IFR FaD Nuclear

The nuclear fission ‘Flyer’

Below is the foreword I wrote, on invitation of Chuck Till and Yoon Chang, for the book “Plentiful Energy” (I included a shorter version in my review of the book on Amazon).

In this short essay, I draw an analogy between the IFR and the Wright brothers’ 1903 ‘ ‘Flyer’. The idea is that successful technology — especially a revolutionary design — is built on the back of many learning-by-doing failures. Yet, once the initial problems have been solved, the remaining pathway for the technology’s development is one of incremental (but often rapid) evolutionary improvements.

I suspect that with just a few more years of serious investment in RD&D, the LFTR ‘Flyer’ could also launch. The molten-salt thorium reactor concept is extremely appealing, and the ORNL prototype, which ran in the mid- to late-1960s, showed real promise. In my view the Th232-U233 fuel cycle would make an excellent complement to the U238-Pu239 fuel cycle offered by the IFR, and both reactor types hold the promise of safe and inexhaustible energy.


Foreword to: Plentiful Energy – The book that tells the story of the Integral Fast Reactor

On a breezy December day in 1903 at Kitty Hawk, N.C., a great leap forward in the history of technology was achieved. The Wright brothers had at last overcome the troubling problems of ‘inherent instability’ and ‘wing warping’ to achieve the first powered and controlled heavier-than-air flight in human history. The Flyer was not complicated by today’s standards – little more than a flimsy glider – yet its success proved to be a landmark achievement that led to the exponential surge of innovation, development and deployment in military and commercial aviation over the 20th century and beyond.

Nonetheless, the Flyer did not suddenly and miraculously assemble from the theoretical or speculative genius of Orville and Wilbur Wright. Quite the contrary – it was built on the back of many decades of physical, engineering and even biological science, hard-won experience with balloons, gliders and models, plenty of real-world trial-and-error, and a lot of blind alleys. Bear in mind that every single serious attempt at powered flight prior to 1903 had failed. Getting it right was tough!

Yet just over a decade after the triumphant 1903 demonstration, fighter aces were circling high above the battlefields of Europe in superbly maneuverable aerial machines, and in another decade, passengers from many nations were making long-haul international journeys in days, rather than months.

What has this got to do with the topic of advanced nuclear power systems, I hear you say? Plenty. The subtitle of Till and Chang’s book “Plentiful Energy” is “The complex history of a simple reactor technology, with emphasis on its scientific bases for non-specialists”. The key here is that, akin to powered flight, the technology for fully and safely recycling nuclear fuel turns out to be rather simple and elegant, in hindsight, but it was hard to establish this fact – hence the complex history. Like with aviation, there have been many prototype ‘fast reactors’ of various flavors, and all have had problems.

Stretching the analogy a little further, relatively inefficient balloons, airships and gliders were in use for many decades before powered flight became possible, even though people could see that better ways of flying really did exist (they only had to look up in the sky, at the birds). Powered aircraft allow people to travel hundreds of times faster, and more safely, than lighter-than-air devices. Similarly, the type of nuclear reactors we have used commercially for decades, although far superior to other methods of generating electricity, have harnessed but a tiny fraction of the potential locked away in uranium. To get at that, you need a very different approach – a nuclear fission Flyer. Enter the integral fast reactor (IFR).

This wonderful book by fast-reactor pioneers Charles Till and Yoon Chang, two of the foundational developers of the IFR during the fabulously productive years of research and development at the Argonne National Laboratory from the 1980s to early 1990s, explains in lucid terms the historical, philosophical and technical basis for truly sustainable nuclear energy. It’s quite a story.

Imagine a reactor that passively responds to critical stressors of the kind that befell Three Mile Island, Chernobyl and Fukushima by shutting down without human operators even needing to intervene. Or one that includes a secure recycling and remote fabrication system that, almost Midas like, is able to turn uranium or even old ‘nuclear waste’ from contemporary reactors into an inexhaustible (and zero-carbon) fuel, as well as simultaneously solving the socio-political problem of long-term disposal.

