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Some Nuclear Energy Backers Say Uranium Alternative Could be a Magic Bullet

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HTMnng

Feokxwvx of VT 1:57PM July 15, 2009

Uranium-233/Thorium nuclear fuel cycle as implemented in Liquid Fluoride Thorium Reactors (LFTR) answer the two most common primary objections to wider application of nuclear power.
Liquid Fluoride Thorium Reactors:
• Provide a proliferation-resistant fuel cycle — there is no production of nuclear weapons-usable Plutonium in spent fuel. LFTR reactors are proliferation resistant but not perfectly proliferation proof. LFTR Reactors produce Uranium-233 which has very poor characteristics as a weapon material. It is possible, but improbable, that a weapon could be built exclusively out of U-233 removed from a LFTR reactor. No weapon has ever been built or tested based solely on U-233. Clever alterations of the basic Thorium Reactors have been proposed but in the end physical security of a LFTR reactor would have to be maintained and no unauthorized material could be permitted to be removed from the reactor while it operates in order to assure safety.
• Eliminate the need for long term storage of high level nuclear waste at facilities like Yucca Mountain by significantly reducing the volume, weight and long-term radio-toxicity of spent fuel [1]. Uranium-233 produced in Liquid Fluoride Thorium Reactors is a fuel that can be burned while producing energy leaving only fission products. The longest lived fission products produced by LFTR Reactors decay to benign levels of the radioactive natural background within 300 years and the majority of fission products of Liquid Fluoride Thorium Reactors decay far faster than that (84% of the fission products of a LFTR reactor decay to natural background levels in 10 years). The nuclear fuel efficiency of Liquid Fluoride Thorium Reactors is in excess of 98% while traditional Uranium-Plutonium cycle LWR used to commercially make electricity in the US only have a fuel efficiency of 2 to 3%.
The new Administration should take responsible steps to lead in initiating a transition from Uranium-Plutonium fuel cycle technology which was developed to meet the combined needs of weapons and power generation to Thorium Fuel Cycle technology which is only suitable for generating abundant electrical power.
[1] Le Brun, C., “Impact of the MSBR concept technology on long-lived radio-toxicity and
proliferation resistance”, Technical Meeting on Fissile Material Management Strategies for
Sustainable Nuclear Energy, Vienna 2005
.

Robert Steinhaus - Lawrence Livermore National Laboratory (Retired) of CA 8:18PM December 20, 2008

This fuel source could safely provide all of our domestic electrical energy requirements. This summarized Washington press release proves that someone is listening:
Sen. Orrin G. Hatch (R-Utah) and Harry Reid (D-NV.) recently introduced legislation that would pave the way for thorium nuclear-fuel reactors in the United States. The Thorium Energy Independence and Security Act of 2008 would establish offices at the Nuclear Regulatory Commission and the Department of Energy to regulate domestic thorium nuclear power generation and oversee possible demonstrations of thorium nuclear fuel assemblies. Using thorium for nuclear power has a number of potential benefits over conventional uranium. As a resource, thorium is abundant in the U.S. and throughout the world.
A thorium fuel rod would remain in the reactor about three times as long as conventional nuclear fuel, cutting the volume of spent nuclear fuel by as much as two-thirds. Also, thorium nuclear fuel would significantly reduce the possibility that weapons-grade material would result from the process. Finally, a thorium fuel cycle could be used to dispose of existing plutonium stockpiles, which is the national security goal.
“Our nation has focused mostly on mixed oxide nuclear fuel cycles, and our regulatory structure reflects that,” Hatch said. “With the growing interest in thorium nuclear power in the world and in the U.S., it’s time we made sure our government has a regulatory infrastructure in place to accommodate this new generation of nuclear power.” Speaking about the bill, Bruce Blair, president of the World Security Institute said, “This legislation reflects an enlightened grasp of the importance of supporting nuclear power while suppressing nuclear proliferation.
“This bill is a giant step for the United States toward the development of a safe, secure and independent energy future,” said Jack Lifton, business development and corporate communications Director of Thorium Energy Inc. (www.ThoriumEnergy.com). Thorium Energy is a resource company that owns property in Lemhi Pass, Idaho, where it is generally believed that the largest veins of thorium-rich minerals in the world are located. Analysis of the deposits shows them to be either the highest grade or in the top tier of the highest grade known anywhere on Earth.

