11 results for month: 04/2006


How much thorium would it take to power the whole world?

How Much Thorium would it Take to Power the Whole World I have claimed on here that thorium, if efficiently utilized in a liquid-fluoride reactor, is an energy source of such magnitude that it is not difficult to conceive of an entire planet powered by thorium. The Calculation So let me lay out the calculations upon which I base my argument. In a fission reaction, thorium-232 (having been transmuted to uranium-233) will release roughly 190 MeV of energy per fission reaction. Assuming that the original thorium had a mass of 232 atomic units (u), then that is equivalent to 190 MeV/232 u = 820 keV/u. How much energy is that? If converted to ...

Does Reprocessing Nuclear Waste Make Sense?

Does Reprocessing Nuclear Waste Make Sense? Recent statements at the federal level indicate that the concept of "reprocessing" nuclear fuel is ready to be looked at again. This controversial decision was originally made by President Ford in the twilight days of his administation in October 1976, and then reiterated by President Carter shortly thereafter--that civilian reprocessing of nuclear fuel was to be ended. A recent article about controversies over reprocessing of spent nuclear fuel. The favored technique for reprocessing spent solid uranium oxide fuel is called PUREX (plutonium-uranium-extraction) and flowcharts of this process can be ...

What’s the difference between a
“Thermal Spectrum Reactor”
and a “Fast Spectrum Reactor”?

What's the difference between a "Thermal Spectrum Reactor" and a "Fast Spectrum Reactor"? When talking to folks about thorium, I often mention as one of the basic advantages the fact that you can "burn" thorium in a thermal spectrum reactor, and don't need a fast spectrum reactor. Which usually elicits the question, "What the heck is a "thermal spectrum reactor" and why should I care that you can burn thorium in one?" It's a good question, and worth taking a little time to explain. The basic idea behind nuclear fission is that you can use an electrically neutral particle, the neutron, to destabilize a nucleus and cause it to split. This is a ...

Chernobyl and the Central Role of the
Temperature Coefficient

Chernobyl, Nuclear Safety, and the Central Role of the Temperature Coefficient 20 Years Ago Twenty years ago, the worst nuclear power accident in history took place in the Ukraine at the Chernobyl Nuclear Power Station. The details of the accident are described extensively on a number of different websites, and I will not go through them here. But I will take the opportunity to talk about nuclear safety. One of the basic differences between the energy in a coal or gas-fired power plant and the energy in a conventional nuclear power plant is that the nuclear power plant contains all the energy in its core that it will liberate over its ...

Dual Fluid LFTR’s are easy to reprocess

Dual Fluid LFTR's are easy to Reprocess The nuclear materials of a properly-designed, two-fluid (LFTR) Liquid Fluoride Thorium Reactor are extremely easy to process. This is because the fuel (one-fluid) and the fertile blanket (the other fluid) are already liquids. This immediately eliminates the first step in typical solid-fuel reprocessing, which is converting the fuel to a liquid. This process is well-described in a document prepared by ORNL (Oak Ridge National Laboratory) scientists and engineers in 1967: Fuel and Blanket Processing Development for Molten-Salt Breeder Reactors (ORNL-TM-1852, PDF, 4.1M). "One of the most attractive features ...

Don’t throw away U233!

Don't throw away U233! When I learned that the entire National Defense Stockpile of thorium (3216 metric tonnes) was slated for burial in the Nevada desert, that was bad enough. But the destruction of our U233 really breaks my heart and hurts so much worse. Uranium-233 is the ideal fuel to start a liquid-fluoride reactor, and there is a very little bit in the world, left over from different attempts to get a thorium-powered future going. Now the DOE is taking great pride in the fact they are going to throw it away. I can only comfort myself with the idea that if they knew how valuable this material is for starting a liquid-fluoride reactor, they ...

How to waste a LOT of Thorium to make very little energy…

How to waste a LOT of Thorium to make very little energy Another semi-recent story concerns the use of thorium as a "fuel" in typical, light-water reactors. I put "fuel" in quotations because the only way to truly utilize the thorium resources of the world is to follow the three-step process I have outlined. First, convert the thorium to protactinium-233, isolate the protactinium until it decays to uranium-233, then introduce the uranium-233 back into the reactor to fission and produce the neutrons to convert additional thorium. As has been mentioned, this process is not only possible in thermal-neutron reactors, but attractive. However, there are ...

Getting out from between “MOX” and a “Hard Place”

Getting out from between "MOX" and a "Hard Place"   In 2003, an article in the Bulletin of the Atomic Scientists, Between MOX and a Hard Place, described the difficulty of disposing of the vast amounts of weapons-grade plutonium and uranium left over from the Cold War. "Weapons-grade" material generally means plutonium that consists predominantly of the isotope plutonium-239, and uranium that consists predominantly of the isotope uranium-235. The plan is to "blend" these materials with standard uranium, and form what is called in the nuclear industry "MOX", for "mixed oxides of uranium". Then the MOX fuel would be introduced into typical ...

Introducing the Liquid Fluoride Thorium Reactor

LFTR Liquid Fluoride Thorium Reactor Development of an Innovative Thorium Reactor The LFTR is an innovative design for a thermal breeder reactor that was developed from the 1950s through the 1970s at ORNL Oak Ridge National Laboratory in Oak Ridge, Tennessee. The reactor utilized a fluid-fuel form, with uranium and thorium fluoride salts dissolved in a matrix of lithium and beryllium fluoride salts. The melted salt was pumped throughout the reactor vessel and generated energy in an interesting manner. As the salt passed through the "core" region of the reactor, moderation provided by solid graphite elements led to neutron thermalization and ...

A Brief History of the Liquid-Fluoride Reactor

In the late 1940s, excitement and enthusiasm about all things "atomic" was common among military planners. Having "harnessed" the energy of the atom for nuclear weapons, naturally they began to imagine how this energy could be used to drive other military activities. About this time a young Navy captain, Hyman Rickover, was beginning to think about the possibilities of nuclear energy (reactor) for powering submarines, and the Air Force, not to be left behind, was imagining long-range bombers that could fly indefinitely, powered only by nuclear energy. The difficulties of building a nuclear aircraft were vastly greater than building a nuclear ...