Climate Change Emissions Nuclear

Integral Fast Reactor (IFR) nuclear power – Q and A

It seems like something that only a crazed conspiracy theorist would come up with. A source of carbon-free energy that holds the potential to provide base load power for the planet for thousands of years hence, and which could be built along the existing transmission grid and even be housed within retrofitted coal-fired power stations. A process that could eat existing nuclear waste instead of needing to store it in highly secure vaults such as Yucca Mountain for hundreds of millennia. A technology that enjoyed large investments in R&D by government, only to have the funding zeroed for political reasons when close to large-scale demonstration — and then the scientists involved told not to publicise this fact.  Well that, in caricature, is the basic story of Integral Fast Reactor (IFR) nuclear power.

Perhaps it is too good to be true — almost everything that’s been hyped as ‘the future of…’ is, after all. But not everything — the exceptions to the ‘hype rule’ now dominate our modern technological society (home computers, mobile communications, satellite communications, etc.). So what if IFR is the real deal? Well, some very clever folks have been looking into this and conclude that it is — or at least worth pushing. As I described in an earlier post, Hansen is among them — at least in terms of seeing the value in giving this tech a fair go — and he’s certainly not alone. Mark Lynas for instance, author of ‘Six Degrees‘, has also pitched in.

There are some great resources out on the web, and a new book, for those of you who want to know more about IFR nuclear — in order to make your own informed judgement about whether you choose to advocate it. Steve Kirsch, a Californian entrepreneur who invented the optical mouse (and former nuclear agnostic), has written a great summary article about IFR here (h/t to JM) and a shorter Silicon Valley newspaper Op Ed here. Steve’s website provides a wealth of links to additional information on IFR and related developments. The PBC television programme ‘Frontline’ recently interviewed nuclear physicist and IFR co-developer Dr. Charles Till — the transcript is available here.

Kirsch summarises the key advantages of IFR as follows:

1. It can be fueled entirely with material recovered from today’s used nuclear fuel.

2. It consumes virtually all the long-lived radioactive isotopes that worry people who are concerned about the “nuclear waste problem,” reducing the needed isolation time to less than 500 years.

3. It could provide all the energy needed for centuries (perhaps as many as 50,000 years), feeding only on the uranium that has already been mined.

4. It uses uranium resources with 100 to 300 times the efficiency of today’s reactors.

5. It does not require enrichment of uranium.

6. It has less proliferation potential than the reprocessing method now used in several countries.

7. It’s 24×7 baseline power.

8. It can be built anywhere there is water.

9. The power is very inexpensive (some estimates are as low as 2 cents/kWh to produce).

10. Safe from melt down because if something goes wrong, the reactor naturally shuts down rather than blows up.

11. And, of course, it emits no greenhouse gases.


Key disadvantages (from the Wikipedia article) are given as:

1. Because the current cost of reactor-grade enriched uranium is low compared to the expected cost of large-scale pyroprocessing and electrorefining equipment and the cost of building a secondary coolant loop, the higher fuel costs of a thermal reactor over the expected operating lifetime of the plant are offset by the increased capital cost of an IFR. (Currently in the United States, utilities pay a flat rate of 1/10 of a cent per kilowatt hour for disposal of high level radioactive waste. If this charge were based on the longevity of the waste, then the IFR might become more financially competitive.)

2. Reprocessing nuclear fuel using pyroprocessing and electrorefining has not yet been demonstrated on a commercial scale. As such, investing in a large IFR plant is considered a higher financial risk than a conventional light water reactor.

3. The flammability of sodium. Sodium burns easily in air, and will ignite spontaneously on contact with water. The use of an intermediate coolant loop between the reactor and the turbines minimizes the risk of a sodium fire in the reactor core.

4. Under neutron bombardment, sodium-24 is produced. This is highly radioactive, emitting an energetic gamma ray of 2.7 MeV followed by a beta decay to form magnesium-24. Half life is only 15 hours, so this isotope is not a long-term hazard – indeed it has medical applications. Nevertheless, the presence of sodium-24 further necessitates the use of the intermediate coolant loop between the reactor and the turbines.


Tom Blees has spend the last few years writing a book on IFR and a few related techs (such as ‘boron power’ for vehicles) called ‘Prescription for the Planet‘, which Hansen referred to, and it has received unanimous highly favourable reviews at Amazon. (side note: if you want a contrasting view, see Helen Caldicott’s book ‘Nuclear Power is Not the Answer ‘). I can’t vouch for the quality of Blees’ book myself, but I’ve ordered it and will post a book review here on BNC once I’ve had it delivered and mentally digested.

Something I found really useful in addressing my doubts and scepticism about the feasibility, safety and scalability of the IFR process, were two Question & Answer overviews / FAQs. This includes a detailed refutation of all of the ‘cons’ listed above. One is written by IFR project physicist Dr George Stanford called ‘Integral Fast Reactors: Source of Safe, Abundant, Non-Polluting Power‘ . The other was put together as a compilation by Kirsch, and integrates a collection of comments from Blees, Stanford, Carl Page and some quotes from those who have reviewed the material.

Read these, judge for yourself, and feel free to post comments here — I (and others I hope) will do my best to answer you or direct you to the right material to get your answers. I’d appreciate continuing the critical examination of this that was started in the two other posts.

Does the above mean I’ve given up on my strong push for large-scale renewables? Absolutely not (!), and for a nation like Australia, solar thermal, wind, wave, geothermal and microalgal biodiesel, along with energy efficiency and conservation, should be a primary focus for the next decade. But I strongly doubt they will ever be wholly sufficient [I’ll explain why in another post. Update I – read here]. That’s why IFR and similar techs also desperately need our support — not our unthinking denigration just because we may have some ingrained distaste for anything nuclear.

We can’t predict what will ultimately deliver the best solutions to society, in terms of securing a near-zero-emissions energy supply and arming us with the tools the avoid catastrophic climate change. To do this, we must use whatever options are at our disposal, and push these potential solutions as fast and hard as we possibly can.

Update II – See comments that follow this posting for a further detailed round of Q&A on the feasibility of IFR.

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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.

117 replies on “Integral Fast Reactor (IFR) nuclear power – Q and A”

Yes, although as always “push as hard and fast as we can” means:

a) Deploy what works. Do not schedule breakthroughs. Do not wait around hoping for breakthroughs.

b) Run a disciplined R&D program, as described recently here.

c) And when you know something works, scale it up and build it cookie-cutter-like (unlike what happened in the last US round of nuclear plants).

While Australia & CA have large wind & solar resources, not everybody does…. and it’s likely easier to replace coal plants with such nuclears, if they work [i.e., because of grid issues.]


“Operation as a breeder (making the plutonium which can be used to make nuclear weapons) will perhaps not be needed for decades. Meanwhile, such operation would easily be detected by inspectors”. (George S. Stanford)

I would ask Mr Stannford if these inspectors would be like the inspectors who were sidelined for political reasons to enable the invasion of Iraq? Or like the inspectors who didn’t stop Israel, Pakistan, N. Korea, India and South Africa from developing the plutonium necessary for their nuclear weapons?

There was at least one smart bloke a few decades ago who though scientists should be standing up to those who were enabling nuclear weapons proliferation:

“Today, the physicists who participate in watching the most formidable and dangerous weapon of all time…cannot desist from warning and warning again: we cannot and should not slacken in our efforts to make the nations of the world and especially their governments aware of the unspeakable disaster they are certain to provoke unless they change their attitude towards each other and towards the task of shaping the future.” (Albert Einstein).

So some are now asking do we have to choose between lowering the risk of climate or nuclear catastrophy? But is this a false dichotomy?

Like Barry and James Hansen, I’m in favor of doing every thing we can for renewables. But unlike Barry, I’ve not yet seen the evidence that renewables won’t do the job (combined with demand reduction through efficiency and culture change). I’m interested to see if Barry has information that contradicts the models by Diesendorf, Saddler, Blakers etc. which show the renewables route is the fastest to route to stabilizing the atmosphere. Not only fastest but safest and most sure as their models do not assume new technology (unlike the developmental Integaral Fast Reactors).


Thanks Mark – as I said, the ‘getting realistic about renewables’ post is coming up next – happy to talk more about that then after the post.

IFR lowers the risk of proliferation since (i) it is difficult to make weapons grade material from IFR product, (ii) IFRs produce relatively little, and (iii) the net effect of IFRs would be to eat up existing nuclear waste and reduce (and soon after eliminate) the need for Gen II LWR which produce much more suitable material. So on balance, I can only see IFRs reducing the proliferation risk. Remember Hansen also said this:

“Some of the anti-nukes are friends, concerned about climate change, and clearly good people. Yet I suspect that their ‘success’ (in blocking nuclear R&D) is actually making things more dangerous for all of us and for the planet. It seems that, instead of knee-jerk reaction against anything nuclear, we need hard-headed evaluation of how to get rid of long-lived nuclear waste and minimize dangers of proliferation and nuclear accidents. Fourth generation nuclear power seems to have the potential to solve the waste problem and minimize the others.”


“Blees argues that it made no sense to terminate research and development of 4th generation nuclear power. Was it thought that nuclear technology would be eliminated from Earth, and thus the world would become a safer place?? Not very plausible – as Blees points out, several other countries are building or making plans to build fast reactors. By opting out of the technology, the U.S. loses the ability to influence IFR standards and controls, with no realistic hope of getting the rest of the world to eschew breeder reactors. Blees suggests, probably rightly, that this was a political calculation for domestic purposes, a case of dangerous self-deception.”


Nuclear waste is a political rather than real world problem. People are not opposed to nuclear because they are opposed to storing waste they are opposed to storing waste as an excuse to be anti-nuclear. You could magicaly turn all nuclear waste into butterflies & the Luddites would come up with another reason to oppose nuclear.


Thanks for posting about this.

One political concern to consider — setting these up drops the value of mining leases on coal and uranium to approximately zero; drops the value of transportation and processing operations for coal and uranium to about zero; and puts pressure on the whole mythology about oil sand use and co2 capture from coal plants.

Good idea. Watch how we handle the Detroit auto business to see how it will be treated.

Question — are countries without either uranium or coal making progress on this technology? Because I expect in the US (and Australia) we’ll be buying the reactors from the countries not already deeply invested in dinosaur tech.


“it is difficult to make weapons grade material from IFR product”

IIRC, I don’t think this (depleted fuel) is where the proliferation risk lies. It’s with intentional use of the reactors as breeders, i.e. inserting natural uranium and letting the neutrons do their work. The resulting product is still nasty in terms of radiation, but getting the Pu-239 out of it is not otherwise difficult.

Also, embrittlement of the reactor structure from those high-energy gammas sounds like a major problem, noting that this would occur throughout the external piping and heat exchangers. In particular, there is the potential for leaks of the pressurized sodium into the water of the secondary loop. I seem to recall that this was one of the reasons for the technology being abandoned.


Very nice and balanced write up. I wish you read the book of Tom Blees soon and post your review. Personally, I found it very impressive and compelling.

