Friday, April 22, 2011

Kurt Cobb on Resources, Energy, Thorium and Molten Salt Reactor Technology

Kurt Cobb, is an energy writer whose vision is in many respects clear headed, and who has acknowledged both the problems and potential while appearing to be intrigued by Molten Salt Reactor/thorium fuel cycle ideas. Cobb has understood that nuclear power offered a solution to the future problems of global energy. In 2009 Cobb identified the problem,
The end of the fossil fuel era is coming sooner than most people believe as exponentially increasing fossil fuel consumption brings us ever closer to the day when production will peak for oil, natural gas and coal and then begin irrevocable declines. The only options left for powering a modern technical society will then be solar, wind, tidal, hydroelectric, geothermal and nuclear. And of these, only nuclear can conceivably be located wherever it is needed at the scale required.
The earth, Cobb argued, had plenty of resources needed to sustain industrial civilization,
granite contains many common metals such aluminum, iron, magnesium, titanium and manganese. Many more minerals including uranium are available in quantities of parts per million. Seawater contains most of the elements on the periodic table, the source of which is the erosion produced by streams and rivers feeding the oceans. The air contains rare "noble" gases that are important to industrial civilization including argon, neon, helium, krypton and xenon.
The visions of the resource optimists may not work out
here's why the future may not work out as Simon and other cornucopians envision. The main energy resources we use today are mineral resources. Oil, natural gas, and coal provide 86 percent of the world's energy. All of these resources are thought to be growing more abundant through the magic of the resource pyramid. But, if you examine the pyramid closely, you will see that not only do low-grade fossil fuel resources require better technology to extract them, they also require increasing amounts of energy to run that technology. At some point the amount of energy needed to bring low-grade deposits of oil, natural gas and coal to the surface and process and transport them will be more than the energy we get from these resources. At that point they will cease to be energy sources, and the vast, remaining ultra-low-grade deposits of these fuels will be useless to us except perhaps as feedstocks for chemicals.
Cobb adds,
Without a transition to vast new supplies of nuclear and renewable energy, the promise that we will be able to go all the way to the bottom of the resource pyramid is a mere daydream. The resource pyramid only shows what is possible. It does not guarantee that humans will achieve it. If peaks in fossil fuel production are nearing, either society will have to learn to get along without many of its critical resources, or it will have to make the transition to alternative energy swiftly as part of an engineering and planning feat that would be unparalleled in human history.
Cobb is pessimistic about the ability of society to make a rapid and timely transition to post fossil fuel energy sources,
Despite the pressing need for a rapid energy transition, it is doubtful that such a transition will be initiated by market forces before fossil fuels become scarce and therefore very expensive. The reason for this is that markets consistently wrongly assess the mineral economy, projecting what resource economist Douglas Reynolds calls "the illusion of decreasing scarcity." That means that prices stay relatively low until shortly before a resource peaks. . .
Because of the very long lead times required to transform our liquid-fuel based infrastructure, for example, into one that runs on electricity, undertaking such a conversion while oil or other fossil fuel supplies are declining could be very challenging indeed. The alternatives may not expand quickly enough to make up for the energy being lost. In that case, the whole transition project would be imperiled by the declining total energy available to society. That means that money and therefore energy would have to be taken from somewhere else in an already squeezed economy to keep the transition going. Contrary to expectations that so-called green industries will create new jobs, this scenario would result in the creation of new green jobs probably at the expense of jobs elsewhere in the economy (that is, barring improbable and extraordinary sudden leaps in the energy efficiency of the economy).
In such circumstances most people would naturally be focused on just making it through the day with little concern or appetite for spending a considerable amount of their incomes to buy electric cars or retrofit their homes for energy efficiency or passive solar heat. Nor would there likely be much appetite for raising taxes for a government-led transition program and/or set of subsidies related to making a transition away from fossil fuels.
Given the current skyrocketing prices of all fossil fuels, it appears that we are very late in the game indeed. It is not clear that a transition program started now would be completed before oil and possibly natural gas began to decline. But, it is clear that the public--at least in the United States--already has little appetite for a government-led solution when the major U. S. presidential candidates are proposing to lower gasoline taxes this summer to ease the burden on family budgets.
Let's take a 500-megawatt power plant which by itself can power a city of 300,000. (A megawatt is one million watts.) It will sit astride a fairly large plot of land. A coal-fired plant near me is just under that capacity (495 MW) and sits on about 300 acres. Most of that land, however, is essentially devoted to undeveloped transmission right-of-way filled with ponds, woods and streams. Only a small portion is covered by plant facilities including coal storage. I estimate less than 30 acres.

