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Thorium and the dream of clean nuclear power -- David Lague & Charlie Zhu

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SPECIAL REPORT-The U.S. government lab behind China's nuclear power push

9:03am EST
HONG KONG, Dec 20 (Reuters) - Scientists in Shanghai are attempting a breakthrough in nuclear energy: reactors powered by thorium, an alternative to uranium.
The project is run by the Chinese Academy of Sciences, a government body with close military ties that coordinates the country's science-and-technology strategy. The academy has designated thorium as a priority for China's top laboratories. The program has a budget of $350 million. And it's being spearheaded by the influential son of a former Chinese president.
But even as China bulks up its military muscle through means ranging from espionage to heavy spending, it is pursuing this aspect of its technology game plan with the blessing - and the help - of the United States.
China has enlisted a storied partner for its thorium push: Oak Ridge National Laboratory. The U.S. government institute produced the plutonium used for the Manhattan Project and laid important groundwork for the commercial and military use of nuclear power.
The Tennessee lab, as it happens, helped pioneer thorium reactors. The Pentagon and the energy industry later sidelined this technology in favor of uranium. The Chinese are now enthusiastically tapping that know-how, in an example of how the rising Asian superpower is scouring the world for all sorts of technology needed to catch up to America in a broad array of scientific fields.
Thorium's chief allure is that it is a potentially far safer fuel for civilian power plants than is uranium. But the element also has possible military applications as an energy source in naval vessels. A U.S. congressman unsuccessfully sought to push the Pentagon to embrace the technology in 2009, and British naval officers are recommending a design for a thorium-fueled ship.
In a further twist, despite the mounting strategic rivalry with China, there has been little or no protest in the United States over Oak Ridge's nuclear-energy cooperation with China.
"The U.S. government seems to welcome Chinese scientists into Department of Energy labs with open arms," says physicist and thorium advocate Robert Hargraves. He and other experts note that most of the U.S. intellectual property related to thorium is already in the public domain. At a time when the U.S. government is spending very little on advanced reactor research, they believe China's experiments may yield a breakthrough that provides an alternative to the massive consumption of fossil fuels.
The technology's immediate appeal for China, both Chinese and American scientists say, is that thorium reactors have the potential to be much more efficient, safer and cleaner than most in service today.
The Chinese plan to cool their experimental reactors with molten salts. This is sharply different from the pressurized water-cooling systems used in most uranium-fueled nuclear plants. The risks of explosions and meltdowns are lower, proponents say.
"If a thorium, molten-salt reactor can be successfully developed, it will remove all fears about nuclear energy," says Fang Jinqing, a retired nuclear researcher at the China Institute of Atomic Energy. "The technology works in theory, and it may have the potential to reshape the nuclear power landscape, but there are a lot of technical challenges."
Other advocates agree on thorium's peaceful promise. Republican Senator Orrin Hatch and Senate Majority Leader Harry Reid, a Democrat, introduced legislation in 2010 calling on the U.S. government to share its thorium expertise.
The unsuccessful bill said it was in U.S. "national security and foreign policy interest" to provide other countries with thorium fuel-cycle technology, because doing so would produce less long-lasting waste and reduce the risk of nuclear proliferation.
Oak Ridge has been free to proceed in spite of that bill's failure.
TURNING BACK THE CLOCK
What China is attempting is to turn the nuclear clock back to the mid-1960s, when Oak Ridge successfully operated a reactor with fuel derived from thorium and cooled with molten salts. The lab also produced detailed plans for a commercial-scale power plant.
Despite considerable promise, the thorium test reactor was shut down in 1969 after about five years of operation. Research was effectively shelved when the Nixon Administration decided in the 1970s that the U.S nuclear industry would concentrate on a new generation of uranium-fueled, fast-breeder reactors. For a range of technical and political reasons, not least the public's fear of nuclear plants, these new uranium reactors have yet to come into widespread commercial use.
The die was cast against thorium much earlier. In the early 1950s, an influential U.S. Navy officer, Hyman Rickover, decided a water-cooled, uranium-fueled reactor would power the world's first nuclear submarine, the USS Nautilus. Rickover was instrumental in the 1957 commissioning of a similar reactor at Shippingport, Pennsylvania - the world's first nuclear-power station.
Admiral Rickover was a towering figure in atomic energy and became known as the father of the U.S nuclear navy. He had clear reasons for his choice, engineers say. The pressurized water reactor was the most advanced, compact and technically sound at the time. More importantly, these reactors also supplied plutonium as a byproduct - then in strong demand as fuel for America's rapidly growing arsenal of nuclear warheads.
"The short answer is that uranium was good for bombs and thorium wasn't," says Kirk Sorensen, president of Flibe Energy, a privately held thorium-technology start-up based in Huntsville, Alabama.
With the launch of the Nautilus in 1955, a course was set that is still followed today, with most of the world's nuclear power generated from this type of reactor.
Although it does not yield byproducts that can be readily used to make weapons, thorium does have military applications.
The fuel could be used to power Chinese navy surface warships, including a planned fleet of aircraft carriers. China's nuclear submarine fleet has struggled with reactor reliability and safety, according to naval commentators, and thorium could eventually become an alternative.