I agree with you that we should push energy efficiency. This is a no-brainer. I also agree that we should push renewables (to be mentioned separately from efficiency), but these technologies have significant environmental side-effects. When used on a large scale, solar and wind technologies have huge requirements for land and fresh water, and they leave a large environmental imprint due to the associated mining for metals. Large scale biomass cultivation will adversely affect the fresh-water balance on the planet, and destroy biodiversity. Geothermal power might vary geological heat distribution whose results range from earthquakes to depletion of earth’s magnetic field (and henceforth the depletion of atmosphere layer due to cosmic irradiation).

All these environmental effects should be seriously studied before we rank the technologies in the order of preference.

About the actual potential of renewables, they might be sufficient, but would have to be constructed on unimaginable scales (covering up the planet with steel and concrete). The brilliant online book of Dr David Mackay, does all the number-crunching. But as I said, the question we have to ask is not “whether renewables will be sufficient ?” or slightly better “whether do we have enough land for renewables ?” but “To what extent are renewable technologies environmentally acceptable ?”.

@Steve Bloom

Nuclear weapons are a serious threat to humanity. But the culprit is not “proliferation”, it is “fissile material”. We are suffering from a dangerously archaic thinking on nuclear weapons. When they framed the NPT, it was thought that if the technology is kept under wraps, nuclear weapons technology would remain in the hands of a select few. It is outrageously stupid : if somebody could make a bomb in Los Alamos, almost anybody can make it at a later point of time. If any country seriously wishes to do so, it can make the bomb in a matter of years (as has been demonstrated by South Africa, India, Pakistan and now North Korea). The scariest thing is that these bombs (and highly weapons-grade fissile material) is not completely safeguarded all over the world. It is only a matter of time this runs into the hands of terrorists.

The only solution to this problem is “complete inventory of fissile material” and “never enriching Uranium and never isolating fissile material”. We should stop at nothing short of this, and we need international bodies to oversee this.

The important thing to note is that the IFR project is completely in terms with my extremely stringent requirements. It will never enrich Uranium and fissile material is never isolated. About the production of Plutonium or its potential to breed more Plutonium, both of these are no worse than existing LWR nuclear reactors. Yes ! Plutonium is produced in every nuclear reactor : it is okay as long as it is not “isolated”. Old reprocessing technology known as PUREX isolates weapons-grade Plutonium, and therefore, is a serious proliferation concern. The IFR reactor never does this, and infact, uses a totally different type of reprocessing known as pyroprocessing.

Sodium-leaks are messy, but nowhere a serious concern as you have imagined. None of the breeder reactor projects (in France, Japan, India, Russia or USA) have stopped because of a Sodium leak. Yes, there were incidants in France and Japan (none in the IFR design of USA), but these were very minor incidants in prototype development – with “no” radiation spills. We handle Sodium metal in several industries today, it is not rocket-science.


> the potential for leaks

Yep. Plenty there; this turned up just poking at the question:


High burnup effects on fuel behaviour under accident conditions: the tests CABRI REP-Na


Thanks Barry, I’ll have to wait for the teaser on renewables.

Re. “IFR lowers the risk of proliferation since (i) it is difficult to make weapons grade material from IFR product, (ii) IFRs produce relatively little, and (iii) the net effect of IFRs would be to eat up existing nuclear waste and reduce (and soon after eliminate) the need for Gen II LWR which produce much more suitable material. So on balance, I can only see IFRs reducing the proliferation risk.”

All this assumes that the IFR’s are being used as we want them to be used. But weapons proliferation is about people using “peaceful” nuclear reactors and technologies in ways we don’t like.

As George S. Stanford admitted it is true that “The IFR was designed as a breeder reactor and can be used in this mode to produce more plutonium than it consumes.”

I respect James Hansen and his work, so also his opinion. Yet his recent letter to Obama did not include a ‘warts and all’ assessment of Gen IV rectors (nor the scale of deployment required to justify denying these massive deployment resources from renewables). I am glad that he prioritised renewables above further nuclear research .

Yet I would council against the implication drawn that criticisms of the nuclear complex are “knee jerk”. This is a claim that doesn’t address the detail of the criticisms.

1. Proliferation through the misuse of IFRs is one real problem that must be attended to. (Perhaps we only differ here on the consequences of misuse rather than intended use).
2. Another issue with Gen IV reactors raised by Michael Dittmar is his concern that no public scientific document seems to exist which quantifies the achieved longer term useful Pu(239) breeding factor.
3. Thirdly using liquid sodium as a coolant has implications. Liquid sodium is extremely flammable and ignites spontaneously on contact with air or water. George Stanford, The key proponent of IFRs, may think this system is remarkably safe, but air and water tend (eventually) to get into systems that we design to be closed.
4. Fourthly, how soon can this technology be deployed? At what scale can it be deployed in that time? What is the CO2 investment? What are the renewable and demand management gains that could be achieved for the same investment (and over what time?). What is the cost to the planet?


As far as I can tell, many of the questions people are asking require the sort of disciplined R&D program I mentioned. Fortunately, the incoming Secty of Energy might actually know about physics and R&D programs.

I have a hard time figuring out how PWR designs can make it widely; certainly the laws here in CA forbid reactors until disposal is resolved.

Hence, if nuclear is going to be a real part of the equation, it seems like it will be via one of these other design approaches.

Prioritization: what does this mean?
It doesn’t mean that the highest priority gets 100% of the funding, it means you spend much of the money ok rollout of what you know works, but you spend some money on other projects at various stages, again as I described I’m talking about progressive commitment.


Articles citing the one I noted above, up to the present year:

(Not claiming this is the technology being discussed for the future, just giving some idea of how this stuff gets looked at.)

One aside — most of the references in this, as in so many areas of science are paywalled and very expensive. This should change — we can’t hope for citizen support without citizens’ being able to read the research and engineering in the fields they’re being asked to help pay for.

We ought to be paying off the publishers with a tenth of a percent of the money going to this work.


Great post. Its really hard not to be skeptical of the claims of
the nuclear industry, on the other hand the solar industry has
had a long time to develope good products and they always
seem to be 5 to 10 years away. My rule of thumb is that when a
researcher tells you a product is 10 years away, this means they
don’t have a clue. When they tell you it is 5 years away, this
also means they don’t have a clue, but that they think they do. How
far away is IFR?


What I don’t understand is — reroofing is the fastest, sloppiest, and maybe most profitable form of home repair. The joke here is, roofers are in a great hurry, and they find the heads are on the wrong end of half their roofing nails when they pull them out of the bucket, that’s why they throw so many off the roof into your driveway and flowerbeds, it’s faster than turning them 180 degrees and using them.

Yet if we had prefab panels that served as combined hot air or hot water heat collectors and a panel that could accept photovoltaic material — easy, cheap, standard, piece-together, suitable to put on when an old roof is ripped off — every roof could be replaced in 30 years with a solar _heat_ collector. Preheating water on its way into the hot water heater or a holding tank is one of the most productive things one can do, along with insulating the attic.

Roofs come in standard ‘squares’ anyhow.

Nobody’s building this sort of thing as far as I can tell.

Hell, even a simple two-layer roof with an air gap that vented hot air out at the top — instead of heating up and then heating up an attic and the living space — would save on air conditioning.

Take that same air gap and suck the hot air down a plenum in the winter and it could preheat incoming air.

Instead we reflect heat with white paint, or insulate the attic to throw the heat away, or both — all summer and all winter.

What’s the total surface area of roofing in any given area, and how much heat can it collect, and why aren’t we using that?

I know, free market. Duh. It’s always so much easier to build big central things and charge people for generation and distribution.


Regarding IFR and the nuclear proliferation issue: it is helpful to frame it in a risk assessment/cost-benefit analysis. In simplified form, we have the following issues to consider.

There is some probability [difficult to quantify] of each of the following outcomes following uptake of IFR:

1. Nuclear proliferation worldwide will increase, e.g. because of more fissible material being ‘bred’, i.e. greater risk of a nuclear war [or leakage/meltdown and release of radioactive material].

2. Nuclear proliferation worldwide will decrease, e.g. because Gen II LWR and weapons grade Pu will be fed into these reactors and converted to a less dangerous form, i.e. risk of nuclear war/meltdown is decreased.

3. Investment in large-scale renewable energy will be less because of the uptake of IFR than it would otherwise have been, and this more than offsets the benefits of reduced fossil fuel use as a result of this substitute power source, i.e. the net result of more carbon emissions over this century than without IFR.

4. Investment in IFR will co-occur with renewables and make ‘alternative’ (zero carbon) energy sources sufficiently viable to provide all of our power needs and more readily displace fossil-based energy, i.e. the net result of less carbon emissions over this century than without IFR.

5. Should 1 and/or 3 be correct, nuclear proliferation via IFR uptake will increase the risk of a regional/global environmental and human catastrophe as a result of one or more nuclear explosions (or indeed a nuclear exchange leading to MAD), and/or the increased CO2 will result in worsened climate change.

6. Should 2 and/or 4 be correct, carbon emissions as a result of pursuing IFR will decrease the environmental and human damage caused by dangerous or catastrophic climate change, and/or reduce the probability of nuclear war.

Now I don’t have the numbers to know what these probabilities are, but they could probably be approximated with some research — at least in terms of setting some reasonable uncertainty bounds. My gut feeling is that proposition 6 is more probable, perhaps by a factor of 10-100, than proposition 5 — thus my recommendation to include IFR as one of the main elements of the future energy tech mix. But really, this seems like another key element of the research programme John Mashey describes.


@ Barry Brook

IFR has absolutely no potential to increase the risk of nuclear proliferation. As I mentioned in my earlier comment, it never isolates fissile material.

This is a key issue, because even if it is being used as a breeder (as acknowledged by Dr Stanford), the produced Plutonium is not isolated and doesn’t qualify as weapons-grade fissile material.

Of course, this doesn’t mean it cannot be used towards building a nuclear bomb. But the technology required to do so is called PUREX, which isolates highly weapons grade Plutonium. If somebody has such technology, he can directly use the nuclear waste out of ordinary LWRs which does contain Plutonium (IFR is thus no worse than LWRs). Now, if you have IFRs, no country shall have an excuse to do PUREX reprocessing. So this technology can be effectively out lawed by international law. Thus IFRs have a significant potential to reduce proliferation threats, in an indirect manner.

More important than Plutonium, the easiest way to build a nuclear bomb is by highly enriched Uranium. This is why the world is alarmed when Iran is proceeding with Uranium enrichment technology. This technology can be used to enrich Uranium to a significantly high purity of U-235 which can be directly used in nuclear bombs.

Unlike LWRs, IFRs do not require Uranium enrichment. Thus in a world of IFRs, Uranium enrichment technology can be outlawed by international law. This has significant potential to reduce proliferation threats, in an indirect manner.

So I think you should re-evaluate your points 1 and 3, because they do not stand for the IFR technology.


