Reducing the Risks of High-Level Radioactive Wastes at Hanford

74 Alvarez
wastes. 182,183 DOE plans to dispose of failed melters in an onsite trench 184 even
though Hanford “currently does not have the capability to ...dispose of failed,
highly contaminated processing equipment.” 185 DOE researchers advise that,
“it is unacceptable to place this waste form in relatively uncontrolled long-term
storage and to continue to add more of the same and other equipment....” 186
Bulk Vitrification. Bulk vitrification is a supplemental treatment technology
which is expected to process 60 to 70 percent of single-shell tank wastes. It
involves the superheating of wastes mixed with soils containing glass-forming
materials (i.e., silica, sand) with large electrodes in a large metal container.
When the wastes are glassified the electrodes (melter) remain embedded in the
glassified material and are disposed with the waste. Numerous bulk vitrification
containers are planned, with a test project using wastes from a Hanford
tank scheduled for next year. Like the melters in the Waste Treatment Plant,
the success and safety of bulk vitrification will be very dependant on pretreatment
and feed preparation. Several processing steps prior to vitrification have
to be worked out such as: dissolution of salts for retrieval, recrystallization,
chemical pretreatment, and a high-degree of moisture reduction in soil and feed.
As mentioned bulk vitrification poses potentially serious long-term groundwater
impacts from secondary wastes. 187 A steam explosion in 1991 at Hanford,
using in situ vitrification with a 6,000 gallon tank, should serve as warning, as
DOE proceed with its initial efforts to deploy this technology.
NOTES AND REFERENCES
1. Robert Alvarez and Arjun Makhijani, Radioactive Waste: the Hidden Legacy of the
Nuclear Arms Race, Technology Review, July 1988.
2. U.S. Department of Energy, Plutonium: The First 50 Years, United States Plutonium
Production, Acquisition, and Utilization from 1944 through 1994 http://www.
osti.gov/html/osti/opennet/document/pu50yrs/pu50yc.html#ZZ15, 20 July 2004.
3. U.S. Department of Energy, Summary data on Radioactive Waste, Spent Nuclear
Fuel and Contaminated Media, Office of Environmental Management, 2001.
4. The Savannah River Site, Aiken SC, the Idaho National Laboratory, Idaho Falls,
ID, the West Valley Vitrification Demonstration Project, West Valley, NY, and Oak Ridge
National Laboratory, Oak Ridge, TN.
5. United States General Accounting Office, Report to the Chairman, Subcommittee
on Oversight and Investigations, Committee on Energy and Commerce, House of
Representatives, “Nuclear Waste: Challenges to Achieving Potential Savings in DOE’s
High-Level Waste Cleanup Program,” GAO-03-593, June 2003. pp, 17, 20 (Hereafter
known as GAO-03-593). “Uncontrolled cost overruns, numerous schedule delays, and
unsuccessfully attempts to develop treatment processes have pushed the overall estimated
cost of the high-level waste program from about $63 billion in 1996 (when the
first comprehensive estimates were developed) to nearly $105 billion in 2003.”
6. GAO-03-593, 2003. p. 17 and p. 20.
7. U.S. Department of Energy, “Review of Generation and Flow of Recycled Uranium
at Hanford, ” Richland Operations Office, DOE/RL-2000-43, Executive Summary, p. 2.