Top British naval engineers last year proposed a design for a thorium reactor to power warships. Compact thorium power plants could also be used to supply reliable power to military bases and expeditionary forces.
Thorium also has military potential for the United States, experts say. But the world's most powerful military is reluctant to pursue alternatives to its uranium-fueled reactors, because it has operated them successfully for almost six decades.
Joe Sestak, a former U.S. congressman and retired two-star admiral, failed in an effort to get the Pentagon to reconsider thorium in 2009. "It is very hard to effect a change in something that has been established for a long time," he says. Sestak says he was unaware of the extent of cooperation between the U.S. and China on thorium technology.
INTELLECTUAL HOME
Flibe Energy's Sorensen, a former NASA engineer, has plans to build thorium-fueled reactors for commercial use in the United States. Sorensen has been instrumental in reviving global interest in the groundbreaking work of the late American nuclear physicist Alvin Weinberg.
It was Weinberg who led research into molten-salt cooled reactors and thorium when he ran Oak Ridge from 1955 to 1973. Weinberg was eventually fired for his persistent thorium advocacy. But he had some powerful supporters. In his last scientific paper, published shortly after his death in 2003, nuclear-weapons pioneer Edward Teller called for the construction and testing of a small, thorium-fueled reactor.
Oak Ridge remains the intellectual home of this technology. The U.S. Department of Energy lab still has a small research project under way on the use of molten-salt coolants for uranium-fueled reactors. The Energy Department is also funding related research at the University of California, Berkeley, the University of Wisconsin and the Massachusetts Institute of Technology.
But the ambitious project under way in China could be the best bet to unlock thorium's promise of safe, cheap and abundant nuclear fuel.
Jiang Mianheng, son of former Chinese president Jiang Zemin, visited Oak Ridge in 2010 and brokered a cooperation agreement with the lab. The deal gave the Chinese Academy of Sciences, which has a staff of 50,000, the plans for a thorium reactor. In January 2011, Jiang signed a protocol with the Department of Energy outlining the terms of joint energy research with the academy.
An electrical engineer trained at Drexel University in Philadelphia, Jiang told a conference on thorium in Shanghai last year China's thorium project "is 100 percent financed by the central government."
The protocol stipulates that intellectual property arising from the joint research will be shared with the global scientific community. It excludes sharing commercially confidential information and any other material that the parties agree to withhold. The pact also specifically rules out any military or weapons-related research. "All activities conducted under this protocol shall be exclusively for peaceful purposes," it says.
Jess Gehin, a nuclear-reactor physicist at Oak Ridge, says the pact allows the two sides to share information about their research.
"The Chinese are very aggressive, very determined and programmed to move forward with this technology," Gehin said. "Right now we agree that we should meet routinely, maybe a couple of times a year."
Jiang did not respond to requests for comment. In a statement posted on the Chinese Academy of Sciences website, he said China and the United States "should boost mutual trust and carry out complementary and mutually beneficial cooperation in the study of thorium-based salt reactors, hybrid energy systems and other cutting edge science and technology."
AN ENERGY HEDGE
Beijing's long-term goal: commercialize the technology by 2040, after building a series of increasingly bigger reactors. The Shanghai Institute of Applied Physics is recruiting nuclear physicists, engineers, project managers and support staff, according to a regular stream of job advertisements it publishes online. Its team is expected to expand to 750 by 2015 and eventually include 1,000 researchers.
A director at the Shanghai Institute, Li Qingnuan, and other senior researchers are wooing top young talent across China to join the project. After lecturing on molten-salt reactor technology at Sichuan University in April, Li invited students from the audience to apply for positions at the institute, according to a report on the university's website.
China's sprawling network of nuclear-research and industrial companies are gearing up to assist. In early June, the China National Nuclear Corporation, the body overseeing all Chinese civilian and military nuclear programs, announced that state-owned China North Nuclear Fuel Company had signed an agreement with the Shanghai Institute to research and supply thorium and molten salts for the experimental reactors.
The push into thorium is part of a broader national energy strategy. The government wants to reduce its dependence on coal-fired power plants, which account for about 80 percent of the nation's electricity but have darkened its skies. Nuclear energy is a big part of the plan: China aims to have 58 gigawatts of nuclear power on the grid by 2020, an almost five-fold increase from 12.57 gigawatts today.
Thorium is a hedge on that nuclear bet. China has 15 conventional nuclear reactors online and 30 under construction. But energy authorities are also investing in a range of different technologies for the future, including advanced pressurized water reactors, fast-breeder reactors and pebble-bed reactors. China has little uranium but massive reserves of thorium. So, the prospect of cheaper nuclear power with secure supplies of fuel is a powerful attraction.
At last year's Shanghai thorium conference, Jiang described how clean nuclear power would allow China to make a "revolutionary" move towards a greener economy.
The bet on unconventional nukes, he said, explains "why China is the first one to eat a crab" - citing an old Chinese proverb about the individual who dares to make a discovery important to civilization. (Editing by Bill Tarrant)