Vakibs, I mostly agree – no direct potential. But there is some very small (at least finite) probability of an IFR reactor providing the ‘cover’ for a nation that was historically not nuclear (e.g. no LWR) to obtain Pu for the IFR fuel and instead use some of it to refine and create weapons or to kickstart that ability — unless the PUREX ban is also enforced, as you suggest. This is the point Mark is making I think — it is just that his assessment of probabilities are different from yours or mine, hence his concern.

As such, my statement above was just a mind map to cover all views, with no explicit probabilities attached (except my ‘gut feeling’ that the benefits of IFR in terms of climate change would far outweight the risks from proliferation or accident, direct or indirect). But that is where some research is needed.

Note that you are only arguing about point 1 – point 3 is disconnected from the proliferation probabilities.


Vakibs @ 17

The following statements sit a little uneasily together:

A: “IFR has absolutely no potential to increase the risk of nuclear proliferation.”
B: “Of course, this doesn’t mean it cannot be used towards building a nuclear bomb [using PUREX].”

PUREX being an acronym for plutonium/uranium extraction. PUREX is a common reprocessing technique (not just for IFRs) and is already considered a large proliferation concern. As such, if it is not currently band under the NPT why not?

Can IFRs be run as fast breeders (employing the ability to breed more fuel than it consumes)? If so what is the limit to the amount of fuel they can produce?


Barry @ 18,

Your 6 points mind map is a very clear and helpful layout for moving forward. There is a human/social/political tension between outcome 1 and 2. The probability of either outcome is difficult to quantify.

Also there is a technical/policy/investment/resource/development tension between outcome 3 & 4. The probability of either outcome is likewise difficult to quantify. Yet some approximation seems possible (if only for the short to medium term) by modelling that deployment of current technologies.

Ziggy’s 2006 report estimates we could build a LWR in 15 years (2024) and which would then payback the invested energy with a further 5 to 14 years of full operation (2030). As there are no commercial IFRs we would need to add extra time for this new development. Perhaps the USA development of commercial IFRs might be in the ball park of Australia’s deployment of LWR (15 years). It might also be prudent to include a to account for complexity delays (2040).

Conservatively 2030 is the earliest the first commercial scale IFR could contribute to reducing net global emissions. Where does Hansen say we have to be for CO2 reductions by 2030? How many of these reactors are necessary in the time frame before we are deep in the zone of non-linear positive feedback?

Alternatively we might interrogate the models for deployment of existing renewables by link or link, which calculate existing renewables can deliver an extraordinary reductions of 40% CO2 emission by 2020.

I guess this is overlapping where Barry’s next post is headed.


Mark @19, I think Vakibs’ point is that proliferation is about a number of different pieces:

(i) uranium enrichment
(ii) PUREX
(iii) LWR breeders
(iv) IFR breeders

Item (i) is paleo-tech in nuclear terms but remains a hot issue because it is dual use for a civil nuclear programme and items (ii) and (iii) could become much more pervasive if we opted for the ‘conventional’ breeder technologies that got parked in the 80s – these are also dual use if we pursue this form of breeder programme and they will remain dual use for as long as we are using second/third generation nuclear technologies. This is what makes them so problematic in a proliferation context as a suspected transgressor will be able to argue that they need these technologies to carry out legitimate civil nuclear projects.

The thing about IFR is that while it can be used in conjunction with items (i) and (iii) to proliferate, it does not *need* these technologies in order to provide a complete civilian nuclear fuel cycle. So if you deploy IFR it becomes possible to create a proliferation regime where PUREX and uranium enrichment are completely outlawed.

As things currently stand the only way you can close off access to these technologies is by prohibiting civil nuclear power entirely (which is the logic of the present Iran imbroglio). Obviously this is a position that a lot of people are perfectly comfortable with, but personally I think the AGW situation is sufficiently threatening that we should not be ruling any potential low-carbon energy solutions out of bounds at this time.



The internal-combustion-in-a-cylinder analogy is helpful in understanding why there is no incongruity in the two statements Mark Byrne suggests are incongruous:

A: “IFR has absolutely no potential to increase the risk of nuclear proliferation.”

B: “Of course, this doesn’t mean it cannot be used towards building a nuclear bomb [using PUREX].”

An analogous pair of statements based on the inextricable round-slider-propelled-by-combustion-gas link between small hydrocarbon-burning engines and guns is

A: “Miller-cycle engine technology has absolutely no potential to increase the risk of gun proliferation.”

B: “Of course, this doesn’t mean it cannot be used towards building multibarrel cannons [using repurposed Miller-cycle engine blocks].”

Both pairs are completely congruous because the various long ways to a goal can be made slightly more or less obstacle-strewn without affecting the likelihood they will be chosen over short well-trodden ways.

It is easy to try to block the long ways to a goal, be completely successful, and still find short ways being taken. Comment 2 refers to some of the short-way takers — “Israel, Pakistan, N. Korea, India and South Africa” — although the stories I’ve read allege that the last-mentioned country developed weapon-grade uranium, not plutonium, and thus had the option, which they took, of completely unmaking it on the day of the revolution by diluting it in depleted uranium or natural uranium.

None of the mentioned proliferators or attempted proliferators seems to have used anything from a sodium-cooled power reactor, nor from any power reactor. That this is not demonstrably impossible is beside the point; it would be a long way around.

— G.R.L. Cowan (How fire can be domesticated)


Point 10 —

Safe from melt down because if something goes wrong, the reactor naturally shuts down rather than blows up.

doesn’t make complete sense. A reactor that naturally shuts down upon malfunction might still melt in so doing. Melting and blowing up are different, and no power station reactor built in any country that respected the advice Hungarian emigre Dr. Edward Teller gave in 1950 has ever built a reactor that had any way of blowing up.


> any way of blowing up.

I recall a problem a while back where a highway accident took out the power lines to a plant, the emergency generators failed to start, and … not much happened — because they’d just recently refueled the plant, so once they dropped the damper rods into it it wasn’t self-heating.

Comment at the time was that if the same accident had occurred late in the fuel cycle — when the fuel rods were full of transuranic fission daughters (which make ‘used’ fuel so dangerously radioactive), they would have not only melted inside but blown the containment open. Perhaps you’d rather say “popped” than “blown” — it would be a steam explosion. That’s not a nuclear bomb, but it’s an uncontained problem.

The real credibility problem unfortunately is with the industry, not the technology. Indian Point is the poster child for that problem: is fairly old, but makes the point that confidence in management was a big problem for a long time.

The first CANDU design did shut down safely, but I think they moved away from that to active cooling in later designs.


I think it is Roberts who often says something like, “you can look these things up”. In the case of residual power subsequent to a given amount of fission it is not an easy lookup, to be sure*, but I’m persistent, and have found that in the first few decades it is closely given, as a fraction, by the Untermyer and Weills rule* —

Delayed power/in-service power
(t+10)^(-0.2) – (t + T_0 + 10)^(-0.2)
-0.87*[(t + 20000000)^(-0.2) – (t + 20000000 + T_0)^(-0.2)]

where ‘t’ is the post-shutdown cooling time in seconds and ‘T_0’ is the pre-shutdown run time in seconds ( , M. Ragheb’s UIUC course notes).

The integral between two values of ‘t’ gives the energy released in the time between in terms of full power seconds. Roberts could check the reasonableness of his assertion, or rather, what he asserts was “comment at the time”, by putting in lower and upper values of, say, 0 s and 300 s and comparing the result for different values of ‘T_0′. If Roberts’ integration skills are rusty or were never metallic in the first place, I’ll be glad to help. It’s not a particularly nasty integral, but it is long.

There’s a short cut: recall that American nuclear power plants have government inspectors permanently stationed on-site, regardless of whether cores are fresh or aged.

I suppose I ought to know whether or not CANDUs do too, since they’re much closer to me, but I don’t.

I do know they have lower power density than submarine-derived reactors, and some of their heavy water is kept below its normal boiling point, so Walter C. Patterson’s book “Nuclear Power”, although in my opinion it urges life-wasting, vested-interest-favouring caution, acknowledges that they have “slow temperature rise in fault conditions”.

— G.R.L. Cowan (How fire can be domesticated)

* There’s something called ORIGEN. I’m not sure any public version is allowed to run on a PC, but if there is such a version, I think it might be rather hard to use. You may not have a banana unless you take the gorilla along with.


Hi GRL Cowan,

It is an interesting analogy (@ 22). I suggest it is not analogous for WMD. Einstein used his last years on earth focusing on nuclear weapons because of their non-linear consequences. MAD would give us another type of climate change.

The difference between nuclear proliferation and conventional arms is evident in the USAs treatment of Iran, and South Korea, Iraq (untruths included).

Hi Luke, thanks for your comments at 22.

I see nuclear proliferation in a social/political context. Over recent millennia humans have incorporated weapons into our evolutionary process (see Diamond’s Guns, Germs and Steel), as such natures experiment with higher intelligence may be very brief indeed.

What is the context of nuclear proliferation? Injustice is a powerful motivator.

We are on the edge of major economic and social transformation. We are facing resource depletion, regional water and food shortages, social dislocation, and a mother load of global injustice. (Can IFRs reduce this in the next 30 years?)

Take what we’ve seen in Iraq, Afghanistan, and threatened in Iran. Add in Dafor, the Congo, Somalia. Project these forward with expansion in the last grasp attempt to exploit resources inline with current growth rates. This offers the potential of tens of millions of people experience major injustices over the next few decades. How will this effect regional and global politics?

How many of these nations should have fast breeder reactors? How will their use be policed? How long can the technology be controlled? Are we considering a form of energy appartite? What will happen if “developing counties” cannot copy our technology?

Surely a mass deployment of renewables (along with culture change) provides the best chance of minimising accessibility to fissile material.

Perhaps IFRs may have the potential to safely dispose of current fissile material (while generating power). But the potential for fast breeding must be controlled not rolled out on mass, or we risk making more fissile material rather than less.

I’m concerned with how compatible human civilisation is in a world with regional and global injustice which is also has competitive access to fast breeders on mass.

Perhaps the UN could administer a limited number of processing plants, but evidence suggest that policing individual nations has not worked.

All this of course is in addition the question of IFRs capacity to help avoid climate tipping points.


Mark@ 28 and Barry @ 29
Get-up at is conducting a survey about future voting intentions, given the disgustingly low target Rudd has just announced. The survey results will be forwarded to the PM. We should all fill in the survey. The only thing that seems to scare the pollies is voting intentions. The end of civilisation as we know it doesn’t seem to rate! Problem is – who do you vote for? There are not enough Greens to cover all electorates. Remember the “No Dams” election? Perhaps that is the way we need to go next time.
It really makes you want to give up – what is the point of weak targets that do nothing for the problem and let others off the hook.


As to why this might be important, I recommend:

Stanford paper on worldwide wind resources.

AS can be seen, both the US and Australia have substantive wind resources, and some reasonably close to population centers.
The reader may want to also check out China and India.

Here’s Worldwide solar insolation.

Australia has great sun, US Southwest is pretty good. India has some hotspots, China not much, and the better insolation areas will take a lot of grid, and they aren’t located very handily, i.e., like the Mojave in CA.

