reactor is more likely to cause fission of a U-238 nucleus in the reactor fuel? (Assume that each type of neutron remains in the reactor core until it interacts with a U-238 nucleus.) A. Thermal neutron B. Prompt fission neutron beginning to slow down C. Delayed fission neutron beginning to slow down D. Neutron at a U-238 resonance energy
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B.
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During a brief time interval in a typical commercial nuclear reactor operating at the beginning of a fuel cycle, 1.0 x 105 delayed neutrons were emitted. Approximately how many prompt neutrons were emitted in the reactor during this same time interval? A. 1.5 x 105 B. 6.5 x 106 C. 1.5 x 107 D. 6.5 x 108
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C.
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A neutron that appears 1.0 x 10-16 seconds after the associated fission event is classified as a ____________ fission neutron. A. delayed B. prompt C. thermal D. spontaneous
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B.
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During a brief time interval in a typical commercial nuclear reactor operating at the beginning of a fuel cycle, 4.25 x 105 delayed neutrons were emitted. Approximately how many prompt neutrons were emitted in the reactor during this same time interval? A. 1.5 x 106 B. 6.5 x 106 C. 1.5 x 107 D. 6.5 x 107
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D.
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In a comparison between a delayed neutron and a prompt neutron produced from the same fission event, the delayed neutron is more likely to... (Assume that each neutron remains in the core unless otherwise stated.) A. cause fission of a U-238 nucleus. B. require a greater number of collisions to become a thermal neutron. C. be absorbed in a B-10 nucleus. D. leak out of the core.
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C.
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