Question 1: Define a chain reaction in the context of nuclear energy.

Answer: A chain reaction is a self-sustaining series of nuclear reactions where the neutrons released from one fission event trigger additional fission events.

Question 2: Describe the basic process that initiates a nuclear chain reaction in a reactor.

Answer: A nuclear chain reaction begins when a fissile nucleus, such as Uranium-235, absorbs a neutron and splits, releasing energy and additional neutrons that can cause further fissions.

Question 3: Explain why control rods are used in a nuclear reactor.

Answer: Control rods absorb extra neutrons to regulate the rate of the chain reaction, preventing it from becoming uncontrollable.

Question 4: Calculate the energy released (in joules) when 1 gram of Uranium-235 undergoes fission. (Given: 200 MeV per fission; 1 eV = 1.6 x 10^-19 J).

Answer: Energy = Number of atoms x energy per atom; First, find number of atoms: Mass of U-235 = 1 g = 0.001 kg Molar mass of U-235 ≈ 235 g/mol Number of moles = 1 g / 235 g/mol ≈ 0.004255 mol Number of atoms = 0.004255 mol x 6.022 x 10^23 atoms/mol ≈ 2.56 x 10^21 atoms Total energy = 2.56 x 10^21 atoms x 200 MeV x 1.6 x 10^-13 J/MeV ≈ 8.19 x 10^10 J

Question 5: Identify three safety precautions that must be observed when handling materials involved in nuclear chain reactions.

Answer: Wearing protective clothing and gloves, using shielding to contain radiation, and following strict handling and storage protocols for fissile materials.

Question 6: In a nuclear reactor, if the number of neutrons produced doubles every second, what type of chain reaction is this considered? Explain your answer.

Answer: This is a supercritical chain reaction because the number of neutrons increases exponentially, leading to a rapid increase in the reaction rate.

Question 7: Describe a practical application of nuclear chain reactions outside of power generation.

Answer: Nuclear chain reactions are used in nuclear medicine for cancer treatment through radiation therapy.

Question 8: What is the main advantage of using controlled chain reactions in nuclear power plants?

Answer: Controlled chain reactions allow for the safe and steady release of energy, providing a reliable power source without risking uncontrolled explosions.

Question 9: Explain what would happen if a nuclear chain reaction becomes uncontrolled.

Answer: An uncontrolled chain reaction can cause a rapid release of energy, leading to explosions or meltdowns in a nuclear reactor.

Question 10: Identify a recent technological advancement that improves safety or efficiency in nuclear chain reactions.

Answer: The development of advanced control rod materials and automated shutdown systems enhances safety and efficiency in modern nuclear reactors.