Will Sodium-Cooled Reactors Bail Out U. S. Nuclear Energy?

  

On March 4 of this year, the U. S. Nuclear Regulatory Commission made history by issuing itsfirst-ever construction permit for a privately-owned nuclear reactor of a type that is advanced beyond the standard light-water reactors (LWRs) that have been the mainstay of the nuclear-power industry in the U. S. since its beginning in the 1950s.  TerraPower, founded by Bill Gates in 2006, obtained the permit to build a full-scale nuclear power plant in Kemmerer, Wyoming.  The plant will use TerraPower's sodium-cooled fast reactor (SFR) technology, which has the potential to solve or alleviate many of the problems with existing reactors.  A recent report in National Review describes how mainly Democratic opposition to nuclear innovation has delayed this type of permit for over fifty years.

 

Although SFR technology is advanced beyond the LWR approach, it isn't exactly new.  In 1950, the world's first breeder reactor using a sodium-potassium mixture as coolant was put into service in Idaho by the Argonne National Laboratory.  A breeder reactor is designed mainly to make more nuclear fuel than it consumes by transforming the relatively non-reactive uranium isotope U-238 into the plutonium isotope Pu-239, which can be used either for reactors or nuclear weapons. 

 

A modified form of the breeder approach is used in TerraPower's reactor, in that as time goes on, a small core of enriched fuel breeds fissionable material in its surrounding non-fissionable nuclear material, which can even be obtained by processing existing nuclear waste from light-water reactors.  In one stroke, this approach both conserves new fuel and gives us something useful to do with some of the nuclear waste that is now sitting around consuming space and worrying people.  The operating parameters of the TerraPower type of reactor can be tweaked to minimize its own waste stream, and avoid producing pure plutonium that would be of interest to terrorists wanting to make their own nuclear weapons.

 

Another advantage of the SFR reactor is that the coolant is liquid sodium, not water.  Admittedly, liquid sodium is not something you want just lying around in your living room.  When exposed to air, especially moist air, it tends to catch fire, as the Russians have discovered while operating some of their own SFR reactors, as they have for many years.  But TerraPower is going to bury most of the nuclear part of their plant underground and submerge the reactor in a passive pool of sodium.  If the nuclear core overheats, the great thermal mass of the sodium pool tends to absorb excess heat until the core self-stabilizes by expansion. 

 

Unlike light-water reactors which have to keep water under high pressures to use it as a coolant, the sodium coolant in an SFR reactor is at atmospheric pressure.  This means the containment vessel can be much thinner and still protect the environment from unplanned releases of radioactive material.  Although TerraPower's first reactor will cost some $5 billion, the hope is that the new design can be standardized so that such reactors can be mass-produced at much less cost.

 

Nuclear power in the U. S. has undergone a checkered career, from boom times in the 1950s when optimists claimed it would make electricity too cheap to meter, to the doomsayer times of the 1980s when the Three Mile Island partial meltdown in Pennsyvania in 1979 and the much worse Chernobyl disaster in Ukraine in 1986 turned the political winds against it.  Ever since then, as Andrew Follett of National Review explains, opponents of nuclear power have tried to obstruct new construction of light-water reactors, and imposed a rigid conservatism that made licensing so-called "innovative" designs such as TerraPower's, almost unthinkable. 

 

Fortunately for TerraPower, the Nuclear Regulatory Commission has sped up its approval process, completing the effort for this license in only a year and a half.  One of the main issues in building new nuclear plants of any kind since the 1970s has been the morass of regulatory hurdles that companies have had to wade through for many years.  It doesn't hurt that TerraPower is backed by one of the world's richest men, but even rich men get bored sometimes. It appears that Mr. Gates has maintained enough interest in TerraPower to bring it to the point of actually constructing a reactor that breaks the restrictive mold of light-water reactors that has held back innovation in the U. S. nuclear industry for decades.

 

Of course, cost overruns are another bête noire for the nuclear industry, and only time will show whether TerraPower can keep construction of the Kemmerer plant within budget and on schedule.  But the simplified requirements for safety and other issues that sodium-cooled reactors provide should make it easier. 

 

This development comes at a time when the U. S. electric grid faces a great challenge:  to meet vastly increased demand for power from data centers that are proliferating across the country.  The data-center boom took the electric industry largely by surprise, and strains are showing in the form of increased rates in some areas and local not-in-my-back-yard fights. 

