The Zumwalt-class destroyers are a class of United States Navy Destroyers, designed as multi-mission ships with a focus on land attack. The class is multi-role and designed for surface warfare, anti-aircraft, and naval fire support. They take the place of battleships in filling the former congressional mandate for naval fire support, though the requirement was reduced to allow them to fill this role. The vessels’ appearance has been compared to that of the historic ironclad warships.
The class has a low radar profile; an integrated power system, which can send electricity to the electric drive motors or weapons, which may someday include a rail gun or free-electron lasers. The total ship computing environment infrastructure, serving as the ship’s primary LAN and as the hardware-independent platform for all of the ship’s software ensembles; automated fire-fighting systems and automated piping rupture isolation. The class is designed to require a smaller crew and be less expensive to operate than comparable warships. It has a wave-piercing tumblehome hull form whose sides slope inward above the waterline. This will reduce the radar cross-section, returning much less energy than a more hard-angled hull form.
The flag ship will be named Zumwalt for Admiral Elmo Zumwalt, and carries the hull number DDG-1000. Originally 32 ships were planned, with the $9.6 billion research and development costs spread across the class, but as the quantity was reduced to 10, then 3, the cost-per-ship increased dramatically. The cost increase caused the U.S. Navy to identify the program as being in breach of the Nunn–McCurdy Amendment on 1 February 2010. While technically classified as a destroyer, the type is only 10.3 feet (3.1 meters) shorter than the WWII-era Deutschland-class ”pocket battleships”, and actually displaces nearly 4000 more tons than a standard-loaded Deutschland. Zumwalt-class destroyers are also both longer and heavier than the Ticonderoga-class cruiser.
Still powered by fossil fuels
The power source of the Zumwalt is a 78 megawatt array of four compressed natural gas-turbine generators, but that’s the extent of the role of internal combustion engines on the ship. Here’s a rundown provided by our friends at the technology association IEEE:
…the Zumwalt’s propellers and drive shafts are turned by electric motors, rather than being directly attached to combustion engines. Such electric-drive systems, while a rarity for the U.S. Navy, have long been standard on big ships. What’s new and different about the one on the Zumwalt is that it’s flexible enough to propel the ship, fire railguns or directed-energy weapons (should these eventually be deployed), or both at the same time.
Speaking of railguns, another energy-intensive weapon system that could come into play is the Navy’s new laser weapons system (LaWS). Unfortunately, the power requirements for the Navy’s Rail Gun appear that the Navy will not be able to do any run and gun maneuvers. It is estimated that the ship would have to be at full stop to rapid fire a rail gun. Of course that could change with a different power plant.
Here’s the money quote:
As the technology advances, and faced with rising and unpredictable fossil fuel costs, the Navy’s next-generation of surface littoral class combatant ship will leverage electric ship technologies in conjunction with new smaller nuclear power plants with the design characteristics of better speed, weight, maneuverability, range, and cost—and capable to power multiple directed energy weapons at full speed.
For the record, the Zumwalt isn’t quite ready for prime time yet. The launch took place on October 28, 2013 at almost 90 percent completion, so there’s more work to be done before it’s fully operational. The Navy expects to have initial shakedowns completed by 2016.
A ship that can fuel its support ships (instead of vice versa) and other tactical vehicles such as helicopters would allow our ships a great tactical advantage in not having to fuel in a port, where ships can be most vunerable to attack.
The “Seawater to Fuels” program is a perfect application for the high heat of a MSR (Molten Salt Reactor) which can crack the carbon trapped in seawater to produce an ultra clean synthetic fuel.
This article is pertinent to how many experts envision a LFTR (Liquid Fluoride Thorium Reactor) producing electricity without the use of water.
Excerpted from an article by Principle Investigator Steven Wright
In most respects, carbon dioxide is an energy problem. The gas is mixed to varying degrees with methane in underground formations and must be stripped before natural gas is injected into pipelines. It’s created by the combustion of carbon fuels and must be vented away from engines. And the build-up of that CO2 in the atmosphere has many implicating it in global climate change.
