Nuclear Fusion / Fission Hybrid?

Guest essay by Eric Worrall

Building an energy producing nuclear fusion reactor remains elusive, but some companies are re-considering an old idea – combining nuclear fusion with nuclear fission in a single reactor, to overcome the disadvantages of both.

Fusion-fission hybrids: nuclear shortcut or pipe dream?

While nuclear fusion’s key milestones remain elusive, could fusion-fission hybrid reactors represent the best of both worlds? Start-up Apollo Fusion aims to make this complex concept a commercial reality, but formidable obstacles remain.

The fusion-fission hybrid concept

Is pure fusion truly only a matter of years away? Opinions vary due to the formidable technical challenges that remain to be solved. But while the likes of ITER, the National Ignition Facility and a host of start-ups and academic labs around the world continue to hammer away at the fusion chestnut, a decades-old alternative concept that combines fusion and fission has resurfaced.

The idea of a fusion-fission hybrid reactor has existed since the early 50s, with the earliest reference attributed to Russian nuclear physicist Andrei Sakharov. The fusion-fission hybrid concept is envisaged as a system that balances the advantages and disadvantages of the two nuclear generation paradigms; fission creates large amounts of energy per reaction, while fusion creates less energy per reaction but can generate abundant neutrons without the need for a chain reaction.

A fusion-fission hybrid reactor, then, would use a fusion reactor to provide neutrons to an encapsulating ‘blanket’ of fissile materials, so fusion is essentially used as a stable fuel source for traditional fission-based energy generation.

What are the advantages of such a hybrid system? For a start, using fusion-derived neutrons to feed fission reactions would massively expand the fuel available to run plants. Conventional fission reactors require one specific isotope of uranium, U-235 (or plutonium-239), which constitutes only 1% of raw uranium deposits, to drive the fission chain reaction. By using fusion as a fuel, a hybrid reactor would be able to use any uranium isotope while capitalising on the higher energy output of fission.

So with fusion feeding fission, a plant could theoretically operate more cleanly and efficiently, massively reducing waste and proliferation concerns while providing a way to use fusion even if positive net energy has not been achieved. In terms of safety, proponents say the concept would be inherently meltdown-proof because it operates in subcritical conditions and the fission would not be self-sustaining.

Read more:

Using a nuclear fusion reactor to stimulate fission in suboptimal fuel is an old idea. To date the concept has languished, because it doesn’t seem to offer any advantages over a more conventional breeder reactor. A report in 1980 by the Los Alamos Scientific Laboratory concluded that there was no point exploring fusion / fission hybrid designs, because they offer no advantage over “conventional” breeder designs.

Summary: The future of nuclear power rests in the hands of a diverse group of decision makers whose motives and methods vary greatly.

In some respects, the two long-term cycles are similar. Each would probably be equally likely to win licensing approval and public acceptance.

In other respects, the advantage could belong to either cycle, depending on who the decision maker is. For instance, if the next generation of reactors is to be manufactured by private industry and operated by utilities, the fast breeder reactor cycle would be preferred. If, on the other hand, the federal government becomes the manufacturer and operator of fissile breeders, the hybrid would have the advantage.

The crucial difference between these two cycles is one of readiness. Whereas the fast breeder will probably be a commercial technology in the near future, the fusion-fission hybrid has yet to be proven scientifically feasible. A decision to commit federal funds for the demonstration and commercialisation of the hybrid would have to be based on a conviction that the hybrid is vastly superior to the LMFBR as a breeder of fissile fuel.

Although the hybrid is indeed superior in some respects, it also has some drawbacks. Furthermore, as is always the case with an untested concept, there is the possibility that unforeseen problems will emerge as the technology becomes better understood.

In the face of an already commercialized fast breeder reactor, there is not sufficient incentive, in our opinion, to demonstrate and commercialize the fusion-fission hybrid

Read more:

Both fission / fusion hybrids and breeder reactors derive the bulk of their energy from burning nuclear waste or other low grade fuel, by bombarding the low grade fuel with a blizzard of neutrons. The difference between the two is how the neutrons are produced – a conventional breeder reactor uses a normal fission core to produce the neutrons, while the fission / fusion reactor uses a nuclear fusion reaction to irradiate the low grade fuel.

