Diatribes of Jay

This is a blog of essays on public policy. It shuns ideology and applies facts, logic and math to economic, social and political problems. It has a subject-matter index, a list of recent posts, and permalinks at the ends of posts. Comments are moderated and may take time to appear. Note: Profile updated 4/7/12

09 June 2012

The Future of Nuclear Power


Introduction
1. The economic dilemma: cheap power from obsolescent plants versus safer but more expensive power
2. Why we still use obsolete designs
3. Designing for safety
Conclusion

[For a description of a possible meltdown-proof design, click here.]

Introduction. Over a year ago, I promised an essay about the future of nuclear power after Fukushima. It’s been a long time coming, but this is it.

The reason for delay is that nuclear power is an exceedingly complex subject. In academic terms, it’s quintessentially “interdisciplinary.” It involves science, technology, engineering, economics, politics, psychology (including industrial psychology), labor relations, community planning, ethics and morality. Next to space travel, nuclear power is probably the most complex thing our species has yet attempted.

Nuclear weapons are much simpler. To meet their design goal, which is primarily deterrence, they just have to work once. Or they have to give the appearance of working as designed. They don’t have to work continuously and reliably, for decades, putting their components and structure under the intense stress of high temperatures, enormous pressures, corrosive chemicals and damaging radiation. And they don’t have to work through natural disasters like the earthquake and tsunami that destroyed the Fukushima plant.

There is also another reason I waited. I wanted to let the political fallout from Fukushima settle. Now that it appears to have done so, two things are clear. First, two of the greatest national engineering paragons—Germany and Japan—are on the verge of abandoning nuclear power once and for all.

That’s not all bad. Nuclear power involves radioactivity, and radioactivity has risks. If Germany and Japan switch to truly renewable power, they might help retard global warming and encourage a global transition to a sustainable civilization.

But to the extent they switch back to fossil fuels, especially coal, Germany and Japan will accelerate global warming and, by example, encourage a global energy suicide rush. If engineering powerhouses like Germany and Japan go back to coal, you can bet that India, Pakistan, most of Africa and Latin America, and large parts of China will, too. Then the ice caps might melt and give us runaway climate change.

The second self-evident aspect of Fukushima’s political fallout is the realization that people and policy makers worldwide know little or nothing about nuclear power. They are just scared.

The conclusion I draw from these facts is that nuclear power requires a thorough, expert, interdisciplinary analysis at the highest level. Ideally, the final report should be global, and preparing it should take at least five years. It should have political input and address some mixed technological-economic-political questions. But its authors should be established and peer-recognized experts.

This plenary analysis should put the tradeoffs—all tradeoffs—before policy makers and the public for open discussion. It should consider at least four alternatives: (1) continuing to exploit our fully depreciated and outdated nuclear power plants; (2) building new plants on the most modern existing designs; (3) developing and testing new designs for the specific purpose of meltdown proofing and avoiding the need for continuously cooling spent fuel; and (4) switching to more advanced nuclear technologies, like liquid fluoride thorium reactors, that promise vastly reduced risk and millennium-scale fuel availability.

Here are the reasons for this proposal.

1. The economic dilemma: cheap power from obsolescent plants versus safer but more expensive power. Nuclear electricity is cheap today. On my table costing various sources of energy for moving cars, it comes in first, i.e., with lowest cost (although the differences with industrial natural gas and solar photovoltaic electricity are not significant).

Why is that so? Is it something intrinsic about nuclear power? Or is it something about the way we’ve used it so far?

Simple accounting suggests the latter answer. The vast majority of nuclear plants in operation today, including the ones now halted in Japan, are based on 1960s designs. Their original designers never expected them to last this long—for half a century.

Although some parts of these plants have been replaced over the years, their most critical (and most expensive) parts are fully depreciated. Their construction bonds are all paid off. The expense of construction has been recovered. The only current costs are for fuel, maintenance, waste disposal and occasional electronic upgrades, and waste disposal is halted, at least in the US. That’s why nuclear power is the cheapest form of energy in use today.

The problem is that, after fifty years or so, these fully depreciated power plants are obsolete. Not only do they have things that even their routine engineering staff would like to repair, replace or redesign if they could find the money. These plants’ basic design concepts are obsolete. Even the goals of their design are.

Imagine yourself driving a car or working on a computer designed in the 1960s. Your car wouldn’t have seat belts, collision bags, fuel injection, automatic braking systems, or skid control, let alone GPS. If American, it would deliver between 11 and 20 miles per gallon. Your desktop and laptop computers, let alone your mobile devices, wouldn’t even exist. With something as complex and potentially as dangerous as a nuclear power plant, the risks posed by obsolete designs are much, much greater than anything posed by an obsolete car or computer.

