Unformatted text preview: Chapter 13 1. Compare the outlook regarding the use of nuclear power in the United States and globally in each of the following decades: 1960s, 1980s, and early 21st century. 2. Describe how energy is produced in a nuclear reaction. Distinguish between fission and fusion. Materials involved in chemical reactions remain unchanged at the atomic level, although the visible forms of these materials undergo great transformation as atoms are rearranged to form different compounds. Nuclear energy, however, involved changes at the atomic level through one of two basic processes; fission and fusion. Fission is a large atom of one element is split to produce two smaller atoms of different elements. Fusion is two small atoms combine to form a larger atom of a different element. 3. How do nuclear reactors and nuclear power plants generate electrical power? They generate electrical power in a nuclear power plant when heat from the reactor is used to boil water to provide steam for driving conventional turbogenerators. 4. What are radioactive emissions, and how are most humans exposed to them? Radioactive emissions are any of various forms of radiation or particles that may be given off by unstable isotopes. Many such emissions have very high energy and can destroy biological tissues or cause mutations leading to cancer or birth defects. 5. How are radioactive wastes produced, and what are the associated hazards? Radioactive wastes are the indirect products of fission, along with the direct products. Any materials in and around the reactor may also be converted to unstable isotopes and becomes radioactive by absorbing neutrons from the fission process. A major concern regarding nuclear power is that large numbers of the public may be exposed to low levels of radiation, elevating their risk of cancer and other disorders. 6. Describe the two stages of nuclear waste disposal. Short term containment: allows the radioactive decay of short-lived isotopes. Wastes can be handled much more easily and safely after this loss occurs. Long-term containment: EPA had recommended as 10,000year minimum to provide protection from the long-lived isotopes. 7. What problems are associated with the long-term containment of nuclear waste? What is the current status of the disposal situation? There is a problem with the security and disposal of the wastes. Currently the United States and most other countries that use nuclear power have decided on geologic burial for the ultimate consignment of nuclear wastes, but no nation has developed plans to the point of actually carrying out the burial. 8. Describe what went wrong at Chernobyl and Three Mile Island. Three Mile Island suffered a partial meltdown as a result of a series of human and equipment failures and a flawed design. The steam generator shut down automatically because of a lack of power in its feedwater pumps, and eventually a valve on top of the generator opened in response to the gradual buildup of pressure. In Chernobyl, while conducting a test of standby diesel generators, engineers disabled to power plant's safety systems, withdrew the controls rods, shut off the flow of steam to the generators, and decreased the flow of coolant waters in the reactor. It ended up blowing up and burning for days. 9. What features might make nuclear power plants safer? What about terrorism? Operator-controlled actions, external power, electrical signals, and engineering devices and structures that makes it virtually impossible for the reactor to go beyond acceptable levels of power, temperature, and radioactive emissions; their operation depends only on standard physical phenomena, such as gravity and resistance to high temperatures. As for terrorists the Energy Policy Act of 2005 has stepped up security measures, with requirements to heighten the kinds of threat nuclear plant security forces must be able to meet, and to conduct "force-on-force" security exercises at least once every three years, among others. 10. What are the four generations of nuclear reactors? Describe the advantages of Generations III and IV. Generation I reactors are the earliest, developed in the 1950s and 1960s. Generation II are vintage, the large baseline power plants, of sever designs. Generation III refers to newer designs with passive safety features and much simpler, smaller power plants. Generation IV plants are now being designed and will likely be built within the next 20 years. Generations III and IV are going to be a lot safer and will be more beneficial. 11. Discuss economic reasons that have caused many utilities to opt for coalburning, rather than nuclear-powered, plants. 12. How do fast-neutron and fusion reactors work? Does either one offer promise for alleviating our energy shortage? Fast-neutron reactors present most of the problems and hazards of standard fission reactors, plus a few more. If a meltdown occurred in a fast-neutron, the consequences would be much more serious than in an ordinary fission reactor. Fusion reactors is a way to carry out fusion in a controlled manner in order to provide a practical source of heat for boiling water to power steam turbogerators. Fast-Neutron reactors are more expensive but they extract much more energy from recycled nuclear fuel, and they produce much less high-level waste than conventional nuclear plants. 13. Explain why nuclear power does little to address our largest energy shortfall. Nuclear power does little to address our largest energy shortfall because it seems to be an obvious choice to use. It's a present economic necessity. 14. Discuss changes in nuclear power that might brighten its future. Reactor safety concerns will have to be addressed. The potential for terrorist attacks and sabotage will also have to be addressed. The industry's manufacturing philosophy will have to change to favor standard designs and factory production of the smaller reactors. The framework for licensing and monitoring reactors must be streamlined, but without sacrificing safety concerns. The waste dilemma must be resolved. Political leadership will be required to accomplish all these developments. ...
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- Spring '08
- Nuclear Fission, nuclear power plants