Fission / fusion hybrids might be safer. There is no risk of the fusion core suffering a fission reactor style meltdown, because any failure of a critical component immediately kills the fusion reaction. The low grade fuel blanket surrounding the fusion core would still have to be carefully designed for safety, to address risks such as loss of coolant, but without the fusion reaction stimulating the burn, it should immediately start to cool in the event of a major failure.

The other intriguing possibility is Fission / fusion hybrids could potentially be made very small. Desktop size electrostatic confinement fusion reactors have been available for decades, they are sold commercially as neutron sources. Desktop fusion reactors cannot produce net energy, and may never be able to do so, so by themselves they are not useful as a power source. But the fusion component of a fission / fusion hybrid reactor does not have to achieve breakeven by itself – it is entirely acceptable for the fusion component to be a net energy drain on the system, providing the fission component more than covers the energy lost to the fusion component. It would be intriguing to discover just how small you could make a fission / fusion hybrid reactor.

Commercialisation of fusion / fission hybrids might also potentially spur pure fusion development. There would be a strong commercial incentive to improve the design of the fusion component of the system, which might improve understanding of how to control pure fusion plasmas to the point that energy producing fusion plasmas become viable.

On the downside – a fission / fusion hybrid is still a fission reactor, so any attempt to build a fission / fusion hybrid is likely to attract all the usual green outcry.

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August 9, 2017 12:03 am

Just the same as an H-bomb! Only about 60 years out of date.
Thermonuclear weapons are fission-fusion-fission devices.

Reply to  Gloateus
August 9, 2017 2:40 am

This seems to work the other way around. An H bomb the fission sets off the fusion. In this the fusion sets off the fission.

Reply to  Gloateus
August 9, 2017 3:11 am

No it’s not the same as an H bomb since it does not involve criticality. The exact opposite in fact, the fission-fusion hybrid discussed here operates further away from criticality than a fission reactor. So it’s safer. In a fission reactor the fission reactions are the source of neutrons so it has to operate close to criticality. But with an independent source of neutrons – the noncritical fusion – the fission can take place much further from criticality.
Which is good. No it’s not like an H bomb at all.

August 9, 2017 12:06 am

To have a fusion/fission hybrid you have to have a fusion reactor to start with. We don’t have – and never will – a fusion reactor.

Reply to  rokshox
August 9, 2017 12:09 am

As noted above, thermonuclear bombs start with a fission reaction, which triggers fusion, the fast neutrons from which reaction excite more fission in the depleted uranium jacket of the device.
Typical yield is about half fission and half fusion.

Reply to  Eric Worrall
August 9, 2017 3:48 am

For the hybrid to work, you need fusion to be close to breakeven. All the existing “table top devices” are orders of magnitude away from the breakeven. No fission will help here.
And we ever be close to breakeven, it will be not too complicated to go over the breakeven: just make the device 2x larger. So, why going hybrid?

DC Cowboy
Reply to  Eric Worrall
August 9, 2017 4:17 am

Eric, would this reactor be able to operate on sources other than Uranium, like Thorium? If so that would make them far more attractive for the US as we have significant quantities of Thorium available within the US, thus making us less reliant on an energy source from unstable/less than friendly areas of the world.

Michael S. Kelly
Reply to  Eric Worrall
August 9, 2017 12:52 pm

“For the hybrid to work, you need fusion to be close to breakeven. All the existing “table top devices” are orders of magnitude away from the breakeven. No fission will help here.”
Actually, that isn’t true. D-T fusion neutrons are highly energetic. When they are absorbed by, say, a Pu239 nucleus, the resulting fission releases an average of 4.6 neutrons, whereas in plain old critical fission, the average number of neutrons per fission is 2.9. Each Pu239 fission produces 211.5 MeV total energy. For a subcritical reactor, there may be an average of only three fission generations until the neutrons escape without causing further reactions. That’s 13 fissions per fusion neutron, for a total energy yield of 2,750 MeV. The D-T fusion cross section peaks at 10 keV, though many accelerator-driven fusion sources run at up to 100 keV. Assuming the latter number, the fusion efficiency required for fission output equal to fusion source input would be 0.00363%. IIRC, dense target fusion experiments have produced fusion yields on the order of 0.02% Orders of magnitude short of fusion breakeven, but well about what would be needed to sustain a subcritical fusion-fission reaction.