Carbon dioxide has some interesting properties, however. Blocks of frozen carbon dioxide don’t melt but, rather sublimate into a gas; solid CO2 is known as “dry ice.” Indeed, CO2 won’t liquefy at all unless a pressure greater than five atmospheres is applied. But at a somewhat greater pressure—around 73 atmospheres—and roughly room temperature, CO2 makes a strange transition from a gas to a state known as a supercritical fluid.
Supercriticality is a hybrid state. A supercritical fluid is dense, like a liquid, but it expands to fill a volume the way a gas does. Small changes in temperature near the critical point—31 °C—will cause large changes in density, similar to boiling where the liquid changes to a vapor. The density change, however, is only a factor of three or four, not a thousand as when water becomes steam at atmospheric pressure.
Similarly, it takes a lot of energy to increase the temperature a small amount when the fluid is near the critical point, much the way the heat of vaporization requires energy to convert a liquid to a vapor. Consequently, a large spike in heat capacity occurs near the critical point of CO2 .
There are also viscosity changes that mimic the viscosity difference caused by transitioning from a very dense liquid-like fluid to a vapor-like fluid. And there are no drops and no bubbles because there can be no free surface.
These properties make supercritical carbon dioxide an incredibly tantalizing working fluid for Brayton cycle gas turbines. Sandia National Laboratory that has investigated these sorts of turbines for power generation, and is now moving into the demonstration phase. Such gas turbine systems promise an increased thermal-to-electric conversion efficiency of 50 percent over conventional gas turbines.
The system is also very small and simple, meaning that capital costs should be relatively low. The plant uses standard materials like chrome-based steel alloys, stainless steels, or nickel-based alloys at high temperatures (up to 800 °C). It can also be used with all heat sources, opening up a wide array of previously unavailable markets for power production.
For these reasons the technology is quite promising.
Sandia began studying these turbines more than five years ago as part of the lab’s work on advanced nuclear reactors. They selected supercritical CO2 as the working fluid operating at approximately 73 bar and 33 °C at the compressor inlet. Under those conditions, the CO2 gas has the density of 0.6-0.7 kg per liter—nearly the density of water. Even at the turbine inlet (the hot side of the loop) the CO2 density is high, about 0.1 kg/liter.
The high density of the fluid makes the power density very high because the turbo-machinery is very small. The machine is basically a jet engine running on a hot liquid, though there is no combustion because the heat is added and removed using heat exchangers. A 300 MWe S-CO2 power plant has a turbine diameter of approximately 1 meter and only needs 3 stages of turbo-machinery, while a similarly sized steam system has a diameter of around 5 meters and may take 22 to 30 blade rows of turbomachinery.
Eventually, this compactness will be a design advantage, but as Sandia develops prototypes to study the concept, it presents a distinct challenge. Early proof-of-concept demonstrations are often performed at the 1-to-20 kWe power level because many research labs have sufficient financial resources and support equipment to fabricate and operate power systems on this scale. It is quite easy to estimate the physical size of turbo-machinery if one uses the similarity principle, which guarantees that the velocity vectors of the fluid at the inlet and outlet of the compressor or turbine are the same as in well-behaved efficient turbo-machines.
Using these relationships, one finds that a 20 kWe power engine with a pressure ratio of 3.1, would ideally use a turbine that is 0.25 inch in diameter and spins at 1.5 million rpm! Its power cycle efficiency would be around 49 percent. This would be a wonderful machine indeed.
But at such small scales, parasitic losses due to friction, thermal heat flow losses due to the small size, and large bypass flow passages caused by manufacturing tolerances will dominate the system. Fabrication would have been impossible until the mid-1990s when the use of five-axis computer numerically controlled machine tools became widespread.
The alternative is to pick a turbine and compressor of a size that can be fabricated. A machine with a 6-inch (outside diameter) compressor would have small parasitic losses and use bearings, seals, and other components that are widely available in industry. A supercritical carbon dioxide power system on that scale with a pressure ratio of 3.3 would run at 25,000 rpm and have a turbine that is 11 inches in its outer diameter. It would, however, produce 10 MW of electricity (enough for 8,000 homes), require about 40 MW of recuperators, a 26 MW CO2 heater, and 15 MW of heat rejection. That’s a rather large power plant for a “proof-of-concept” experiment. The hardware alone is estimated to cost between $20 million and $30 million.
