Nuclear fission and fusion, chain reactions, fertile and fissile isotopes and radiation hazards - One Line Questions

1. An 'uncontrolled' chain reaction, as in a nuclear weapon, is characterized by: — A rapidly increasing rate of fission.
2. What is a 'prompt neutron' in nuclear fission? — A neutron emitted almost instantaneously during the fission process
3. A 'controlled' chain reaction, as in a nuclear power reactor, is characterized by: — A constant and manageable rate of fission.
4. Neutron activation is the process by which: — A stable nucleus becomes radioactive after absorbing a neutron.
5. What is a common method used to shield against beta radiation? — A few millimeters of aluminum or plastic
6. The process of converting a fertile isotope like Uranium-238 into a fissile isotope like Plutonium-239 involves: — Absorption of a neutron followed by decay
7. What type of radiation consists of high-energy photons and has no mass or charge? — Gamma rays
8. Which type of radiation is essentially a helium nucleus (2 protons and 2 neutrons)? — Alpha particles
9. Which of the following is NOT a form of ionizing radiation? — Visible light
10. Which type of radiation has the greatest penetrating power and requires thick shielding like lead or concrete? — Gamma rays
11. What is a 'fertile' isotope in the context of nuclear reactions? — An isotope that can be converted into a fissile isotope
12. What is the unit of absorbed radiation dose commonly used in medicine and health physics? — Gray (Gy)
13. What are the main reactants in the fusion process that powers the Sun? — Hydrogen and Helium
14. Which process involves the release of energy due to the strong nuclear force binding nucleons together? — Nuclear fission and fusion
15. What is a major challenge in achieving controlled nuclear fusion on Earth? — Containing the extremely high temperatures required
16. What is the term for the minimum amount of fissile material needed to sustain a chain reaction? — Critical mass
17. What is the primary hazard of internal radioactive contamination? — High dose of radiation delivered directly to internal organs
18. What is the term for an isotope that can undergo fission when it absorbs a neutron? — Fissile isotope
19. What is the term for an isotope that can be readily fissioned by fast neutrons? — Fissionable isotope
20. What is the unit of equivalent dose or effective dose, which accounts for the biological effectiveness of different types of radiation? — Sievert (Sv)
21. What is the primary mechanism by which ionizing radiation damages biological tissues? — Causing chemical changes in molecules, including DNA
22. Which of the following is a primary requirement for initiating a nuclear fission chain reaction? — Sufficient quantity of fissile material
23. Which of the following is a potential long-term health effect of significant radiation exposure? — Increased risk of cancer
24. What is the primary hazard associated with neutron radiation? — It is highly penetrating and can damage living tissue
25. Uranium-238 is considered fissionable but not fissile because: — It requires very high energy neutrons to fission, unlike thermal neutrons.
26. Nuclear fusion requires what conditions to occur? — High temperatures and high pressures
27. Which of the following is a significant source of background radiation? — Cosmic rays and naturally occurring radioactive elements in the Earth's crust
28. What is the term for the phenomenon where a neutron is captured by a nucleus without causing fission? — Neutron capture
29. What are 'delayed neutrons' in nuclear fission? — Neutrons emitted by fission products after beta decay
30. What is the process by which two light atomic nuclei combine to form a single heavier nucleus, releasing energy? — Nuclear fusion
31. Which of the following is the primary energy source of stars, including our Sun? — Nuclear fusion
32. What is the term for the process where a radioactive nucleus loses energy by emitting particles or electromagnetic waves? — Radioactive decay
33. What is the process by which a heavy atomic nucleus splits into two or more lighter nuclei, releasing a large amount of energy? — Nuclear fission
34. Control rods in a nuclear reactor are typically made of materials that: — Absorb neutrons strongly
35. Beta particles are actually: — Electrons or positrons
36. What is a common method used to shield against alpha radiation? — A thin sheet of paper or the outer layer of skin
37. What is a 'breeder reactor' designed to do? — Produce more fissile material than it consumes
38. What condition is necessary for a nuclear chain reaction to be sustained (i.e., not die out)? — The average number of neutrons produced per fission that cause further fission must be greater than one.
39. What is the main source of energy released during nuclear fission? — The conversion of mass into energy (E=mc²)
40. A 'chain reaction' in nuclear fission refers to: — The process where neutrons released from one fission cause further fissions
41. A 'critical' chain reaction occurs when: — The rate of fission remains constant.
42. Why are delayed neutrons important in the control of nuclear reactors? — They allow for a more gradual and controllable increase in reactivity.
43. What is the main reason for using moderators (like water or graphite) in nuclear reactors? — To slow down fast neutrons to thermal energies, making them more likely to cause fission in Uranium-235.
44. What are the typical fission products of Uranium-235? — Two lighter nuclei with approximately half the mass of Uranium-235
45. What is the most common product of nuclear fission that poses a long-term waste disposal challenge? — Fission product isotopes with long half-lives (e.g., Cesium-137, Strontium-90)
46. What is a common material used for control rods in nuclear reactors? — Cadmium or Boron
47. Which of the following is a fertile isotope that can be converted into a fissile isotope (Plutonium-239)? — Uranium-238
48. Which isotope is often used as a target for producing transuranic elements through neutron bombardment? — Uranium-238
49. Which of the following is a common example of a fissile isotope used in nuclear reactors? — Uranium-235
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