Once you’ve read this book, you’ll understand how this technological wizardry is performed and why other options – those alternatives to the Flyer – never quite worked out. Moreover, you’ll have a much deeper appreciation of the true potential of fission energy in a low-carbon and energy-hungry world – and an insight into what has stopped it reaching its potential, to date. There is something here for the non-specialist scientist and engineer, but also for the historian, social scientist, and media commenter. It is wrapped up in a grand narrative and an inspiring vision that will appeal to people from all walks of life – indeed anyone who cares about humanity’s future and wants to leave a bright legacy for future generations that is not darkened by the manifold problems associated with extracting and burning ever dwindling and environmentally damaging forms of fossil carbon, like coal, oil and gas.

For the sake of averting crises of energy scarcity, mitigating the ever mounting global problem of anthropogenic climate change, as well as drastically reducing the pressure on society to make huge swathes of productive landscapes hostage to biofuels and other diffuse forms of energy collection, we need to continue the historical impetus towards ever more energy-dense fuels. It’s time for the Integral Fast Reactor ‘Flyer’ to take flight, because, as Till and Chang explain, the sky is the limit…

By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

26 replies on “The nuclear fission ‘Flyer’”

An excellent analogy that recognizes the value of failures in engineering practice. Indeed, the profession can ONLY advance through failure, as has been observed by others.

The IFR ‘flyer’ is now poised at the opening to a great future. What we do not yet know is the identity of the brave individuals and nations who will apply this technology to solving the worldwide problem of energy supply.


“In this short essay, I draw an analogy between the IFR and the Wright brothers’ 1903 ‘ ‘Flyer’.”

Ouch. That’s unfortunate, because I like to analogize the ‘Flyer’ to Fukushima, and use it to indicate the absurdity of comparing Fukushima to modern plants (it’s like comparing the ‘Flyer’ to a modern jet!)


Jeremy, I think my comparison is better, for reasons that the essay explains — it is not a discussion about relative safety, it’s about operability. Yours is more a comment on the fact that technology continues to evolve — things that work can still improve, with experience and real-world lessons.


I am not sure it is a valid comparison at all. The IFR is more a branch of nuclear reactors rather than a whole new concept.

To me the Wright Flyer of nuclear is the carbon pile underneath the stands of University of Chicago when the Italian navigator entered the new world.

To me this was the technological equivalent the Wright Flyer. Not many carbon piles are around anymore nor could this exact design be used commercially. This is exactly the same as the Wright aeroplane where the prone control position, canard planform, and twin wing mounted pusher propellors gave way quickly to tractor biplanes and monoplanes like the Bleriot.
(Yes the canard has be used since, oh fans of Bert Rutan, however conventionally tailed aircraft do dominate)

The IFR, whether or not the concept is sound, has never been used commercially. The fuel production system has never been scaled up to commercial proportions out of the lab. If you read the necessary conditions that the fuel production needs to be done in:
There are formidable technological problems to overcome. Until a working IFR fuel processing factory can be reliably built and operated it still remains a lab prototype only.

Aviation history is littered with technological ideas that never made it out of the lab.

even a nuclear aircraft

The point is that despite the promise of these in the lab they never translated into workaday aircraft.

I really do not think the IFR is the Wright Flyer of nuclear.


Ender, the McFarlane article you linked to does not, as far as I can see, describe any formidable technical problems that need to be resolved. Could you please quote the sentence(s) that say this? BNC commenting rules prohibit misquoting, for obvious reasons.

Have you read the book ‘Plentiful Energy’ and the descriptions of the IFR fuel cycle contained therein? Or are you speculating?

In my analogy, the Chicago Pile 1 is the Gondolfier Bros hot air balloon – it flies, but not as efficiently as is possible. Gen III reactors are the Zeppelins and gliders of the aviation world. The IFR is the powered fixed wing aircraft. My analogy stands on its merits.


I also don’t like the analogy of the IFR with the Wright plane for the reasons expressed by Ender.

Furthermore I also think that gives a bad image to the new nuclear efforts like IFR, since every failing in aviation comported a complete loss of the plane and almost always deaths. That’s not necessarily so with new nuclear technologies. Failings can be mostly contained or even minimized. They aren’t always catastrophic like in aviation.

Better to change analogy.


Re Ender’s citation of Harold Mcfarlane’s article on proliferation resistance to support his reservations about the IFR: During my three decade career as an INEL/INEEL/INL “Consulting Scientist”, I never read/reviewed any official ANL technical document which candidly addressed that concept’s potential drawbacks – Dr. Mcfarlane’s essay certainly didn’t break with that tradition & neither does “Plentiful Energy”.