Patrick Kennedy of TX 2:28AM October 31, 2008

Ray Van De Walker> Thorium is close to useless for weapon grade material production. Breeding of U233 from Th232 inevitably creates U232 add-mixture, which cannot be separated due to identical chemistry and very close mass. U232 is very radioactive (half time ~74y), with many strong gamma emitters in its decay chain.
For this reason, any warhead created ou Th bred fuel will be intensively radioactive, even detectable from space satellites, with similar issues (though perhaps less grave) that making warhead from reactor-grade3 Pu posses - all the manufacturing have to be robotic in hot cells with heavy shielding (opposed to simple glove box manufacturing with weapon grade Pu), the warhead would be much hotter (~200 W for RG-PU) due to radioactivity, electronics of the warhead would have to be heavily shielded to protect from radiation damage over time, and due to the strong gamma emissions, the warhead would be easily detected.
Simply put, reactor grade materials are a nightmare for nuclear weapon design, extremely difficult to work with, and with properties very unsuitable for what a warhead needs.
At the same time, there are 60 years old textbook technologies, well known and guarantied to work due to extensive experience, producing weapon grade materials with exactly the desirable properties - high fissile concentration, predictable yield, low radioactivity enabling simple manufacturing, long shelf life, concealment, no problems with radiation damage to the chips etc.
So far any nation which desired to develop a weapon, followed one of the known paths to get clean WG material - U235 enrichment or Pu239 baking in graphite piles or other dedicated "research" reactors, for the above reasons. Any nation who so decides can make a nuke following one of these easy paths (as demonstrated the starving North Korea indeed) - therefore to suggest that nuclear power technologies, which would require much more complicated warhead fuel manufacturing, shaping and packaging, perhaps facing insurmountable difficulties in warhead construction (a sphere radiating ~200W closely packed by explosives?), would certainly make the warhead easily detectable, less dependable, with uncertain yield, and short shelf time, to suggest that this creates a proliferation risk, just does not add up.
Proliferation problem is a political problem: How to make countries not desiring to acquire a weapon. Commercial nuclear power adds nothing to the equation, but perhaps to the contrary - without a clean, affordable and scalable energy resource broadly available to all nations, the potential for conflict, and thus the desire to acquire a nuke (by one of the above two proved paths, and independently on nuclear power) is greater.

ondrej of NY 6:37PM October 21, 2008

The main negative is that it's very difficult to make nuclear weapons using a Thorium fuel cycle. The Uranium fuel cycle was originally conceived as a dual-use technology, providing both weapons and civilian energy.
However, for smaller nations without nuclear ambitions, a small, 100 MWe thorium-cycle reactor would be a wonderful option.
The main practical obstical to development of a Thorium cycle reactor is the U.S. nuclear regulatory commission. Cost of licensing a standard light-water reactor design are now more than thirty million dollars, and rising. The NRC is so irrationally conservative (mere proof of correct operation is not enough), that no novel, non LWR nongovernmental design has ever been licensed.

Ray Van De Walker of CA 3:59PM October 21, 2008

Thanks, Kent, for the article. You mention many of the strengths of thorium nuclear fuel, but not a single negative. Why is this? Obviously, there are some offsetting negatives, or we'd already be using this stuff. What are they? A more-balanced article the explores both sides of the argument would be more convincing if, as you suggest, thorium is a truly superior alternative to traditional uranium reactors.

Daniel Barlow of IN 4:32PM October 18, 2008

One initiative being explored world wide (US, Czech Republic, France, Russia) is to develop Thorium technology based on the Molten Salt Reactor (MSR). This reactor design is quite innovative: it uses a mixture of molten Lithium and Beryllium Fluoride salts as the working fluid in the reactor. Added directly to these or similar molten salts mixtures is a relatively small quantity of Thorium and Uranium-233 Fluoride salts. The resultant salt mixture simultaneously works as a moderator, coolant, and fuel medium. As it happens, the technology was first successfully tested in the 1960s, but recent advances in materials, fuel processing, and energy recovery systems, have made the technology very compelling.
There are numerous advantages to this technology:
Concerning Waste: The Th232-U233 fuel cycle, which unlike the U235- U238-Pu239 fuel cycle, produces almost no transuranic nuclear waste. As a result, the waste products have decay times measured in hundreds of years, as opposed to millions. Also, MSRs tend to burn up most of their nuclear waste, with a waste stream that is approximately 1 percent of a light water reactor.
Concerning Proliferation: The nuclear materials from the molten salt reactors contain as a byproduct of the reaction U232, which is a strong gamma radiator. This makes the reactor products practically impossible to redirect for illicit purposes due to the inherent detectability of U232. This property is essential in effort to prevent nuclear proliferation.
Concerning Safety: MSRs have an inherent, strong negative coefficient of reactivity as a function of temperature. This means that there is no possibility of the runaway thermal event that occurred at Chernobyl, which had a regime in which there was a positive coefficient of reactivity. It is also possible to design MSRs with passive safety systems. Thus the single most catastrophic event for a water moderated reactor, namely, a container vessel rupture, would not be a particularly dangerous situation for molten salt reactors, as the salt would drain away into specially designed tanks, stopping the reaction.
Concerning Siting: Because the boiling temperature of molten salts is so high (1500 C), MSRs can and will be designed to run at higher temperatures. This also enables them to use dry air cooling instead of water cooling. The latter fact is important as this, for the first time, enable reactors to be built far from water cooling sources like lakes or rivers, and therefore further away from population centers. In fact, the compactness of MSRs make them amenable to being built underground, which has obvious siting and safety advantages.
In short, Molten Salt Reactors promise to be safe, efficient and clean, and as such represent a significant departure from present designs. I believe that United States, with its large Thorium reserves, would benefit immensely from such a technology.

Dr. Honzik of CA 9:42PM October 16, 2008

In light of the current economic turmoil, the development of thorium as a fuel will likely become a back burner item if not forgotten. Like another trip to the Moon, such developments demand dollars which shouldn't be borrowed and added to the enormous foreign debt accumulated by such things as Iraqi Freedom. America will need to become extremely selective in the future in order to overcome current economic problems and serious decay of infrastructure.

T. C. Jackson of FL 9:27AM October 16, 2008

You write "Unlike a uranium reaction, a thorium fuel reaction doesn't produce weapons-usable plutonium, which would allay concerns about developing countries pursuing nuclear weapons under the pretext of nuclear energy."
But the thorium fuel cycle does produce U-233 which is weapons material. In fact, the USA has successfully tested a U-233 weapon.

Berol Robinson of MA 11:07PM October 15, 2008