Thorium in Space – And a New Idea

At Moon, Mars, or Asteroids, Which is the Best Destination for Solar System Development? Dennis Wingo discusses the future of space endeavors.  Among his very good comments is this:

<blockquote> Thorium reactors can be an export from the Moon to provide megawatts of power for space ships and to be delivered to Mars to provide power on the surface there.</blockquote>

Yes and yes.  Dennis shows that he is keeping up with developments on the Thorium LFTR front.  LFTRs are Liquid Flouride Thorium Reactors, and they are the absolute future of energy production on the planet.  Unless someone comes up with a damned good reason otherwise, LFTRs will replace all coal, oil, gas, and nuclear power plants.

In Space

Thorium reactors will be needed in space, on Mars, on the Moon, and on asteroids.

I am jumping out of my skin, waiting for the first Thorium LFTRs to get up and running. Actually the second ones. Alvin Weinberg had one up and running 50 years ago at Oak Ridge.  So, you see, this is not a pipe dream.  Why not?  Because Alvin Weinberg also happens to be the man who invertned the current light-water nuclear reactors, the ones currently used in most nuclear power plants today.  If he invented LFTRs and had one running (for YEARS), you can be assured that it is not some pipe dream.

This is our future. This much Thorium will provide all the energy you will need for an entire lifetime.

As applied to space, the advantages of Thorium are (at least):

1. Inherently safe, almost unbelievably so.
2. Scalable, down to whatever size is going to be needed on a spacecraft.
3. Thorium is super plentiful
4. It is plentiful on the Moon (so we don’t have to ship it there)
5. It’s energy output is extremely dense
6. It can be used as an energy source for ship’s systems
7. It should be able to be adapted to fuel spacecraft propulsion, in tandem with ion propulsion
8. This much thorium ( is enough for a person’s entire lifetime needs
9. The thorium on the Moon can fuel essentially ALL future extra-lunar flights. No need to take fuel to the Moon.
10. Thorium can actually be used to power lasers and mining equipment on the Moon, Mars, and asteroids
11. IMHO, Thorium in tandem with lasers can be used to ablate asteroids (and probably comets), to steer them away from Earth (or perhaps, in time) TO Earth so they can be mined here, in Earth orbit
12. Thorium can power Lunar ore processing, ore furnaces, machining, manufacturing, and assembly of more Thorium LFTR reactors – as well as building space craft. (This obviates the need to take everything to the Moon from Earth.) I would advocate the design of robotics solely for lunar use (which may or may not be made on Earth).

That list is not intended as as comprehensive list.

Does all of that sound expensive? Compared to using the huge rockets to lift only a few tons of cargo from Earth? Not in the long run.

HiJACKINg a ride on a Thorium-driven asteroid

If 11 is possible, it might, in time, mean that we can use asteroids’ inherent momentum to navigate the solar system – simply by steering them. They are already going over 20 km/sec. Why not use that to our advantage? If we get to one, why NOT hitch a ride on it, and then hijack it and steer it elsewhere?  All we would need to do is to supply the side-thrust for steering.  If we use the Thorium to power a laser, and aim that laser at the asteroid, the expulsion of material will push it sideways.  Not counting the Thorium reactor part of this, NASA already has such a plan high on its list of possible ways of diverting asteroids that might hit Earth.  So this idea is just putting the two ideas together for a new use.

(In fact, the LFTR-Laser tandem could be the best way to divert asteroids, in and of itself.)

In this scenario once the hijacked asteroid arrives at another asteroid, if it’s course is steered to parallel the target, the relative speed is already there. Matching speeds is fairly straightforward, and may be minimal.  It might not even be necessary to decelerate much at all.

A hair-brained idea? To be honest with you, I don’t think so. Every new technological process or method involves using the inherent advantages of what is available, in the materials and their chemistry and material properties. In space and with Thorium, we are only just beginning to learn what is possible and what we are working with.

15 responses to “Thorium in Space – And a New Idea

  1. I drive me nuts that we don’t have an active plan for Thorium power. China is beating us on this. Add to the fact that our grid cant hold the power requirements of the future, but small and safe reactors close to consumption can use local grids more efficiently. Basically turning the power grid into a matrix of smaller grids. Much safer, and much more reliable. Hot standby capable too. Just because Thorium produces no weapons capable byproducts…… Sad, how can we be so smart and so ignorant at the same time.

    • Thorium reactor can produce material for a bomb. One just has to wait for the protactinium isotopes to decay by 20 half life’s.

  2. Jeff –

    You make extremely good points.

    What will we do with the high-tension towers and the copper in the millions of miles of high-tension wires? We can get rid of those monstrosities and the just as bad windmills.

    Hot backup – good point. Any two neighboring LFTRs could be gridded together to provide backup for each other. It needs to be no larger than that.,

    It is mind boggling how much potential there is in this – what kinds of changes can this make to the future as we now envision it.

    — Desalination plants on the coasts of Saudi Arabia, Morocco, Western Africa, Namibia, Australia… in order to irrigate those deserts

    — The low cost energy available to 3rd world countries, to help enable them to come into the developed world.