Hence, it may well be that the only way to shut down coal in India and China is via nuclear (with of course, as much efficiency + renewables as can be done).


Thanks John,

Germany’s achievements with solar power stand out here considering their relatively low solar insolation. They put us to Shame. India and China have between 3 and 4 grades higher solar insolation than Germany.

No doubt that solar power is the greatest resource we have available to tap into.


The class notes file is quite helpful.

As I recall the key phrase that turned up in the group of reports was something like “beyond design basis accident” — here’s what’s currently online.

I didn’t find the particular report I recall (which was on an FTP site before the Web, long ago).

The new Westinghouse design is said on one of its reference pages to be the only current licensed design with passive safety built in (not sure what, but I’m in favor of the idea).

As to

> There’s a short cut: recall that American nuclear power plants
> have government inspectors permanently stationed on-site,
> regardless of whether cores are fresh or aged.

You can’t possibly imagine how reassuring I find this.

No, seriously, if you do read around on the NRC pages, they did acknowledge that TMI happened because of a series of failures and great overconfidence, and they’re trying to improve.

One anecdote from this page suggests further improvements:

” DuPont redesigned his gunpowder plants both to improve the quality of gunpowder and to enhance safety. According to legend, the major change was that the managers’ offices were located just above the rooms where the gunpowder was made. If true, this would have been an early example of a corporate decision to ensure management’s total commitment to safety….”


Repeating, does anyone know of a comparison between the Westinghouse current model and the IFR? How different is the IFR from what’s currently licensed and possible to build soon?

“I think now it is very difficult for people to invest in things that are meant to be regulated in America, because they have fallen down on the job.”


Ah, the IFR had the same ‘disadvantage’ as the original CANDU design — it didn’t produce a stream of waste suitable for extraction of plutonium.

“… ‘reprocessing’ was synonymous with PUREX, which creates plutonium of the chemical purity needed for weapons.”

We have to remember the choices for civilian nuclear power were, like the design of the Interstate Highway system, dictated by military needs
(the highways were designed to the requirements for rapidly dispersing ICBMs on trailers). You know how to find that.

Forgetting certain aspects of design criteria is always a problem when discussing this kind of thing. Getting them all out to talk about is even harder to accomplish.

Producing lots more light water reactors to keep the PUREX plants working is of interest to someone. But who?


Roberts said

I recall a problem a while back where a highway accident took out the power lines to a plant, the emergency generators failed to start, and … not much happened — because they’d just recently refueled the plant, so once they dropped the damper rods into it it wasn’t self-heating.

Comment at the time …

was to the effect that this had been a matter of luck. He seems to have moved on to other inflammatory insinuations, but says M. Ragheb’s notes were useful to him. They should have made doubt the unnamed authority or authorities he cited. Did they? How?

— G.R.L. Cowan (How fire can be domesticated)


If you don’t like the questions, Mr. Cowan, please suggestfind answers. The authority I recall was from the NRC FTP site, but that was a long while ago. You’ll find similar work at the current link looking at safety issues.

I’m not attacking your investment, or your industry.

Are you arguing against the suggestion Dr. Hansen makes about reviving development of this sort of liquid sodium cooled reactor? If so what would you do instead?

I’m trying to understand how what he proposes differs from and improves on the current proposal, which I gather is that Westinghouse design.

What you think should happen? Are you arguing for some alternative process?

If you don’t believe the Interstate Highway design criteria, you certainly can look it up, it’s no secret.


Mr. Cowan, if you’re objection is to the suggestion that the current program favors Purex, did you read Stanford’s comments linked at the top of the thread?

“It is PUREX (aqueous) reprocessing, needed for
cycling plutonium back into thermal reactors, that
produces chemically pure plutonium.”

What are the uses of chemically pure plutonium?


If you don’t like the questions, Mr. Cowan,

It was more the moving-on that bothered me. I’d like to get one little nit thoroughly picked. Do you now understand that if loss of electrical power at a nuclear powerplant could cause the coolant to be come stagnant — actually it “thermosiphons” — and therefore blow up, it would make no difference whether the plant had operated an hour or a year?


I should be more precise. No difference to the force of the hypothetical explosion, since it can only be driven by very fast-decaying isotopes that are in equilibrium long before the first hour of operation ends. If such explosions could occur, they would of course disperse more long-lived radioactivity after a year than after an hour. But they wouldn’t be any more possible.


I’ll take your word that a current design (all current designs?) at the end of the fuel cycle can lose outside and backup power safely as long as the core stays submerged (thermosyphoning). That’s consistent with what I recall as well.

The worrying scenario at the time was the what-if, if they’d had a loss of pressure or of actual coolant, while without power for the emergency pumps.

Back on topic, I hope, is there anything in the NRC area now relevant to the development of the kind of reactor discussed above? Is that a “fourth generation” design, or later than that?

I found two mentions of recent work with liquid sodium at the NRC site:

NRC: Speech-08-010 – Interactions of the U.S. Nuclear Regulatory …
Mar 4, 2008 … The NRC has also been increasingly involved in the potential licensing of a Toshiba-built, small liquid-sodium-cooled reactor. …

NRC: Fact Sheet on Next-Generation Reactors
PRISM: The Power Reactor Innovative Small Module design uses a modular, pool- type, liquid-sodium cooled reactor. The reactor fuel elements are cylindrical …


This Scientific American article from 2005 is a great overview of IFR (they actually refer to them as Advanced Liquid Metal Reactors [ALMR] – the liquid metal is the sodium coolant/neutron mediator) and how it compares to standard thermal reactors. There is also a good description (with nice pictures) of how pyroprocessing differs from PUREX, which addresses some of the comments above. Also a diagram of the IFR test reactor. Definitely worth a read.

If I may answer your query Mark @44, the answer is – it all depends on whether government want it to. If they do, the amount it contributes to emissions reduction also depends on how serious we get about the tech.


Hank Roberts wrote,

I’ll take your word that a current design (all current designs?) at the end of the fuel cycle can lose outside and backup power safely as long as the core stays submerged (thermosyphoning). That’s consistent with what I recall as well.

The worrying scenario at the time was the what-if, if they’d had a loss of pressure or of actual coolant, while without power for the emergency pumps.

OK. That wasn’t mentioned in comment 24. If the fool would persist in his folly, he would become wise.

That posting also featured surprising news about transuranics. Also there was the arresting phrase “blown the containment open”, which certainly makes for an impressive web posting. Does that still seem possible to Roberts?

— G.R.L. Cowan (How fire can be tamed)


Hank, as I understand it, the Westinghouse AP1000 design is a Gen III+ advanced LWR (if this is what you are referring to). State of the Art, but a fundamentally different technology tree to IFR – it’s still a slow (thermal) reactor, with very well designed and essentially fool-proof safety features (remembering that Chernobyl was set in train by human error during a test).

Some description is given here. Wiki also has a review.


I understand that PRISM is indeed an IRF. Some other details here. I need to read Blees book, because I think he discusses PRISM.

Kirsch said:
“GE has created a commercial plant design called the S-PRISM. GE is ready and willing to build a plant (a) to demonstrate the technical feasibility of a commercial-scale operation, and (b) to narrow the existing uncertainty in the final cost. They are not proposing, yet, to plunge into mass production of S-PRISMs. We can start building a reactor vessel for around $50 million…

The good news is that DOE is trying to restart IFR with the GNEP (Global Nuclear Energy Partnership) initiative. The GNEP, if it is allowed to proceed, will involve a commercial demonstration that will establish the degree of economic competitiveness of the recycling process. General Electric thinks they can build an economically viable system and they already have a complete commercial design completed (S-PRISM)…

From a risk management point of view, you certainly want to cultivate and develop at least a small portfolio of silver bullets, i.e., “silver buckshot.” After spending a lot of time talking to the people who built this technology, it’s clear to me that the IFR deserves a place in that portfolio. The research at Argonne should be restarted now and someone should ask GE to build one; either a big utility or Congress should give DOE the money so they can have GE build a pilot S-PRISM test plant.”

There is more about it in the Q&A page I linked to above:


Thanks, Barry, that’s helpful.

Mr. Cowan, it hadn’t occurred to me that you might be thinking anyone could believe transuranics in well-used fuel could explode — even to attribute it to me. Is that what you’re trying to suggest? Strawman. Doesn’t make any sense. Maybe you’ve met someone who imagined it, but hey, there are nitwits in every field. Don’t assume the worst.

You must know the NRC was worried about a power loss plus any other failure exposing late-cycle fuel. It’s a classic scenario, much discussed.

Can we go back to real situations now? Barry’s given the important information — and there’s a real example, PRISM, to talk about.


1) James Hansen was giving a talk at our local town center last night and a few of us were lucky to have dinner with him beforehand.

2) The talk was a slightly newer version of this talk, for which page 31 is especially relevant to this discussions. I.e., we’re around Peak Oil, not quite there yet on Peak Gas, but the big problem is coal [and unconventionals (UFF) like tar sands, shale oil, mehane hydrates]. We’ll burn all the oil and a lot of the gas.

3) In dinner & later in reply to conversations he was quite succinct:

a) Efficiency
b) Renewables
c) R&D for Gen4 nuclear and/or coal with carbon sequestration, although even with the latter, he had reservations about whether or not coal could ever be “clean” (mercury). Key reason: India & China, who will certainly

(see my comment in this thread, on wind&solar)

He says he got a lot of angry email from people for whom even the word “nuclear”was too much.

4) Someone asked what he thought of Steven Chu’s nomination to Secretary of Energy in US.

A: “I can’t imagine a better person.”


Hank Roberts, from comment 50:

it hadn’t occurred to me that you might be thinking anyone could believe transuranics in well-used fuel could explode — even to attribute it to me. Is that what you’re trying to suggest?

From comment 24,

… if the same accident had occurred late in the fuel cycle — when the fuel rods were full of transuranic fission daughters (which make ‘used’ fuel so dangerously radioactive), they would have not only melted inside but blown the containment open …

it appeared to be what you were trying to suggest.

Strawman. Doesn’t make any sense. Maybe you’ve met someone who imagined it, but hey, there are nitwits in every field. Don’t assume the worst.

You appear impenitent for the way your words could easily have misled anyone not in the field and not closely following it. Perhaps if you corrected that appearance it would be easier to avoid assuming the worst.

Or if you just answered my most recent question: do you believe that used fuel in American power reactors, however “well-used”, could under any circumstances blow the containment open?

You seem to be acknowledging that non-nitwit people in the field would not believe this, but suggesting that the mooting of the possibility is somehow due to me. Isn’t it actually your fault?


> used fuel … under any circumstances …

Good question. You wouldn’t rely on my belief, I have no basis. I can look with Scholar and find papers on that question.

