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Nuclear Waste.

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Presentation on theme: "Nuclear Waste."— Presentation transcript:

1 Nuclear Waste

2 Radioactive Waste Unwanted or discarded items that contain radioactive material. Hazardous to life and the environment Low Level Waste High Level Waste

3 Low Level Waste Articles contaminated with radioactive material, or that became radioactive because of exposure to neutron radiation. Generally, low activity or small amounts Examples: radio-chemicals, medical items, contaminated gloves, papers, machine parts etc.

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5 Low Level Waste Stored on-site until activity has decayed to safe levels (becomes non-radioactive trash) or Disposed of in shallow trenches at privately owned sites in Nevada, South Carolina, Utah and Washington.

6 Low Level Waste disposal

7 High Level Waste Fission Products: elements that result from the fission process. A couple of important examples are 137Cs and 90Sr. Actinides: Formed by neutron absorption by the original fuel. Elements with atomic numbers greater than 88. Extremely toxic chemically as well as being radioactive. Example: 239Pu.

8 High Level Waste Spent (no longer useful to generate electricity) reactor fuel Waste materials left after fuel is reprocessed Materials from nuclear weapons upgrades and decommissioning

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10 High Level Waste Encapsulate it.
Store long term in dry, geologically stable sites until activity decays to safe levels.

11 After 600 years, radioactivity has dropped by a factor of over 10,000
After 600 years, radioactivity has dropped by a factor of over 10,000. A reasonable storage time is 1000 years.

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13 The largest producer of radioactive waste is the military defense programs
80,000,000 gallons of liquid waste are stored at Hanford, Washington. (500,000 gallons leaked into the ground over a number of years.) The waste from 1 years operation of a 1000MW plant is approximate 2 m3.

14 Spent nuclear fuel is currently stored on site in pools

15 Long Term Disposal

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17 Yucca Mountain The Nuclear Waste Policy Act (1982) and its Amendment Act (1987) established a national policy for nuclear waste disposal. In 1987 the Yucca Mountain, Nevada site was selected as the primary candidate for the long term deposit site. The site was extensively evaluated

18 It just looks like a place to store nuclear waste.

19 Basic Characteristics
The rock formation is 13 million year old volcanic tuff. Very dry climate (less than 6 in of rain per year.) The water table is 1700 feet down. Groundwater travel laterally about 1mile in 3400 to 8300 years. Nearest surface water is 30 miles away.

20 Tuff can trap any radionuclides that may leak by adsorption within the rock.
The government already owns the site. Funding ended for the site in 2011, and the site has been closed.

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23 Plans called for multiple barriers
Waste is first encapsulated in glass or ceramic beads. Waste is placed in stainless steel canisters Canisters are located in storage rooms in stable rock formations. Rooms are backfilled with material to retard penetration of water

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25 Routes for Nuclear Waste

26 Funding ended for the site in 2011, and the site was been closed.
The Government Accountability Office (GAO) stated that the closure was for political reasons In August 2015 work was resumed on evaluating the site.

27 Non US governmental organizations currently have no long term storage sites for high-level waste
The US government stores waste at the Waste Isolation Pilot Plant in New Mexico. Other waste is stored on-site.

28 Current Nuclear Waste Storage Sites

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