Sandia’s development approach was to compromise a bit on the performance, they selected a size that could fit within the Department of Energy’s nuclear energy budget. Sandia currently has two supercritical CO2 test loops. (The term “loop” derives from the shape taken by the working fluid as it completes each circuit.)
A power production loop is located at the Arvada, Colo., site of contractor Barber Nichols Inc., where it has been running and producing electricity during the developmental phase. The loop has the design capabilities to produce 240 kilowatts of electricity.
The turbo-alternator-compressor designed by Barber Nichols relies on such key enabling technologies as gas-foil bearings (both journal and thrust), a permanent magnet motor/generator, advanced labyrinth seals, the use of seal leakage for bearing cooling, and a reduced rotor cavity region to manage and control frictional power losses.
In addition to the turbo-machinery, the other enabling technology for the S-CO2 power cycle is made possible by the use of printed circuit heat exchangers that are manufactured by Heatric. Those heat exchangers are composed of sheets of steel with flow passages etched into them. The parts are diffusion bonded to provide a core-block that can have heat transfer areas exceeding 1,000 square meters per cubic meter. The heat exchangers are very compact and can withstand very high pressure and high temperatures. The high-temperature recuperator and gas chiller also use this technology.
Those technologies and the advanced high power switching electronics that made it possible to build a small proof-of-concept S-CO2 power loop have only recently become commercially available.
In this cycle the peak inlet temperature was selected to be 538 °C, and the pressure ratio was limited to 1.8. The lower pressure ratio increased the volumetric flow rate through the compressor, which increased its diameter and lowered the shaft speed to something that is within the range of gas foil bearings or magnetic bearings.
Other changes to the system were to use two 125 kWe motor/generators rather than one. This choice was made because the high-speed permanent magnet generator power level was limited by rotor dynamics.
The final modification selected was the use of a re-compression Brayton cycle, which uses two recuperators and splits a fraction of the flow. Part of the flow is sent to a re-compressor that increases the temperature rise in the high-pressure leg of the recuperators to assure that the temperature rise there nearly equals the temperature drop in the low-pressure leg. It also reduces the likelihood of a pinch point, which occurs when there is little or no temperature difference between the hot- and low-temperature legs in the recuperator, so no heat flows from one to the other. The re-compression cycle has large amounts of recuperation (note that the recuperators transfer 2.8 MW while the heater only supplies 0.78 MW).
A second loop, located at Sandia, is used to research the unusual issues of compression, bearings, seals, and friction that exist near the critical point, where the carbon dioxide has the density of liquid but otherwise has many of the properties of a gas.
Immediate plans call for Sandia to continue to develop and operate the two small test loops to identify key features and technologies. Test results will illustrate the capability of the concept, particularly its compactness and efficiency; confirm models; and demonstrate the scalability to larger systems.
Down the line, Sandia wants to commercialize the technology. That would entail the development of an industrial demonstration plant at 10 MW of electricity, perhaps in partnership with industry. Sandia would use or modify its loops to study the behavior of various types of components not previously tested (for example, other types of seals or bearings). Alternatively, the Brayton loop could be reconfigured to test the behavior for other types of power cycles that may more optimally couple to nuclear power plants.
Brayton-cycle turbines using supercritical carbon dioxide would make a great replacement for steam-driven Rankine-cycle turbines currently deployed. Rankine-cycle turbines generally have lower efficiency, are more corrosive at high temperature, and occupy 30 times as much turbo-machinery volume because of the need for very large turbines and condensers to handle the low-density, low-pressure steam. An S-CO2 Brayton-cycle turbine could yield 10 megawatts of electricity from a package with a volume as small as four to six cubic meters.
The turbines would have advantages in coal-fired plants. If carbon capture and sequestration become a requirement for coal power, a fraction of the electricity generated will be diverted to run the CCS equipment. The high efficiency that can be achieved in an advanced pressurized oxy-combustion process with pulverized coal when coupled to a supercritical CO2 power plant could make up for those losses, and thus keep zero-emission coal power plants economically competitive.