 

But if the nuclear industry can get back on track with standardized, predictable designs that produce less nuclear waste, have a greater capacity for meeting peak loads (as the TerraPower design does through the great thermal mass of sodium and auxiliary molten-salt heat storage), and store enough fuel in them to run for thirty or forty years, the future looks brighter for nuclear power than it has in my lifetime, and I'm 73. 

 

As with any innovative design, TerraPower's Kemmerer plant will be under extreme scrutiny.  Any accident or mishap, no matter how small, is likely to be seized upon by opponents as evidence that the new design is "too dangerous."  So I hope the firm is using an extra measure of caution to ensure that the eggs they are walking on will not break, and the U. S. can look forward to a power-production source that is more reliable than most renewable sources and produces less nuclear waste than existing designs. 

 

Sources:  The article "After 52 Years, Democrats' Red Tape Unravels" appeared on the National Review website Mar. 21, 2026 at https://www.nationalreview.com/2026/03/after-52-years-democrats-red-tape-unravels/.  I also referred to Wikipedia articles on sodium-cooled fast reactors, TerraPower, and experimental breeder reactors. 

Will New U. S. Nuclear Plants Be Safe and Cost-Effective?

That's a question a lot of people are asking as the field of nuclear-powered electricity attempts a comeback in the U. S.  An article in the MIT Technology Review examines some critical issues that will affect the answers to that question. 

 

U. S. nuclear power has had a checkered career.  Beginning in the 1950s, nuclear power plants were built by the leading nuclear-bomb-making countries:  the old Soviet Union, England, and the U. S.  A building boom in the U. S. for nuclear plants peaked in the late 1970s, and some years since then, as much as 20% of total U. S. power came from nuclear sources.  However, after about 2000, with cost overruns and bad publicity such as the accidents at Three Mile Island in Pennsylvania in 1979 and Chernobyl, Ukraine in 1986, utilities quit planning new plants, and shut down several old ones. 

 

But with the rising concerns about climate change, nuclear power plants began to look better for the environment than fossil-fuel plants.  They also have a huge advantage over most renewable sources such as wind and solar, which are subject to the vagaries of nightfall and wind speed.  A properly-run nuclear plant can be an extremely reliable source, stabilizing a grid with renewables that might otherwise run out of energy on a still, dark night.

 

The Technology Review article points out some problems in getting a new nuclear-power industry started.  The fuel, for instance, is typically something called "high-assay low-enriched uranium" (HALEU for short).  It has between 5% and 25% U-235, the highly-fissionable isotope of uranium which makes fission plants using uranium workable.  Right now, the only source of new HALEU is Russia, although the U. S. government has a stockpile that it's currently doling out to experimental plants.  This issue needs to be resolved before new conventional nuclear plants go online here in a major way.

 

Another issue is safety.  While avoiding publicity, the Trump administration has relaxed some safety and security measures and environmental regulations pertaining to nuclear plants.  One can argue that excessive regulation and time-consuming permitting processes were big factors in putting the kibosh on nuclear in the first place.  But regulations are like preparing for war, in that you never know whether you did an inadequate job until something bad happens, and by then it's too late.  Time will tell whether the new regulation situation will merely speed up the construction of new plants or lead to problems with safety.  And unlike fossil-fuel plants, cleaning up a nuclear-plant accident can be orders of magnitude more expensive and dangerous, as we learned from the Fukushima nuclear-plant accident in 2011.

 

Finally, will new nuclear plants make a profit for their investors, or will they turn into financial albatrosses that bankrupt their owners, as has happened in the past with reactor projects that went way over budget?  One measure of how attractive nuclear plants are compared to other kinds is the cost per installed kilowatt.  Fossil-fuel plants can be built for around $1600 per kilowatt or less.  China reportedly builds their nuclear plants for between $2,000 and $3,000 per kilowatt.  Estimates for the various types of new U. S. nuclear plants vary, but figures between $6,000 and $10,000 per kilowatt seem realistic for the first new advanced models.  The price could come down if the nuclear industry learns to standardize models rather than building each plant from scratch, which practice has contributed to cost overruns in the past.  But going to a standardized model will require changes in the regulatory environment which may or may not come to pass.

 

Here in Texas, startup reactor builder Last Energy has teamed with Texas A&M University to build a 5-megawatt pressurized-water reactor at the RELLIS campus, a former air force base ten miles away from the main campus in Bryan-College Station.  News releases predict the facility will go critical in the summer of 2026, which is ambitious but possible.  The pressurized-water reactor design is not innovative, having been used for the first nuclear-powered submarines in the 1950s.  But with modern construction and control techniques, designers may be able to build on the decades of experience gained with the design to produce a standardized module that can be scaled up fairly easily to commercial size, in the 20-megawatt or larger range.

