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Finding a Space for Waste. ¡noah! NCSS 7/27/06. Alternative Energy Sources. Alternative Energy Sources. Alternative Energy Sources. Alternative Energy Sources. “temporary” holding tanks at reactor sites are filling up. Some of the waste has been kept there over 3 decades!. - PowerPoint PPT Presentation
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Finding a Space for WasteFinding a Space for Waste
¡noah!¡noah!
NCSS NCSS
7/27/067/27/06
Alternative Energy Sources
Alternative Energy Sources
Alternative Energy Sources
Alternative Energy Sources
On-Site Waste StorageOn-Site Waste Storage
“temporary” holding tanks at reactor sites are filling up. Some of the waste has been kept there over 3 decades!
Nuclear Reactor Fuel RodsNuclear Reactor Fuel Rods
Only <3% Only <3% 238238U actually U actually used in “once-through” used in “once-through” open fuel cycle.open fuel cycle.
Spent fuel (right) is a Spent fuel (right) is a form of HLW and is the form of HLW and is the primary concern for primary concern for permanent disposal.permanent disposal.
Yucca Mountain
• ~90 miles NW of Las Vegas, Nevada• Capacity: 77,000 tons--will be full by 2020 (scheduled
to open in 2017)
will only be part of the solution.
Under the seabedUnder the seabed
• Burial hundreds of meters under the middle of the Burial hundreds of meters under the middle of the tectonic platestectonic plates
• ~70% of Earth’s outer core = an essentially ~70% of Earth’s outer core = an essentially limitless storage capacitylimitless storage capacity
• Funding for research cut 20 years ago to focus on Funding for research cut 20 years ago to focus on Yucca MountainYucca Mountain
Considering a Disposal Area: Worst Case Scenarios
• For seabed: can sea creatures carry leaked waste to ocean surface?
• Experiments show that radionuclides would not travel more than a few meters through the seabed clay in 105 years!
WCS for Yucca Mountain Groundwater
contamination is the biggest concern
YM is 300 meters above the water table
Leaked waste could be transported by rain water to water table, so chemistry of the waste must be considered
Pros & Cons for Yucca Mountain’s WCS
PROS
•Volcanic Tuff contains zeolite
•Pu4+ (most abundant form) is insoluble and therefore settles as sediment in groundwater instead of being transported
CONS
•Possible for Pu4+ to transport by binding to natural colloids and microorganisms
•Np5+ is soluble and is not stopped very well by zeolite
Vitrification
Puts radioactive waste into glass or ceramic lattice
immobilized, can’t transport through water
Does not shield radiation, so canisters still have to be used
Enormous cost: special plants built/designed only to produce glass logs, can only build one log/day, and each log costs ~$1.4M
Acknowledgements:
me.
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