Finally, supercritical carbon dioxide Brayton-cycle turbines would be natural components of next generation nuclear power plants using liquid metal, molten salt, or high temperature gas as the coolant. In such reactors, plant efficiencies as high as 55 percent could be achieved. Recently Sandia has explored the applicability of using S-CO2 power systems with today’s fleet of light water reactors.
Replacement of the steam generators with three stages of S-CO2 inter-heaters and use of inter-cooling in the S-CO2 power system would allow a light water reactor to operate at over 30 percent efficiency with dry cooling with a compressor inlet temperature of 47 °C. Compared to power systems such as gas turbines and steam plants, the supercritical carbon dioxide Brayton system can increase the electrical power produced per unit fuel used by up to 50 percent, provided the cycle is correctly designed for the heat source and the heat source combustor/heater is efficient at getting the energy into the CO2 . In addition, very compact, transportable, and affordable systems are possible due to the combination of low-to-modest turbine inlet temperatures (which enable the use of standard engineering materials such as stainless steel) together with high efficiency and high power density. The small overall size of the system will allow for advanced-modular manufacturing processes and a smaller footprint, both of which ought to decrease costs.
S-CO2 power systems can use all heat sources and can operate at power levels ranging from a single megawatt to hundreds of megawatts. That flexibility should provide for applications in a variety of systems, improving the economics and marketability of the power cycle.
Sandia is not alone in this field, but are, however, among the leaders in developing this technology. They’re past the point of wondering if these power systems are going to be developed and commercialized; the question is who will be first to market. Sandia and the U.S. Department of Energy have a wonderful opportunity to support the United States power needs by fostering this commercialization effort.
Commentary by Jon Morrow-
The South China Post reported on March 18th that the Chinese government has greatly accelerated its plans to produce a commercialized LFTR (Liquid Fluoride Thorium Reactor), which is a type of MSR Molten Salt Reactor. The previous goal set for the development of this reactor was within 25 years and that goal has now been reduced to just 10 years.
In the past, the development of a LFTR by China was due to a massive energy shortage in China. China’s energy shortage is the result of millions of Chinese living in the third world that are dreaming and reaching for a first world lifestyle (that a majority of many Americans and Europeans today enjoy). The adoption of a very shrewd brand of American capitalism by the China government has allowed China the prosperity and wherewithal to pursue scientific endeavors such as the LFTR. These types of projects were previously reserved to capitalist countries like the United States, France, and Canada.
Unfortunately, the economy of America and many other countries has not allowed the pursuit of their own technologies due to their struggling economies. Many economist blame this upon a very expensive regulatory burden that has been imposed upon American companies. Business tend be be like water and tend to flow to countries that have the least costly regulatory burdens. This allows companies to be more competitive in a world with everything else being equal.
The reason given for the acceleration of the LFTR program by the China government is due to smog and air pollution brought on by the massive amount of manufacturing that has left America’s shores and other countries to set up business in China. Many out of work Americans in our struggling economy would like to have that problem. While China is exploiting its natural resources to produce prosperity for its citizens, America has adopted a policy of putting many of its natural resources off limits to protect the environment.
What is particularly ironic is that MSR technology was invented by America and Americans conceived the LFTR, but the same regulatory environment in America that has pushed American jobs overseas also prevents American companies from commercializing its own conceptual technology. A technology that could make many dirtier forms of energy naturally obsolete in a free market economy and give America a competitive edge.
China’s commercialization of LFTR would be a game changer that would allow an already very competitive China to have much more affordable energy and have a pollution free environment.
America’s energy policy is currently largely focused upon the development of renewables, and in particular, those renewable technologies that are not concentrated, base-load, or are power upon demand. Arguably, this means America has set its energy policy upon developing the most inefficient forms of renewable energy (wind and solar as compared to hydro or geothermal), which to economist (that are not scientifically biased and believe in the free-market system), means America is building energy expense and inefficiency into the foundation of its already struggling and un-competetive manufacturing arsenal.