Start, e.g., here — then read some of the the related and citing papers:

Assessment of boiler tubes overheating mechanisms during a postulated loss of feedwater accident

Among the related links is one discussing the “Korea Standard Nuclear Power Plant (KSNP) and Advanced Power Reactor-1400 (APR-1400)”:

On some salient unresolved issues in severe accidents for advanced light water reactors
Nuclear Engineering and Design, Volume 235, Issues 17-19, August 2005, Pages 2055-2069
J.H. Song, S.B. Kim, H.D. Kim

Some of the outstanding issues of the severe accident are evaluated from the synthesis of the results from the research programs of the simulation of naturally arrested thermal attack in the vessel …. the thermal margin for the failure of the reactor vessel is challenged for these reactors. The observation of the energetic spontaneous steam explosions in the TROI suggests that proper measures should be taken to avoid and/or lessen the risk of an in-vessel or ex-vessel steam explosion….”

So, I believe I can’t tell you there can’t be a problem.

And I believe it’s wise to be careful, and not optimistic.

We could do worse than reread Rickover, who had the sort of perspective I hope is rediscovered as the next generation of fission plants IS built.

I believe we need them — Chu and Hansen, particularly are convincing.

So was Rickover:

Click to access Rickover.pdf

From 1953, talking about the distinction between the academic reactor plant and the practical reactor plant:

“… unfortunately for the interested public, it is much easier to get the academic side of an issue than the practical side…. Those involved with practical reactors, humbled by their experience, speak less and worry more.

“Yet it is incumbent on those in high places to make wise decisions …. It is consequently incumbent on all of us to state the facts as forthrightly as possible”

If it weren’t for papers like those in Google Scholar being available, all I’d be reading were PR press releases.

John, thank you for the PDF link for the Hansen program and the discussion. That’s encouraging reading.


PS, seriously, page through the related documents mentioned.

Many articles refer to designs that sound like the IFR — including “natural circulation of the primary coolant… and a passive decay heat removal system.”

Nuclear Engineering and Design, Volume 213, Issues 2-3, April 2002, Pages 165-182

“… The design being considered here is a pool type reactor that burns actinides and utilizes natural circulation of the primary coolant, a conventional steam power conversion cycle, and a passive decay heat removal system. Thermal-hydraulic evaluations of the actinide burner reactor were performed to determine allowable core power ratings that maintain cladding temperatures below corrosion-established temperature limits during normal operation and following a loss-of-feedwater transient. ….”

They had to improve the passive cooling to keep it from exceeding that corrosion limit in a failure condition, while being able to run the core hot enough in normal use to attain economic criteria for selling electric power (the hotter the heat, the better the efficiency of the steam turbine, roughly speaking).

This is the kind of reassurance I like seeing. People really are attending to these concerns.


Short answer from various NRC pages — if the cooling system relies on a river to take heat away from the secondary heat loop, the primary loop can thermosyphon and transfer heat to the secondary, and the secondary to the river, as long as the river doesn’t get too warm (sometimes they do, climate change is an issue).

If the secondary boils water off, the passive system works as long as the secondary water can be replaced (I found one study estimating about 8 hours before the secondary loop boiled dry, at which point the primary starts to heat up).

And if it’s a reactor with a weak containment that uses large baskets of ice to cool any excess steam, instead of a strong containment building, then the passive cooling works til the ice melts. Oboy.

Yup, I am increasingly in favor of moving rapidly to 4th Gen. systems. We need them as ultra-reliable backup power sources for the previous generations!


Here’s a GE PowerPoint (Feb. 2007), illustrating PRISM (“FBR” or “FR”) side by side — showing comparisons to — a pressurized light water reactor (“PWR” or “LWR”).

Page 7– big difference in economies of scale:
• The complexity and availability of a PWR is essentially constant with size
• Due to the lower specific heat of sodium, six or more loops are required in a large FR. [Much more complicated as it gets bigger]
The Economy of Scale is Much Larger for LWRs then [sic] FBRs
This is pictures-and-talking-points stuff, no detail, no references.

If anyone knows how this PRISM design compares to whatever’s being thought about, please speak up. And I’ll quiet down and try to stop being a headache ….


Hank, some discussion I read from George Stanford was that rather than one FBR (fast big reactor) the concept was for multiple FSR (fast small) within a single site – which could even be a former coal-fired power station.

Q. Can you convert existing coal plants to be IFR plants?

One nice thing about the S-PRISM is that they’re modular units and of relatively low output (one power block of two will provide 760 MW). They could be emplaced in excavations at existing coal plants and utilize the same turbines, condensers (towers or others), and grid infrastructure as the coal plants currently use, and the proper number of reactor vessels could be used to match the capabilities of those facilities. Essentially all you’d be replacing is the burner (and you’d have to build a new control room, of course, or drastically modify the current one). Thus you avoid most of the stranded costs. If stranded costs can thus be kept to a minimum, both here and, more importantly, in China, we’ll be able to talk realistically not just about stopping to build new coal plants but replacing the existing ones, even the newest ones…

Q. How much would it cost to build a 1 GW IFR plant?

Competitive with dirty pulverized coal plants. But f you factor in the external costs of coal plants there’s no contest, even if you don’t include global warming!

The first one will probably cost around $1 to $2 billion. Sound like a lot? Read on…

You’ve probably read about the Meerwinds North Sea wind farm, and Pickens’ proposed mondo wind farm. Using their own figures, the cost per gigawatt from them is going to be in the neighborhood of $15 billion. If you just look at the figures they like to throw out there it doesn’t look that expensive because all they tell you is peak production, and they conveniently disregard capacity factors. But capacity factors is what it’s all about: how much electricity they’ll actually produce over time. Are you familiar with the Spanish mirror/tower solar generator? The amphitheater-like tracking mirrors that focus on a cooker at the top of a tower that turns a turbine? They’re going to build several of them. The cost per GW? Probably in the vicinity of $30 billion! Again, there’s that pesky capacity factor to take into account. Compare this to the expected cost of a 3rd generation nuclear reactor from Westinghouse at about $1 billion/GW, or even a 3rd generation ABWR that can be built (and are being built) for $1.2-1.4 billion/GW. The IFR could be expected to be in the same range, and you don’t have to wait for the wind to blow or the sun to shine. So when you look at this, which technology do you think will win out if we can get past the political minefields? Why? Concentrated energy. There’s nothing like E=mc2


If you’ve read all the links from the original post you’ve seen this — comments from the Union of Concerned Scientists, from one of their people with long experience in commercial nuclear power, and responses. It’s a bit oversold in the doc that references it (not all the UCS points of concern are answered, particularly one about the regulators failing to enforce their own rules; but the proponent modifies his text on an important issue in response to another of the UCS points, that of provision for unexpected failure and replacement (one of the classic failures in design of commercial fission plants, the access ports were all too small to do needed repair). The summary at the end is an unabashed recognition of the failures to date.

It’s hopeful about having learned from them. I suggest jumping to it:

Click to access ifrUCSresponse.pdf


Barry @45,

Do you agree with the estimate I make @20, which suggest that IFRs cannot reduce net emission before 2030? If so, is this significant for non-linear positive feedbacks?

Re getting “serious…about the tech” Are you convinced IFRs can be made proliferation safe? – Considering the combined potential for fast breeding, the ingenious nature of humans and their complex motivations (ref post @26)?


Barry @45, “it all depends on whether government want it to. If they do, the amount it contributes to emissions reduction also depends on how serious we get about the tech.”

Do you agree with the estimate @20, which suggest that IFRs cannot reduce net emission before 2030? If so, is this significant for non-linear positive feedbacks?

Re getting “serious…about the tech” Are you convinced IFRs can be made proliferation safe? – Considering the combined potential for fast breeding, the ingenious nature of humans and their complex motivations (ref post @26)?


Mark, yes, I believe IFRs can reduce net emissions substantially by 2030, should sufficient attention be given to the technology by decision-makers. The first step is awareness, the second is education. Of course, by 2030 we also need to have already rolled out a massive energy efficiency push and have large-scale renewables being installed in appropriate locations. It all has to be happening by then – if we are still talking at that point about what is possible or what to do, it’ll be in terms of regret for times past.

Yes, I am convinced that the net effect of IFR is to reduce, not enhance the proliferation risk – and as to the extend, my humble opinion is ‘quite substantially if not completely’, but I’d prefer a more thorough analysis from an independent review/committee to draw a conclusion on this.


For mine, the whole proliferation argument against nuclear energy is a red herring. If a particular nation wants nuclear weapons badly enough, they’ll get wherewithal to do it independently, from scratch if necessary, irrespective of whether allies or neighbours have civilian reactors. Recent admissions to the nuclear club have been down to key knowledge transfers and acquisitions, not availability of materials.


Barry, do you know if there’s a document identifying _which_ coal plants, or which type/spec/design if that’s available, can have a PRISM dropped in? As far as I know coal plants may vary as much as fission plants do, or more.

Above I noted a description of improving cooling on a fast liquid-metal reactor so it could attain a high enough normal core heat to be economical in operation (and still self-cool). Hotter heat, higher thermodynamic efficiency in the steam turbine cycle.

I gather that’s why only some kind of liquid-metal-cooled reactor (or pebble-bed?) could be dropped into a coal plant — current fission plants using water don’t put as much heat into the steam-pressure turbine side.

I hope someone’s documenting that there are standard coal plants with a design where this replacement is practical as a drop-in approach.

(And that the coal companies haven’t been favoring plant designs that preclue retrofitting them to eliminating the use of coal — somehow I doubt it’s a design feature they find they want to see happening.)


Oh. This is an advocacy site, but maybe their numbers are good?
——excerpt follows——-

Why use nuclear pebbles instead of conventional nuclear reactors?

A 550°F conventional nuclear reactor can’t power a 1,000°F coal plant . . . It simply isn’t hot enough.

Coal can produce heat over 2,000°F. Coal power plants use 1,000°F steam for high efficiency. Conventional nuclear reactors cannot produce steam hotter than 550°F, so conventional nuclear reactors cannot be used to produce coal’s 1,000°F steam. …..

——end excerpt———

And, oh, again — coal plants are going hotter and hotter:


A postscript — if we get real worried about CO2, putting fission plants as _preheaters_ on preexisting fossil fuel plants might even look good. Use the fission plant to get the water as hot as that can, then bring it up to supercritical steam (or whatever the turbine is designed for) using the fossil fuel burners, in the interim.

That’d be about the time the oceans are burping sulfur compounds and the top seafood is squid.
Could happen.


That’d be about the time the oceans are burping sulfur compounds and the top seafood is squid.

More likely jellyfish – they’re doing just fine (and, having only 3 layers of cells, are one of the more ‘parsimonious’organisms that got through the Permian crunch and will do so again). Squid – not so confident they’d hang around.


Barry @64, Thanks again Barry,

The design intention is that the IFR breeded material and waste material are processed to be safer than that from LWR. One question I would like clarified is can the IFR process be tampered with?

It might be a tricky question, as we can employ the same human ingenuity that created the IFR it to tamper with it. Like writing anti-viral software it may be impossible to account for all contingencies. When creating material that can end civilisation there are immense consequences that require special consideration.

