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Paula L. Diaconescu. NUCLEAR POWER AS ALTERNATIVE ENERGY. Why talk about nuclear energy?. http://copper.chem.ucla.edu/pldgroup/index.htm. Whitesides Science 2007. The news. Nuclear power now generates 15% of the world's electricity.
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Paula L. Diaconescu NUCLEAR POWER AS ALTERNATIVE ENERGY
Why talk about nuclear energy? http://copper.chem.ucla.edu/pldgroup/index.htm
The news • Nuclear power now generates 15% of the world's electricity. • The International Atomic Energy Agency expects at least 70 new plants to be opened within the next 15 years. This could result in a doubling of the amount of electricity produced by nuclear plants. • The small- and medium-sized reactors now in development could help meet energy needs in the more remote areas of the world. They don't run on fossil fuels so their location isn't constrained by access to oil, gas or coal. Nor do they require the expensive infrastructure of national electricity grids. Time to Embrace the Nuclear Option – The Wall Street Journal, February 3, 2010
Why not more? • a combination of alternative and plentiful energy sources, high costs, the impact of the Chernobyl disaster as well as scare campaigns MWC News, February 5, 2010
The problem: nuclear waste • Perhaps the single biggest expense of the nuclear power is the storage of nuclear waste. • Currently: temporary storage • Viable long-term solution has yet to be found (storage needed on the order of thousands of years). • Nuclear power is the only energy industry which takes full responsibility for all its wastes, and costs this into the product. http://www.world-nuclear.org/education/wast.htm
Radioactivity • Radioactivity arises naturally from the decay of particular forms of some elements, called isotopes. • Types of radioactivity • alpha • beta • gamma • neutron radiation: only inside a nuclear reactor • All of these kinds of radiation are, at low levels, naturally part of our environment. Any or all of them may be present in any classification of waste. http://www.world-nuclear.org/education/wast.htm
Types of radioactive waste • Low level: hospitals, laboratories and industry, as well as the nuclear fuel cycle • paper, rags, tools, clothing, filters, which contain small amounts of mostly short-lived radioactivity • it is often compacted or incinerated before disposal. • 90% of the volume but only 1% of the radioactivity • Intermediate level: higher amounts of radioactivity and may require special shielding • resins, chemical sludge, and reactor components, as well as contaminated materials from reactor decommissioning • 7% of the volume and has 4% of the radioactivity • High level: may be the used fuel itself or the principal waste from reprocessing it • 3% of the volume but 95% of the radioactivity • Whether used fuel is reprocessed or not, the volume of high-level waste is modest, - about 3 cubic meters per year of vitrified waste or 25-30 tons of used fuel for a typical large nuclear reactor. http://www.world-nuclear.org/education/wast.htm
Temporary storage of fuel rods • Most nuclear power plants have a temporary storage pool next to the reactor. • The pool is filled with boric acid, which helps to absorb some of the radiation given off by the radioactive nuclei inside the spent rods. • The spent fuel rods are supposed to stay in the pool for only about 6 months, but, because there is no permanent storage site, they often stay there for years. http://library.thinkquest.org/17940/texts/nuclear_waste_storage/nuclear_waste_storage.html
Dry-cask storage containers • Another method of temporary storage because of the overcrowding of pools • It is used after the waste has already spent about 5 years cooling in a pool. • It entails taking the waste and putting it in reinforced casks or entombing it in concrete bunkers. • The casks are also usually located close to the reactor site. http://library.thinkquest.org/17940/texts/nuclear_waste_storage/nuclear_waste_storage.html
Permanent fuel storage/disposal • Bury under the ocean floor • Store underground • Shoot into space • Deep geological disposal • little groundwater flowing through • little geological activity1 http://library.thinkquest.org/17940/texts/nuclear_waste_storage/nuclear_waste_storage.html
Yucca mountain, Nevada • Extremely dry area of Nevada • The Yucca Mountain Deep Geological Repository is projected to be ready by the year 2010 • The casks will be buried about 1500 feet underground http://library.thinkquest.org/17940/texts/nuclear_waste_storage/nuclear_waste_storage.html
