Thorium-based nuclear power

A sample of thorium.

In recent years there has been renewed interest by experts in using thorium as a nuclear fuel in place of uranium to create nuclear power. Thorium, as well as uranium and plutonium, can be used as fuel in a nuclear reactor. A thorium fuel cycle, however, offers several potential advantages over a uranium fuel cycle, including much greater abundance on Earth, superior physical and nuclear properties of the fuel, enhanced proliferation resistance, and reduced nuclear waste production.

Tim Dean, science editor of Cosmos magazine, states that thorium could be “the key to unlocking a new generation of clean and safe nuclear power,” and science author Richard Martin sees thorium as a potential new “superfuel” and a “green energy source for the future.” In a paper published in 2005, nuclear scientists Ralph W. Moir and Edward Teller, considered the “father of the ‘H’ bomb,” after studying the feasibility of using thorium, concluded that thorium nuclear research should be restarted after a three-decade shutdown, and a “small prototype plant should be built.”

Research and development of thorium-based nuclear reactors, primarily the Liquid fluoride thorium reactor (LFTR), MSR design, has been or is now being done in India, China, U.S., Japan and Russia, along with a few other countries.

Background and brief history

After World War II, nuclear reactors using uranium as a fuel were built to produce electricity, similar to reactor designs used for producing nuclear weapons. However, at the same time the U.S. government made the decision to build them, it had also been considering an alternative design based on thorium instead of uranium for its primary fuel. But in 1973, the government shut down all thorium-related nuclear research which had by then been ongoing for approximately twenty years at Oak Ridge National Laboratory. The reasons were because uranium breeder reactors were more efficient, the research was proven, and byproducts could be used to make nuclear weapons. In Moir and Teller’s opinion, the decision to stop development of thorium reactors, at least as a backup option, “was an excusable mistake.” Martin notes that the director of Oak Ridge National Laboratory at the time, Alvin Weinberg, lost his job because he “championed safe thorium reactors:”

Weinberg realized that you could use thorium in an entirely new kind of reactor, one that would have zero risk of meltdown. . . . his team built a working reactor . . . . and he spent the rest of his 18-year tenure trying to make thorium the heart of the nation’s atomic power effort. He failed. Uranium reactors had already been established, and Hyman Rickover, de facto head of the US nuclear program, wanted the plutonium from uranium-powered nuclear plants to make bombs. Increasingly shunted aside, Weinberg was finally forced out in 1973.

Despite the documented history of thorium nuclear power, many of today’s nuclear experts were nonetheless unaware of it. Nuclear physicist Victor J. Stenger learned of it in 2012:

It came as a surprise to me to learn recently that such an alternative has been available to us since World War II, but not pursued because it lacked weapons applications.

Others, including former NASA scientist and thorium expert Kirk Sorensen, agree that “thorium was the alternative path” that was not taken, calling it the "next giant leap" in energy technology: the "potential energy in thorium is staggering."

Potential benefits

The World Nuclear Association explains some of the benefits :

The thorium fuel cycle offers enormous energy security benefits in the long-term – due to its potential for being a self-sustaining fuel without the need for fast neutron reactors. It is therefore an important and potentially viable technology that seems able to contribute to building credible, long-term nuclear energy scenarios.

Moir and Teller agree, noting that the advantages of thorium include “utilization of an abundant fuel, inaccessibility of that fuel to terrorists or for diversion to weapons use, together with good economics and safety features . . . “ Thorium is considered the “most abundant, most readily available, cleanest, and safest” energy source on Earth", adds Martin.“

• Abundance. It is four times as abundant as uranium and as common as lead. The Thorium Energy Alliance (TEA), estimates "there is enough thorium in the United States alone to power the country at its current energy level for over 1,000 years." "America has buried tons as a by-product of rare earth metals mining," notes Evans-Pritchard. "Norway has so much that Oslo is planning a post-oil era where thorium might drive the country’s next great phase of wealth. Even Britain has seams in Wales and in the granite cliffs of Cornwall. Almost all the mineral is usable as fuel, compared to 0.7pc of uranium. There is enough to power civilization for thousands of years."

• Safety. It is safer and cleaner than uranium because its radioactivity is significantly lower;“A chunk of thorium is no more harmful than a bar of soap,” states Martin.

• No meltdown possible. LFTR reactors offer many attractive passive safety features. Kirk Sorensen notes that because LFTRs operate at atmospheric pressure, hydrogen explosions as happened in Fukushima, Japan in 2011, are not possible. "One of these reactors would have come through the tsunami just fine. There would have been no radiation release.” Meltdown is impossible, since nuclear chain reactions cannot be sustained, and fission stops by default in case of accident.

• No nuclear weapons byproducts. It is nearly impossible to make a practical nuclear bomb from a thorium reactor's byproducts. According to Alvin Radkowsky, designer of the world’s first full-scale atomic electric power plant, "a thorium reactor's plutonium production rate would be less than 2 percent of that of a standard reactor, and the plutonium's isotopic content would make it unsuitable for a nuclear detonation."