For new wind projects huge 5-megawatt wind generators are just now being deployed. If we take these as typical (and they are not), then using an estimate of the direct land footprint for wind towers of 0.38 acres per tower, we find that we'd need 100 towers covering 38 acres. But wind turbines run at only about 30 percent capacity because the wind doesn't blow all the time. This compares to about 70 percent capacity for coal-fired power plants. So we need to multiply 100 towers by about 2 1/3 to get the number of towers we'd need to match the operating capacity of one coal-fired plant. That means we'd need about 233 towers with a direct land footprint of 87 acres. That doesn't seem too bad. And, the land under the turbines is still available for farming and other purposes. The overall direct effects on the land and water are certainly less when compared to the coal plant.

But we're not done. The spacing between towers is typically at least five diameters of the rotor. That doesn't sound like much. But for the 5-megawatt towers in this example, the spacing would be 2,065 feet times 232--we don't need to separate the last tower from another tower beyond it. Then we'd add the diameter of the rotors--413 feet times 233--and we get a distance equivalent to about 110 miles. So, we'd need a line of 5-megawatt turbines stretching 110 miles. In theory, we'd want to split them up and put them in various locations in which the wind blows hardest at different times. But the total length of the line would still be at least 110 miles. If we take the largest separation recommended between towers which is 10 diameters of the rotors, we'd have to just about double that distance.

By comparison most people who live 110 miles from a coal-fired power plant are rarely even aware that it might be a source of electricity for them. And, the plant is certainly not a direct irritation. The lesson here, however, is not one of aesthetics. It is an illustration of the disparity in power densities between those energy sources on which we currently rely and the alternatives now being proposed and deployed.

The power density problem for solar energy is no less daunting.
Cobb then puts his finger on the problem,
We will be obliged to devote vast tracts of space--far more vast than the buildings they serve--to support the energy use of our current infrastructure.

This may not be impossible, but it will certainly be costly and socially disruptive.
In 2008 Cobb saw the failure of the first nuclear age as a potential tragedy for humanity. Cobb wrote,
It is a sad commentary that so many who knew the planet would one day run short of fossil fuels were unable to convince the world to embrace nuclear power in a more thoroughgoing way. With enough development, with careful and serious attention to the waste problem, and with lower-cost, decentralized designs that maximize safety, nuclear power might have succeeded in making any decline in fossil fuel availability just another historical footnote--but only if deployed on a large enough scale and far enough in advance of such a decline.

Now it may be too late. The time for the development of the nuclear economy appears to have come and gone with few people even realizing it.
Yet in the same essay, Cobb criticized the Price-Anderson Act by characterizing it as limiting the
liability for nuclear plant operators.
In fact Price-Anderson arguably protects the government from the consequences of having to pick up the first ten billion dollars of the bill, in the event of a major nuclear accident. The major accomplishment of Price Anderson is to set up an insurance pool that protects under funded nuclear operators.

Even in 2008 Cobb was prepaired to engage in real dialogue with nuclear supporters, and too acknowledge,
The solution, of course, is to build breeder reactors and I have seen designs which address the proliferation problem, in part, by using a hybrid technology that allows non-breeder and breeder operation in sequence and so the reactor doesn't have to be refueled for something on the order of 50 years.
Cobb was pessimistic about such a future,however,
I have come to the conclusion that the regulatory hurdles facing such designs are so great that it is unlikely they will be approved and built in time to address the energy deficits we will be facing after fossil fuels peak.
Cobb believed that the idea of using thorium as a basis for the nuclear fuel cycle was promising, and
besides availability, thorium has three additional distinct advantages over uranium fuel. First, thorium fuel elements can be designed in a way that make it difficult to recover the fissile uranium produced by breeding for bomb making. This reduces the likelihood of nuclear weapons spreading to nonnuclear nations that adopt thorium-based fuel technologies.

Second, the waste stream can be considerably smaller since unlike current reactors which often use only about 2 percent of the available fuel, thorium-fueled reactors with optimal designs could burn nearly all of the fuel. This is the main reason besides its sheer natural abundance that thorium could provide such long-lived supplies of fuel for nuclear power.

Third, the danger from the waste of the thorium fuel cycle is potentially far less long-lived. The claim is that the reprocessed waste will be no more radioactive than thorium ore after about 300 years. This claim is based on the idea that virtually all of the long-lived radioactive products of breeding will be consumed in the reactor before the final round of reprocessing takes place.
Cobb also notes the potential usefulness and value of Molten Salt Reactors in managing the thorium fuel cycle,
There are also practical hurdles for reprocessing solid fuel. But advocates of the so-called molten salt reactor claim that this design lessens the problem of reprocessing since the products of breeding can be continuously extracted and processed from the molten liquid stream inside a closed fuel cycle. They also claim that the design is far less prone to accidents which might release radioactive materials into the environment. None of this, of course, solves the problems of existing reactors that use solid fuel assemblies. But it does suggest a plausible course for vastly expanding nuclear power generation with little worry about fuel supplies and fewer concerns about nuclear weapons proliferation.
Cobb points to what he believes is a possible problem with MSR nuclear technology,
The main concern about these replacements is whether they can be built fast enough to head off an overall reduction in the amount of energy available to society.
I will address this concern.