China produces many of the solar panels and wind turbine generators (due to China’s near monopoly of rare earth elements used in their construction) used in America’s fleet of renewables, while China itself has gambled its present day prosperity and its future upon the development of nuclear technologies to provide safe, reliable, and clean energy.
Wind and solar in America struggle just to compete with coal and natural gas, LFTR is predicted to produce electricity at half that of natural gas and coal (and do so with less environmental harm to the planet than the large footprint of wind and solar) while producing no long-lived waste. Many Americans are used to living with Washington making bad energy policy decisions but, many cannot understand why we are aiding the Chinese in the development of commercializing MSR technology. To the layperson and even many experts this seems to be akin to shooting ourselves in our own foot. While America struggles to climb the ladder out of economic recession our legislators have adopted a policy of pursuing clean energy at any cost and a policy of assisting China at pursuing the development of clean and safe energy at an affordably competetive cost.
Shouldn’t we be pursuing clean, efficient, safe, and affordable energy?
Who are the winners in this current strategy?
More poor, desperate people died today trying to get gasoline from an overturned tanker than in the history of nuclear power.
A truck carrying fuel veered off the road into a ditch, caught fire and exploded in Nigeria’s oil-rich delta on Thursday, killing at least 95 people who had rushed to the scene to scoop fuel that had spilled, an official said, in a tragic reminder of how little of the country’s oil wealth has trickled down to the poor.
Shall we ban the use of gasoline?
The liquid fluoride thorium reactor (LFTR) has the potential to make electric power cheaper than from coal. Typical costs for electric power bought by US utilities average around 5-6 cents per kilowatt hour generated by coal, hydro, and natural gas sources. Government regulations are requiring utilities to buy solar- and wind-generated power at 20-30 cents/kWh. LFTR’s potential cost advantage of 3 cents/kWh is the economic incentive to stop burning CO2-emitting coal, without economically injurious carbon taxes and politically obscured feed-in tariffs. In this way LFTR can improve both the environment and the economy.
Click to read full post…
After the luncheon panel on “Green Technology: What’s Now & What’s Next” at the Fortune Brainstorm Tech conference, in Aspen, I confronted Amory Lovins and asked him a simple question: “Is there any potential technological innovation that would cause you to reconsider your views on nuclear power?”
Lovins is the founder of the Rocky Mountain Institute and his anti-nuclear stance is well-known, as exemplified by this article entitled “Forget Nuclear.” Lovins claim is that nuclear is both unsafe and uneconomical as compared to new wind and solar capacity. His answer to my question was, essentially, “No.” When I mentioned that I am the writer of the thorium feature that ran in Wired last year he replied “Well, I recall thinking that you got the economics and the technology backward.”
I have great respect for the work of the Rocky Mountain Institute and I will not detail here the ways in which he has it wrong on thorium-based nuclear power (for that please see the book version of the thorium story, due out next spring from Macmillan Science)—other than to note that the close-mindedness epitomized by his reply is what got us into our current energy crisis in the first place. What I will do is share some of the insights from the panel, which featured futurist Peter Schwartz, co-founder of Global Business Network, and Andy Karsner, CEO of Manifest Energy. The consensus was that there’s great reason for optimism on the technology side and little reason for it on the policy and politics side.
“We’re in a remarkable period of this great storm of innovation worldwide,” said Schwartz. “The problem is in the U.S.” The problem, he added, was the inability of the government to take concrete, rational policy steps that will clear the way for green-technology innovation to reach the market and for innovative companies to succeed.
The unexpected boom in natural gas from shale deposits, said Karsner, could serve as a relatively low-carbon bridge to the renewable-energy-based economy of the future, but that the obstacles of pervasive regulation and perverse incentives could prevent that from happening.
“We’re just an anti-energy development country,” declared Karsner. “That’s where we are.”
In his new book Reinventing Fire, due out in the fall, Lovins argues that by 2050 we can build a non-fossil-fuel based energy industry that includes no nuclear, significantly less natural gas, no oil, and that essentially runs on wind and solar and other renewables, with an 80 percent decrease in carbon emissions and 180 percent growth in GDP. (I do not share that optimism.)