• Less waste. There is much less nuclear waste—up to two orders of magnitude less, states Moir and Teller, eliminating the need for large-scale or long-term storage; "Chinese scientists claim that hazardous waste will be a thousand times less than with uranium." The radioactivity of the resulting waste also drops down to safe levels after just a few hundred years, compared to tens of thousands of years needed for current nuclear waste to cool off.

• Uses only thorium. According to Moir and Teller, "once started up [it] needs no other fuel except thorium because it makes most or all of its own fuel." Because it is non-fissile, it can also be used with fissile material, such as uranium and plutonium, as a nuclear fuel.

• Lower reactor construction costs. Since LFTR the core is not pressurized, it does not need the most expensive item in a light water reactor, a high-pressure reactor vessel for the core. Instead, there is a low-pressure vessel and pipes (for molten salt) constructed of relatively thin materials. Also due to low opertating pressure, a containment structure only slightly bigger than the reactor vessel can be used, compared to containment a thousandfold bigger in volume in traditional light water reactors.

• Lower fuel costs. Since all natural thorium can be used as a fuel, and the fuel is in the form of a molten salt instead of solid fuel rods, expensive fuel enrichment and solid fuel rods' validation procedures and fabricating processes are not needed, greatly decreasing LFTR fuel cost.

• Reduced reliance on coal. It could significantly reduce coal as a primary source of electricity in numerous large countries. Coal is expected to become the world's single largest source of energy before 2030, and is currently the world's largest source of carbon dioxide emissions, while also affecting the Earth's climate. It makes up 42% of U.S. electrical power generation and 65% in China. Reducing coal as an energy source, according to science expert Lester R. Brown, director of The Earth Policy Institute, would significantly reduce medical costs from breathing coal pollutants. Comparing the amount of thorium needed with coal, Nobel laureate Carlo Rubbia of CERN, (European Organization for Nuclear Research), estimates that a ton of thorium can produce as much energy as 200 tons of uranium, or 3,500,000 tons of coal. Brown has calculated that coal-related deaths and diseases are currently costing the U.S. up to $160 billion annually."

Summarizing, Martin writes, "Thorium could provide a clean and effectively limitless source of power while allaying all public concern—weapons proliferation, radioactive pollution, toxic waste, and fuel that is both costly and complicated to process.

From an economics viewpoint, U.K. business editor Ambrose Evans-Pritchard writes that "Obama could kill fossil fuels overnight with a nuclear dash for thorium," suggesting a "new Manhattan Project," and adding, "If it works, Manhattan II could restore American optimism and strategic leadership at a stroke . . ." Moir and Teller estimated in 2004 that the cost for their recommended prototype would be "well under $1 billion with operation costs likely on the order of $100 million per year," and as a result a "large-scale nuclear power plan" usable by many countries could be set up within a decade.

Possible disadvantages

Gordon Edwards has said that the idea of "thorium reactors" is "a very old idea that is now being dressed up in modern clothes and made to seem like a major scientific breakthrough, which it is not". Arjun Makhijani has said that contrary to the claims made by thorium proponents, thorium "doesn’t solve the proliferation, waste, safety, or cost problems of nuclear power, and it still faces major technical hurdles for commercialization".

Some experts note possible specific disadvantages of thorium nuclear power:

• Thorium reactors need an initial charge of fissile material, such as plutonium, enriched uranium-235 or uranium-233, as a "driver" or "primer" to initiate a chain reaction which can then be maintained. However, thorium-based reactors can be designed to breed its own fissile material in thermal neutron spectrum, a unique feature not possible with uranium fuels.

• Significant and expensive testing, analysis and licensing work is first required, requiring business and government support.

• There is a higher cost of fuel fabrication and reprocessing in designs that use traditional solid fuel rods

• It may not solve the proliferation problem.

• There will still be radioactive nuclear waste, although the quantity will be substantially less.

Current thorium projects

Research and development of thorium-based nuclear reactors, primarily the Liquid fluoride thorium reactor (LFTR), MSR design, has been or is now being done in the U.S., U.K., Germany, Brazil, India, China, France, the Czech Republic, Japan, Russia, Canada, Israel and the Netherlands.

• China. In early 2011, China announced a program to develop a thorium-fueled reactor. In addition, Dr. Jiang Mianheng, son of China's former leader Jiang Zemin, led a thorium delegation in non-disclosure talks at Oak Ridge National Laboratory, Tennessee. The World Nuclear Association notes that the China Academy of Sciences in January 2011 announced its R&D program, "claiming to have the world's largest national effort on it, hoping to obtain full intellectual property rights on the technology" According to Martin, "China has made clear its intention to go it alone," adding that China already has a monopoly over most of the world's rare earth minerals.

In early 2012, it was reported that China, using components produced by the West and Russia, planned to build two prototype thorium molten salt reactors by 2015, and had budgeted the project at $400 million and requiring 400 workers.Martin claims it "would make China the most advanced nuclear power station on Earth."

• India. India's government is developing up to 62, mostly thorium reactors, which it expects to be operational by 2025. Martin notes that it is the "only country in the world with a detailed, funded, government-approved plan" to focus on thorium-based nuclear power. It currently gets under 3% of its electricity from nuclear power, relying for the rest on coal and oil imports. After its new plants are built it expects to produce around 25% of its electricity from nuclear power. In 2009 the chairman of the Indian Atomic Energy Commission said that India has a "long-term objective goal of becoming energy-independent based on its vast thorium resources."