The latter is a well-written, genuinely interesting, and informative book. However, its authors perpetuate a policy (?) of filtering-out facts (i.e., any mention of ORNL’s almost two decade-long, molten salt thorium breeder reactor program) inconsistent with the notion that ANL’s IFR represents the only sensible approach to achieving “plentiful energy”.

One of the biggest hurdles facing advocates of a US nuclear renaissance is the credibility of documentation produced by R&D organizations which routinely exercise command influence over the reports written by their employees; i.e., virtually all of DOE’s nuclear contractors. That influence generally manifests itself in terms of what’s not included in technical reports (e.g., unambiguous answers to obvious questions such as, “how much ‘Ceramic Waste Form’ would be generated by a GWe-year’s worth of IFR power” or “what fraction of the fissile going into its pyroprocessor would end up in waste streams?”), rather than by what is included. The resulting seemingly never-ending uncertainty about a proposed/studied system’s key technical parameters combined with the fact that the same management culture has recently generated a string of fabulously expensive radwaste boondoggles (e.g., INL’s “Steam Reformer” – aka IWTU) means that utility CEOs have become leery about committing to anything being developed/recommended/promoted by DOE’s NE experts.


Darryl, Till and Chang make no comments about ORNL or the MSR programme because they never worked there and are not in the best position to judge/comment on its feasibility. They know fast reactors, and that is what they talk to. The best people to write the same type of book on the MSR are, unfortunately, all dead, and we need a new generation of reactor chemists to launch a LFTR programme of a similar spirit to the IFR programme of 1984-1994. I sure hope it happens (perhaps in China?), but until then, a book on the hard-won engineering experience of the LFTR will have to wait.


Barry Brook – “Ender, the McFarlane article you linked to does not, as far as I can see, describe any formidable technical problems that need to be resolved”

The article does contain this:

“In the IFR concept, the fuel would be recycled on site using a technique that has at various times been known as pyroprocessing, electrometallurgical treatment or dry reprocessing. Completely different from aqueous reprocessing that has been industrialized as PUREX, pyroprocessing uses a molten salt in the separations process. Various mixtures of chloride or fluoride salts have been used,
but all must operate in high temperature (450 C and up) and in a dry argon atmosphere.”

Is this not a pretty good description of the fuel process? I did not say the article says that there are technological processes to overcome. To achieve the IFR fuel processing there has to be set up a remotely operating plant in intense radiation that has to have a completely dry and inert atmosphere. Not impossible but can be tricky because the consequences of any failure is huge ie: you don’t get many second chances with radiation. No-one knows yet if it can be done on the required scale. Until it is attempted you have no idea of the problems that will be encountered on the way. For instance all the electronics of the robots will have to be radiation hardened. Not impossible but instead of being able to use the $5.00 part from Dick Smith you will need to the use the $50.00 part that is radiation certified. Which is why satellite electronics cost millions of dollars for parts that for a ground based application would cost thousands. In the same way radiation affects alloys and seals in different ways and affects their service lives leading to special design and materials being required rather than off the shelf gear.

“In my analogy, the Chicago Pile 1 is the Gondolfier Bros hot air balloon – it flies, but not as efficiently as is possible.”

I am not sure that is valid. Hot air balloons use a different method of flying – lighter than air. They are a completely different branch of aviation. The Wright Flyer pioneered heavier than air flight which is a sub branch of aviation/aerospace that includes lighter than air flight and even rocketry. The Chicago-1 pile generated heat that could be used to heat water in the same way as the IFR – nuclear fission. We were generating heat for electricity production long before nuclear fission. The Montgolfier brothers balloon is analogous to the the first steam generators ( that used generated DC to distribute electricity with the Wright Flyer being the Chicago Pile 1. A different way of heating water in the overall tree of heating water to generate electricity.

IMHO you might have been better to compare the current state of development of the IFR to the jet engine if you wanted use an aviation theme.

“This engine, which had a single-stage centrifugal compressor coupled to a single-stage turbine, was successfully bench tested in April 1937; it was only a laboratory test rig, never intended for use in an aircraft, but it did demonstrate the feasibility of the turbojet concept.”