Schwartz—who does not share Lovins’ knee-jerk opposition to nuclear power—mentioned that we are on the verge of a “new industrial revolution” based on new energy technologies, that will transform many businesses. “Where that will lead manufacturing, energy, and other industries is an open question,” Schwartz added. “What’s unquestionable is that the range of options will continue to grow.”
Mutiplying options was another theme that each of the panelists promoted. Lovins mentioned the work of RMI spinoff FiberForge, which has led the way in developing cars made from ultralight materials, chiefly carbon fiber, that will require one-third the energy to power them. He claimed that at least three carmakers (including most visibly BMW) have adopted this strategy and four others are in process of adopting it—representing a “radically different competitive path in automaking.”
As options for energy sources, particularly in transportation, multiply, one risk is “consumer confusion,” said Schwartz. If there are cars on the market with multiple forms of power sources—plug-in hybrid, hydrogen battery, serial hybrid, diesel, biofuel, and so on—the question for buyers become “What do I want, and how amI supposed to think about that?”
Given the rapid advance of clean-energy technology, the larger question, said Karsner, is one of national competitiveness: “Will we use these new resources, including natural gas and the new technology ideas, to address our greatest problems [in the United States] or will we export the gas, deploy solar manufacturing facilities, and send our better ideas to China, to collateralize our debt to China to pay the Saudis?”
Three things to point out about this discussion:
a) It’s remarkable how many discussions of the future of energy come down to Us vs.Them, i.e., the U.S. vs. China.
b) There is broad agreement that technologies will be available to meet broad carbon-emission goals by 2050, if national policy is shifted.
c) It’s remarkable that in a discussion that centered around energy density and efficiency, nuclear power was hardly even mentioned.
I really enjoyed the opportunity to be a part of Jim Puplava’s “Financial Sense Newshour” recently. Jim opened the interview with almost exactly the question I wanted to talk about: what are we going to do about our staggering dependence on fossil fuel?
Before I ever knew about thorium or LFTR, I would read about a lot of different energy technologies that promised to someday be 5% or 10% of our overall energy picture. I was always left wondering–what’s the 80% answer? What’s the 90% answer? What’s the technology that’s going to shoulder the burden of the planet’s energy needs into the future.
At one point I thought it was space solar power, but I was wrong. Later I thought it would be controlled thermonuclear fusion, but more education in that area left me highly doubtful. Ocean thermal-electric conversion looked very appealing, but it looked like is was only going to be a 5-10% type answer.
When I first read “Fluid Fuel Reactors” and learned about thorium and LFTR technology, it seemed like that was the “silver bullet” as Jim Puplava put it, but my own ignorance and fear of being wrong led me to second-guess my beliefs. That’s why I started working on a nuclear engineering degree. That’s why I wanted to get the scanned ORNL documents up on the Web and why I started to blog–to answer the simple question: is this as good as it looks to me?
I’m convinced now that it is.
I hope you enjoy the interview, which you can download in a variety of different audio files or read the transcript (but I think the audio versions are better).
Almost half of new electricity demand over the last decade has been generated from coal, meaning that “achieving the goal of halving global energy-related CO2 emissions by 2050 will require a doubling of all renewable generation use by 2020 from today’s level.”
And how does the IEA suggest that renewable generation be doubled in the next nine years? Through increased investment in renewable technology – most importantly, so-called “clean coal.”
“Extensive deployment of carbon capture and storage is critical to achieve climate change goals,” the report claims, calling for around 100 large-scale CCS projects by 2020, and over 3,000 by 2050. There are five large-scale CCS in operation today – none of which are commercial deployments.
I’m sorry, but building 10 CCS plants a year over the next nine years is a fantasy. In 2009 I produced a report for Pike Research on CCS that punctured the notion that commercial coal plants will be retrofitted with carbon-capture systems in the near-term.
“The addition of CCS systems to power plants will likely add between 50% and 70% to the cost of producing electricity,” I calculated. The challenges include uncertainty about the costs of the technology, the lack of a pipeline network to transport CO2 to geological storage sites, and most notably the absence of a price on carbon emissions. “The intensive short-term financing, radical policy shifts, and R&D advances that would be required for multiple deployments of CCS in the next five years appear unlikely,” I concluded.
