• Nuclear safety and security demand thorium
    By
     | April 03,2012
     

    I’m pro-nuclear, -thorium and -renewables but strongly anti-uranium.

    Nuclear is dominated by uranium-plutonium reactors, bombs, potential nuclear terrorism, and pre-emptive wars to counter these threats. Compared with uranium, thorium in the liquid fluoride thorium reactor (LFTR) design is better and safer for power generation, produces meager and benign waste, and is no good for bomb making. Touted as “green,” uranium actually has the worst, while thorium has the best, total energy conversion statistics and “green” credentials. Converting to LFTR-nuclear would eliminate the bomb threat, the waste problem, and accidents like Chernobyl and Fukushima. The resulting power grid could be dispersed, resilient, efficient and green.

    World scarcity of uranium contrasts with ample thorium. Thorium and rare earths, critical to high tech, occur together but are currently depressed by China’s cheaper production. Converting to thorium, and mining our own, solves the rare earth strategic problem also.

    Take a look at YouTube’s “Energy from Thorium” by Kirk Sorenson that explains the “liquid fluoride thorium reactor” (LFTR — pronounced “lifter”). A real eye-opener of how great minds and ideas can be squelched by politics.

    Thorium is so energy-dense a chunk in your hand can supply your energy needs for a lifetime. It is four times as plentiful as uranium — a thousand years’ supply exists in the U.S. lower 48.

    If we consider the energy conversion efficiency of the two, thorium can contribute more than 200 times the energy, while leaving 200 times less waste with isolation requirements 200 times shorter than uranium. Less than 1 percent of uranium is “burned up” in the reaction. Ninety-nine percent becomes bad waste — a uranium worker’s gloves are supposed to be isolated for 24,000 years. In contrast, thorium is almost completely “burned up” in the reaction, with little n-waste left over, and leaves decay products that require isolation for only 300 years. Contrasted with the unsolvable waste management quagmire of uranium, thorium waste storage is a very solvable problem.

    Uranium plant control rooms resemble several 747 cockpits side by side. The great over-complexity is necessary to “prevent meltdown.” LFTRs, by contrast, are simple, self-cooling and safe. If they get too hot, the liquid fluoride salt the thorium is suspended in expands and less nuclides are available for splitting — it cools automatically. If it gets too cold, the salt contracts and excess nuclides are radiated, and it heats back up. As if this weren’t enough safety factor, a pipe leads down into a drain vessel. In normal operation salt freezes as a plug in the pipe. If it overheats, the plug melts and the liquid salt drains down where there is no chance of reaction. In the Oak Ridge LFTR experiment (which ran four years), they shut off power to the LFTR on weekends — it drained, cooled and rested. Try shutting off the power to a uranium plant for the weekend. For cooling a nuclear plant, draining liquid fluoride salts downhill is a lot more dependable than pumping water uphill.

    Another leg up LFTRs have over uranium plants is pressure: The latter have to be highly pressurized to get the boiling point of water up to an economic level to drive the steam turbines. This is what forces the giant containment structures that dominate both the size and the cost of uranium plants. In contrast, the molten fluoride salts have to be at this economic threshold temperature just to be molten — the whole plant can run at atmospheric pressure, within a minimum containment structure.

    Uranium-plutonium bomb making is not rocket science. It takes only 20 pounds of plutonium, and lots is unaccounted for. In contrast, it’s almost impossible to make bombs with LFTRs — that’s why research on them was canceled during the Cold War. If the U.S. was the world leader in LFTRs, we could partner with Iran to develop their peaceful power grid — no fear of bomb making — pre-emptive wars unnecessary.

    By the early 1970s, thorium research was shut down by a uranium dynasty — classic turf protection. The father of LFTRs, Alvin Weinberg, was fired from the project because he favored LFTRs and feared uranium’s inherent cooling problems. He was vindicated at Chernobyl and Fukushima.

    The world has four times more thorium than uranium, whose supply is precarious: 92 percent of U.S. uranium is foreign-produced. World production of uranium is 62 percent of world usage, augmented by cannibalizing Cold War Russian stocks — they intend to terminate that program. As Japan comes back on line, and China brings on its 100 planned new uranium power plants, a severe supply crisis is predicted.

    Thorium occurs with the rare earths, critical to high tech (wind, solar, computers, HDTV, hybrid cars, multiple military uses, etc.) One rare earth, neodymium, is our most strategically vulnerable mineral. Ninety-seven percent of rare earth production is in China, mined with cheap North Korean labor plus some of the world’s largest and newest machines, in one mega-mine. This has halted rare earth mining and exploration (except in China). We are strategically vulnerable. Because REs have a strong market and thorium a weak one, thorium is being stockpiled. Aggressive thorium nuclear is the obvious solution to both problems.

    Thorium reactors can be built big, but, because of comparative simplicity, reliability and safety from radiation, LFTRs can also be built small, cheap, fast and safe. There is talk that LFTRs could be built on an assembly line like airliners, cutting costs hugely. LFTRs’ low operation and storage radiation risk allows a disseminated, resilient, energy-efficient and green power grid. Vermont could have 10 100-megawatt LFTRs and get the rest of its electrical energy from wind turbines in each of its 7,000 farmers’ fields.

    China, Russia, India and Germany are really getting into thorium as an alternative. But LFTRs let the little guy get into the act — the Czech Republic is aggressive in transitioning to thorium. If it can, Vermont can too — retrain Vermont Yankee’s engineers for thorium — to transform Vermont and then the world. Vermont needs a big piece of that action! We should shut down Vermont Yankee, retrain, and have a crash effort in converting to thorium-LFTR, renewables and conservation — the growth industry of the millennia. If we have another 20 years of nuclear business as usual we will lose our window and China will have a monopoly on rare earths and thorium, as well as nuclear reactors.

    John Sales lives in Barre.

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