Considering the net proliferation question, a key difference between current LWR and the IFR proposal is scale. At the moment we have 450 Gen II installations in a handful of countries. (450 LWR & HWR have allowed 7 or more countries to proliferate nuclear weapons). But the IFR proposal is at least an order of magnitude greater.

It is possible that IFR may be technically safer in some respects, but with human ingenuity, and motivation to tamper, combined with a massive jump in scale, I am not confident that the net effect of IFR is to reduce proliferation.

“If our objective is to get to 20% nuclear in our energy mix, that means we must build one 3GW plant per week for the next 25 years” (Steve Kirsch)

This wish is a bit fantastic. We cannot physically produce more than a handful in the next decade even if we suspended all safety regulations and avoided all technical and construction hold ups. But these allowances are also fantasy. It is highly probable we will have no more than a handful in the next 20 to 25 years. These will then have to payback their energy inputs.

In the mean time the heavy lifting will be needed from energy efficiency, culture change and renewables. Yet every dollar invested in IFRs is a dollar not available to the three heavy lifters that are essential to minimise the risk of climate tipping.


If we merely allowed the regulations on nuclear plant safety to be as lax as those for coal, the hold-ups would go away. Not that I’m advocating lax safety standards, I’m talking about how horrible coal burning is.


If I had an IFR design, and the inclination to produce bomb-grade material, and a plentiful supply of thorium metal, I’d ‘enhance’ the reactor design with an outer ring of fuel cell slots, and pack them with thorium rods, or possibly thorium-zirconium. If I could then add robot machinery to extract just those rods, on a fairly short cycle, I’d be getting fairly pure 233_U from the 232_Th. I fancy that neutron capture by the 233_U to 234_U is not as serious a bomb problem as n + 239_Pu -> 240_Pu. But it’s not really any easier than building a short-cycle LWR reactor to do the same thing, or to produce plutonium at bomb grade concentrations, which the recommended cycle period of the IFR doesn’t do, and its chemical waste refinement is designed to make the product highly unattractive. On the other hand, if you’re one of these guys who believes it’l get him 72 virgins in the afterlife, you might just try to smuggle out the fission waste, and make a dirty bomb with that. I think you’d need a bucket-line of martyrs to do it though, because the stuff’s really virulent. Again, you’d probably do better to bomb a sufficiently unprotected nuclear plant’s cooling pond.


A personal note about energy efficiency:

For 14 years, as a serious environmentalist, I rode a bicycle to my workplace seven miles away. In terms of time, at rush hour it was competitive (by actual accidental experiment) with my neighbor’s commute by automobile.
As an essay in the use of biofuels, it was clearly superior to the biofuel cost of the 18th century gentleman’s option, riding a horse. I eat less than a horse does, even when exercising vigorously.

But the existence of one unthinking, impatient, discourteous automobile driver, who found the urgency of his business so insistent that he ran a red light, proved to me that I could not in good conscience recommend my approach to others who might fare worse when knocked down than I in fact did. I suffered pains in the muscles of my chest, and a temporary scar on my face, other slight bruises, that was all. For the remainder of my employment, I allowed myself to contribute to the carbon dioxide burden by the amount necessary to propel my share of the Washington Metro system.
Filthy as coal is, it was a cleaner approach than even a car pool.

An IFR would have relieved me of this burden.


I’ve read the Prescription for the Planet book and I found the basic argument to be persuasive. Commenters who have questions should get a copy and read it.

Blees is saying the technology was all ready to go for a full scale test reactor when Clinton killed it in the 1990s. He says the design is passive safe, i.e. they tried to blow it up by disabling whatever they could and it couldn’t be done.

Where Blees is at his weakest is when he criticizes other technologies, such as solar or wind, as he makes his case that his solution, the IFR is the only possible one. As you read, you find him making types of arguments in support of his position that he criticized supporters of solar or wind for making. But this is a side issue. The IFR is fascinating if only as a solution for the high level nuclear waste everyone has been saying they were worried about all these years: Blees says just feed it into the IFRs and its gone.

On the other hand, I would be more comfortable with an assessment made by a group such as the InterAcademy Council, the IPCC, or even a just a group something like what MIT puts together for its studies. Blees is critical of the MIT The Future of Nuclear Power study, and I found that a bit disturbing. However, I have the MIT nuclear study and I’ll see what I can make of it given Blees’ critique.

One tantalizing detail is that Blees believes that John Holdren, President elect Obama’s chosen science advisor, is familiar with the technology. Hansen is currently in communication with Holdren as well, i.e. using him as a conduit to pass letters on to Obama. Holdren is known to be a friend of Obama’s going back some time, at least, Obama’s spent a lot of time in Holdren’s company, and people who know Holdren say this means Holdren is presenting his concerns with no holds barred.

What a difference from the Bush years.


More on the temperature range involved and the material in use:

—–excerpt follows——–

“The use of X20 and P91 in power stations

By P.K. Saha, Contributing Writer
January 16, 2003

Of all the materials used for high-temperature steam piping, X20 (12 percent chromium, 1 percent molybdenum, 1/4 percent vanadium) and P91 (9 percent chromium, 1 percent molybdenum, 1/4 percent vanadium) stand out because of their very high creep rupture properties, even at elevated temperatures.

X20 was introduced in the 1950s in Germany and used in steam lines operating at temperatures of 530 degrees C and higher for fossil fuel-fired power generating sets of 150 megawatts and more. However, two factors limited its use: the extreme care needed for its fabrication and welding and its noninclusion in the American Society of Mechanical Engineers (ASME) Code B31.1….

… The U.S. had been trying to develop a new material since the middle 1970s to bridge the gap between ferritic P22 and austenitic steels with respect to creep rupture strength for high-temperature service from 540 to 600 degrees C. Development of any new material, especially for high-temperature service, requires many years, because creep rupture strengths are established based on longtime exposure to a range of intended service temperatures.

As a result of these developmental efforts, a new material, designated P91, was introduced in the U.S. in the 1980s by Oak Ridge National Laboratory (ORNL,, assisted by Combustion Engineering. This material has proven to have such good strength and fabrication properties that the use of X20 has practically been discontinued in Europe. In fact, even renovations of old power plants are being made with P91 material for steam circuits operating in the creep range….

… A Promising Future

At temperatures higher than 540 degrees C, P91 has increasingly higher allowable stress than X20. It now is possible for fossil fuel-fired power stations to achieve higher pressure and temperature parameters on main steam piping, and thereby realize higher thermal efficiency, using this material. This saves recurring fuel costs and also reduces pollutants, because less fuel is burned.

P91/T91 may be used to replace sections of boiler header and pressure parts that occasionally reach temperatures higher than permissible design limits for P22 or other low-alloy chromium-molybdenum-vanadium steels. T91 also is being applied in superheater and reheater circuits, which used to require austenitic steel because of the design temperatures.

P91 also has been used recently in petrochemical plants for cracking and hydrotreating furnaces that employ higher operating temperatures to increase the yield of unleaded, high-octane fuels.


To: Mark Byrne:

I have just been told about this very interesting site. I’ve not had a chance yet to read much of the correspondence,but I note that you asked this question early on (Question #2):

“I would ask Mr Stanford if these inspectors would be like the inspectors who were sidelined for political reasons to enable the invasion of Iraq? Or like the inspectors who didn’t stop Israel, Pakistan, N. Korea, India and South Africa from developing the plutonium necessary for their nuclear weapons?”

It’s a good question, and the answer is “Yes, the same kind of inspectors.” Inspectors can enforce nothing — they serve merely as a (very valuable) early-warning system. The point is that nuclear power is being deployed globally at an accelerating pace, and along with it will come increased need for enriched uranium for thermal reactors and fuel-processing facilities for fast reactors. Both of those processes can be diverted to the production of weapons material. Therefore it behooves the international community to devise a system that assures countries that, if they forgo deploying their own enrichment and processing facilities, they will still have an iron-clad guarantee of access to reactor fuel from elsewhere at a reasonable cost.

The DOE’s GNEP (Global Nuclear Energy Partnership) is a step in that direction, in that it would confine such facilities to “supplier nations” that already have nuclear weapons, and therefore no motivation to divert the civilian facilities to weapons purposes. Inspectors there could provide additional assurance to the world that the facilities are being properly used.

Nuclear energy will not be halted. It’s vital, therefore, for the United States to take a leadership role in this process — there’s no other entity with the influence to keep the spread of weapons-capable facilities from spreading without adequate controls.


Thanks very much for taking the time to give some feedback here, George. If you have anything further to add after looking through the comments, we’d be most pleased to hear it!


Is there a technology race of sorts? I read that coal power plants are pushing toward extremely high operating temperatures:

Click to access Proj456.pdf

I wonder if the trend is toward trying to replace the heat source in the older lower-temp coal plants with fission heat, while continuing to build advanced coal plants that operate at temperatures hotter than a fission plant can be designed to produce in utility type service.

That’d be a political solution — keep the coal people happy, insist (maybe) on cleaner burning new technology, and phase out the older dirtier coal plants by replacing the heat source.

Just speculating from what I’ve gathered, noted above, about operating temperatures generally in both types of service.


Very roughly speaking — the molten salt reactor mentioned here:
describes (theoretical?) 700-800C outlet temperature; that’s about the operating temperature described for the newest technology ultra-uber-mega-supercritical coal plants being talked about. Ballpark, anyhow


Promoting a nuclear option is a sign of desperation, offering a non-choice between a “greenhouse summer” and a “nuclear winter”.

This is because as nuclear materials proliferate and transport links extend, the possibility-come probability-come certainty of nuclear accidents and nuclear sabotage increase exponentially.

Can anyone give a reason why solar/thermal (already operational on grid-base level in California), geothermal/hot-rocks (with a huge promise in the Cooper Basin), plus ancillary wind utilities, tide power sources, even space reflectors, are not preferable as power generators to enriched Uranium and Plutonium – the most toxic substances known to man?


Andrew #81: Given your background/history of advocacy, I’m very surprised by your response for a number of reasons.

1. “Promoting a nuclear option is a sign of desperation” – so, by implication, you no longer believe the situation is desperate? [and actually, promoting IFR is not a desperate act]

2. You clearly haven’t read the details about IFR. On-site pyrometallurgical processing eliminates the need for transport of U-235 or Pu-239, except for a one-off transport of spent thermal reactor oxides and decomissioned weapons material to the IFR reactor plant – a transportation link that would be required even if we simply decided to sock it all into Yucca Mt type repositories.

3. Because it’s so diffuse (solar, wind, tidal) that it will require huge areas and massive backup/capacity redundancy and storage capacity. There is not enough readily available geothermal areas, and the tech, whilst promising, if far less developed than IFR.

4. IFR does not require PUREX-type enriching of U-238 to produce U-235 or Pu-239. It will be eliminating these and other long-lived actinides in the power-generation process.


Thanks Barry,

Regarding “desperation” – my readings are that this sentiment has been only growing in Australia following Rudd’s meaningless 5/15 “target”. In a following comment I will copy my 8.1.09 comments in this regard.