So the basic economic dilemma is clear. We can continue to have cheap electric power coming from fully depreciated plants of obsolete design. But we can do so only if we’re willing to accept the risks of another Chernobyl or Fukushima. That the people of Germany and Japan have signaled they are unwilling to do.

There are alternatives, including the four more modern approaches listed in the introduction to this post. All have two common features: (1) they reduce the risk of disasters substantially, some to the vanishing point, but (2) they are going to cost a lot. All also offer the same general advantage of nuclear power as today’s mostly obsolete plants: they are carbon neutral and won’t accelerate global warming.

So here we have the dilemma. We can continue to rely on nuclear power and even expand it. In doing so, we can solve our energy “crisis” and (with electric cars and trains) makes ourselves fully energy independent. But if we want to do so safely, we are going to have to spend some money, probably a lot of money.

From a short-term economic perspective, all we’ll really get for that money is safety. So the spending is a hard, hard sell. If we continue on our present course, we can continue to enjoy cheap nuclear power at some risk. But after the next Fukushima, the public may reject nuclear power globally, as Germany and Japan appear to be doing. Then the world may return to fossil fuels and accelerate global warming.

2. Why we still use obsolete designs. Why is our species running hundreds of nuclear power plants based on now-obsolete design concepts? The answer is mostly history, plus a bit of inertia.

Nuclear power grew out of the search for nuclear weapons, not vice versa. After World War II had started in Europe, but before the US became involved, Albert Einstein wrote his famous letter to President Roosevelt. In it, he suggested that an atomic bomb might work, that the Nazis were working on it, and that we ought to try to develop one first.

That was 1939. The first “atomic pile”—an experimental nuclear heat- and radiation- generating device—demonstrated the principles of nuclear power in 1942. But it was just a stepping stone in what eventually become the Manhattan Project, whose explicit goal was developing nuclear weapons. So the first use of the theories of physics that underlie both nuclear weapons and nuclear power was military.

Later, as engineers and physicists began working on power generation, their primary goals were also military. They wanted power plants for submarines that didn’t need frequent refueling and that didn’t produce any gaseous exhaust to asphyxiate the crew or give away the sub’s location. Nuclear power fit the bill precisely, enabling relatively safe, silent, hard-to-detect subs that could stay under water as long as their crews could stand to be confined.

Admiral Hyman Rickover is famous for his comments on the difficulty of nuclear-power engineering. But to understand his remarks, you have to understand his principal concern. His goal was nuclear-powered submarines carrying nuclear weapons, not a civilian power program. He wanted power plants small enough to fit on subs, and he wanted them now, in the context of the Cold War.

So Rickover, like everyone else in the budding nuclear power industry, took all his clues from the military. The industry used the few published papers and as many results of secret military research as they could discover. They adapted the concepts learned in developing nuclear weapons and submarine power plants to civilian, terrestrial use.

Wars colored everyone’s view in those days. We had just ended history’s most destructive war (in the Pacific) with the first use of nuclear weapons. We were in a nuclear arms race with the Soviet Union and, to a lesser extent, with “Red” China. We weren’t worried about proliferating nuclear weapons because our two most dangerous adversaries already had them. We were worried only about how fast and how well we could increase and enhance our nuclear arsenal to maintain supremacy and effectively deter a first strike.

An engineer’s designs depend on the goals you give him. In those days, nonproliferation, the spread of fissionable material, and the risks of radioactivity were farthest from our minds. We didn’t care if nuclear power plants produced fissionable material suitable for weapons. In fact, we wanted such plants. For over a decade, an important goal of our nuclear reactors was to help produce fissionable material for weapons. Our first commercial nuclear power plant, at Shippingport, PA, did not open until 1957, a year after the first large-scale nuclear power plant in England. And ours was based on design concepts that Rickover had helped develop for submarines.

These historical facts explain why the vast majority of our nuclear power plants today are obsolete. Not only are their basic design concepts outmoded. The very goals that motivated the designs are, too.

Today our goals are quite different. We no longer want want nuclear power plants to use or generate fissionable materials suitable for weapons. We have so many excess weapons that we have agreed to cull them. And we fear what emerging nations and even non-state actors might do with nuclear power plants that produce fissionable material for nuclear weapons as by-products.

Today we also worry about the risks of nuclear power much more than we did then. In those days, there wasn’t much fuel, spent or otherwise, to worry about. We didn’t really understand the public-health implications of radioactivity until the fallout from nuclear-weapons testing in the atmosphere began to motivate treaties banning it. That didn’t happen until the mid-1960s. Although we understood the theory of nuclear-plant meltdown by about the same time, the first real meltdown, at Chernobyl, didn’t occur until 1986.