 

Newer designs are also in the works.  Some designs use boiling water rather than pressurized liquid water, and this simplifies the design.  Other designs use liquid metals for coolants, fuel in pebble rather than rod form, and other variations on the conventional design.  But there is a long road between experiments and a commercially profitable plant, and many previously-announced plans for smaller modular plants have been cancelled. 

 

Nevertheless, if some new designs can be shown to work safely and not cost an arm and a leg during the current administration's fairly favorable regulatory environment for nuclear power, the industry could make a substantial contribution toward the nation's energy needs, which have recently soared due to the boom in data-center construction. 

 

Building nuclear plants to run data centers is not going to appeal to your typical activist, and there are downsides to nuclear energy, notably the problem of waste.  Some of the newly proposed reactor schemes generate much less waste than conventional U-235 reactors, but again, these are only proposals, not working reactors.  The current policy in the U. S. of keeping waste stored locally rather than transporting it and concentrating it at one big waste facility seems to be working so far.  But "so far" compared to the dangerous centuries-long lifetime of nuclear waste is not very long, and it would be better if we could produce less waste to start with rather than making lots of it and figuring out what to do with it afterwards.

 

The next couple or three years may be a make-or-break time for nuclear power in the U. S.  From many points of view, it is a sensible and proven way to generate electricity.  If we can adjust the regulatory environment and adapt to new modular manufacturing techniques without compromising safety, nuclear power could make a climate-friendly and reliable contribution to our future energy needs.  But that is currently a big "if," and only time will tell us whether hopes for a more-nuclear future will be justified or dashed.

 

Sources:  The MIT Technology Review article I referred to, "Three Questions About Next-Generation Nuclear Power, Answered," appears at https://www.technologyreview.com/2026/02/05/1132197/nuclear-questions/.  I also referred to the website https://www.nei.org/resources/statistics/us-nuclear-generating-statistics for statistics on nuclear power and the sites https://news.tamus.edu/stories/last-energy-texas-am-collaborate-to-launch-microreactor-pilot-at-texas-am-rellis/and https://www.neimagazine.com/news/last-energy-funded-for-pwr-5-pilot/?cf-view for information on the Texas A&M 5-megawatt RELLIS unit.

 

The Case for Nuclear Power

 

In the fall 2022 issue of the technology-and-society journal The New Atlantis, authors Thomas and Nate Hochman examine the pros and cons of building new nuclear power plants in the U. S.  The case of nuclear power is fraught with political issues that are inextricably tied up with technical issues, but the Hochmans do a good job of laying out the problems facing nuclear power and some possible solutions.

 

If nuclear power had not been invented until 2010, say, it would probably be welcomed as the keystone in our society's answer to climate change.  Imagine a source of the most fungible type of energy—electricity—that takes teaspoons of nuclear fuel compared to carloads or pipelines full of fossil fuels, emits zero greenhouse gases, and when properly engineered runs more reliably than wind, solar, hydro, or sometimes even natural gas, as the misadventure of Texas's Great Freeze of February 2021 showed.  What's to oppose?  Well, a lot, as the Hochmans admit.

 

It is perhaps unfortunate that the first major use of nuclear technology was in the closing days of World War II, when the U. S. became the only nation so far to employ nuclear weapons in wartime, killing hundreds of thousands of Japanese with bombs dropped on Hiroshima and Nagasaki.  The long shadow of nuclear war has cast a darkness over the technology of nuclear power ever since, despite optimistic but misguided attempts to promote peaceful uses in the 1950s. 

 

The Hochmans describe the golden era of U. S. nuclear power plant construction, which ran roughly from 1967 to 1987, as a period in which the two major U. S. manufacturers—GE and Westinghouse—offered "turn-key" plants that were priced competitively with coal-fired units.  The utilities snapped them up, and the vast majority of existing plants were built in those two decades.

 

The turn-key pricing turned out to be a big mistake, however.  Manufacturers expected the cost per plant to decline as economies of scale kicked in, but for a variety of reasons both technical and regulatory, the hoped-for economies never materialized.  The particular pressurized-water technology that was used was adapted from early nuclear submarines, and in retrospect may not have been the best choice for domestic power plants.  By the time the companies realized their mistake and switched to cost-plus contracts, they had lost a billion dollars, and utilities became much less enthusiastic when they had to pay the true costs of building the plants.