New nuclear power technologies • Reprocessing: the missing step • one of the major transuranic wastes, 239Pu, is extracted from the spent fuel rods. • plutonium-239 is fissile and can be reused in power plants. • High-temperature breeder reactors • The transuranic elements are bigger than uranium and generally don't fission in a regular reactor. However, if placed in a high-temperature reactor in which the neutrons are much more excited, there is a much better chance that they will fission. • In a reactor being developed by Argonne National Laboratory, almost 100% of the transuranic nuclear wastes produced through neutron capture can be caused to fission. • The fission products created have shorter half-lives and are not as dangerous. • Fuel is not weapons grade quality. http://library.thinkquest.org/17940/texts/nuclear_waste_storage/nuclear_waste_storage.html
Recycling nuclear fuel • 104 power reactors in the US: 20% of the nation's electricity • 95% of the used fuel could be recycled for future use • Over the past four decades, America's reactors have produced about 56,000 tons of used fuel. That "waste" contains roughly enough energy to power every U.S. household for 12 years. Beach in Kenting, China National Nuclear Power Station No. 3 in the background Masked student protestors voice their opposition at an antinuclear rally. http://ehp.niehs.nih.gov/members/2005/113-11/focus.html
Recycling nuclear fuel: The French do it, why can't oui? • France has embraced nuclear energy and now obtains 80% of its electricity from nuclear power. http://ehp.niehs.nih.gov/members/2005/113-11/focus.html
Obstacles to recycling nuclear fuel • The US developed the technology to recycle the nuclear fuel decades ago, then barred its commercial use in 1977. • Anti-nuclear fear mongering has proved baseless. The French have recycled fuel like this for 30 years without incident: no terrorist attack, no bad guys stealing uranium, no contribution toward nuclear weapons proliferation, and no accidental explosions. http://www.heritage.org/press/commentary/ed010108d.cfm
How to educate the students Basics of nuclear energy
Lesson plan Radiation • http://www.nrc.gov/reading-rm/basic-ref/teachers/unit1.html
Objectives • Teacher • To help students become more literate in the benefits and hazards of radiation. • To stimulate student interest in the biological effects of radiation. • To ensure students understand how nuclear energy is generated. • Student • Distinguish between natural and man-made radiation. • Detect and measure radiation using a Geiger counter. • Investigate the "footprints" of radiation using the cloud chamber. • Describe the principle of half-life of radioactive materials and demonstrate how half-lives can be calculated. • Identify and discuss the different types of radiation.
Beginning of class • Note: Give each student a 5x7 index card as he/she enters the classroom. • Greeting... • "Radiation" (written on the board) • When you see or hear this word what do you think about? What do you think it means? • I would like you to share your thoughts with me by writing on the card what you thought about when I wrote "radiation" on the board. Do not put your name on the card! • [Collect the cards and mix them up. Read several out loud to the class and stimulate discussion on each. Do not attempt to connect any child with a particular note. Write key words from student opinion on the board for future reference.]
Introduction • Radioactive materials are composed of atoms that are unstable. • An unstable atom gives off its excess energy until it becomes stable. • The energy emitted is radiation. • We measure ionizing radiation in units called millirems. • We can classify radiation as being either natural and man-made.
Biological effects • Large amounts of radiation -- far above the levels encountered in daily life -- can produce cancer and genetic defects in living organisms. Radiation causes damage and alters the body's normal cells and normal cell function. This breakdown in normal cell function may result in an uncontrolled growth of cells, hence the potential for malignant/cancerous tumors.
Materials • Pitch blende (UO2) • Ethanol • Dry ice • Gloves and goggles • Petri dish • Black felt • Flashlight • Styrofoam plate • Warning: Gloves must be worn when handling uranium! Do not ingest or inhale any free flowing powder! Dry ice should not be held for longer than few seconds when wearing rubber gloves. Dry ice will burn, so do not touch with bare hands.
Procedure • Place the radioactive source in the center of the Petri dish that is painted with black spray paint and lined with a strip of black felt. Cover the dish with a clear plastic lid and place on a block of dry ice. Shine a flashlight through the transparent lid and observe short, dense alpha particle trails be emitted from the radiation source. The angle of light may have to be adjusted for better viewing.
Questions • Why are elements that break apart called unstable? • How do things become less radioactive as time goes by? • What materials are best for shielding? • Gamma radiation, a powerful type of radiation emitted from some radioactive isotopes, has no weight. What other types of radiation particles have no weight? • Because you could not see the radiation, what kind of observation did you experience? • What is happening to the radioactive source? • What radiation "footprints" did you see? Describe them.