So the basic design concepts of nearly all our nuclear power plants in use today derive from the military goals of World War II and its aftermath, including the Cold War.

Inertia explains the rest. The period under discussion above, from 1942 to about 1965, saw the greatest investment in engineering, physics, and related technological infrastructure in our nation’s history, perhaps in our species’. The Manhattan Profect alone, for example, commandeered about 10% of our electrical power (for uranium enrichment), as well as large fractions of our advanced industrial output and the best of our tech-savvy manpower nationwide.

Of course neither we Yanks nor anyone else could sustain that sort of massive investment in a single endeavor indefinitely. So as the Cold War lapsed into stalemate and eventual resolution, there was no effort to review and revise the designs of nuclear power plants that had arisen in wartime, let alone their basic principles or goals.

As a result, America’s nuclear power industry is stuck with designs for nuclear reactors that use and/or produce uranium 235 and/or plutonium, the only two isotopes also used in nuclear weapons. Alternative designs, such as liquid fluoride thorium reactors, we abandoned because the isotopes they used and the isotopes that were byproducts of their operation were not useful in making weapons.

In the national relaxation from that intense and pressure-filled era, our nuclear-power industry just coasted. It used the designs it had because they worked and because there was a pre-existing industrial infrastructure to provide fuel for them. There were no other reasons. These designs weren’t particularly fuel efficient, and they weren’t particularly safe. But they were there.

So inertia gave us the plants we have today. And the inertia only increased once those plants were fully depreciated and their construction bonds paid off. What executive would spend huge capital resources just to get the same thing she now gets—electric power—more expensively but also more safely? So we are now getting cheap power from obsolete plants whose basic design concepts addressed wartime goals.

3. Designing for safety. In the frenzied forties, fifties and sixties, no one having much to do with nuclear weapons or power worried much about safety. We worried about whether the Nazis and later the Soviets would get better weapons first.

Knowledge of the dangers of radiation to individual survival and public health emerged only slowly. The wartime annihilation of Hiroshima and Nagasaki produced lots or horrific data, but both the US and Japan kept it secret to avoid causing public alarm. And no one suspected that reactors for civilian nuclear power held similar dangers.

The public became aware of the dangers of atmospheric dispersion of radioactive materials only in the sixties. That awareness ultimately motivated bans on atmospheric testing of nuclear weapons. The risk of meltdowns didn’t enter the public consciousness until the near-meltdown at Three Mile Island in 1979. Full awareness didn’t strike until after the Chernobyl disaster in 1986. Now Fukushima has brought awareness home for good.

So it’s not as if designing really safe nuclear power plants is impossibly hard. It may be relatively easy. We just don’t know, because we’ve never tried. We’ve only tried modifying basic designs based on obsolete concepts developed in an era when safe and widespread use of nuclear power was not even an important goal, let alone the dominant one.

We do have good reasons to believe that making nuclear power much safer is well within our capability. Theory tells us so.

I’ve explained the theory in detail elsewhere and won’t repeat the description here. But the basic principles are simple enough for anyone to understand. Nuclear reactions that produce electric power occur when separate blobs of fissionable material are brought close enough together to form a nearly critical mass. Then they spontaneously emit large volumes of neutrons and other radiation, which produce heat. Move the blobs apart, and the reaction dies down.

These basic principles suggest how to prevent meltdowns and how to make spent fuel much safer. If you let gravity move the blobs of fissionable material apart in an emergency, you don’t have to rely on complex electronic and physical precautions that require reliable external electric power to work. If gravity can move the blobs far enough apart, you don’t even have to cool them continuously. Imagination suggests a simple design that might work.

Of course the same principles apply, in theory, to spent fuel. Move the rods far enough apart, or disassemble them into even smaller blobs, and convective or conductive cooling can keep them safe, without the need for constant circulation of cooling water requiring electric power.

Implementing these precautions might require much bigger reactors and much more space for storing spent fuel than we use today. But that’s precisely the point. Designing for safety might change existing designs radically. It certainly would radically change nuclear- reactor designs for the confined spaces and limited resources of submarines.

Then there’s the concept of liquid fluoride thorium reactors. According to competent nuclear engineers, who should know, we built at least one reactor on this principle during the Cold War. It worked. The radioactivity of its fuel, operation and spent fuel was orders of magnitude smaller than that of the uranium and plutonium reactors in use today. It required far less water cooling, and in theory could be air cooled. And we have enough thorium right here in America to supply all our current power needs for a thousand years.