Reply to  Eric Worrall
August 9, 2017 3:47 pm

@DC Cowboy:
Present U reactors can run on Thorium, as can the proposed hybrids. There is a company that makes thorium bundles for LWR types, plus the CANDU is advertized as multifuel (U, Th, Pu, & MOX).
The USA ran a Th reactor in the early years. It isn’t hard. You do need to bootstrap the thing with U-235 until you get some U-233 from the Th exposure to neutrons, but now that we have reactors everywhere, we are well past the bootstrap issue. Just expose some of your Th fuel bundles to form some U-233 in them and use them as your core in the new reactor, wrap it in more Th in your blanket.

Malcolm Carter
Reply to  Eric Worrall
August 9, 2017 10:22 pm

These Subcritical reactors have been under development for some time. Some with neutrons provided by fusion, others with neutrons produced by spallation as high energy particle beams strike beryllium targets.
Even Wikipedia has an article on Subcritical Reactors.

Reply to  Eric Worrall
August 13, 2017 5:32 am

“The USA ran a Th reactor in the early years. It isn’t hard.”

DC Cowboy
Reply to  Eric Worrall
August 13, 2017 7:56 am

Demonstrably true
“government scientists built two complementary prototypes during the 1950s and ’60s.
They weren’t good for making nuclear weapons, though, among other reasons, so bureaucrats pulled funding for the revolutionary energy technology. The last working molten-salt reactor shut down in 1969.”

Reply to  Eric Worrall
August 13, 2017 12:52 pm

DCCowboy, RE your linked article:
‘Shippingport proved that you could use thorium as an inexpensive and safe nuclear fuel in a light-water reactor and that you could breed additional fuel with it. This was not alchemy, but it was close.’
False. Some thorium was bred to U-233. Determined by external separations of the thorium targets. Proving double-ought nothing. They had already done it at Savannah River. None of the U-233 produced fissioned; it contributed nothing to the nuclear reaction. The U-233 later isolated in separations was never used.
Breeding thorium to uranium was a good idea in the 1950s and 1960s. Uranium was rare and expensive. Then we discovered more. Uranium is not rare and it’s not expensive. Killing any thorium efficacy for the next 400 years.

Reply to  rokshox
August 9, 2017 1:17 am

we have lots of fusion reactors. Just none that a produce stable net energy on earth
Billions otherwise – the sun and all the stars of course

Kaiser Derden
Reply to  rokshox
August 9, 2017 6:00 am

we have fusion reactors just not self sustaining …

Reply to  rokshox
August 9, 2017 6:48 am

Oh, yes we have. Fusion reactors are fairly simple to build – they have literally been built by amateurs in their basement. What is difficult is to build a power producing fusion reactor. Which, as pointed out above, might not be necessary to run a hybrid.

Tom in Denver
Reply to  tty
August 9, 2017 11:27 am

Pulsed Neutron generators (Minitron) have been commercially applied in oilfield logging equipment for decades

Mariano Marini
August 9, 2017 12:20 am

So nano nuclear explosion could power an engine?

Reply to  Mariano Marini
August 9, 2017 1:20 am

I’ve always been whimsically attracted to the idea of an IFE
Internal Fusion Engine. Just like a petrol engine but replace the petrol with tritium and deuterium or something and the spark plug with a high intensity laser…

August 9, 2017 1:24 am

Liquid salt reactors could accomplish the same things. An overheating reactor would simply melt a thermal plug, the fuel would drain out into a tank below and the reactor would shut down – no active components required. This technology have been around for decades.

August 9, 2017 1:25 am

sorry Eric, this is more like the sign in a pub in Bali
“Free beer tomorrow”

Robert of Ottawa
August 9, 2017 2:50 am

Hmmm sounds a bit like a fast breeder reactor, another good thing.

Martin A
August 9, 2017 3:05 am

Fusion power has always been fifty years in the future and always will be.

Reply to  Martin A
August 9, 2017 6:34 am

I don’t know. I’d always thought flat screen TVs would be cool, but it never seemed to happen and then suddenly there they were and I don’t even know if you can get a non-flatscreen TV/monitor any more. Same with general purpose robots, though I don’t know if the ones I read about really live up to the hype you see in the news. In technology,, unlike Climate “science” , there really are tipping points.