Frank Whittle’s first engine was a laboratory boiler plate design and it took many years before a flying prototype took to the air. The IFR is in the lab prototype stage. In the development of the jet engine is an important lesson. Commercial jet aviation started with the deHavilland Comet which first flew in 1949. However problems with metal fatigue lead to a series of crashes that grounded the plane. Who in 1949 would have thought that square windows were a bad idea? The point is even with all the expertise that deHavilland had at the time they still made a mistake that cost the company dearly. The crashes allowed the Boeing 707 to have the jet monopoly for years and the rest is history. Even given this a company such as Boeing with all it’s expertise still took 4 or 5 years longer than projected to bring a composite airliner, the 787, to production. It is still only just starting to reach customers today after many delays and problems.

Your analogy does not really hold up. You are mixing different forms of flight with their own development history and uses. I may not know a lot about nuclear energy however I am an aviation/space enthusiast from about the age of 8 which is a long long time ago. I also believe that you are glossing over the problems that the IFR will have in transitioning from laboratory to commercial operation if it ever makes it.


All analogies are imperfect, and the effectiveness of them does depend on audience. Ender, the main point of my analogy for the IFR is that many attempts at doing fast reactors prior to the IFR never quite worked out, but they got things right for the IFR and if you were going to do a commercial fast reactor, this would be the model to follow — like the Flyer provided the model for future aircraft, because it worked. Fast reactors with metal fuels and liquid metal coolants really are very different to pressurized water reactors, so I don’t think the airship vs plane contrast is stretching it too much.

But I also like your alternative – that the IFR is the modern jet engine and the PWR is the propeller-driven plane. Using that analogy, I’d say the first generation of sodium-cooled fast reactors were the Comet and similar — they worked okay, but also had problems that needed correcting — which is what the IFR programme set out (successfully) to do. I’d strongly encourage you to read the ‘Plentiful Energy’ book and judge for yourself. I believe you cannot understand the technology properly, or make a rational judgement on its feasibility, until you have done so.


Barry Brook – “Fast reactors with metal fuels and liquid metal coolants really are very different to pressurized water reactors, so I don’t think the airship vs plane contrast is stretching it too much.”

OK I guess analogies are dependant on audiences.

“Using that analogy, I’d say the first generation of sodium-cooled fast reactors were the Comet and similar — they worked okay, but also had problems that needed correcting — which is what the IFR programme set out (successfully) to do.”

I would only beg to differ here. I really think you are still in the Gloster Whittle/HE 178 stage rather than the Comet. The Comet would be analogous to the first commercial IFR built by a utility when that happens.


The IFR as a total concept includes the power module ( the reactor) and the fuel cycle (including pyroprocessing). Its a collection of technologies. And they don’t all need to be fully developed before parts of it can be useful.

We can get a start on deployment without waiting for pyroprocessing to be available. The power module is ready to go, in the form of the GE-Hitachi PRISM reactor. GEH have offered to build one in the UK within 5 years, with a money back guarantee if it doesn’t work. That is a measure of both the readiness of the technology.

The PRISM does not include the pyroprocessing unit. It is being proposed to run on fuel converted from waste at Sellafield. If the UK takes up GEH on their offer (and they should), it will be an excellent opportunity to gain operational experience with the power module, understand how to improve build times and costs, and so on.

Fuel for a rollout of PRISM modules does not require pyroprocessing. It can be obtained from existing used LWR fuel, such as from France’s stockpile, using France’s reprocessing capability. This could go on for a long time.

So the power module development and the fuel cycle development can proceed on different trajectories. If pyroprocessing is immature, that does not hold up deployment and development of the IFR.

In the meantime, pyroprocessing is under active development, such as in the fuel cycle programme in the Korean Atomic Energy Research Institute, who are also collaborating on a large number of collaborative research programmes with the US on the technology. Pyroprocessing was demonstrated at pilot scale in the original Argonne work, Korea is working on a demonstration facility, and I don’t doubt the capability of applied engineering to translate this work into a productionizable set of designs and processes.

So the reactor itself can be deployed immediately , and pyroprocessing will intercept the development pathway down the track. It may be sooner or later, but it doesn’t matter because there is no particular urgency and there are alternatives. The important thing at this point in time the immediate status of pyroprocessing need not delay deployment of the PRISM, and the beginning of operational experience with IFR technology.


I’ve seen that analogy before:

“Solar power is now a fact and no longer in the “beautiful possibility”stage. [It will have] a history something like aerial navigation. Up to twelve years ago it was a mere possibility and no practical man took it seriously. The Wrights made an “actual record” flight and thereafter developments were more rapid. We have made an “actual record” in sun power, and we hope for quick developments” – Frank Shuman, 1914.


