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The Rare Promise of Thorium Reactors

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By Llewellyn King

If you want to design a new automobile, there are choices, but there are also parameters. For example, you would be advised to start with four wheels on the ground. You could design it with three, but the trade-offs are considerable.

When it comes to designing a new nuclear reactor for generating electricity, there are no such absolutes. A nuclear reactor only needs a safe nuclear reaction and the ability to harness the resulting heat. That means that nuclear reactors can be configured in all kinds of ways with considerable variety in the design of the fuel, the size of the reactor, the cooling system and the moderator (usually water).

Not only can the configuration of the fuel vary with differing results, but the fuel also can vary. It can be, for example, the intriguing metal thorium, which is plentiful in nature. It is fertile but not fissile, which means it takes uranium or plutonium to get a nuclear reaction going. When that happens, a thorium reactor appears to have advantages, from the availability of the fuel to the safety of the reactor.

Yet most of the world’s commercial civilian reactors – more than 400 — have just one basic design: uranium-fueled light water. The moderator is water.

Adm. Hyman G. Rickover, the father of the nuclear Navy, favored this technology. Recognizing that left to their own devices, nuclear engineers would come up with dozens of reactors, and would stymie the effort get industry off the ground, Rickover pushed light water. The admiral was a man who got what he wanted. So the light water reactor (LWR) became the world standard with some national exceptions.

Canada developed a very successful reactor that uses natural uranium, but requires heavy water: water with an extra hydrogen atom. Britain built two different reactor designs, the Magnox and the Advanced Gas Reactor, but finally has come around to the light water reactor. The Soviet Union went ahead with its own designs, including the disastrous Chernobyl design.

Although LWR construction steams ahead in China, and more hesitatingly elsewhere, there is a sense that it is time for change. Time to look at other designs and fuels.

In the United States, the Department of Energy has stimulated interest in a new generation of small modular reactorsand some ideas, which got pushed aside by light water technology, are doggedly holding on and even fighting back. Among these are various gas reactor concepts and fast reactors, where the neutron flux is not slowed down and which can do amazing things, including burning a certain proportion of nuclear waste.

The molten salt thorium reactor continues to have its advocates, although this technology is not included in DOE’s small modular reactor program. It is not a new idea, but it is one that has been given short shrift from the nuclear establishment in recent years. Promising work on it was done at the Oak Ridge National Laboratory in Tennessee in the 1960s, under the legendary scientist and laboratory director Alvin Weinberg. He died in 2006, and I was lucky to have known him. 

Proposed thorium molten salt research reactor. Source: Thorium Energy Alliance

Proposed thorium molten salt research reactor. Source: Thorium Energy Alliance

When I attended the Thorium Energy Alliance annual conference, held in Palo Alto, Calif., this year, I felt I had stumbled into an old-fashioned revival meeting. They are believers. Work on thorium-fueled reactors is ongoing in China, India and Russia.

But the best hope for thorium future may not lie in the nuclear sphere at all. It may rest with rare earths, and the global appetite for these in a high-tech world. A simple way to understand rare earths is that in technology they are great multipliers, making products in consumer electronics, computers and networks, communications, electricity generation, health care, advanced transportation, and across a wide range of defense materiel, more effective. With a small application, say to the turbine in a wind generator, the efficiency may increase several times.

Rare earths — which are not really rare at all — are found in conjunction with thorium, often in phosphate mining. When the world gets serious about the rare earths supply, it has to get serious about thorium, especially in the United States.The Thorium Energy Alliance would like to see thorium put into a national stockpile, so that it is available when the pendulum in reactor design swings to thorium, and that becomes the future. 

Can the 17 rare earth elements become the thorium reactor’s enabler? Some devoutly believe so. — For the InsideSources news service.

 

The Rare Earths Problem: A U.S. Solution

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Rare earth elements – there are 17 of them – have the world’s manufacturing by the throat. They are, as John Kutsch, director of the Thorium Energy Alliance, says, “the great multipliers.” They make metals stronger, generators more efficient, cell phones smaller, television sets sharper, and laptops lighter. They are, in their way, as important to modern manufacturing as energy.

At one time, the United States was a major supplier of rare earths — with supplemental supplies coming from countries around the world, including Australia and Brazil. Today, 90 percent of the rare earths the world uses come from China.

The use of rare earths is as important in lasers and jet engines as it is in aiming cruise missiles, which means the United States, and the rest of the world, has a huge vulnerability: China controls the supply of new war-fighting material. All U.S. defense manufacturers – including giants Boeing, General Electric and Lockheed Martin — are dependent on China. Now China is demanding that U.S. companies do more of their manufacturing there: China wants to control the whole chain.

Yet, as the rare earth elements industry is quick to assert, rare earths are not rare; they are scattered generously throughout the world. So why China’s dominance?

China has three main advantages. The first is that in 1984, leader Deng Xiaoping adopted a major initiative, the so called 863 Program, to move China from being a simple supplier of raw materials and products, enhanced by cheap labor, to being an industrial powerhouse and scientific giant. Rare earths were one of the areas singled out in the program.

The second advantage is that the Chinese ignored – and, to a large extent, still do — the environmental costs of rare earths’ extraction. The environmental damage is described by those who have been to one of two major Chinese sites, which have a combined population of 17 million, as catastrophic, with mountains bathed in acid to remove the sought-after rare earths, resulting in lakes of acid.

China’s third advantage is a natural one: It has a lot of ionic clay, which contains rare earths without the associated uranium and thorium.

About the time China was ramping up its plans to dominate the world rare earths market, the United States, in conjunction with the International Atomic Energy Agency in Vienna, began to regulate so called source materials. These are materials which, at least in theory, could be fashioned into weapons. In reality, those associated with rare earths are not in sufficient quantity to interest potential proliferators.

But the regulations are there. Many in the rare earths elements industry believe that it was these regulations — particularly as affecting thorium — that crippled production around the world and essentially closed down the U.S. industry, just as demand was escalating.

There is a commercial market for uranium. While hardly any thorium is used nowadays, it was once used in some scientific instruments and mantles for lighting. Thorium is akin to uranium in atomic weight, and it is a fertile nuclear material. That means that it can be used in a nuclear reactor, but it has to be ignited by a fissile material, such as enriched uranium or plutonium.

Thorium is radioactive, but mildly so. It is an alpha emitter, which means it can be shielded with tissue paper and will not penetrate the skin. However, it has a half-life of 1.5 billion years.

The answer, according to James Kennedy, a science consultant and rare earths expert, is to develop a reactor using thorium instead of uranium. This reactor, called a molten salt reactor, is inherently safe, say its passionate advocates, and would be a better all-around nuclear future. The technology was pioneered by one of the giants of the early nuclear age, Alvin Weinberg, at the Oak Ridge National Laboratory, but abandoned under pressure from enthusiasts for light water reactors, the kind we have today.

The Thorium Energy Alliance believes that the United States and other countries should develop a cooperative to source rare earths from the existing mining of phosphates and metals and store the thorium until it becomes a useful fuel. A bill to do this is making its way through Congress, but its chances are slim. Short of putting a value on thorium and isolating it, the chances of a rare earth elements industry reawakening in the United States, or elsewhere, is rare. — For the Hearst-New York Times Syndicate