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Looking at Nuclear Glass Darkly
by Henry Robertson, Green Party of St. Louis
Greens agree that we should end nuclear waste transport and stop the Yucca Mountain repository. To this end the Michigan Greens have added a plank to their platform embracing the technology of in situ vitrification (ISV) to store nuclear waste at power plants encased in lumps of glass.
They should have heeded the larger goal succinctly stated in the GPUSA platform: “Shut down nuclear power plants.” If ISV ever came into commercial use it would only serve to perpetuate nuclear power.
Recipe for ISV:
Insert four electrodes into the ground in a square about 18 feet on a side. Zap in enough electricity to liquefy the soil; 2.5–4 megawatts ought to do it. Heat to 1500–2000ºC. Allow newly formed glass to cool. Yields up to 150 tons per day. Repeat as often as necessary. The electrodes bore deeper, melting soil to a maximum depth of about 20 feet.
Collect toxic gases in a stainless steel hood erected over the melt. Pipe to an off-gas treatment system for a sequence of quenching, scrubbing, de-watering, heating and particulate matter filtration until you have satisfied whatever air pollution regulations apply. [1]
The Glass Isn’t Greener
Vitrification is apparently the best method currently known for immobilizing radioactive and other contaminants in soil. It’s also the most expensive. If the electricity costs 7¢ per kilowatt hour the price of ISV ranges from $250–$750 a ton. [2]
The process isn’t perfect. Cracks in the glass could cause rapid leaching of radioactivity into the soil and groundwater. [3] Brookhaven National Laboratory rejected ISV after a pilot study in 1996 raised questions about its effectiveness. [4]
In 1996 an explosion occurred at a “treatability study” on Cold War-era nuclear waste at Oak Ridge, Tennessee. It was blamed on failure to install vent pipes deep enough to relieve pressure at the lower levels of the melt. The explosion lifted the 7.5-ton off-gas hood off the ground, releasing steam containing small amounts of radioactive material. [5]
Then there was the explosion (still unexplained) at Maralinga, Australia in 1999 where soil contaminated by British nuclear weapons tests was being remediated. [6] The project was abandoned over concerns with both safety and the quality of the end product. [7]
Note that ISV works on soil, the source of the glass. The metallic content must be no more than 15%. Radionuclides have to be incorporated into the soil. Containers like sealed drums may burst under the pressure and release gases that could escape through the melt.
In many hours of online research I have seen no hint that ISV has ever been used or even considered for power plant waste like spent fuel rods. Nuclear power plant waste has been vitrified off-site, but this is a different, complex process conducted in a highly protected, factory-style setting with the glass ending up in steel canisters.
Paul Gunter of the Nuclear Information Resource Service (nirs.org) told me that vitrification would turn reactor assemblies and fuel pellets into a corrosive soup. Vitrification of fuel rods would be expensive and the stability of the end product uncertain. The nuclear power industry isn’t even considering ISV, only deep geological repositories.
If ISV ever came into commercial use it would only serve to perpetuate nuclear power.
Arjun Makhijani of the Institute for Energy and Environmental Research (ieer.org) said that spent fuel is too hot (radioactive) for ISV and is not chemically suitable. ISV is not a good technology in general; the quality of the waste form is inconsistent. In his opinion, spent fuel can’t be disposed of on-site.
Who Needs Reprocessing?
The Michigan Greens argue that ISV would prevent the nuclear industry from recycling spent fuel by reprocessing it. But what’s to stop them from simply mining more uranium?
Estimates of world uranium reserves range from enough for several decades to 250 years at present rates of consumption. Uncertainty isn’t the only reason for this wide range; the lower estimates reflect a low price for uranium. A higher price would intensify extraction from conventional deposits and, if the price goes high enough, from unconventional sources like seawater, which contains a virtually boundless supply. [8] If breeder reactors become practical they will be able to make plutonium from nonfissile uranium and fissile uranium from thorium, which is three times as plentiful as uranium. [9]
Humanity is rapidly exhausting the Earth’s stocks of oil and natural gas; prices for these fossil fuels are climbing and probably won’t fall significantly. [10] Nuclear power is beginning to look increasingly attractive as a supplement to coal for generating electricity. If Greens are going to resist the nuclear revival, let’s put all our solar energy into backing the true green alternatives—energy efficiency and renewable power.
References
1. Behm, Edward, Matthew Gross, Dan Quesenberry & Dan Vipperman, “In Situ Vitrification,” 1997; CMPS&F-Environment Australia, “Appropriate Technologies for the Treatment of Scheduled Wastes,” Review Report #4, Nov. 1997, chapter 17.
2. Behm et al.
3. Fioravanti, Marc and Arjun Markhijani, “Containing the Cold War Mess,” p. 130, 1997, Institute for Energy and Environmental Research, www.ieer.org.
4. ISV Factsheet, www.bnl.gov.
5. “Containing the Cold War Mess,” p 130.
6. Maralinga Rehabilitation and Technical Advisory Committee, “Rehabilitation of Former Nuclear Test Sites at Emu and Maralinga,” 2003, www.radioactivewaste.gov.au.
7. Holland, Ian, “Radioactive Waste and Spent Nuclear Fuel Management in Australia,” 2003 (chronology, March 21, 1999).
8. Canadian Nuclear FAQ, section G.4, www.nuclearfaq.ca; Leventhal, Paul, and Steven Dolley, “The Reprocessing Fallacy: An Update,” nci.org,1999.
9. Goodstein, David, Out of Gas, 2004, p. 107.
10. Goodstein; Deffeyes, Kenneth, Hubbert’s Peak: The Impending World Oil Shortage, 2003; Heinberg, Richard, The Party’s Over: Oil, War and the Fate of Industrial Societies, 2003.
[27 nov 04]