Fission Knowledge-Based Download PDF

Questions

1. 1.

   In the context of nuclear fission, what term refers to the minimum mass of fissile nuclide required to sustain a continuous, self-supporting nuclear chain reaction?

   • A) Threshold mass
   • B) Binding mass
   • C) Stoichiometric mass
   • D) Critical mass
2. 2.

   In a thermal nuclear fission reactor, what is the primary function of the moderator material, such as heavy water or graphite?

   • A) Absorbing excess neutrons to suppress the reaction rate during rapid power increases
   • B) Converting captured fast neutrons directly into electrical potential across the core
   • C) Circulating thermal energy away from the reactor core to spin steam-driven turbines
   • D) Decreasing the kinetic energy of fast neutrons through non-absorbing collisions to enhance further fission
3. 3.

   In a nuclear fission reactor, which statement correctly identifies the primary function of control rods?

   • A) To slow down high-energy neutrons to thermal speeds to increase the probability of fission
   • B) To absorb excess neutrons to regulate and sustain a steady rate of the fission chain reaction
   • C) To transfer thermal energy generated by fission away from the core to drive steam turbines
   • D) To provide physical shielding that blocks gamma radiation and escaping neutrons from leaving the reactor vessel
4. 4.

   Which of the following statements best explains why the nuclear fission of a heavy nuclide releases a tremendous amount of energy?

   • A) The total number of protons and neutrons increases as the parent nucleus divides into multiple fragments.
   • B) The resulting fission products have a greater binding energy per nucleon than the original heavy nucleus.
   • C) The strong nuclear force is completely eliminated, converting all proton mass directly into thermal energy.
   • D) The emitted free neutrons immediately annihilate with atomic electrons, releasing intense gamma radiation.
5. 5.

   Which of the following statements correctly describes the process of induced nuclear fission in a heavy nucleus such as uranium-235?

   • A) The nucleus captures a neutron to form an unstable intermediate that splits into two lighter daughter nuclei, releasing additional neutrons and a large quantity of energy.
   • B) Two light nuclei collide at high thermal energy to coalesce into a single, heavier nucleus while emitting positrons.
   • C) The nucleus spontaneously ejects a helium-4 nucleus to transform into a lighter isotope without releasing extra free neutrons.
   • D) An inner orbital electron is absorbed by a nuclear proton, converting it into a neutron and emitting a neutrino without changing the mass number.