Cobb's latest essay on nuclear technology is titled, "The Road to Fukushima: The Nuclear Industry's Wrong Turn." While Cobb does not mention either Nuclear Green or Charles Barton, many of the ideas in this essay parallel, indas I have frequently expressed. The lead sentence to Cobb's essay states,
Nuclear researchers knew long ago that reactor designs now in wide use had already been bested in safety by another design.
Then Cobb asks,
Why did the industry turn its back on that design?
This is indeed a very troubling question, and one to which I have devoted a number of posts on Nuclear Green. Cobb asks,
Imagine a nuclear reactor that runs on fuel that could power civilization for millennia; cannot melt down; resists weapons proliferation; can be built on a relatively small parcel of land; and produces little hazardous waste. It sounds like a good idea, and it was a well-tested reality in 1970 when it was abandoned for the current crop of reactors that subject society to the kinds of catastrophes now on display in Japan.

This rather remarkable design is called the molten salt reactor (MSR), and it lost out for two reasons: 1) It wasn't compatible with the U.S. government's desire to have a civilian nuclear program that would have dual use, that is, that could supply the military with nuclear bomb-making materials. 2) Uranium-fueled light water reactors, which are in wide use today, already had a large, expensive infrastructure supporting them back in 1970. To build MSRs would have required the entire industry to retool or at least create another expensive parallel infrastructure. And, that's how MSRs became the victim of lock-in.
Much of this simply parafrases Nuclear Green, although I have recently offered a somewhat more complex view on why the government turned its back on Molten Salt Reactor technology.

Whatever the actual reason for the exclusion of Molten Salt Reactor technology by the United States Government, Cobb is quite correct about the consequences of that decision,
Lock-in has worked in much the same way for the nuclear industry. The decision within U.S. government circles to focus on light water reactors and abandon MSRs relegated the latter to a footnote in the history of civilian nuclear power. And, because the United States was the leader in civilian nuclear technology at the time, every nation followed us.
Then Cobb points to an important question,
So, should the world look again at this "old" technology as a way forward for nuclear power after Fukushima?
Cobb answers his own question,
My sympathies are with the MSR advocates. If the world had adopted MSR technology early on, there would have been no partial meltdown at Three Mile Island, no explosion at Chernobyl, and no meltdown and subsequent dispersion of radioactive byproducts into the air and water at Fukushima. It's true that MSR technology is not foolproof. But its very design prevents known catastrophic problems from developing. The nuclear fuel is dissolved in molten salt which, counterintuitively, is the coolant. If the reactor overheats, a plug at the base melts away draining the molten salt into holding tanks that allow it to cool down. Only gravity is required, so power outages don't matter.

As for leaks, a coolant leak (that is a water leak) in a light water reactor, can quickly become dangerous. If there is a leak from an MSR, the fuel, which is dissolved in the molten salt, leaks out with it, thereby withdrawing the source of the heat. You end up with a radioactive mess inside the containment building, but that's about it.

If the world had adopted MSRs at the beginning of the development of civilian nuclear power, electricity production might now be dominated by them. And, we might be busily constructing wind generators and solar panels to replace the remaining coal- and natural gas-fired power plants. Would there have been accidents at MSRs? Certainly. Would these accidents have been large enough and scary enough to end new orders for nuclear power plants as happened after the 1979 Three Mile Island accident in the United States? I doubt it.
Cobb is still pessimistic however,
Having said all this, I believe that MSR technology will never be widely adopted. The same problem that derailed it early in the history of civilian nuclear power is still with us. We still have lock-in for light water reactors. Yes, the new designs are admittedly quite a bit safer. But these designs still don't solve as many problems as MSRs do, and they continue to rely on uranium for their fuel. MSRs have shown themselves capable of running on thorium, a metal that is three times more abundant than uranium, and 400 times more abundant than the only isotope of uranium that can be used for fuel, U-235. This is the basis for the claim that MSRs fueled with thorium could power civilization for millennia. . . .

. . . in the United States it is easier to predict that we'll see little progress. In the U.S. it is the industry that tells the government what new nuclear technologies will be developed rather than the other way around. And, the American nuclear industry is committed to light water reactors.