Reply to  daved46
August 9, 2017 3:52 pm

We have made LOTS of progress on fusion. 50 years ago, it was 50 years away, now it is only 25! In another 50 years, it ought to be only 12.5 years away!,
True, but still a 😉 due

Clyde Spencer
Reply to  Martin A
August 9, 2017 4:52 pm

The fifty year joke has been around as long as fusion research. However, as to the accuracy, I’m not as confident as you that it will always be in the future. My crystal ball isn’t as clear as yours! Never say never!

August 9, 2017 3:17 am

For reference, no affiliation or endorsement:

August 9, 2017 3:29 am

It sounds like a brobdigandian idea that will all too easily morph into disaster.

DC Cowboy
Reply to  hunter
August 9, 2017 4:18 am

Big enders were right!

Stan Vinson
August 9, 2017 4:19 am

The Watermelons (Greens) will not be accepting of any power source that provides abundant and cheap energy for the masses. Affordable energy causes the masses to be difficult to manage.

Reply to  Stan Vinson
August 9, 2017 8:00 am

Elegantly stated.

Reply to  Stan Vinson
August 9, 2017 4:50 pm

Quite true, however, the Greens are just a means by which the suppression of abundant and cheap energy for the masses is accomplished, not the root cause. The importance of State control / centralisation / monopolisation of energy provision is second only to that of money provision for the imposition of collectivism.

Brian Mays
August 9, 2017 4:57 am

“Fission / fusion hybrids might be safer. There is no risk of the fusion core suffering a fission reactor style meltdown, because any failure of a critical component immediately kills the fusion reaction.”
Meltdowns are caused by the heat generated from the decay of fission products, not from any continuing fission or fusion reaction. As long as you have fission products, you’ll have decay heat.

Reply to  Brian Mays
August 9, 2017 11:33 am

Yes, but you don’t have enough fissionable material to go critical. Supplying neutrons from a different source than your fuel itself, you would have a really really hard to time to make the fission reaction self-sustaining or provide a runaway reaction. With low or un-enriched fuels even if the heat overwhelmed the cooling system at worst you have a melted core of (not very) radioactive heavy metals. Not nice to deal with, but also not a too hard to handle.

Reply to  Rob
August 9, 2017 12:28 pm

All current fission reactors go critical. They are critical all the time when they are making power. You clearly do not understand the terminology of the technology. And from the comments, it appears that many other people who talk about nuclear energy do not understand it, either.
The comment about fission products being the problem for meltdowns is 100% correct. Even molten salt reactors will have to deal with this issue, because every bit of power that they generate will be accompanied by the same fission products as a non- molten salt reactor. Maybe the distribution will be slightly different, but the overall effect is exactly the same.
Reactors with discrete fuel elements contain the FPs inside the fuel elements. Liquid salt reactors circulate them in the coolant, but they do remove them, in a continuous stream, in a reprocessing operation. They must be stored somewhere, until their heat load is low enough that they can be dispatched in a form for disposal to a repository, or for some other use. Until then, the container that holds them must be cooled to prevent it from failing and releasing the FPs in an uncontrolled fashion.
“So with fusion feeding fission, a plant could theoretically operate more cleanly and efficiently, massively reducing waste and proliferation concerns while providing a way to use fusion even if positive net energy has not been achieved. In terms of safety, proponents say the concept would be inherently meltdown-proof because it operates in subcritical conditions and the fission would not be self-sustaining.”
This statement is so filled with gibberish/rubbish that I don’t know where to start.

Stephen Duval
Reply to  Brian Mays
August 11, 2017 5:14 pm

Sodium Fast Reactors are “walk away safe” when designed with metallic fuel and pools. All the active safety systems can be disabled and then all power to the reactor turned off. The SFR will enter a steady state with no meltdown and no manual action required. The fission reaction stops and decay process heat is removed via physical properties of the material and design of the reactor.
SFR is the only reactor to have demonstrated “walk away safe”. In 1987 EBR-II was operating at full power, all safety systems were disabled and all electric power to the reactor was switched off. The reactor entered a safe state with no core damage and no manual intervention.

Martin A
August 9, 2017 5:09 am

This is well past its sell-by date.
From the referenced (“read more”) pdf (Read more:
Created: Sat 27 Apr 1996 17:15:38 CEST

August 9, 2017 5:17 am

“Using a nuclear fusion reactor to stimulate fission in suboptimal fuel is an old idea. To date the concept has languished”
Umm… until we can actually get a stable working fusion reactor, this is completely academic isn’t it?