A look at the chart accompanying the IEA report tells you all you need to know about the flawed priorities behind the Agency’s projections. Under the scenario contemplated here, by 2050 expanded nuclear power will account for 6% of the carbon-emissions reductions required to reach the “Blue Map” goal for total worldwide CO2 emissions; CCS will provide 19% of the desired reductions. If you reverse those totals you’d have a much more realistic, and achievable, set of goals.
Meanwhile overall venture funding for clean energy is up: “Venture capitalists invested $2.57 billion in the clean technology sector in the first quarter,” Reuters reports, citing figures from Cleantech Group LLC, “up 31 percent from a year earlier, with most of the money going to companies involved in solar power.” That’s the most since 2008, before the financial crisis shoved the world economy into a ditch. None of that went into advanced nuclear power, although Khosla Ventures, one of Silicon Valley’s most admired and imitated venture funds, is a backer of TerraPower, which is developing traveling-wave reactors.
President Obama, having watched his energy policy go down in flames at the start of his administration, is readying a revamped and scaled-down plan to move away from fossil fuels. But the radical new budget proposal from Republican Rep. Paul Ryan, the chairman of the House budget committee, would essentially abandon all government support for renewable energy while preserving federal subsidies for fossil fuels.
The plan “rolls back expensive handouts for uncompetitive sources of energy, calling instead for a free and open marketplace for energy development, innovation and exploration,” Ryan wrote in an op-ed the week in The Wall Street Journal. Translation: forget about solar tax credits and government-support loans for wind-energy projects, and don’t touch subsidies to Big Oil.
So what is to be done? The plan outlined by Kirk on this blog is a great place to start. I would add that the steps in the plan – particularly No. 2, “Restart LFTR Research & Development” – should be thoroughly costed-out. In his July 2010 post on Energy From Thorium entitled “Energy Cheaper Than From Coal,” Robert Hargraves makes some initial calculations. A realistic, fully developed cost model for developing liquid-fluoride thorium reactors is the first step in demonstrating that advanced nuclear power is the only way out of our current dilemma. And that organizations promoting clean coal, and ill-founded goals for carbon capture and sequestration like those found in the new IEA report, are “talking moonshine,” to quote Lord Rutherford.
And, by the way: Abu Dhabi, the scene of today’s ministerial meeting, last month “broke ground on the proposed site of its $20 billion first nuclear plant, part of the emirate’s plan to diversify its energy mix and free-up more fossil fuels for lucrative export.” To where do you think they’re planning to export that excess oil?
This is why:
Militants in Pakistan attacked a fuel supply convoy yesterday, killing at least four, that was bound for US military facilities inside Afghanistan. Twelve tankers were set ablaze and crews struggled throughout the night to put out the fire.
What does this have to do with thorium or LFTR?
A small rugged LFTR could provide electrical energy to these bases in Afghanistan that currently rely on shipments of vulnerable petroleum. Furthermore, the high-temperature capabilities of LFTR mean that we could also synthesize hydrocarbons to fuel vehicles on site, rather than trucking them in.
How would it work?
A small LFTR unit would be brought in to a military site in the form of a few standard containers. One would hold the reactor, its fuel and blanket processing system, and the primary heat exchangers, all within a strong and sealed containment system. The fact that LFTR operates at low pressure would mean that this containment would be close-fitting to the reactor. This is very different than the containments required on today’s water-cooled reactors, where they have to accommodate the expansion of high-pressure water into steam that can happen if pressure is lost. In a LFTR, the system is at low pressure and there is no high-pressure water or other gases inside the containment. The only thing that goes in is coolant salt and the only thing that comes out is coolant salt.
This whole assembly would be lowered into a below-ground concrete bunker. The gas turbine power conversion system would be brought in and attached to the coolant salt system. Coolant salt would heat gas that would drive turbines and generate power. The gas used in the power conversion system would be air-cooled via large air intakes and outlets.