    — Large companies with their own power plants…

    — Small towns with their own…

    — The obsolescence of gasoline cars… replaced by electric cars powered by thorium plants. The energy cost factor may be the straw that broke the camel’s back; at, say, $0.25 per fill-up, will anyone complain that a car only gets 200 miles per charge?

    — Petroleum needing to only be used to make chemicals and plastics instead of burning it up in moving us from point A to point B. Petroleum fields will last much longer.

    — Burning up all the old LWR nuclear waste – and utilizing vastly more of its energy this time around.

    — Really almost free energy. What could a world like that be like?

    — The only place I can see it not working is for jet travel. Perhaps electric prop planes will become the norm for many flights. Or maybe someone will come up with really fast propellers and motors so that prop planes can fly 550 mph. I know that some WWII prop planes were capable of over 400 mph, so maybe it isn’t that big of a leap.

  3. Steve,

    Your list itself should be more than enough for anyone to agree with TP as the next solution for our energy needs. I am sure we could add the simple fact that nearly all dependence on fossil fuel in energy and transportation would be gone if we decide to move forward with this approach. As for jet travel, in the 50’s we had a working nuclear jet engine. The reactor actually flew hot in the belly of a b-36, and the engines were test fired many times on the ground. With TP, that would allow a jet(using just compressed air heated with TP) to fly for years without refueling. See this link for more info: AND more here
    And the Russians:


  4. Thanks for putting all this out there, but when those videos are watched, it turns out that the aircraft never actually made it off the ground under nuclear power.

    Jeff –

    You got me looking into it, and here is what I have found out – from your links and from googling:

    Kirk Sorenson, the young nuclear scientist who “re-discovered” the LFTR story and is the main lecturer on the subject says that the LFTRs were never actually deployed on the planes. That doesn’t make it true, but one of the comments in the SciAm article reads:
    08:30 AM 12/6/08
    I worked as a nuclear physicist at General Electric Aircraft Nuclear Propulsion Dept. from 1956-59.Radiation shielding was my concern. We only talked about bombers not passenger planes. The reactor was always within the body because it is heavy and never on the wings. The 3MW reactor flown on the B36 had absolutely nothing to do with powering the plane and was water cooled not air cooled.It was used for shielding experiments.One to power an aircraft would have a power level of 300-400MW and would be air cooled in GE’s Direct cycle, and liquid metal cooled in the Pratt Whitney system. Turbine temperatures would be 1800 degrees or more. [emphasis added]

    This agrees with Wikipedia:

    This aircraft, designated the XB-36H (and later NB-36H), was modified to carry a 1 MW, air-cooled nuclear reactor in the aft bomb bay, with a four-ton lead disc shield installed in the middle of the aircraft between the reactor and the cockpit. … The reactor was operational, but did not power the aircraft; its sole purpose was to investigate the effect of radiation on aircraft systems.

    The WS-125 per Wiki:

    The WS-125 was a proposed super long range bomber, designed in the United States during the cold war as a nuclear aircraft and was scheduled to be named as B-72.
    In 1954, the USAF issued a weapons system requirement for a nuclear-powered bomber, designated WS-125. In 1956, GE teamed up with Convair (X211 program) and Pratt & Whitney with Lockheed in competitive engine/airframe development to address the requirement.
    In 1956, the USAF decided that the proposed WS-125 bomber was unfeasible as an operational strategic aircraft. Finally, after spending more than 1 billion dollars, the project was cancelled on March 28, 1961 [John Kennedy shut it down after finding out the real state of things]. [Note no mention of it ever flying under nuclear power.]

    This all seems to support Sorenson. It seems to clearly be saying they never actually powered the aircraft with the LFTR. The full length video at , at 15:50 states that the first test flight referred to was on Sept 17, 1955. 46 other test flights followed.

    It turns out, if you watched the entire video(s) that neither the US nor Soviet programs were ever successful. The Soviet program includes this shocking sentence:

    The massive amount of liquid sodium, beryllium oxide, cadmium, paraffin wax and steel plates; were the sole source of protection for the crew against the deadly radiation emerging from the core.

    First of all, liquid sodium – do you know how dangerous that is? Sodium reacts extremely energetically (read: very explosively) in the presence of ANY water. And beryllium is terrifically poisonous. And if that plane had ever crashed, what a disaster that would have been, not even counting the reactor. “Massive amounts” of either or both – what a recipe for contamination and death and destruction…

    Sorenson also discusses how even the LFTR nuclear scientists (including Alvin Weinberg himself) working on the project only took it on because it was the only way they had to develop the LFTR – but that they never thought the project was a good idea.

    The video(s) and Wiki all mention that it was GE that was involved in the program on the reactor end. That clearly means that they were using a LWR, a U-235 reactor. Bad idea. That latter fact would also indicate that there IS some hope of a nuclear airplane in the future – if it is powered by a LFTR, as was the purpose of the Molten Salt Reactor program in the first place.