 

In the meantime, the National Environmental Policy Act (NEPA) was passed in 1970, making it much harder to obtain permits to build complicated things like nuclear plants.  In the pre-Act days, permitting a plant sometimes took less than a year, but once NEPA passed, such speediness (and the resulting economies of fast construction) was a thing of the past. 

 

Then came the Three-Mile Island nuclear accident in 1979 and the Chernobyl plant fire and disaster in 1986, further blackening the reputation of nuclear power in the public mind.  Add to that the not-in-my-back-yard problems faced by attempts to find permanent storage locations for nuclear waste, and by 1990 the U. S. nuclear industry was in a kind of coma from which it has not yet recovered. 

 

The Hochmans point to France as a counterexample of a nation that made a conscious decision to go primarily nuclear for its electric power, and even today about 70% of France's power is nuclear.  But even France is having problems maintaining their aging plants, and French nuclear promoters face the same sorts of political headwinds that prevail in the U. S.

 

Now that climate change is an urgent priority for millions of people and dozens of governments, the strictly technical appeal of nuclear power is still valid.  It really does make zero greenhouse gases in operation, and when properly engineered, it can be the most reliable form of power, providing the essential base-load capacity that is needed to stabilize grids that will draw an increasing amount of energy from highly intermittent solar and wind sources in the future.  Eventually, energy-storage technology may make it possible to store enough energy to smooth out the fluctuations of renewables, but we simply don't have that now, and it may not come for years or decades.

 

In the meantime, there are plans on drawing boards for so-called "modular" plants.  If every single automobile was a custom design from the ground up, including a from-scratch engine and body, only the likes of Elon Musk could afford to drive.  But that was how nuclear plants were made back in the day:  each design was customized to the particular site and customer specifications.

 

If manufacturers had the prospects of sales and freedom to develop a modular one-size-fits-all design, they could turn the process into something similar to the way mobile homes are made today:  in factories, and then shipped out in pieces to be simply assembled on site.  And newer designs favoring gravity feeds over powered pumps can be made much safer so that if anything goes wrong, the operators simply walk away and the plant safely shuts itself down.

 

Standing in the way of these innovations are (1) the prevailing negative political winds against nuclear power, enforced with more emotion than logic by environmental groups and major political parties, and (2) the need to change regulations to allow such technical innovations, which currently are all but blocked by existing laws and rules. 

 

In the Hochmans' best-case scenario, the U. S. begins importing modular plants from countries where an existing base of nuclear know-how allows efficient manufacturing, which these days means places like China.  Even if the U. S. nuclear industry turned on full-speed today, it would take a decade or more to recover the expertise base that was lost a generation ago when the industry collapsed.  Regulations and regulatory agencies would change from merely obstructing progress to reasoned cooperation with nuclear-plant manufacturing and installation.  And we would derive an increasing proportion of our energy from a source that has always made a lot of technical sense. 

 

On the other hand, things may just go on as they are now, with old plants closing and no new ones to take their place. That would be bad for a number of reasons, but reason hasn't been the only consideration in the history of nuclear energy up to now.

 

Sources:  Thomas Hochman and Nate Hochman's "Nuclear Power Comeback?" appeared on pp. 3-19 of the Fall 2022 issue of The New Atlantis.

Will The Fusion Sun Ever Rise?

Back when I was in high school almost fifty years ago, I attended a talk about fusion power.  The speaker explained how fusion reactors worked differently than fission reactors, and used only water as fuel instead of highly radioactive uranium or plutonium.  He spent a good bit of time on the difficulties standing in the way of commercial power generation with nuclear fusion reactors, and dwelled on how hard it was to keep a thin, extremely hot gas (plasma, really) from wriggling around and extinguishing itself on the chamber walls.  After his talk, I waited in line to ask him a question that had occurred to me:  whether you could apply feedback of some kind to stabilize the plasma?  He kindly told me that my idea was one of many "under consideration," and I went away with the sense that I could participate in a great human achievement in the future: the harnessing of fusion energy for peaceful purposes.  I don't recall exact figures, but I believe the speaker said that he hoped fusion power would become a practical reality in ten or twenty years.

