Страница: 7/8
Before any nuclear plant can be built and go into service, the utility must obtain many different licenses and operating permits from federal, state and local agencies. The Nuclear Regulatory Commission requires that its conditions be met and allows for public hearings to be held before the Commission issues a construction permit. After construction is done, the NRC issues an operating license, again after a public hearing. During and after construction, the Commission stations full-time inspectors at the plant. Other visiting inspectors are sent to do on-site inspections. This assures that the plant is operated according to its license.
Each utility checks its plants for radioactive releases. The records are sent to and examined by the Nuclear Regulatory Commission and the Environmental Protection Agency. Abnormal conditions or operations are reported to these agencies.
Nuclear waste
Since the first commercial nuclear power plant began producing electricity in 1957, the total amount of accumulated spent fuel (classified as high-level waste) is 9000 tons. For comparison, the Environmental Protection Agency reported that in 1982, 46 million tons of poisonous waste (that is, not nuclear) were disposed of. In comparison the amount of nuclear waste is very small.
Nuclear wastes are, for the same power output, some 3.5 million times smaller in volume than the wastes from coal plants. High-level nuclear wastes can be disposed of by diluting them with twice their own volume of neutral materials as they are changed into glass or ceramic form. The reprocessed waste volume form a 1,000 megawatt nuclear power plant would fit easily under a typical dining room table. A coal plant of the same capacity (1,000 megawatts) produces some 10 tons of waste per minute.
After changing it to stable form, the volume of all nuclear waste produced until the year 2000 (including low-level waste from the entire U.S nuclear power industry) would fit into a cube 250 feet on each side. The high-level waste portion would fit into a cube 50 feet on each side within the 250-foot block.
Low-level wastes contain little radioactivity. They require little or no shielding, and no cooling. They are the discarded used, disposable protective clothing from the medical facilities and nuclear power plants, water-treatment resins and filters, compacted trash, contaminated lab equipment, plastics, metals, and liquids. They are the result of good housekeeping practice in which non-radioactive waste is separated from slightly contaminated waste.
Most low-level wastes are solidified, put into drums and buried at a commercial disposal site. There they are placed at the bottom of trenches (about 20 feet deep). At the Barnwell, SC, site, for example, trenches are back filled with sand and covered in clay each day to keep moisture from getting in. When full, trenches are mounded and capped with clay, and finished off with a foot of topsoil. Grass is planted to help prevent erosion. The collection, transportation and burial of low-level radioactive wastes are all closely monitored and controlled by the Department of Transportation and the Nuclear Regulatory Commission.
When properly managed, these low-level wastes do not pose a hazard. The industry now has 30 years of experience in handling and shipping these materials. There never has been an accident with these wastes that had serious health results due to radioactivity.
The 1980 Low-Level Waste Policy Act makes each state responsible for providing he disposal of its own waste. Also encouraged are joint efforts among several states for a shared site.
Conclusion
In this report I tried to show how does the activity of a Man influences on our common home. I have shown different kinds of pollution (I mean water and air pollutions) and the consequences of wasting our environment (for example, global warming, acid rains, greenhouse effect and etc.).
I suppose that our main problem is the following: we try to solve ecological problems because it became hard to live with poisoned air and water, but not because of their respect to the planet they live on and to the birds and animals they live with. People try to take care of the planet just because of their egoism.
Реферат опубликован: 20/12/2006