How could we generate hydrocarbons? Using the electricity from the LFTR, we crack water electrolytically to generate hydrogen and oxygen. The hydrogen is reacted with carbon (either brought in to the site or extracted from CO2 in the air) to form synthetic hydrocarbons to power vehicles and aircraft.
The fuel for the LFTR would be brought in separately from the reactor, and when it was time to leave it would be removed from the reactor first. The reactor would not be transported with fuel or blanket material onboard.
Why consider LFTR versus other designs?
LFTRs can operate at low pressures. Pressurized-water reactors can’t and gas-cooled designs like the pebble-bed reactor can’t. Low-pressure operation means you can have a compact unit with a close-fitting containment and no risk of high-pressure explosions.
Liquid-metal-cooled designs like sodium-fast reactors can also operate at low pressures, but they have reactive coolants that would be much too risky in a combat zone. You need a reactor that can take a lot of punishment and not risk a sodium fire or an supercriticality accident.
LFTRs can operate at high temperatures. This is important for generating power efficiently, but it’s even more important for making gas turbine power conversion (Brayton-cycle) and air-cooling feasible. With lower temperature reactors like water-cooled and sodium-cooled reactors, you have to use steam turbine power conversion (Rankine-cycle) and it’s really hard (not impossible, but really hard) to air-cool these systems without excessive penalty.
LFTRs are easy to fuel and keep running. Nobody wants to try to swap fuel rods or reprocess solid fuel elements in a remote environment. The liquid fuel used in LFTR can be shipped separately from the reactor. Don’t try that with a solid-fueled reactor. LFTR’s liquid-fuel is already in the right form for simple processing techniques like fluorination/reduction. Thorium in the blanket/shield of the LFTR absorbs neutron and gamma radiation while making new fuel to keep the reactor running.
LFTRs are stable and self-controlling. You don’t want a whole bunch of reactor operators trying to keep your reactor happy in a remote environment. You want a reactor that runs itself. LFTR can do that, through a strong negative temperature coefficient that makes it follow the load well, and the simple removal of xenon gas that would otherwise make changes in power level difficult. It’s the same reason why they wanted liquid-fluoride reactors for aircraft sixty years ago–they’re good at controlling themselves.
LFTRs can be protected against enemies. Liquid fuel means that “just-in-time” denaturing of the uranium-233 fuel is possible. If it looks like the bad guys are going to overrun your base, you hit a button and dump depleted uranium tetrafluoride in the core. Now no one will ever start your reactor again, and the U-233 is thoroughly denatured against any other use. (It’s always sad to trash U-233, but if the bad guys are coming, don’t you want to have the option?) Solid-fuel reactors can’t do just-in-time denaturing. You’ve got what you’ve got in the fuel and you can’t change it out in the field.
I spent two years as a civilian working at the US Army Space and Missile Defense Command, and had the privilege of working with men and women in uniform who had been over to the “sandbox”. I have talked with senior officials who have seen the problem firsthand that we face with vulnerable fuel convoys. I have talked to a general who wrote the letters to mothers and fathers telling them that their son or daughter had been killed transporting fuel through a combat zone. He had a simple question for me: would this reactor make a difference?
Yes sir, it would. It would make a big difference.
The People’s Republic of China has initiated a research and development project in thorium molten-salt reactor technology, it was announced in the Chinese Academy of Sciences (CAS) annual conference on Tuesday, January 25. An article in the Wenhui News followed on Wednesday (Google English translation). Chinese researchers also announced this development on the Energy from Thorium Discussion Forum.
A Chinese delegation led by Dr. Jiang travelled to Oak Ridge National Lab last fall to learn more about MSR technology and told lab leadership of their plans to develop a thorium-fueled MSR.
The Chinese also recognize that a thorium-fueled MSR is best run with uranium-233 fuel, which inevitably contains impurities (uranium-232 and its decay products) that preclude its use in nuclear weapons. Operating an MSR on the “pure” fuel cycle of thorium and uranium-233 means that a breakeven conversion ratio can be achieved, and after being started on uranium-233, only thorium is required for indefinite operation and power generation.
The Chinese now have the largest national effort to develop thorium molten-salt reactors. Whether other nations will follow is an open question.