I am sure the IFR technology is far superior to the current “conventional” reactors, not to mention fast breeders.

A couple of questions:

(1) How long would it take to develop a generation of IFR to replace coal and oil burning? If at least 10 years or more, do we have this time (before the atmosphere exceeds 500 ppm CO2)?

(2) If, for example, the “powers to be” go ahead and replace all coal-burning generators with IFR, namely thousands of the latter around the world, how long would it take before terrorists can lay their hands on decommissioned weapons grade material?

(3) Say, in principle, humanity can “stabilize”* the climate, can anyone doubt that, human nature being what it is, enriched uranium (in “dirty” bombs) and/or weapons grade material will eventually go off, by accident or design.

(4) With time – possibilities become statistical probabilities become certainties.

(5) Do we wish to replace one type of nightmare with another?

* as you know I have great difficulty with the concept of stabilization in view of evidence from the ice cores.



Andrew #83:

IFR are a type of fast breeder reactor – but all nuclear fission methods can breed Pu. IFR is different in that it ‘burns up’ all the Pu (and other actinides) it produces as fuel, thereby using 99% of the energy content of uranium rather than 1-5% of light water (thermal) reactors (LWR).

(1) It depends how committed “we” are, but to answer it another way, I believe much faster and more comprehensively than via renewables alone. Energy efficiency is the big initial gain to be made, after that it’s a massive IFR scale up with whatever contribution renewables make being an extra boost (but not the primary solution). I suggest reading this for some of the reasons why:

(2) IFR material is not suitable for weapons. You would need a dedicated PUREX plant. IFR *reduces* (substantially) the existing proliferation/terrorist risk from LWR products – it doesn’t enhance it! Go back and read the above posting and hyperlinks, and the comments section above.

(3) IFR doesn’t enrich the U-238 to U-235 or U-233 and then dispose of this – it breeds fissionable isotopes and then burns them, without them ever leaving the plant. A large scale IFR adoption will eliminate all enriched U and thereafter feed off depleted U.

(4) Given the passive safety features of IFR, an independent risk assessment put the probability of a Three Mile Island style meltdown as occurring once every 435,000 years – if the entire planet was powered by IFR. That is, for an individual IFR, the risk of meltdown was ~1 in 200 million per annum.

(5) No. I wish to save the planet and avoid the duel nightmares of global warming and fossil-fuel driven energy wars. IFR is not a nuclear nightmare – it is likely to be one of our best hopes.



From an inconvenient truth to a moral vacuum

It is a good question what Al Gore, the premier virtual guest in Rudd’s climate summit of April-2007, thinks about the Rudd government’s White Paper’s 5/15 percent emission cut by 2020 relative to 2000 levels, a third or less than the EU 25/40 target and likely future US targets.

While not referring directly to Australia, Gore stated at Poznan: “We, the human species, have arrived at a moment of fateful decision. It is unprecedented and in some ways even laughable to imagine that we could actually make a conscious choice as a species. But that is nevertheless the challenge that now faces us because our home, Earth, is in danger.” (12.12.2008)

Given the above, no excuse can justify jeopardizing any chance for an effective outcome in the Copenhagen 1990 climate summit by a meaningless 5/15 percent target.

Not that 25/40 is any longer consistent with an arrest of the accelerating global climate change. As indicated by John Holdern, Obama’s White House new Director of science and technology, global change is a misnomer: “It implies something gradual, uniform and benign. What we’re experiencing is none of these” (CT 3.1.09).

Consistent with the view of many scientists that the atmosphere is reaching, or soon will pass, a climate tipping point, manifest by rapid disappearance of Arctic Sea ice in a few years, spring ice melt increasing by over 10% per year. Once Greenland remains an isolated island, this can only be followed by accelerated melting of its ice sheet and rapid meters-scale sea level rise.

While precise ice melt lag effects and sea level rise are difficult to estimate, a rise of atmospheric CO2-e to 550 ppmv, higher than the level at which the Greenland and east Antarctica ice sheets formed, renders many metres-scale sea level rise through the 21st century inevitable

Elevated methane release from Arctic Sea sediments and sub-Arctic permafrost were recently recorded (Walter et al., 2006) (Rigby, 2008).

With a rise in mean Arctic temperatures as high as 4 degrees Celsius in 2008 relative to 1951-1980 an onset of methane emission has reached a threshold at which this gas, with X21 times the greenhouse effect of CO2, threatens to escape from the permafrost and shallow marine sediments. (Ocean and ocean floor sediments > 16,000 billion tons Carbon; permafrost ~900 billion ton Carbon).

In a new paper titled “Reframing the climate change challenge in light of post-2000 emission trends” Anderson and Bowes (2008) of the Tyndall Centre for Climate Change Research state, among other: “It is increasingly unlikely that an early and explicit global climate change agreement or collective ad hoc national mitigation policies will deliver the urgent and dramatic reversal in emission trends necessary for stabilization at 450 ppmv CO2-e.

Similarly, the mainstream climate change agenda is far removed from the rates of mitigation necessary to stabilize at 550 ppmv CO2-e. Given the reluctance, at virtually all levels, to openly engage with the unprecedented scale of both current emissions and their associated growth rates, even an optimistic interpretation of the current framing of climate change implies that stabilization much below 650 ppmv CO2-e is improbable.” And … “Ultimately, the latest scientific understanding of climate change allied with current emission trends and a commitment to‘limiting average global temperature increases to below 4 degrees C above pre-industrial levels, demands a radical reframing of both the climate change agenda, and the economic characterization of contemporary society.”

As the world’s premier coal exporter, enjoying one of the highest per-capita income, Australia faces what the Garnaut Report described as a “diabolic policy problem”, though the administered remedy, 10 percent emission reduction relative to 2000 by 2020, can be described at best as symbolic. .

Carbon sequestration is a costly too-little-too-late method which can only serve as a small part of the effort of arresting the rise of atmospheric CO2 levels, currently by 2.2 ppm per year. (Cost of coal CO2 capture, sequestration and storage – $0.06 – 0.010 per kWh – Table SPM.3; $30-70 per ton CO2 Table SPM.4

This would be analogous to the fate of the Australian Synroc project for the storage of high-level radioactive waste underground, developed in the 1970s but never applied on a large scale. To date billions of gallons of radwaste continue to leak toxic substance, for example 440 billion gallons disposed into the ground and Columbia River.

In so far as Rudd’s description of climate change as the “greatest moral challenge of our times” has been a key to the ALP’s election, the government is now locked on the horns of a dilemma of its own making.

Doubts have been rising climate change “skeptics” within the government may have had a field day, when Rudd started referring to climate scientists in terms such as “My experience is not all scientists agree and you can have people who have different views“ and “there is always going to be “argy bargy” in the political debate”. and references to “extreme green groups” and “Guys in white coats who run around and don’t have a sense of humor”

Not very funny when juxtaposed with Al Gore’s “Earth, is in danger” statement.

The ALP government has two alternatives:

It may honor its central commitment to voters, risking losing the next election to a massive campaign by vested interests and their mouthpieces. (A proviso: Acceleration of climate change and public understanding of its gravity may occur on shorter time scale than the election cycle).

Or the government may continue its retreat from the central platform on which it has been elected, hoping that those who recently showered the White Paper with compliments, for example in The Australian newspaper, may help them get re-elected.

Should the Government choose the first alternative, Rudd/Gillard/Wong/Garrett will be hailed as heroes, saviors of the young and of future generations.

This would be consistent with Dietrich Bonhoeffer’s moral dictum, expressed among other where he stated: “If I see a madman driving a car into a group of innocent bystanders, then I can’t, as a Christian, simply wait for the catastrophe and then comfort the wounded and bury the dead. I must try to wrestle the steering wheel out of the hands of the driver.”


Can anyone give a reason why solar/thermal (already operational on grid-base level in California), geothermal/hot-rocks (with a huge promise in the Cooper Basin), plus ancillary wind utilities, tide power sources, even space reflectors, are not preferable as power generators to enriched Uranium and Plutonium – the most toxic substances known to man?

Yes: the premise is false. Enriched uranium has only the toxicity typical of other heavy metals such as lead. More than bismuth, less than thallium, I think.

Plutonium* has what is known as radiotoxicity — aside: this is really confusing, like calling army ants toxic, and saying someone chewed by them is suffering from mandible poisoning — they being not stinging ants, just biting — but it has a lot less of it than naturally occurring radioisotopes such as radium, radon, and polonium.

Radium, in particular, exposes people to vastly more radiation than any artificial thing because it is in their bones.

— G.R.L. Cowan (How fire can be domesticated)

* If you could slow plutonium’s alpha decay down about 10,000-fold, this would reduce its “radiotoxicity” by the same factor. Enriched uranium has this much radiotoxicity, but it is little enough to make essentially no difference to its safe handling.



In my earlier comment (#83) I wrote

“I am sure the IFR technology is far superior to the current “conventional” reactors, not to mention fast breeders.”

I was referring to early fast breeder models which burn and produce excess plutonium, subsequently transported to other facilities via sea routes, vulnerable to accidents, terrorist attacks etc.”



I’ll use this thread as it is a quote from the linked “Unleashed” article, but I still don’t get comments like “Cap-and-trade systems to reduce emissions by some percentage are a good example of an ultimately useless ‘half-fix’ policy.”

They are only useless if the % is useless… but whatever the % is it is still the lowest cost method of reaching that %. At least the criticism should have included a Carbon Tax not just an ETS.

You note the resistance from both sides to Nuclear… well I’m pretty green and I’m all for this IFR technology…so you see we can all let go a bit… and scientists are just going to let economists help them out if we are going to get through this in one piece.

[Ed: I’ll post it over here as a separate post in a day or so, once it’s had its run on ABC Unleashed]


This thing is cooled by liquid sodium, one of the most dangerous chemicals to play with that I can think of, which needs a secondary coolant system of its very own. It’s inherently implausible that it will ever be safe or cheap to operate. Since it’s only been built on an experimental prototype scale, the amount of up-front capital investment necessary to scale it up and build industrial plants will be huge – it would basically require a discount rate of zero to ever be rated as commercially viable.

Why not get enthused about pebble-bed reactors instead? At least they’ve actually been built. Or start asking why we’ve structured our power demand so as to need huge amounts of baseline capacity in the first place?


James #91: The sodium can only react explosively if atomised. It will of course react with water, but does not corrode stainless steel, which is what the reactor tub and piping is made from. An inert pure argon atmosphere layer atops the sodium tank, and fills the room containing the secondary cooling loop. In the extremely unlikely event that you do get leakage from the secondary loop and get a sodium fire despite the argon surround, it would occur in a different room to the reactor core, and thus would not threaten the stability of the reactor. That is the reason for the additional coolant look – multiple (redundant) levels of safety.

But if even this doesn’t convince you, then there are similar fast neutron spectrum reactor designs that are cooled by lead-bismuth or helium. The INL site has some good info:

Pebble bed reactors suffer from the same limitation as other GenII-III+ reactors – it uses the uranium very inefficiently and produces long-lived high level waste. LWR will be useful in the short term as we transition to AFRs.