Kaiser Derden
Reply to  kcrucible
August 9, 2017 6:01 am

no a self sustaining fusion reaction is not required …

August 9, 2017 5:26 am

There is more to pure fusion that ITER–see a summary of the race here:

August 9, 2017 5:30 am

This reactor combines the disadvantages of fusion and fission reactors — immaturity/inefficiency of fusion reactors, production of abundant radioactive waste by fusion reactors.
Breeders and thorium reactors already solve the problem of amplifying the supply of fissile material, and both have been proven as functioning prototypes. Among all these, thorium reactors produce the least amount of long-lived heavy radioactive isotopes.

Stephen Duval
Reply to  Michael Palmer
August 11, 2017 5:00 pm

“thorium reactors produce the least amount of long-lived heavy radioactive isotopes.”
Sodium Fast Reactors with pyroprocessing produce very little long lived radioactive isotopes as waste, less than thorium reactors. Pyroprocessing recycles SFR spent fuel back into the reactor with only .1% remaining in the waste product.
When the reactor hits end of life, the core is moved to the replacement reactor. It could be a long long time before the reactor is replaced as sodium does not react with ordinary stainless steel and the reactor has no moving parts as an electromagnetic pump is used on the molten sodium metal.
If it is ever necessary to shut down the SFRs, the SFRs can be converted from breakeven reactor (producing as much fissile material as they consume) to burners that eat up radioactive isotopes. Eventually two cores would be combined into one core and the surplus reactor closed. In this manner almost all the radioactive material would be burnt up. Almost all of what is left is fission products that return to background radiation levels after 300-400 years.

David P. Zimmerman
August 9, 2017 5:36 am

I brought up this idea a while ago. Using a farnsworth hirsch fusor as a neutron source for the trigger for a thorium fission reactor. The nice thing would be the ability to turn off the fission reaction at the flip of a simple electrical switch. Maybe I need to dust off my science fiction writing skills and create a novel with these devices in them. No one takes real science seriously until scifi has explained it, 😁.

Tom Schaefer
August 9, 2017 5:56 am

Mis-print: “Desktop size electrostatic confinement *fusion* reactors…”. I’m sure you meant fission. Back to the future!

David P. Zimmerman
Reply to  Tom Schaefer
August 9, 2017 6:05 am

He meant fusion. Read about the farnsworth hirsch fusor.

Reply to  Tom Schaefer
August 9, 2017 6:08 am

” I’m sure you meant fission.”

August 9, 2017 6:19 am

Since it’s capable of burning all isotopes of uranium it might be something useful if we ever start running low on U-235. In about 10,000 years or so.

Reply to  MarkW
August 9, 2017 3:56 pm

Try never. We have proven tech to get U effectivly forever at reasonable costs to run reactors.

August 9, 2017 6:25 am

The trend is for privately funded aneutronic fusion reactors, which produce no radioactive waste:

The most advanced reactor of this type is developed by LPPFusion in Middlesex, NJ. I’s operating principles are described here… it’s extremely compact. It is now in the final development phase. It is #5 on the fusion leader board, but has yet to load in duterium Boron fuel.


G. Karst
Reply to  sarastro92
August 9, 2017 8:44 am

This is the most exciting of the “outside the box” fusion concepts current. I hope it remains well funded. It could solve the future energy problem. Thxs. GK

Reply to  G. Karst
August 9, 2017 11:05 am

I agree. I’m mesmerized by the LPPFusion team which relies on keen insight into the behavior of plasmas rather than brute force. Sort of a “whisperer” approach.
This project is underfunded and turning to retail investors, and crowd sourcing for completing the efforts.. This final experimental phase requires only $2.5 million.

Reply to  sarastro92
August 9, 2017 9:29 am

As the Lawson criterion for p-B is more than two orders of magnitude higher than for D-T, I think that it can safely written off.

Reply to  Akatsukami
August 9, 2017 11:01 am

The LPPFusion device has already met 2 of the three Lawson Criteria reaching 3 BILLION degrees C and holding it for a few nanoseconds required. These are peer-reviewed published results and were obtained without the final materials/ design/ fuel.
The last challenge has been getting a symmetric burn which requires the elimination of oxides from the chamber. The LPP team has gone through a tedious process of meeting those requirements (which are pretty soft targets).
They are now installing the final configuration with beryllium electrodes ( a light metal more conducive to the task at hand) … and a new electrode configuration. So there should be results this Fall that will be make or break. Once resolved, then the p-B fuel will be loaded. The physics is the same as the earlier test fuel. This is all near term, low cost R&D.

