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Nuclear Energy

Nuclear Energy. G4 Radioactive Waste. Radioactive Waste. Nuclear power plants produce radioactive wastes. About 32 metric tons of spent fuel is produced by a typical reactor each year. This waste could be reprocessed into 1.5 tons of extremely radioactive materials.

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Nuclear Energy

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  1. Nuclear Energy G4 Radioactive Waste

  2. Radioactive Waste • Nuclear power plants produce radioactive wastes • About 32 metric tons of spent fuel is produced by a typical reactor each year • This waste could be reprocessed into 1.5 tons of extremely radioactive materials • But such work is a dangerous and would produce waste that is much more hazardous • Nuclear plants also produce large quantities of low-level nuclear wastes during the course of normal operation

  3. Radioactive Waste • Radiation is unhealthy for living things • Cells that are activelydividing, such as skin cells and the blood-cell producing cells in bone marrow, are especially sensitive to radiation • The amount of exposure determines the extent of damage • Large doses can cause severe, immediate effects including skin burns, anemia, and even death • Causes changes in DNA, leading to long-term effects such as cancer and genetic mutations

  4. Radiation Exposure • Radiation exposure is measured in rems • Most Americans receive between 0.2-0.5 rems per year from background radiation • Most background radiation comes from naturally occurring elements in our surroundings. • Earth – rocks, water, carbon-14 (living organisms) • Cosmic – sun, space, other stars • Food – potassium: bananas, potatoes, beans • Medial – dental x-rays, skeletal x-rays, medications

  5. Types of Radioactive Waste • High-Level Waste - wastes that emit large amounts of radiation • Includes used uranium, fuel rods, control rods, and water used to cool and control the chain reactions • The vessel that surrounds the fuel rods is also radioactive • These wastes are very dangerous to handle and may also be poisonous

  6. Types of Radioactive Waste • Medium-Level and Low-Level Waste – are not as radioactive as high-level, although a much larger volume of these wastes is generated • Can be anything from the mine wastes scattered around a uranium mine to the contaminated protective clothes of a power plant worker • Low-Level wastes are also produced by hospitals and laboratories • The damage to people's health is not as obvious as the damage caused by high-level wastes • But they pose a greater risk because they are more common and effects can add up over time

  7. Radioactive Waste Disposal • Radioactive wastes are very difficult to dispose of safely • Low-level wastes can be dangerous for 300 years or more • High-level wastes may be dangerous for tens of thousands of years

  8. Radioactive Waste Disposal • The US government has decided on the following criteria for disposing of nuclear waste safely • Must be sealed in containers that will not corrode for thousands of years • The US has decided on sealing the wastes in thick blocks of glass • The site must be geologically stable • An earthquake or volcano could spill the stored wastes into the environment • Must also be stored deep under the ground • The cost of this disposal method is very high

  9. Radioactive Waste Disposal • Almost all the high-level radioactive wastes in the world have not been disposed of permanently. • They sit in storagetanks outside nuclear power and weapons plants • Many tanks have begun to leak, contaminating groundwater and the environment • These wastes must be permanently removed before the contamination gets worse

  10. Radioactive Waste Disposal • The government predicts that the cleanup of 20 of the most contaminated nuclear weapons sites in the United States could cost $600 billion. • At theHanford nuclear weapons facility in Washington state, large amounts of radioactive wastes have been released into the environment. • The Columbia River has been contaminated several times. • The Hanford was shutdown in 1987. Cleanup at the site has begun

  11. Safety and Cost • Nuclear power plants are very expensive because the required safety measures are very costly • The danger that radioactive contamination creates makes safety at nuclear power plants very important • If the cooling or control systems in a reactor core fail, the chain reaction can no longer be controlled • The core will grow hotter, causing the fuel rods and even the reactor vessel to melt • This is called a meltdown. • A full meltdown would release huge amounts of radiation into the environment.

  12. Section Review • Answer the questions in the section review

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