Wired features Kirk Sorensen, Thorium and the LFTR

Kirk Sorensen, a young NASA engineer, is an important figure in the internet discussion of energy issues. He may lead a revolution that will change the lives of every person on Earth. Kirk's principal contribution is to revive interest in the thorium fuel cycles, and in the use of the liquid salt reactor concept that Oak Ridge scientists developed two generations ago. Last summer Kirk traveled to Manchester, England where he spoke before a blue-ribbon panel preparing a report on AGW mitigation technology for world leaders attending the Copenhagen 15 Conference. The Manchester Report panel was extremely impressed with Kirk. They stated,

Although the panel are not in a position to assess the feasibility of liquid-fluoride thorium reactors, Sorensen’s articulate and knowledgeable advocacy made a persuasive case that this electricity generation technology deserves renewed investigation. Other ways of extracting energy from thorium should also be explored – both to reduce emissions and to help limit the production of the most dangerous nuclear waste.

Wired magazine has just published an article written by Richard Martin, titled Uranium Is So Last Century — Enter Thorium, the New Green Nuke. Martin briefly interviewed me some time ago while investigating the background for the study, and a few of my observations appear to have made their way from his notes into the Wired article. Kirk deservedly is featured in the article. Martin describes Kirk's epiphany moment in 2000 when as

(a) rookie NASA engineer at the Marshall Space Flight Center, Sorensen was researching nuclear-powered propulsion, and the book’s title — Fluid Fuel Reactors — jumped out at him

from a colleague's book shelf. Kirk's investigation of the book led to his discovery of Molten Salt Reactor technology, and of the Thorium fuel cycle. Martin briefly lays out the story of Molten Salt Reactor research in Oak Ridge, and places the AEC's decision to fire Oak Ridge National Laboratory Director Alvin Weinberg and to terminate Molten Salt Reactor research into its political context, and identifies Admiral Hyman Rickover's role in the affair.

Highly-regarded ORNL chemist, Raymond C. Briant, suggested the idea of using the thorium fuel cycle in a Molten Salt Reactor to Alvin Weinberg, and Weinberg took the ball and ran with it. As a consequence the development of a thorium-breeding liquid-salt reactor as a solution to world energy needs became Weinberg's passion for the rest of his ORNL career.

By 2000 when Kirk Sorensen rediscovered liquid-salt reactor technology, the MSR was regarded as dead. Sorensen, however, saw the potential and the need. As Richard Martin notes

Sorensen spearheads a cadre of outsiders dedicated to sparking a thorium revival. When he’s not at his day job as an aerospace engineer at Marshall Space Flight Center in Huntsville, Alabama — or wrapping up the master’s in nuclear engineering he is soon to earn from the University of Tennessee — he runs a popular blog called Energy From Thorium. A community of engineers, amateur nuclear power geeks, and researchers has gathered around the site’s forum, ardently discussing the future of thorium. The site even links to PDFs of the Oak Ridge archives, which Sorensen helped get scanned. Energy From Thorium has become a sort of open source project aimed at resurrecting long-lost energy technology using modern techniques.

Kirk coined the term Liquid Fluoride Thorium Reactor (LFTR) for the type of Molten Salt Reactor that uses the Thorium fuel cycle. In Europe the same type of reactor is called the Thorium Molten Salt Reactor. Kirk's term is a more accurate one because a MSR using chloride salts is possible, and potentially has some very desirable desirable features.

"Why thorium," you ask. For example, Russian scientists B.D. Kuz’minov, and V.N. Manokhin have stated,

Adoption of the thorium fuel cycle would offer the following advantages:
- Increased nuclear fuel resources thanks to the production of 233U from 232Th;
- Significant reduction in demand for the enriched isotope 235U;
- Very low (compared with the uranium-plutonium fuel cycle) production of long-lived radiotoxic wastes, including transuraniums, plutonium and transplutoniums;
- Possibility of accelerating the burnup of plutonium without the need for recycling, i.e. rapid reduction of existing plutonium stocks;
- Higher fuel burnup than in the uranium-plutonium cycle;
- Low excess reactivity of the core with thorium-based fuel, and more favourable temperature and void reactivity coefficients;
- High radiation and corrosion resistance of thorium-based fuel;
- Considerably higher melting point and the better thermal conductivity of thorium-based fuel;
- Good conditions for ensuring the non-proliferation of nuclear materials.

Martin points out that other advanced reactor

technologies are still based on uranium, however, and will be beset by the same problems that have dogged the nuclear industry since the 1960s. It is only thorium, Sorensen and his band of revolutionaries argue, that can move the country toward a new era of safe, clean, affordable energy.

Yes the LFTR is at the core of a revolutionary energy paradigm. The revolutionary implications of the thorium paradigm can be fully realized only when one becomes aware that as the result of very limited geological surveys in the late 1960's the USAEC determined that there was enough thorium available in the United States for all of its energy for at least the next two million years. World thorium resources appear to be huge and largely unexplored. Indeed there appears to be enough recoverable thorium in the earths crust to last us for as long as the Earth is a habitable planet.

"But why the LFTR," you ask. Scientists from all over the world have looked at LFTR-type MSR technology. Most have concluded that it represents a major breakthrough in nuclear technology. Yet, as Richard Martin points out,

LFTRs face more than engineering problems; they’ve also got serious perception problems. To some nuclear engineers, a LFTR is a little … unsettling. It’s a chaotic system without any of the closely monitored control rods and cooling towers on which the nuclear industry stakes its claim to safety. A conventional reactor, on the other hand, is as tightly engineered as a jet fighter.

But it is the simplicity of the LFTR is its major advantage. The LFTR core may require specially designed and carefully manufactured metal alloys to withstand its harsh environment of heat, neutron bombardment, and potentially corrosive salts, but it would be far easier to manufacture than a conventional reactor core. Canadian Physicist David LeBlanc argues that all you need for a LFTR core is two tubes, one inside the other. The LFTR core could be manufactured in in a few minutes in a factory. Other LFTR parts would take longer, but the whole thing is not nearly as complex as a conventional reactor.

Martin, tells the thorium-LFTR story, but like any brief telling it is incomplete. Still it is a breakthrough. One day the geeks will rule the Earth, and the geeks read Wired. The LFTR movement has been from the start a grass-roots movement. The LFTR may not be talked about in the halls of Congress, or even at Idaho National Laboratory, but on the Internet there is a growing buzz. If the LFTR will create a revolution it will be because there will be a popular demand for it, not because our leaders see its potential. Kirk shows us that a revolution can begin when a young man gets curious about a book.