Implementing either of these approaches—meltdown proof designs and/or liquid fluoride thorium reactors—would require a huge effort and lots of money. We would have to do more research, more testing, and educate and nurture a whole new phalanx of nuclear engineers and physicists. (Since Three Mile Island and Chernobyl, nuclear engineering hasn’t exactly had the popularity of investment banking as a career choice. Fukushima didn’t help.)

Power executives making easy money operating fully depreciated and paid-off power plants don’t see the need for making that investment. They think we are safe enough. They think, “We’ll never be as careless as those fools at Chernobyl and Fukushima!”

Looking at dismal records of executive and commercial hubris, including those of our banking sector, the public is full of doubt. In Germany and Japan, the public wants to abandon nuclear power, with its obsolete and fully depreciated plants. But it takes that view largely because no one is offering any serious nuclear alternative. All on offer is just more of the same.

The rest of the world is caught in between. One more serious nuclear disaster, anywhere in the world, could spell the industry’s global demise, even if the disaster didn’t compare to Chernobyl or Fukushima.

Conclusion. Nuclear power is a complex business. When you consider fuel extraction, possible scarcity, military implications, the fuel cycle, and spent-fuel disposal—let alone the advanced industrial infrastructure needed to support all these things—it looks like the most complex thing our species has yet attempted, save sending men to the Moon.

No wonder the public is hesitant! It doesn’t understand any part of this complex puzzle, because no one has developed the necessary information. All the public knows is that an innocent slip—in one of two human societies best known for the quality and care of its engineering—rendered parts of Japan’s most populated region unfit for human habitation for generations, and that there are other ways of generating electric power.

The public doesn’t fully understand the three principal benefits of nuclear power. First, it offers “baseload” electricity, to fix the intermittency of free wind and sun, with a zero carbon footprint that will not accelerate global warming. Nuclear energy is the only technology that offers enough of this sort of power to serve the entire globe, regardless of geography.

Second, because nuclear power doesn’t use fossil fuels, its increased use will help avoid the continuing, intermittent economic “crises” that inevitably arise from the scarcity and increasing prices of fossil fuels. It will take some time and much more widespread use than we now make of fissionable materials before their scarcity and increasing prices will raise the price of electric power significantly.

Finally, radically new designs like liquid fluoride thorium reactors (LFTRs) promise to ameliorate or eliminate other limitations of nuclear power. They have two key advantages.

First, the spent fuel of LFTRs has a much lower level of radioactivity, with a much shorter half-life, than the spent fuel of any uranium- or plutonium-cycle plant. LFTR’s would reduce the level of spent-fuel storage danger and its persistence by several orders of magnitude.

Second, LFTRs are scalable, just like like natural-gas plants, solar plants and wind farms. They need not be as big or as grand as the huge nuclear-power plants now operating in the countryside and serving whole cities or regions. In theory, they could be small enough to power a single building or building complex, or to provide baseload backup for a small solar array or wind farm. And with a millennium of thorium here in our own country, the problem of scarcity-induced economic issues would be remote.

So there are lots of promises, but as yet no action. The power industry is content with the status quo. The public is not. The two are on a collision course, with the industry likely the long-term loser.

To prevent that collision, what we need is a plenary review of the entire industry, emphasizing new designs and future prospects. The public wants more safety but has no idea how to achieve it or how much it would cost. The industry has no idea what direction to take, so it stays the current (and unacceptably dangerous) course. Lack of knowledge produces mutual paralysis.

It goes without saying that any reliable, plenary analysis must come from experts, not politicians or economic/policy think tanks. It should involve the most knowledgeable and respected experts not only here in the US, but worldwide. And it must include experts from every relevant field: nuclear physics, nuclear proliferation, nuclear engineering, nuclear safety, radiation medicine, public health, energy economics, and power-plant economics.

There is no reason why this study should not be a global collective effort. After all, a subsidiary goal would be to reduce the risk of weapons proliferation and develop a power-plant cycle with no risk of encouraging weapons development or making it easier. And in the short-to-medium term, who wouldn’t want to help one’s neighbors (or even adversaries) reduce their use of fossil fuels, thereby lowering their cost for everyone and retarding the acceleration of global warming?

A delayed decision is a poor decision. While advocates for this or that plead their cases, mostly based on personal or institutional self-interest, the obsolete plants continue to run, bringing the next nuclear catastrophe closer and closer. If another one happens anytime soon, the rest of the world will likely take the path of Germany and Japan.

Ultimately, that might not be the worst outcome. But as an intelligent species, we shouldn’t make that fateful choice without proper study and consideration.

