TWR: A Nuclear Way Forward?
By Bill Moore
Posted: 28 Jan 2010
Last night during the State of the Union address, President Obama called for a renewed look at nuclear power. Specifically he stated, "To create more of these clean energy jobs, we need more production, more efficiency, more incentives. And that means building a new generation of safe, clean nuclear power plants in this country."
America's current fleet of nuclear power plants are aging, as is the labor pool to engineer, build and maintain them. Concerns about cost overruns and stranded assets now weigh as heavily on fate of the industry as worries about nuclear proliferation, accidents and waste storage. The financial black hole that is the latest generation of reactor being built in Finland, as well as concerns over the quality of its construction and potential safety issues doesn't help the call for a nuclear renaissance in America, despite the ongoing construction of new plants in India, Korea and China.
I've had the opportunity to stand atop the world's very first nuclear power reactor, touched the light bulb it lit back in the late 1940s at what is now Idaho Falls National Laboratory. I've looked into the pool of glowing blue water where the facility's own spent fuel is stored. I've even come close to accepting nuclear power, only to cautiously back away from edge of the 'pool.' I like the idea that nuclear power has such a small physical and -- depending on your perspective -- environmental footprint. Certainly, it is far cleaner than coal, which I am told releases more radiation than all the world's 400 or so power plants put together. All the world's nuclear waste, removed from its protective cladding and stacked shoulder-to-shoulder would fit into one standard American football field at the height of five feet. Its carbon dioxide emissions is a fraction that of coal or natural gas.
Still, I keep coming back to the problem of waste and proliferation, with operational safety ranking third given the industry's track record to date. The problem with our current technology is that we only use something like 8% of the available energy in the nuclear fuel rods that power our reactors. The only way to get more use out of them is to reprocess them, which creates its own host of problems from environmental to economic. And little discussed in the media is the growing problem of depleted uranium, the waste left over from the initial enrichment process. According to Dr. John Gilleland, who is the featured speaker in the video below, there are 38,000 cylinders of DU like those depicted above at just one storage site in America. The only practical use we've found for this is to put it in the tips of our munitions to destroy armored vehicles, and not without serious public health consequences, it's alleged.
These problems haven't escaped the notice of people in the industry, and some very bright people are looking for ways to solve them. One of those businesses is Intellectual Ventures, which is working on a several decades-old idea called Traveling Wave Reactors (TWR). Think of it as a very slow burning bullet. At one end of the fuel assembly is the primer, in this case a small amount of enriched U-235. Packed like gunpowder in the rest of the 'cartridge' is depleted uranium. The primer ignites the DU immediately around it and this sets off a chain reaction that propagates forward through the fuel at a rate that would take anywhere from months to decades, possibly as much as a century. The Intellectual Venture computer drawing below illustrates what a first generation TW reactor might look like.
In the following video, shot last Spring at UC Berkeley's Nuclear Engineering Department, Dr. Gilleland, who heads up TWR project for IV, estimates that the value of just the DU stored at the Paducah facility might be worth the equivalent of $100 TRILLION dollars in electricity. Others estimate that there's enough DU stored around the planet to provide electric power for all of the people on Earth for the next millennium.
So, what's the hang up? At the moment, all this is just pure theory based on computer models; and as Gilleland explains, there's no real practical way to build a working "model." We'd have to pretty much build something full scale to see if the computer simulations and the equations they're based on would actually work. And the system still produces its share of waste, but at a "factor of ten" below that currently being created by Light Water Reactors, the most widely used design today. However, it would also take less time to cool before being placed in permanent storage or itself reprocessed.
And because this is all based on theoretical models, how much the system would cost is still being worked out. While other forms of power are projected to remain either relatively stable in the coming decades or, as in the case of wind, solar and geothermal, decrease; nuclear power is likely to continue to increase in cost, despite attempts to reduce this by building more modular, cookie cutter types of plants; something TWR lends itself too.
So, here I am again looking over the edge of that glowing pool, pulled by an irresistible urge to see us move beyond the 18th century and towards a Type One civilization that has figured out how to peacefully, safely harness the power of a star for the good of all.
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