There is nothing ‘inherently implausible’ about it. Regarding ‘the amount of up-front capital investment necessary to scale it up and build industrial plants will be huge‘ you could make the same argument about large-scale renewables. When you are talking about taking over most of the grid supply, it’s not just multiple wind turbines or solar collectors, it’s a whole ‘nuther ball game.

This above is not meant to dismiss renewables. All I’m saying that when we are talking about an energy transition on the scale required, it’s going to require massive up-front capital and scale-up R&D and learning-by-doing no matter what path we take. Renewables, nuclear or both (ideally).


I know you said you’d put your unleashed up here in a day or so… but I find it amazing that som many people post blog entries based on the title “Nuclear Power: A real solution” (paraphrased)…. but have clearly not even read your article let alone the links!

[Ed: I know. And that wasn’t my title – it was “Nuclear power is imperative to solve climate change fully” – i.e. a necessary PART of the package]


Some interesting words from Stephen Chu on Nuclear Power:

Commitment to nuclear power

Chu expressed a firm commitment to nuclear power, as well as to the cleanup of the nuclear waste left over from the Cold War.

He said Obama’s plans for nuclear power build on “a continued commitment to nuclear power and long-term plan for waste management and disposal.” Nuclear power and waste management, along with renewable energy, energy efficiency, oil and gas development, and energy research “will be my primary goal as secretary to make the Department of Energy a leader in these critical efforts,” Chu said.

“The point here is that nuclear power is going to be an important part of our energy mix,” Chu said. “There is certainly a changing mood in the country, because nuclear is carbon free, that we should look at it with new eyes.”

Particularly important to the progress of new U.S. nuclear power plants is the federal loan guarantee program. Bingaman noted that there has been “a lot of frustration in our committee about the length of time it takes to implement” the program, which has yet to disburse loan guarantees. Bingaman and several other senators asked Chu for a firm commitment to getting the loan guarantees disbursed quickly — as well as any new funds that may be DOE’s responsibility in the expected economic stimulus package, which Chu readily confirmed.

Chu said his plan for the nuclear program at DOE “first is to accelerate the loan guarantee program.” He said his second nuclear priority is the development of a long-range plan for safe disposal of the waste and finally to continue to research and develop a more “perfect” nuclear waste recycling technology.

Obama said he opposes the long-term geologic disposal site at Yucca Mountain, Nev., “so going forward we need a new plan,” Chu said. He did not go into specifics of what that plan may be, but he said recycling could play a part at some later time.

“Long-term recycling can be a part of that solution,” Chu said. “Right now, even though France has been recycling, Japan is, Great Britain has started looking at this, from my limited knowledge of that, the processes that we have are not ideal.”

But he said DOE under his leadership would look “very closely” at research and development of the recycling process and also hope to see some international collaboration on the subject. He also pointed out that there is an economic feasibility issue associated with recycling that has not been solved either.
Cold War cleanups

Chu also said he understood the serious issues that DOE faces in the cleanup of waste left from the Cold War.

“I take this responsibility extremely seriously, and I am committed to working with the president, national laboratories, other agencies, Congress … to assure a safe and reliable nuclear stockpile and to address proliferation concerns as part of a long-run vision of a world without nuclear weapons,” Chu said. To do this, Chu said he will work to improve management and program implementation, a serious issue the cleanup program has faced in the past.

Sen. Feinstein said she endorsed this vision and hoped Chu and Obama would implement such a plan to shrink the nuclear weapons stockpile in the new administration’s nuclear posture review due in 2010.

Alex Flint, a lobbyist for the Nuclear Energy Institute, said he was “very pleased” to hear Chu’s comments about the loan guarantee program and fuel recycling. “It is tremendously refreshing to see Democratic appointees to the Department of Energy approach the issue as pragmatically as he is,” Flint said. “I think his science background and his appreciation for the magnitude of the challenge we face with climate change bode very well for nuclear.”


Hi all,

I am a high schooler we does policy debate, this year we are debating about alternative energy, and our debate teams advocates IFR technology.

Our team had a couple of questions:

1. What is the difference between a “fast reactor” and an IFR, if there is any?

2. Would any of you say that IFR technology could solve for waste management concerns, i.e. Yucca Mountain storage?

3. Is there a big difference between Purex reprocessing and pyroprocessing, and can the two even be grouped together?

Any help on any of these would be great,



Chris Torgeson: The answers to all your questions are in the links provided in this post. But briefly:

1. An IFR is a fast spectrum reactor. There is no ‘difference’, but the Integral part of Integral Fast Reactor refers to the systems design that includes on-site pyroprocessing of the nuclear fuel.

2. Yes, it can solve the waste storage problem completely if adopted widely. The only waste that might then be stored in Yucca is the vitrified fission products which would reach background radiation levels within a few centuries, and because of its low heat, you could put it all and more in Yucca [or drop it into the deep ocean].

3. Both are forms of fuel reprocessing. PUREX is plutonium and uranium extraction and can be used to enrich and purify. Pyroprocessing does not extract Pu or U from the other actinides and so cannot be used to make weapons grade material.


And what do you think about the Thorium Molten Salt Reactor – the same advantages, plus those coming from the fact that the fuel is liquid with online waste and composition processing – The university of Grenoble has been developing on the basis of the Oak Ridge Laboratory MSR experiment. –??


David Broman: The prospects for the thorium liquid-fluoride MSR are excellent and it has a number of unique advantages — but the technology is somewhat less mature than IFR. This doesn’t mean the R&D to finalise and test the MSR concepts, through to commercial deployment, can’t be (and shouldn’t be) hastened – it should! (GIF are working on this as one of 6 designs).

The emphasis on sodium-cooled reactors here is: (i) because they well tested thanks to the Argonne programme and are on the cusp of deployment (the S-PRISM demonstrator reactor that can be used to ‘prove up’ the economic prospects of IFR is designed by GE/Hitachi and ready to build!) and (ii) IFRs will be very effective at gobbling current stockpiles of nuclear waste, purified plutonium and extract a heap of useful energy from the piles of depleted uranium sitting around not doing much apart from armouring a few M1A2 Abrams tanks — this additional role of IFRs is obviously highly desirable from multiple standpoints (elimination of the long-lived ‘waste’ problem and proliferation reduction).

Thorium is abundant, especially in places like India (their beaches are loaded with it) and there is no theoretical reason why MSR won’t be working alongside SCR (or other types such as lead cooled, gas cooled or even supercritical water reactors). It is also the most abundant heavy element in coal slag (ironic that the slag from a coal-fired power stations contains more energy in the thorium that’s thrown away than was liberated from burning the black carbon).

Charles Barton runs a super website called “Energy from Thorium“. I highly recommend taking the time to explore its details on the MSR and its future prospects.


The IFR Emperor has no clothes. As with conventional reactors, IFR can easily be used to irradiate U/DU blankets/targets to produce high-purity plutonium. Or thorium blankets/targets to produce fissile U-233.


You can only irradiate extra blanket material if you put in more room for it. The PRISM design has no room inside the reactor vessel, and the silo around it fits it pretty snugly. One could clandestinely modify the design I suppose, but would also have to have a purex process to go along with the irradiation process.


No design documents. I’m going by a recollection of the first GE design, called ALMR. I have found a presentation by GE that shows a schematic cross-section of the PRISM reactor vessel (slide 8). The red rectangle labelled “core” is the driver, and the blanket would be the next rectangle surrounding that. Then there is an annular thing I believe would be neutron or gamma shielding. Then there is some annular space for cool sodium flow, the reactor vessel, and then the annular spaces for aux air cooling flows. You could put some source material in those various spaces, but not much compared to the legitimate blanket before you started impacting the cooling systems. And it would be outside the shielding.

So, you could make some clandestine Pu, but how much? It takes about a gram of fissile material to produce a megawatt-day of energy. So the entire breeding blanket of a 400 MW (thermal) PRISM module would be producing about 150 kg per year of Pu, assuming it was operated for replacement. To get a weapon’s worth in a year (around 3 kg) you would have to have an extra 2 percent of blanket clandestinely inserted, and that would be at the average blanket radius. Out towards the periphery of the system, you’d need much more volume because the blanket is designed to use as much of the neutron population as possible. Pickings are much slimmer out there.

The PRISM presentation is at

Click to access 2007RIC.GE.NRC.PRISM.pdf


And it would require PUREX separation, which is extraneous to the IFR fuel cycle.

Bill, thanks for those slides from Loewen. Close inspection of slide 3 leaves me much clearer on the pyroprocessing processes, too.


this additional role of IFRs is obviously highly desirable from multiple standpoints (elimination of the long-lived ‘waste’ problem and proliferation reduction)

Maybe one can reduce the theoretical potential for power reactors to be involved in proliferation, but their actual history of involvement is zero, and so not subject to reduction.

This potential remain like that of car engines to be made into multibarrel cannons: it could happen, and guns do proliferate, but never that way.

(How fire can be domesticated)


Jim Green, if you wish to direct people to a critique IFR, fine.

But if you want to come here and start personally insulting one of my respected, regular commenters, with name-calling, then you have no place here. Take it as a friendly warning.


Barry: for your info – the Thorium MSR’s would also burn current nuclear wastes – and would have an inbuilt nuclear treatment facility (since the fuel is liquid) – resulting very little wastes of any kind. Thanks for this web site – the other possible worlds will not be able to come to without nuclear power. It is just a matter of finding the most “natural” was to use nuclear reaction for energy. MHO


“IFR can be built anywhere there is water” – and elsewhere too, I hasten to add. Any power station that uses steam turbines needs to re-condense its steam for its next cycle through the boiler tubes. That is cheaply done with lots of pipes in a cooling tower, sprayed with fresh water. However, with more expense in piping, that could also be done with low quality water or even just air. So water is not a prerequisite for nuclear power.


i have read this all too hurriedly to comment. I will go back and read it again. i seem to get contradictory info on IFRs in Japan and France. if they are working well there why do we not just go ahead with it? What are the knowledgeable arguments against doing that? Where does the new energy czar stand on this?


IFRs are not in use anywhere as far as I know. Other countries seem to have made statements from time to time since the project was cancelled here that they are thinking of or planning to build some. That’s all. France and Japan did contribute a little funding to the IFR program before it was cancelled though, in return for some rights to the technology.


Hi Barry,
I’m busy telling a greenie mate why I think IFR’s are an option and I find this on the wiki… is this true?

“”Others counter that actinide removal would offer few if any significant advantages for disposal in a geologic repository because some of the fission product nuclides of greatest concern in scenarios such as groundwater leaching actually have longer half-lives than the radioactive actinides. The concern about a waste cannot end after hundreds of years even if all the actinides are removed when the remaining waste contains radioactive fission products such as technetium-99, iodine-129, and cesium-135 with the halflives between 213,000 and 15.7 million years” [6]”

The quote seems to come from Page 30 on this Google books record.


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