Reply to  Akatsukami
August 9, 2017 2:24 pm

No–the key goal in fusion is more energy out of the entire device than you put into it. Because with pB11 efficiency both in and especially out can be much higher than with DT, where a heat-cycle conversion is required, the required density-time-temperature (Lawson) product is not that far off in the two fuels. pB11 certainly requires much higher temperatures than DT, but we have already demonstrated the achievement of those temperatures in peer-reviewed papers. More details in the New Fusion race video.

August 9, 2017 6:45 am

The idea of using a fusion reactor to treat nuclear waste is attractive. link You could power the country for a long time just by using the nuclear waste we already have. link
These are all wonderful ideas but, as is the case for all promising technology, don’t hold your breath waiting for any of them to become reality. 🙂

michael hart
August 9, 2017 7:17 am

It’s always interesting to read about alternative fission/fusion avenues being explored, even if they are “old” ideas. Obviously many technological ideas fail because they are unworkable or just plain dumb [insert “green” example here], but many good ideas have also been abandoned in the past for reasons other than practicality or cost. The best idea doesn’t always win.
Nuclear ideas remain exciting because the potential rewards are so huge and the basic principle has already been shown to work.

August 9, 2017 7:29 am

Not sure how this “hybrid” would prevent meltdowns. In most cases, meltdowns are caused by decay heat after intentional power production is terminated. See, e.g. Three Mile Island and Fukushima Dai’ichi. The problem is the decay of fission products, which will be present in any U or Pu fuel, enriched or not. If melt-prevention is inherent in the fuel type, like PBMR or CerMet, then that would be true of a non-hybrid type as well.

Reply to  MCPR
August 9, 2017 12:26 pm

Its the neutrons. The hybrid operates at significantly less than criticality. Without the neutrons from the fusion the fission effectively stops. Fission works by chain reaction, neutrons are provided by the fission itself The hybrid provides the neutrons from a different source than the fission reaction so has greater control.

Clyde Spencer
Reply to  seaice1
August 9, 2017 5:15 pm

It is not the neutrons! You have demonstrated that you don’t have a grasp of the technology. MCPR just said (as have others) that the fission byproducts with short half-lives are a major source of heat that contribute to problems after the reactor has been ‘shut down.’ It the heat from radioactive decay isn’t removed by circulating fluids, then the rods containing them will melt, even if fissioning isn’t taking place.
So, even if you can turn off the neutron source with “the flip of a switch,” you have to maintain cooling of the mass that was previously experiencing fissioning. It would take a completely different design where either the fissionable material would inherently cool rapidly either because of its much reduced mass, or a fail-safe system of convection cooling would remove heat.

Tom Halla
August 9, 2017 7:37 am

The green blob will oppose this proposal as it might work. Remember, having cheap and abundant power is like giving an idiot child a machine gun.

Walter Sobchak
Reply to  Tom Halla
August 9, 2017 9:39 am

More to the point.

Bill Yarber
August 9, 2017 7:56 am

“It would be intriguing to discover just how small you could make a fission / fusion hybrid reactor.” I loved Isaac Asimoff’s “Foundation” trilogy in HS! Maybe SciFi will fortell science once again!

August 9, 2017 7:58 am

Anyone familiar with advanced nuclear reactor technology would laugh at the notion that any technology other than molten salt reactors is the future of nuclear power. And amazingly, this article seems totally ignorant of what can only be characerized as a proven technology, recently become practical due to advances in metalurgy and moderators and imminently commercializable by half a dozen companies and two nations (China,India) . These reactors are also very strongly anti-proliferation and cannot meltdown and are inherently, boringly safe, can produce power cheaper than ANY technology, can burn either uranium or widely available Thorium, and can extract far more energy from uranium than current Light Water Reactors. They can be located anywhere and produced in varying sizes in factories, requiring minimal site preparation, making cost overruns a thing of the past.

Reply to  arthur4563
August 9, 2017 4:01 pm

Anyone familiar with the history of technology would laugh at the notion there is only one good viable tecnology to meet an end.

Reply to  E.M.Smith
August 16, 2017 10:13 pm

Thanks, E.M. I was afraid everyone would let this silly statement stand.
There’s a lot uneducated discussion on this topic. A pity.

