Nuclear Energy Assessment Answer Key

1. Label the Atom a. Energy level—(shells) where electrons orbit b. Nucleus—center of atom, composed of protons and neutrons, positively charged c. Proton—positively charged, mass of 1 d. Neutron—no charge, mass of 1 e. Electron—negatively charged particle, very small 2. Five Renewable Energy Sources: hydropower, biomass, wind, solar, geothermal 3. Five Nonrenewable Energy Sources: coal, petroleum, natural gas, uranium, propane 4. Answers may vary. Students may draw pictures of their model generator with coils of wire and magnets in motion. 5. Nuclear reactions may release: heat, light, alpha particles, beta particles, energy 6. Uranium must be enriched because less than 1% of natural uranium is U-235, but only U-235 can undergo fission. Uranium is enriched to bring the level of U-235 to 3-5% to create a sustained fission/chain reaction. 7. A moderator slows neutrons and controls the rate of the chain reaction. Moderators are graphite, purified natural (light) water, or heavy water. 8. Label the Nuclear Reactor a. Reactor—contains the fuel assembly, control rods, and water. b. Fuel Rods—contain uranium fuel that undergoes chain reaction. c. Pressurizer—in a pressurized water reactor, the pressurizer holds the water at a high pressure so that it doesn’t boil. d. Containment Structure—an important security layer made of cement with a steel lining, designed to prevent leakage of radioactive gases, steam, and water into the atmosphere should a leak occur inside. e. Control Rods—contain boron or cadmium to absorb or capture neutrons, slowing or stopping the nuclear fission chain reaction. 9. Nuclear proliferation describes the spread of nuclear weapons, fissile materials, and nuclear technology. The Non-Proliferation Treaty was designed to help control proliferation. Uncontrolled nuclear proliferation is cause for concern when safeguards and peacekeeping are considered. 10. The biggest challenge with spent fuel in the U.S. is storage and disposal of high level waste. 11. Lessons from Nuclear Accidents a. Three Mile Island—safety designs are effective, but also led to additional improved safety features being implemented in nuclear plant designs b. Chernobyl—automatic plant safety features should not be turned off, secondary containment is important, improved training for operators is needed c. Fukushima—ensure back-up systems to cool reactors, modify hardware for use during emergencies, protect back-up generators and batteries 12. Safety Features (possible answers include): containment structure, training of operators/workforce, automatic shut down/control rods automatically drop, water in the containment structure, dual layers of containment structure and reactor vessel (cement and steel) 13. Historical Event—Answers will vary. Events may include the use of the atomic bomb in WWII, the first nuclear power reactor, the incidents at Chernobyl, Three Mile Island, and/or Fukushima. 14. Nuclear science has benefited society through nuclear medicine (x-rays, nuclear imaging, cancer treatments, etc.), smoke detectors, powers Navy vessels, food irradiation, etc.