I question whether widespread IFRs are politically possible for greenfields sites or defunct coal stations. It seems to me they will work best at long established nuclear sites with accumulated starting material. I can’t see convoys of high level material delivering the startup charges to new IFRs in the industrial fringe suburbs.

If the S-PRISM is the forerunner model then many of them will be required to replace ageing gigawatt scale coal and Gen 2 nuclear plants. Thus the Sellafield decision could be make or break for early IFR adoption. It is tempting to keep burning coal for another 20 years and kid ourselves that weak carbon taxes and a few PV panels make a difference. A major shift in public opinion will be required before IFRs appear on the outskirts of cities.


Barry, my observations of human behavior has taught me that we don’t always have to be in the “best” position to say/do something in order to say/do something (witness: my paper, “Improving the Integral Fast Reactor’s Proposed Salt Waste Management System”, has been accepted for publication in NUCLEAR TECHNOLOGY – it describes work performed at my home for a total of about $400). If Drs Till and Chang’s book had been named “The Integral Fast Reactor” instead of “Plentiful Energy” and if it wasn’t promulgating a breeder-based nuclear fuel cycle, I’d be less critical of their decision to not mention that other equally(?) qualified experts (e.g., Weinberg, Wigner, & Urey) had concluded that a molten salt-based thorium breeder cycle represents a more attractive alternative.
I suspect that the IFR scenario could indeed be made to work if subsidized sufficiently; however, I also feel that the “reactor chemists” should be given a fair opportunity to show that the same goal (clean, cheap energy) could be reached with reactors that don’t ‘breed” plutonium.


‘Plentiful Energy’ is the topic over at Atomic Insights too, in the comments is a link to a series of email exchanges from the 90’s: Here’s the link: (a lot of interesting discussions on nuclear power and other topics their too).

One of the concerns with the IFR struck me – it seems to solve problems that do not really exist, namely: uranium supply, safety, proliferation, and waste. If we fix these political issues then the need for the IFR arguably disappears. If these political issues are not solved then the IFR has the issue both being a fast reactor and using a reactive coolant. What would happen if a nutbar gets a model of IFR filled with water, and drops a block of sodium into it on live TV?

That, and how would an IFR be maintained. If there is an accident and debris are in the reactor vessel, how exactly would they be retrieved?

Are these concerns answered in the book?



Thanks for this report. We will return to nuclear energy because the nucleus is where energy is stored as rest mass (E = mc^2)*.


1. Leaders of nuclear industry must be candid; avoid deception.

2. Explain how radioactive waste will be encapsulated and used as a heat source to power steam generators, etc.

3. Do not repeat past deception by telling the public the waste problem will be solved later, buried underground, under Yucca Mountains, etc. ad infinitum.

*The “Cradle of the Nuclides” on the front cover of the Proceedings of the 1999 ACS symposium organized by Glenn Seaborg and me show how nuclear energy is stored as mass in mixtures of two forms of one fundamental particle (neutron/hydrogen atom) that comprise atoms:

Oliver K. Manuel


I am very excited about this book, and have already ordered it on Amazon. I look forward to favorably reviewing it after I am finished reading it. I hope that it covers technical details about the technology that aren’t already available online, it would be cool to broaden my technical knowledge. The future for the technology is bright simply because there are no alternatives. Sure, there are those who favor thorium reactors or fast reactors cooled by lead, lead-bismuth, or even helium, but these technologies are still fission breeders that don’t directly compete. We will probably use a mix of breeder technologies, but the IFR is the best right now and closest to fruition. As for coal and gas, I think that we are very close to the global peak, as Tad Patzeck has demonstrated. The U.S. and China can only barely increase coal volumes, and lower-grade coals are increasingly being used, which are less energy dense and have a lower EROEI. There will be massive coal shortages by 2020, when China is gobbling up 60 percent of global coal extraction. Shale gas is a chimera with a very low flow rate and EROEI like tarsands. Light water reactors are on the way out after Fukushima and with Megatons to Megawatts coming to an end. I am convinced that there is no alternative. Renewables are a joke, and global demand for oil may outstrip supply this year. I sent a message to Energy Bulletin notifying them about the book, and they published a story on it.


Reading the title of the article I really thought somebody was going to construct nuclear-propelled plane…
A bit misleading


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