August 9, 2017 7:59 am

In anticipation of a possible nuclear renaissance, there has been an enthusiastic renewal of interest in the fusion-fission hybrid concept, driven primarily by some members of the fusion community. A fusion-fission hybrid consists of a neutron-producing fusion core surrounded by a fission blanket. Hybrids are of interest because of their potential to address the main long-term sustainability issues related to nuclear power: fuel supply, energy production, and radioactive waste management.
A fusion-fission hybrid is defined as a subcritical nuclear reactor consisting of a fusion core surrounded by a fission blanket. The fusion core provides an independent source of neutrons, which allows the fission blanket to operate sub-critically.
The fundamental mission of the fusion-fission hybrid is to address an important national and worldwide problem — namely, converting nuclear power from its current deployment path, which is sustainable only for perhaps another 50 to 100 years, to one that is sustainable for millennia. A realistic expectation of long-term sustainability might also motivate a more rapid expansion of conventional nuclear power to help meet our energy needs in the near-to-midterm.
For a detailed technical discussion of the fusion fission hybrid concept see:

August 9, 2017 9:33 am

For a detailed technical discussion of the fusion fission hybrid concept see:
This article is dated Jan 27, 2009. Any progress in the past 8 years?

Gary Pearse
August 9, 2017 9:51 am

Canadians’ modest hide-your-light-under-a-bushel personality (er… there are some exceptions!), results in people not knowing many of the tech and science novel contributions that have been made. The Candu (my spell checker doesn’t even know the name) fission reactor used in Canada and in Korea and a few other places uses non-enriched U, has a good safety record, doesn’t produce weapons grade waste and, of course, never gets a mention in the tons of paper written by top experts in the nuclear power field. Canada was beaten in the market place in the early days internationally because of bullying tactics by competitors (we scoutish folk wouldn’t play the corruption/kickback game) as a result, the best tech with fewest negatives, excellent safety record works quietly and is totally outside the nuclear discussion.
Roger Sewell listed the major drawbacks of present day nuclear plants. I believe there were 5 that were deepsixing nuclear as a choice. The Candu solved them all 50yrs ago! You don’t have to shut them down to fuel them, you can toss in waste from other types of reactors and it can take on Thorium as a fuel already while the rest of the world is busy doing “cutting edge” reinvention of the wheel.
The beat up on BlackBerry phones was of a similar kind. The superior operating system made them de riguer even in the US government for 20yrs for its unparalleled security.This little company was stolen from and the target of predatory pricing and market manipulation by latecomers (can someone tell me why Apple is the darling of the left?)
Maybe Candu can use a Canuck like me to break the news to the world of this half a century ignored tech that already is in he holy grail it was s desperately looking for!

Michael J. Dunn
Reply to  Gary Pearse
August 9, 2017 11:30 am

Well said. I was reading through the “Carthago delenda est” of the thorium proponents and was annoyed at the ignorance of the CANDU (CANada Deuterium Uranium) operating concept–which came about because the Canadian nuclear physicists, privy to the Manhattan Project, said “Good Lord, we can’t afford to build uranium enrichment plants. We’ll have to figure out how to achieve fission with raw uranium.” And went ahead and did it. Rather puts me in mind of the Avro Canada CF-105 Arrow, another technological marvel.

Daryl M
Reply to  Gary Pearse
August 9, 2017 1:32 pm

The CANDU reactor is still a pressurized water reactor and suffers from the same issues as other pressurized water reactors and other uranium-based fusion reactors. The liquid fluoride thorium reactor is completely different and has many advantages over pressurized water reactors, including the CANDU.

Gary Pearse
Reply to  Daryl M
August 9, 2017 4:39 pm

Steam engines were pressurized water energy ‘generators’, too. What you cite is one of the many troubles the other technologies have. You are hard to impress! The worst accident Candu has had is spillage of a few litres of water in a plant that Sent lefties for their playdough but nothing more worrying. Don’t you think it a revelation that you can refuel without shutting down a nuclear reactor and that nuclear experts don’t know such a system exists!
Here are other bulletins for you that my Canadian modesty didn’t want to burden you with: a Thorium reactor was also invented in Cda and operated over half a century ago, the first commercial Candu reactors, three of them at Pickering Ontario (eastside Toronto) essentially right in town, are 600MeW each and each was the largest nuclear reactor in the world (and nuclear experts didn’t know about the Candu!), finally to floor you: because of Canada’s nuclear research capability and infrastructure, begun in 1942!!!, the Manhattan Project contracted the facility to produce the enriched Uranium for its work. Oh it also developed Co90 for cancer therapy in the 1950s and I believe produces 85%i of world requirements and Technetium – 99 for world medical use. There’s more but er… modesty and all the that…