So the public needs to know from experts how safe nuclear power can be made and how much safety will cost. It needs to hear from experts about the benefits of nuclear power, the extraordinary benefits promised by LFTRs, and the cost and time frames for realizing them. Only then can policy makers, let alone the public, make rational decisions.

The most likely consequences of the present vacuum of reliable public information are: (1) a return to fossil fuels, (2) accelerated global warming, and (3) a series of scarcity-induced economic crises as even shale gas runs out. If we use shale and other natural gas to replace coal and run our cars, shale gas will last us less than four decades.

So we’d better get cracking on safe nuclear power. Since the field is so complex and expensive, the first step is a thorough, expert and preferably international study of the options for research, development and implementation.


Footnote: Here I refer to the reactor, reactor vessel, systems for moderating the reaction and shutting it down, containment structure, spent-fuel storage pools, cooling systems, and their supporting physical structures: pipes, tubes and valves. The instrumentation and control electronics have been updated from time to time. But the basic designs of the things that generate power and pose risks of meltdown and the spread of radioactivity in a failure (like Chernobyl) or natural disaster (like Fukushima) are nearly half a century old. The result is like putting new avionics in a World-War-II piston-propeller aircraft.

Coda: A Possible Meltdown-Proof Design

The idea of a meltdown-proof fission reactor is not just bare theory. With a little imagination, one can conceive of real designs that could work.

In our present, outmoded reactor designs, cylindrical rods contain the nuclear “fuel,” i.e., the fissionable material whose approach to critical mass causes the nuclear reaction that generates heat. But suppose the fuel-containing elements were spheres inside those cylinders. Suppose further that their “skin” was a metal or ceramic with a very high melting point that was relatively permeable (and impervious) to neutron fluxes, so as not to retard the nuclear reaction in normal operation.

Now suppose that these fuel spheres were stored in vertical cylinders of the same “skin” material. At the bottom of the spheres, a circle of the same material, able to support the spheres’ weight at normal temperatures, would hold them inside the cylinders. But what would hold that circle in place against the weight of the fuel spheres above would be bolts or other fasteners made of an alloy that melts at a specially selected temperature.

That melting temperature would be high enough above the reactor’s normal operating temperature to provide a reasonable margin of operating error. But it would be low enough to provide a considerable margin of safety. That is, the fasteners would be designed to melt, and let the fuel spheres fall out of their vertical holding cylinders, long before the reactor’s temperature reached levels dangerous to the containment vessel or the reactor itself.

Underneath the collection of fuel-sphere-containing cylinders would be a thing that looks like the working part of a old-fashioned lemon juicer. It wouldn’t be like the modern plier types. Instead, it would look like a symmetrical mountain with grooves in its slopes. The grooves would be larger than the fuel spheres and would radiate out in all directions.

When the reactor reached the critical temperature in an emergency, the fasteners would melt. Propelled by gravity, the fuel spheres would fall out of their containing cylinders onto this “mountain,” where the grooves would direct them outward in all directions. They would roll outward in their separate grooves until there were nothing resembling a critical mass of fuel anywhere in the reactor vessel.

When the little spheres of fuel rolled far enough apart physically, the reaction would cool down. If the spheres’ collecting points were numerous enough and far enough apart, they would roll to a point where no further cooling would be necessary—certainly none that required continuous water cooling.

To prevent meltdowns, all this sort of design would rely on is two ineluctable natural phenomena: the melting points of materials and the force of gravity. It would need no electric power, no delicate instruments, and certainly no continuous cooling to stay safe.

With modern automated robots inside the containment vessel, this design could have another advantage. After the emergency had passed, robots inside the containment vessel could install new bottoms and meltable fasteners in the fuel cylinders, pick up the dispersed fuel spheres, and put them back in. They thus could restore the reactor to normal operation again with the help of restored electric power.

Not only would this design pose virtually no danger to human society outside the reactor vessel. It could prevent the reactor from damaging itself, allowing it to resume normal operation unless a major disaster, like the earthquake and tsunami in Fukushima, destroyed it completely.

Of course there would be engineering challenges in implementing this design. Creating a near critical mass for normal operation might require using small cylinders of fuel, rather than spheres, inside the master cylinders. That would make the “juicer mountain” more difficult to design. And making the fuel-unit “skin” for the spheres, mini-cylinders and containment cylinder, as well as the meltable fasteners, might require some advances in materials for use in the hellish, radioactive environment inside a nuclear reactor.

But the simple facts of history remain. No one thought of anything like this sort of design at the time the basic concepts of our current nuclear reactors were conceived. No one thought of it because reducing the risk of meltdown was not a design criterion. The first real meltdown came at Chernobyl in 1986. Our designs were conceived in the 1960s.

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