I believe that even if the Fukushima accident had not occurred, nuclear power generation would probably have done no more than maintain its share of the total energy pie in the coming decades. Now, I am convinced that that share will shrink as people in democratic societies reject new nuclear plants.
Yet Cobb also acknowledges that one nation is interested in developing Molten Salt Reactor Technology,
The Chinese have announced that they are interested in pursuing MSRs and the use of thorium to fuel them. Perhaps in China--where the nuclear industry is synonymous with the government and therefore does what the government tells it to--MSRs might actually be deployed. I have my doubts. Even China suffers from the lock-in problem.
I disagree with Cobb's pessimism. Although I believe what he calls the "Nuclear Industry, the current small set of reactor manufactures outside Canada, India and China are wedded to Light Water Reactor technology, the path to the development and deployment to Molten Salt Reactors is open wide open. Molten Salt Reactors are simpler, will require less labor to construct, and fewer building materials than Light Water Reactors. This means that there is a high likelihood that Molten Salt Reactors will be cheaper to manufacture, and simpler to deploy. This gives MSRs superior scalability. MSRs are also more efficient than LWRs. MSRs can do things that neither renewables nor LWRs can do. They can produce industrial process heat of up to !200 C. With their lower costs, MSRs can offer back up generation and peak generation capacity to the electrical industry.

Thus the question is will MSRs spread from China, which appears to be committed to the development of MSR technology, or will MSR technology be developed by other societies as well? There are several paths to MSR development. MSRs could be developed in the United States by one or more National Laboratories, MSR technology can be developed as a ship propulsion technology by the United States Navy. MSR technology can be developed by the United States military as a means of supplying electricity to military bases, and for military operations. MSR technology can be developed by private manufacturing businesses, which are interested in turning their manufacturing skills into a new source of energy related revenue. MSR technology could be developed by large fossil fuel energy companies, which seek a means of remaining in the energy business after their fossil fuel business declines. MSR technology could also be developed by a group of nations, which are attracted by the energy advantages MSRs offer. Thus there are many potential pathos to MSR development, and once adventurers start down one of them, other paths are likely to quickly open up.

When I began to write about MSRs in 2007, virtually no one had heard of them. On the Internet I found, Bruce Hoglund's Molten Salt Interest Pages, and Kirk Sorensen's Energy from Thorium. Fast forward to 2011, and the Molten Salt Reactor, mainly in the form of Liquid Fluoride Thorium Reactor, a name given by Kirk Sorensen, is widely known. The idea of a thorium fuel cycle Molten Salt Reactor has been adopted for development by China as a promising new nuclear technology, as Kurt Cobb has pointed out. Other parties are looking with interest, but have not announced plans yet. I expect some MSR development plans to emerge before the end of 2012.

8 comments:

Neurovore said...

Good article, but one small nitpick.

"They can produce industrial process heat of up to !200 C."


What is the temperature that you meant to type, there?

Charles Barton said...

When I refer to a temperature by writing a number followed by the letter C, I refer to a temperature on the Celsius (or Centigrade) scale. When I use a number followed by an F, I am referencing the Fahrenheit scale. Being an American, I use the Fahrenheit scale in my ordinary life, but scientist and everyone else outside the United States uses the Celsius scale and thus in writing about the heat produced by the nuclear process in a MSR, I follow the scientific convention.

Anonymous said...

1200 C.

Soylent said...

Charles, I believe he's refering the exclamation point that is masquerading as a one in !200 C.

Charles Barton said...

My readers by now should know that I have poor vision and sometimes don't see typos. With Blogger it is worse because there is no way to edit a comment. it is a problem because my computer seems to sometimes add accents without me even typing them.

donb said...

Kurt Cobb wrote:
Despite the pressing need for a rapid energy transition, it is doubtful that such a transition will be initiated by market forces before fossil fuels become scarce and therefore very expensive.

That may be what it takes to focus the minds of our citizen and politicians. A high level of focus was achieved before during WWII, when we when from nothing to operating reactors in less than two years! This time around, we have a head start in that we already have the the knowledge and prototype designs in hand. What is lacking is the focus (political will) to do anything with what we already have.

SteveK9 said...

Most of the focus in the article is on the US. The key to nuclear development now lies in China and India. In a few years, due to technology transfer, they will know everything the West knows. After that, they will start moving past us. We will have to see how the 'molten salt thorium reactor' (China) develops, but just the fact that they have shown the interest they have, at the level they have indicates they are not locked into standard thinking. India has it's own thorium program of course. Although Charles may view their approach as over-complicated, the fact that they recognize thorium as the fuel of the future makes it seem likely that they will give molten salt technology a look, ESPECIALLY if the Chinese have any success.

Charles Barton said...

Steve, At the moment my focus is on changing United States policy, which appears to be based on technological ignorance, and directed for plunging this country into poverty. I have in the past discussed the wiser nuclear policies of India and China.

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