Daryl M
Reply to  Daryl M
August 10, 2017 1:25 pm

@Gary Pearse, you need to brush up on the issues with pressurized water reactors. There are many. While there have been no major issues with CANDU reactors, they rely upon high temperature and high pressure, and suffer from embrittlement of pipes no different than other pressurized water reactors. They also produce large volumes of waste that must be disposed of. Do yourself a favour and read up on the LFTR. It operates at low pressure (relative to pressurized water reactors) and low temperature (relative to liquid sodium cooled reactors). It also has a completely different fuel cycle that doesn’t produce massive amounts of waste. It’s also very easy to refuel (on the fly) and it’s inherently stable. Lots of advantages and very few disadvantages.

Clyde Spencer
Reply to  Gary Pearse
August 9, 2017 5:20 pm

The story of how VHS recorders beat out Betamax is the classic example of how superior technology does not always win.

Gary Pearse
Reply to  Clyde Spencer
August 9, 2017 8:04 pm

Yeah, Clyde, after two working lifetimes and still at it, I’m getting used to that!

August 9, 2017 10:51 am

“There is no risk of the fusion core suffering a fission reactor style meltdown, because any failure of a critical component immediately kills the fusion reaction.”
“Meltdowns” or fission product releases are usually not caused by the fission reaction, they are caused by the inability to remove decay heat from the core after the fission reaction is stopped. I don’t see anything here that eliminates decay heat.

Hiro Kawabata
August 9, 2017 1:52 pm

Mr. Worrall,
If memory serve, the LENR E-CAT was going to solve all our energy needs in the imminent future 😉

Tom in Florida
August 9, 2017 2:17 pm

How does a nuclear reactor make electricity? It is just a different method to boil water which creates steam which drives turbines. Why does it appear that many of the comments above seem to imply that the nuclear reaction itself produces electricity? I think there a lot less expensive ways to boil water. Or do I owe a bunch of commenters an apology.

Gary Pearse
Reply to  Tom in Florida
August 9, 2017 4:55 pm

Yeah Tom, oil gas, coal wood, solar tower ops, waste. Eventually, the atom will reign. But thankfully this slowly advancing tech takes a good part of a century to perfect and its good we startled the early.

Phil's Dad
Reply to  Tom in Florida
August 9, 2017 5:11 pm

Mostly true but not always.
For example the lppfusion approach will create a beam of ionised helium to drive a solenoid (no boiling water required – although I suspect there will be some usable heat produced so maybe a bit of both)

Michael J. Dunn
Reply to  Phil's Dad
August 10, 2017 10:16 am

According to Wikipedia (!): “Direct energy conversion was developed at LLNL in the 1980s as a method to maintain a voltage using the fusion reaction products. This has demonstrated energy capture efficiency of 48 percent.” The energy of the 14 MeV neutron will be lost.

Reply to  Phil's Dad
August 10, 2017 5:10 pm

Dad… the LPPFusion process will generate electricity directly in two ways: by induction from an ion beam, which is the product of the fusion reaction from the plasmoid; and secondly by the photo-electric effect from foil that capture x-rays.
Because no boilers an turbines are needed, the process produces incredibly cheap electricity without great capital expense.

Reply to  Tom in Florida
August 9, 2017 8:00 pm

Pretty much everyone knows nukes boil water. That’s why nobody is dwelling on it.
Nukes boil water cheaper and with less emmissions than anything else.
Finding better ways to improve what you know is a good idea.
I’m not seeing the problem…

Tom in Florida
Reply to  E.M.Smith
August 10, 2017 4:50 am

Not if you factor in construction costs.

August 10, 2017 9:00 pm

My thought is that anything related to ‘nuclear’ power will find it more difficult to overcome public hysteria whipped up by the idiot media than to overcome whatever technical obstacles are involved.

August 18, 2017 9:42 am

Actually this is called the Tsar Bomba

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