In late June, 2012, India announced that their "first commercial fast reactor" was near completion and would rely on thorium for its fuel: "We have huge reserves of thorium. The challenge is to develop technology for converting this to fissile material, stated their former Chairman of India's Atomic Energy Commission. That vision of using thorium in place of uranium was first set out in the 1950s by physicist Homi Bhabha. After returning from studying the technology in the U.K., he recognized that India's vast thorium reserves could be the best source for a nuclear fuel.

• U.S. In its January 2012 report to the Secretary of Energy, the Blue Ribbon Commission on America's Future notes that a "molten-salt reactor using thorium [has] also been proposed. Such systems could potentially offer many of the combined benefits of the alternatives listed. However, these systems have not received systematic study and the component technologies for these types of systems are less well developed." That same month it was also reported that the U.S. Department of Energy is "quietly collaborating with China" on thorium-based nuclear power designs using a molten salt reactor. However, some experts feel that thorium should be "the pillar of the U.S. nuclear future."

Alvin Radkowsky, chief designer of the world’s first full-scale atomic electric power plant, located in Shippingport, Pennsylvania, founded a joint U.S. and Russian project in 1997 to create a thorium-based reactor, considered a "creative breakthrough." He had also been chief scientist for the U.S. nuclear submarine program directed by Admiral Hyman Rickover. Although retired from the navy in 1972, Edward Teller "urged him to restart his thorium work" which he began 20 years earlier. In 1992, then seventy-seven years of age and a resident professor in Tel Aviv, Israel, Radkowsky founded a U.S. company called Thorium Power Ltd. near Washington, D.C. to build thorium reactors, hoping to help create a "new era of nuclear power."

• Japan. In June, 2012, Japan utility Chubu Electric Power, still recovering from three nuclear plant meltdowns in 2011, wrote that they regard thorium as “one of future possible energy resources.”

• Israel.In May 2010, researchers from Ben-Gurion University in Israel and Brookhaven National Laboratory in New York, began to collaborate on the development of thorium reactors aimed at being self-sustaining, "meaning one that will produce and consume about the same amounts of fuel," which is not possible with uranium in a light water reactor.

• U.K.. In Britain, a few organizations are either promoting or examining research on thorium-based nuclear plants. One such organization, Friends of the Earth, formerly known for its anti-nuclear power positions, is moving away from calling for an immediate shutdown of the UK’s nuclear power stations, and now supports research into thorium-fueled nuclear power. House of Lords member Bryony Worthington is promoting thorium, calling it “the forgotten fuel” which could alter Britain’s energy plans. However, in 2010, the UK’s National Nuclear Laboratory (NNL) published a paper on the thorium fuel cycle, concluding that for the short to medium term, "the thorium fuel cycle does not currently have a role to play," in that it is "technically immature," and would require a significant financial investment and risk without clear benefits," and which it feels have been "overstated."

World sources of thorium

Thorium is mostly found with the rare earth phosphate mineral, monazite, which contains up to about 12% thorium phosphate, but 6-7% on average. World monazite resources are estimated to be about 12 million tons, two-thirds of which are in heavy mineral sands deposits on the south and east coasts of India. There are substantial deposits in several other countries (see Table below).

World thorium sources (2007)|
Country	Tons	% of total
Australia	489,000	19
USA	400,000	15
Turkey	344,000	13
India	319,000	12
Venezuela	300,000	12
Brazil	302,000	12
Norway	132,000	5
Egypt	100,000	4
Russia	75,000	3
Greenland	54,000	2
Canada	44,000	2
South Africa	18,000	1
Other countries	33,000	1
World total	2,610,000

Types of thorium-based reactors

According to the World Nuclear Association there are seven types of reactors that can be designed to use thorium as a nuclear fuel. The first five of these have all entered into operational service at some point. The last two are still conceptual, although currently in development by many countries:

• Heavy water reactors (PHWRs)
• High-temperature gas-cooled reactors (HTRs)
• Boiling (light) water reactors (BWRs)
• Pressurized (Light) water reactors (PWRs)
• Fast neutron reactors (FNRs)
• Molten salt reactors (MSRs, LFTRs)

The Oak Ridge National Laboratory designed and built a thorium-based demonstration MSR using U-233 as the main fissile driver, and was operational from 1965 to 1969.

• Accelerator driven reactors (ADS)

See also

• Breeder reactor
• Generation IV reactor
• Flibe Energy
• India's three stage nuclear power programme

External links

• "Energy From Thorium: A Nuclear Waste Burning Liquid Salt Thorium Reactor", video, 1 hr. 22 min., Kirk Sorensen's presentation at Google's Tech Talk, July 20, 2009
• Uranium Is So Last Century — Enter Thorium, the New Green Nuke Wired Magazine article
• Thorium Energy Alliance - advocacy and educational organisation dedicated to thorium energy
• International Thorium Energy Organisation
• International Thorium Molten-Salt Forum