Thorium and the dream of clean nuclear power

Fri Dec 20, 2013 9:05am EST
(This story is part of a series, "Breakout," and accompanies a special report, "The U.S. government lab behind China's nuclear power push")
Dec 20(Reuters) - China isn't alone in turning to thorium as a potential source of power. Enthusiasm for exploiting this alternative to uranium is on the rise across the world, even as the cleanup continues from the Fukushima nuclear accident in Japan.
A new generation of scientists and nuclear engineers argue that thorium could be the key to realizing a dream of safe, cheap and plentiful nuclear power for an energy hungry world.
Thorium deposits, estimated to be about four times more abundant than uranium, are widely distributed: Substantial reserves have been found in ChinaAustralia, the United States, Turkey, India, and Norway. About 6,600 tonnes of thorium used to power the most efficient proposed reactors would provide enough energy to replace all of the fossil fuels and nuclear energy consumed globally each year, proponents say.
Uranium-poor India has a long-term research effort under way and has decided thorium will become the mainstay of its nuclear energy industry later this century. The French government has a research program. Companies in the United States, AustraliaNorwayand the Czech Republic are working on reactor designs or thorium fuel technology.
Energy from thorium is not just scientific theory. On April 25, Thor Energy, a private Norwegian company, began producing power from thorium - named after the Norse god of thunder - at the Halden test reactor in Norway.
"It is the fundamental first step in the thorium evolution," says company CEO Oystein Asphjell. The tests are aimed at showing the fuel could be a valuable alternative to uranium for existing reactor operators. Nuclear giant Westinghouse, a unit of Toshiba Corp, is part of an international consortium that Thor Energy established to fund and manage the experiments.
A Westinghouse spokesman said the company was "providing viewpoints" on the research.
Asphjell says burning thorium in current pressurized water reactors could boost safety and provide greater fuel security, especially for countries with limited access to uranium. Eventually, proponents want to pair thorium with a new kind of reactor, cooled not by water but by molten salt. That, booster say, would realize thorium's full potential as a fuel.
Thorium is a shiny, slightly radioactive metal. In its natural form, thorium isn't fissile - meaning that, in contrast to uranium, it can't split to sustain a nuclear chain reaction.
But if thorium is bombarded with neutrons from a small amount of fissile nuclear fuel acting as a starter, either uranium-235 or plutonium-239, it is converted to uranium-233 - a form of uranium that is a first-rate nuclear fuel. Once started in a reactor, the process is self-sustaining, with subsequent fissions of uranium-233 in turn converting more thorium to nuclear fuel.
In the kind of molten-salt cooled reactor favored by many thorium proponents, the uranium-233 fuel would be dissolved in a coolant of liquid fluoride salts contained in a graphite core. Surrounding the core would be a blanket of thorium, also dissolved in liquid fluoride salts.
When the fuel in the core fissions, it produces heat and a barrage of neutrons that pass through the graphite and convert some of the thorium in the blanket to uranium-233. This is then removed from the blanket and fed into the core, while fresh thorium is supplied to the blanket. The coolant and fuel mixture from the reactor core is circulated through a heat exchanger, so that the energy can be extracted to power a turbine and generate electricity.
One advantage of this system is that the fluoride salt coolant has an extremely high boiling point of 1,400 degrees Celsius, far higher than the reactor's operating temperature of about 750 degrees Celsius. That means the whole system can operate at close to normal atmospheric pressure.
In a conventional water-cooled reactor, the cooling system must be designed to withstand high pressure. That means reactors also must have massive, heavily engineered and expensive containment structures to minimize the danger from leaks or pressure explosions.
Because the core in a thorium molten-salt reactor is already liquid, it can't melt down. The design calls for a plug of frozen salt at the bottom of the system. If the reactor overheats, the plug would melt and the fuel and coolant would drain into a containment vessel below, where it would rapidly solidify and could be recovered for future use, proponents say.
These reactors could be much more efficient than most current nuclear plants, which extract between three and five percent of the energy in uranium fuel rods. In a molten salt reactor, almost all the fuel is consumed.
One tonne of thorium fuel would deliver the same amount of energy as 250 tonnes of uranium in a pressurized water reactor, according to a briefing paper published by the United Kingdom All Party Parliamentary Group on Thorium, a group of UK lawmakers who advocate adoption of the alternative fuel.
Also, because most of the fuel is consumed, thorium yields little waste and is much less radioactive, proponents say. Most of the residue will become inert within 30 years, with about 17 per cent needing secure storage for about 300 years.
The most dangerous waste from current generation reactors requires storage for 10,000 years.
The molten-salt reactor may have one further benefit. Some advocates believe they can be used to burn off existing nuclear waste.
A privately owned U.S start-up, Transatomic Power of Cambridge, Massachusetts, says it plans to build molten salt cooled reactors to burn some of the 270,000 tonnes of nuclear waste accumulated worldwide. "There is enough waste just in the U.S to power the country for a century," says Russ Wilcox, company CEO and co-founder. (Reporting By David Lague; edited by Bill Tarrant)


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