Wednesday, September 4, 2013

Dealing With Our Nuclear Spent Fuel

Over the last couple of months, there has been a lot of talk about finally doing something with the spent fuel inventory that is steadily increasing on site at our nuclear reactors.  The problem is, there is no solution to permanently dispose of this waste, and there is no realistic technology available to even render it less dangerous.  It simply must be isolated from the environment.

Spent fuel is the “used up” fuel from a nuclear reactor.  A fresh fuel rod contains 97% Uranium 238, and 3% U235 (the fissionable form of Uranium.)  After about 2 years of use in a reactor, it is “spent,” and now has a composition of about 96% Uranium 238, 1% U235, 1% Plutonium 239 (which is created by neutron capture of U238), and 2-3% fission products (formed when U235 fissions.)  The fuel rods are typically removed and stored in a pool to keep them cool, and provide shielding from the high levels of radioactivity that they emit.  Hence, it is called high-level waste.  After about five years, the fuel has somewhat stabilized with many of the fission products having decayed; but the remaining ones, as well as the Plutonium, remain highly radioactive for many thousands of years.  This material needs to be contained and shielded, and continues to give off heat as a byproduct of its radioactive decay. 

There is about 70,000 tons of spent fuel stored at reactor sites in the U.S., and utilities are running out of room in their fuel pools as they keep adding to the volume.  Many are opting to place these fuel bundles into dry-cask storage…large heavily shielded canisters that typically sit on a pad outside, and are air-cooled.  At Humboldt Bay, there are 6 casks, and it cost close to $70 million to put the fuel into dry storage.  It costs about $12 million/year for security, monitoring, and maintenance.  It is estimated that we would need some 6000+ casks to contain our current spent fuel inventory.  $80 billion + ??? in today’s dollars.

Nuclear fuel is owned by the government’s Department of Energy, and it is “rented” out to nuclear utilities.  The 1982 Nuclear Waste Policy Act mandated that by 1998, the government would have a deep geologic repository ready, and would take possession of the spent fuel.  This has not happened…not even close.  Many years, and $15 billion have been spent on Yucca Mountain, a possible repository site north of Las Vegas.  Aside from all the politics, the bottom line is that the DOE could not meet the EPA criteria and standards for containment of radioactivity at this site.  This isolation from the environment needs to be for a minimum of 10,000 years, even though radioactivity will remain there for 100,000 years or more.  The sealed central storage of so much radioactivity would produce high amounts of heat that would unpredictably create changes in the geology of the mountain, and threaten the integrity of the casks themselves.  Cask failure could lead to the release and mixing of fuel that could trigger fission processes, explosions, contamination of ground water, and a host of other unknown reactions during the thousands of years this material is active.  Allison MacFarlane (the new chairwoman of the Nuclear Regulatory Commission, and a noted geologist) concludes the obvious in her excellent book “Uncertainty Underground.”   We do not know enough to be able to model and predict what will happen so many years into the future.

The recent push by the nuclear industry, wanting to rid themselves of the responsibility of spent fuel, is pushing for a new “independent” review of Yucca Mountain.  President Obama’s Blue Ribbon Committee of a few years ago came to the conclusion that there is no solution to this waste problem.  Congress will now form another committee to “come up with a solution.”  This is not a political problem.  It is the scientific reality that radioactivity is an atomic-level process, and not a molecular one that can be manipulated and neutralized.  We cannot make it go away.  The early nuclear pioneers understood this, but in the glory days of nuclear bombs and “electricity too cheap to meter,” they rushed ahead hoping that someday, someone would figure it out.  70 years down the road, we don’t even have a clue.  Oh, what to do?

There are several possible courses of action, which will be looked at and proposed over the next couple of years.  The first is to continue characterizing Yucca Mountain or finding some other geologic site somewhere…Texas, New Mexico, Mississippi ???   We are not alone, since other countries are also beginning to look at solutions for their wastes.  Sweden, with its relatively small amount of spent fuel, is currently storing it in copper casks in a geologic cave, with the idea that it can be retrieved when a better solution is found.  Problems have already begun to surface.  Germany has recently reopened their  investigations, going back to the drawing board.  Japan doesn’t have a clue with what they are going to do…right now they’re “underwater.”

A second option is an idea that has been around for a while and involves creating a central Monitored Retrievable Site.  Take all the casks, and ship them to one location.  The leading contender is Skull Mountain in Utah, where the 35 members of the Goshute Indian Rancheria were offered $50 million to use a portion of their land for this purpose.  Too bad it is directly in the flight path of an Air Force practice bombing range!  Placing all this material in one place is very risky, especially with current terrorist and climate change possibilities.  Transporting 6000+ casks and storing them in the open air…???!!!  And then transporting them again if/when a repository is built, or maintaining/re-casking the spent fuel 50-60 years down the road?  Security?  Very expensive and dangerous.

A third option, which the nuclear industry wants, is probably more insane than the initial creation of the entire nuclear power business.  Reprocessing, or recycling as they call it, involves taking the fuel rods, grinding them up and dissolving them in acids, and then separating out the U238, the unused U235, and the Plutonium, which would then be put into new fuel.  This is what was done in Hanford to acquire the Plutonium for our nuclear bombs. The remaining liquids, containing the highly radioactive fission products, would then be concentrated, and “vitrified”…converted into a glass/ceramic log that will have to be disposed of in a geologic repository for thousands of years.  Sounds great?  Ed Lyman, a prominent scientist with the Union of Concerned  Scientists says “reprocessing actually increases, not decreases, the total volume of long-lived nuclear waste that must be stored and eventually buried in a geologic repository  It only slightly reduces the volume of high-level nuclear waste that must be disposed of in a repository.”  Can we really do this?  At what cost?  The “new” vitrification plant under construction at Hanford is half completed, 12 years behind schedule, and 13X over budget at a current $13 billion. How many of these plants would we have to build, and where?  How would we be transporting all this dangerous material around?  We’d have to build new power plants to burn the “new” mixed-oxide fuel and Plutonium fuel?  How much would it cost to build this whole new infrastructure?  We tried this in West Valley, New York back in the 70’s and it turned into an economic and environmental disaster.  

Reprocessing produces more problems that it can solve.  It hasn’t worked for England, Germany, and Japan.  The French are reprocessing for the Japanese, and are nowhere near dealing with their own spent fuel.  We don’t know much about the Russian program, but are very concerned with the possibility of Iran and North Korea developing the process to build nuclear weapons. The bottom line is that reprocessing would be a very, very expensive proposition that the taxpayer would wind up funding.  Hundreds of billions of dollars.

There are other options out there…putting it in rockets and shooting it into the sun, dumping it in the deep sea trenches, drilling a deep hole into the earth’s crust and dropping the canisters down.  The most recent moronic idea comes from the chairman of the Oregon Republican Party…”sprinkle nuclear waste over the oceans from airplanes…”

The best strategy seems to be to place spent fuel in dry-cask storage, and keep that material on site until a better solution comes up…which may be never, meaning that the 30+ nuclear sites would become defacto waste dumps.  At least the casks can be monitored, maintained, and repaired if need be.  There are several sites, such as California’s Humboldt Bay, Diablo Canyon, and San Onofre, where special safety issues  such as earthquake, tsunami, and flooding, might require moving these casks to a more secure location. 

Whatever we decide to do, it will be very EXPENSIVE for a very long time.

Some source material:

And then, there is Low-Level Radioactive Wastes…a whole other story:

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