Well, it's nearly half a century later, and nearly a century after British physicist Sir Arthur Stanley Eddington realized that smashing hydrogen nuclei together to make helium would yield an astonishing amount of energy.  My career led me in other directions than fusion research, and perhaps it's just as well, because fusion power is still like the glow that appears before the sunrise:  promising, but not delivering yet.  While there have been dozens of projects big and small (considering the scale of this type of research, I should say "big and bigger") in the intervening years, the frontrunner these days is an international collaboration called ITER.

ITER stands for "International Thermonuclear Experimental Reactor" and is also Latin for "the way," as in "iterate."  Although the machine itself is to be built in France, its finished components come from South Korea, Russia, India, Japan, China, the U. S., and other European nations as well.  The project has been going in some form or other since the 1990s, and so far about 15 billion euros (almost $21 billion US) have been spent.  The project's managers estimate it will be another six or seven years before they can flip the switch and expect anything good to happen, and another seven years or so before the unit could be used for commercial power generation.  That gets us to 2027.  If I'm still around then, I'll be 74.

Why have so many people spent so much time and effort on an idea that seems determined not to be born?  Its attraction is captured in a slogan that was popular in the early days of the promotion of fusion energy:  "too cheap to meter."  This phrase was originated in the days when the fuel cost of energy was the main concern, and fossil fuels were relatively expensive compared to water.  The deuterium in water, plus perhaps some lithium, which is not as cheap as it used to be but is still relatively abundant, are the only fuels needed for the type of thermonuclear fusion that is under development at ITER.  Ten thousand gallons of water, which would fit comfortably in a cube 12 feet (4 meters) on a side, contains about a gallon and a half of heavy water, the kind that contains deuterium.  I calculate that this much deuterium could provide enough electricity to run a thousand average households for over three years. 

Another advantage advertised for fusion is that it produces much less radioactive waste than nuclear fission reactors do.  Fission reactors are the kind we currently use for electric power generation commercially.  Fusion makes no long-lasting radioisotopes to bury for ten thousand years or otherwise dispose of inconveniently.  And the risk of meltdown or a violent explosion is practically nil.  It's taken the physicists eighty years to get close to getting it to run, and so you take away one little adjustment from the complex of conditions needed to operate the thing, and it just flashes and dies harmlessly.

With all these attractions, it's understandable that hordes of physicists and their funding sources have poured decades of effort and resources into the search for "ignition," which is their term for getting more energy out of the reaction than you put in.  If all you want is ignition and don't care about controlling it, that's easy—just steal a thermonuclear bomb, which has been around in one form or another since 1952.  It's the control part of the problem that has kept the promise of peaceful thermonuclear energy just out of reach for all these years.

I hate to be a spoilsport, but what if the complexity and maintenance of a commercial-grade fusion reactor is so high that, despite all the international efforts, the thing simply doesn't ever manage to pay for itself?  After all, paying the bills is the test of an engineering idea, and whatever the physicists say, the pursuit of fusion power has been as much an engineering effort as a physics effort.  The basic physics was figured out by 1950 or so—everything since then has been practical details.  Already, the ITER project is giving off bad signs of disregard for costs.  Currently, according to a recent report in the New Yorker, the project managers have no accurate estimate of how much it will cost to finish.  The thing is beginning to resemble the United Nations organization, and not in a good way.  It is becoming increasingly hard to imagine how a technology with such a scary financial record will ever be considered seriously by those who actually expect to make money from an investment before dying, even after the technical achievement of ignition has been accomplished.

The crystal ball is always cloudy, but wouldn't it be ironic if, just when ignition is achieved and the physicists at ITER break out the champagne, the rest of the world greets them not with a cheer but with a yawn?  "You mean we have to build more power lines across our back yards to use that so-called free energy?  You mean we have to pay X billion euros to retire the bonds it took to build this thing?  No, thanks."  As the curve of complexity and expense it takes to achieve nuclear fusion has been going up, the curve of what the world will tolerate in terms of a new major source of electricity has been going down.  For the sake of all those who have dedicated their professional lives to the cause of commercial nuclear fusion power, I hope that when and if we get it, we'll really want it enough to pay for it.

Sources:  Although I had not finished reading the article before this blog was completed, the part of Raffi Khatchadourian's article "A Star In A Bottle" in the Mar. 3, 2014 issue of The New Yorker that I read was very informative.  I also referred to Wikipedia articles on thermonuclear fusion, thermonuclear weapons, ITER, Arthur Eddington, nuclear fusion, and fusion energy.  The website by C. R. Nave at Georgia State University has a good summary of the basic fusion reactions used in fusion energy at

http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fusion.html.