Nuclear Waste Disposal in USA - Dr. James Conca @ TEAC11
Dr. James Conca's main presentation at TEAC11 was on the state of America's nuclear waste disposal program.
Categories of Nuclear Waste In the USA:
(Different than Europe because of the larger amount of defense waste.)
Spent Nuclear Fuel (SNF)
High Level Waste (HLW)
Transuranic Waste (TRU-CH&RH)
Low Level Waste (LLW)
Deep Geologic Disposal is required for SNF, HLW and TRU.
National Academy of Sciences (NAS) concludes in 1957 that the most promising disposal option for all radioactive waste is in massive salt deposits.
“Salt at great depth ‘flows.’ It will encapsulate any waste placed at depth and isolate it from the surface environment for eons.” - NAS
“The great advantage is that no water can pass through salt. Fractures are self healing..” – NAS
Disposal options for different waste streams begins to diverge in the 1970s.
1957 - Deep geologic disposal adopted; salt chosen as best.
1970 - AEC establishes new category for transuranic waste, distinct from low- and high-level radioactive waste but with significant overlap in radioactivity. EPA formed.
1976 – Reprocessing of commercial spent fuel put on hold; separate retrievable disposal concept born for SNF/HLW not to go into salt; TRU still to go into salt.
1982 – Nuclear Waste Policy Act…
But the idea of retrieving SNF in the future took hold, killing salt as the host rock and by 1987 the candidate sites were narrowed from 17 to 3:
Yucca Mt, Nevada
Hanford, Washington State
Deaf Smith, Texas
In 1987, Speaker of the House was Jim Wright from Texas, House majority lead was Tom Foley from Washington State. A new junior, Harry Reid, was from Nevada. SoNevada was chosen. Harry Reid became Senate Majority Leader and led the effort to shut down the Yucca Mountain project. In 2008, the YM license application submitted. In 2009, YMP was halted and President Obama put a Blue Ribbon Commission together to develop a new strategy.
Extreme re-engineering, and great cost (~$200 billion extra) is required to counter-act the choice of the wrong rock:
-reducing inverts
-shotcrete
-ceramic coating
-titanium drip shield
-vitrified waste
-package supports
-gravel backfill
Yucca Mt. is a highly fractured, oxidizing, variably saturated, dual porosity, hydrologic system that sits on the edge of the Las Vegas Shear Zone.
Unknown to most, transuranic waste (bomb waste) continued oninto the salt as planned, leading to the Waste Isolation Pilot Plant.
WIPP is ahead of schedule and under-budget.
Only defense-generated TRU waste presently permitted: 100 nCi/g to 23 Ci/L of alpha-emitting 239Pu equivalents but WIPP was originally designed to handle all nuclear waste.
At the 2000 lbs/inch2 pressure at this depth, the salt exhibits significant creep closure, i.e., the salt completely closes all fractures and openings, even micropores, making the salt extremely tight, such that water cannot move even an inch in a billion years.