# Study guide based on Quiz 1 - NUC 120

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2015-11-10 13:14

## Quiz 1 - Neutron Life Cycle

Question | Answer |
---|---|

1. The effective multiplication factor (K eff) can be determined by dividing the number of neutrons in the third generation by the number of neutron in the __________ generation. | Second |

2. What condition describes a nuclear reactor that is supercritical? | K eff > 1 |

3. The fast fission factor (ε) decreases as fuel pin diameter __________ and as moderation __________. A. Decreases; increases B. Increases; decreases C. Increases; increases D. Decreases; decreases | A. |

4. As core life increases, __________ A. Fast and thermal neutron leakage increases. B. Fast and thermal neutron leakage decreases. C. Fast neutron leakage increases and thermal neutron leakage decreases. D. Fast neutron leakage decreases and thermal neutron leakage increases. | B. |

5. As steam voids form in the reactor, A. Fast and thermal neutron leakage increases. B. Fast and thermal neutron leakage decreases. C. Fast neutron leakage increases and thermal neutron leakage decreases. D. Fast neutron leakage decreases and thermal neutron leakage increases. | A. |

6. Why does resonance escape probability (p) decrease over core life? A. Some U-238 transforms into Pu-240 and Pu-240 is a higher resonance absorber. B. Some U-235 transforms into Pu-240 and Pu-240 is a higher resonance absorber. C. Some Pu-240 transforms into U-238 and U-238 is a lower resonance absorber. D. Some U-238 transforms into Pu-240 and Pu-240 is a lower resonance absorber. | A. |

7. As the core ages, A. The amount of U-235 decreases and the amount of gadolinium decreases. B. The amount of U-235 increases and the amount of gadolinium decreases. C. The amount of U-235 decreases and the amount of gadolinium increases. D. The amount of U-235 increases and the amount of gadolinium increases. | A. |

8. What is the effect on the thermal utilization factor (f) from increasing the enrichment of U-235? A. It increases f because the thermal neutron macroscopic cross section for absorption for U-238 is greater than the thermal neutron macroscopic cross section for absorption for U-235. B. It increases f because the thermal neutron macroscopic cross section for absorption for U-235 is greater than the thermal neutron macroscopic cross section for absorption for U-238. C. It decreases f because the thermal neutron macroscopic cross section for absorption for U-238 is greater than the thermal neutron macroscopic cross section for absorptionfor U-235. D. It decreases f because the thermal neutron macroscopic cross section for absorption for U-235 is greater than the thermal neutron macroscopic cross section for absorption for U-238. | B |

9. Which of the following statements is true? A. The neutron yield per fission for Pu-239 is lower than for U-235, and the production of Pu-239 is higher than the depletion of U-235 as the core ages. B. The neutron yield per fission for Pu-239 is higher than for U-235, and the production of Pu-239 is higher than the depletion of U-235 as the core ages. C. The neutron yield per fission for Pu-239 is higher than for U-235, and the production of Pu-239 is lower than the depletion of U-235 as the core ages. D. The neutron yield per fission for Pu-239 is lower than for U-235, and the production of Pu-239 is lower than the depletion of U-235 as the core ages. | C. |

10. Which of the following factors have values greater than one? A. Resonance escape probability and fast fission factor. B. Reproduction factor and fast fission factor. C. Reproduction factor and resonance escape probability. D. Resonance escape probability and non-leakage probabilities. | B. |

11. What variable causes the reproduction factor to change? A. Reactor pressure. B. Moderator temperature. C. Core age. D. Fuel temperature. | C. |

12. The resonance escape probability (ρ) decreases as core age __________ and fuel temperature __________. A. Decreases; decreases B. Decreases; increases C. Increases; decreases D. Increases; increases | D. |

13. As moderator temperature increases, the resonance escape probability (p) __________ and the thermal utilization factor (f) __________. A. Decreases; decreases B. Decreases; increases C. Increases; decreases D. Increases; increases | B. |

14. What is affected by an increase in fission product poison concentration? A. Fast fission factor (ε) B. Resonance escape probability (p) C. Thermal utilization factor (f) D. Reproduction factor (η) | C. |

15. A cross section plot is a graph of __________ vs. __________. A. Neutron energy on X-axis and microscopic cross section on Y-axis. B. Neutron energy on Y-axis and microscopic cross section on X-axis. C. Neutron energy on X-axis and macroscopic cross section on Y-axis. A. Neutron energy on Y-axis and macroscopic cross section on X-axis. | A. |

16. Which nuclide has the most probable fission cross section for fast neutrons? A. U-235 B. U-238 C. Pu-239 D. Pu-241 | B. |

17. As fuel atomic density __________, the fast fission factor (ε) __________. A. Increases; decreases B. Decreases; increases C. Decreases; decreases D. Fuel atomic density is not related to fast fission factor. | C. |

18. As the core ages, the amount of U-235 _________ and the amount of Pu-239 __________. A. Increases; increases B. Increases; decreases C. Decreases; increases D. Decreases; decreases | C. |

19 What is the cause of Pu-239 formation? A. Neutron emission of Pu-240 B. Neutron capture of U-238 C. Alpha decay of Pu-241 D. Beta decay of Am-239 | B. |

20. What is affected by an increase in fuel temperature? A. Fast fission factor (ε) B. Resonance escape probability (p) C. Thermal utilization factor (f) D. Reproduction factor (η) | B. |

Question | Answer |
---|---|

What does the symbol ε represent? | Fast fission factor |

What symbol represents Fast Non-leakage Probability? | Lf (L sub f) |

What symbol represents Resonance Escape Probability? | p |

What does the symbol p represent? | Resonance Escape Probability |

What symbol represents Fast Fission Factor? | ε (lower case epsilon) |

What does the symbol Lf (L sub f) represent? | Fast Non-leakage Probability |

What does the symbol Lth (L sub TH) represent? | Thermal Non-leakage Probability |

What symbol represents Thermal Non-leakage Probability? | Lth (L sub TH) |

What symbol represents Thermal Utilization Factor? | f |

What does the symbol f represent? | Thermal Utilization Factor |

What symbol represents Reproduction Factor? | η (lower case Eta) |

What does the symbol η (lower case Eta) represent? | Reproduction Factor |

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