    The LFTR would be able to solve all but one of the problems listed in the videos: Weight, shielding, thrust. and dirty exhaust could all be deal with, because:
    1. The LFTR is inherently lighter in weight, so they might well be able to size a lightweight reactor up to give enough thrust,
    2. It could be connected to the Indirect Cycle to eliminate the dirty exhaust
    3. The weight saved could be put into shielding

    The one thing even the LFTR can’t do is that it cannot be guaranteed to not crash. What would be the problems with a LFTR reqactor strewn across the landscape? Mostly fluidized U-233 and irradiated fluidized thorium, plus highly radioactive Protactinium-233, also fluidized – all splashed over hill and dale, and impossible to clean up.

    So, no successful flights (the article about the Soviet one was a hoax).

    I was amazed that they had been able to compress air itself to anywhere close to producing enough thrust. Personally, I would think heating water to steam would have been a better option. But then water as the fuel might have limited the range, due to how much water on board might be necessary. For their military purposes that is bad. However, for a civilian nuclear plane limited range would not be a problem. But how many people would have the guts to expose themselves AND run the risk of being in a nuclear plane crash?

  5. …For the shielding, I wonder if they ever considered angling the lead shields so that the gamma radiation had to go diagonally through the shield, adding length to the path through? A nice steep angle could have added shielding without adding weight. 60° would have doubled the shielding.

  6. Jeff –

    A bit more about the nuclear plane, from a different site:

    After the November presidential election, Eisenhower decided to let the incoming administration of John F Kennedy have the final say on the fate of the ANP.

    Not only a new administration was ushered in but also a new way of thinking about government policy especially in the area of national defense, Kennedy’s appointment of Robert McNamara as the new secretary of defense epitomized that shift. Formerly president of Ford Motor Co., McNamara had been told by Kennedy “to take a fresh look at everything and make it better” and what he looked at were the defense programs that might pass his cost-effectiveness test. He defined this as the maximization of military capabilities through the rational allocation of available resources-getting the biggest bang for the buck.

    McNamara was a systems analyst who believed that most of the significant items of a defense program could be reduced to computer-processed numbers. Brought to its logical conclusion, this outlook came close to saying that, since the atomic bomb had changed the rules, now war itself need not be fought-it could be managed, instead, just like Ford Motor Co, As for the ANP it did not pass the cost-effectiveness test. McNamara wisely felt the need to distinguish between what was possible and what was needed, between what could be done and what should be done. Instead of the nuclear plane, he wanted to increase appropriations for ICBMs-to end the so-called missile gap-and for conventional war capabilities without greatly enlarging the Eisenhower-designed defense budget. The decision was made that the ANP not merely be cut back but rather be canceled entirely.

    After briefly considering whether to continue development of Pratt & Whitney’s indirect-system engine, Kennedy agreed to the cancellation, and in his March 28, 1961, national security message he said that “nearly 15 years and about l billion dollars have been devoted to the attempted development of a nuclear-powered aircraft; but the possibility of achieving a militarily useful aircraft in the foreseeable future is still very remote,.. .We propose to terminate development effort on both approaches on the nuclear power plant…and will avoid a future expenditure of at least a billion dollars which would have been necessary to achieve first experimental flight.” Shortly afterward, the ANP program was terminated.

    And that was that. Neither the United States, nor the Soviet Union, nor any other country was ever able to develop a true atomic-powered aircraft. But a nuclear plane of sorts did manage to fly This was the NB-36H test airplane, authorized along with the X-6 design back in 1951. Its original B-36H airframe had been extensively modified, most notably with a 12-ton shielded crew capsule in the nose, a 4-ton lead disc shield in the middle and a number of large air intake and exhaust holes to cool the reactor in the aft section. The reactor was a 1000-kilowatt design weighing 35,000 pounds and situated in a removable mounting in the aft bomb bay Its operation was observed from the crew capsule by closed circuit television. When the plane was not being flown, the reactor was kept in a specially prepared pit near the runway at Convair’s Fort Worth, Texas, facility.

    NB-36H flew with its radioactive cargo 47 times between 1955 and 1957, and, although it did not power the airplane, the reactor provided considerable data on the effects of radiation emitted during night. Flying alongside NB-36H on every one of its flights was a Boeing C-97 Stratocruiser transport carrying a platoon of armed Marines ready to parachute down and surround the test airplane in case it crashed. This certainly deserved hazardous duty pay. Pity the poor troops assigned to this outfit, jocularly dubbed the “glow-in-the-dark platoon.” Fortunately there never was a crash, and the test plane was eventually decommissioned at Fort Worth in late 1957. After languishing as a hulk for many months, it was scrapped.

    This was a somewhat ignominious end for a program that had begun with such giant visions. The fatal flaw as McNamara and others pointed out, was that a small, light, high-powered and adequately shielded reactor had not been developed. In retrospect, it is clear that the Air Force should never have been involved in designing an airplane until the AEC had completed work on the reactor.

    Though I don’t see a solution to the plane crash problem, it might be time to revisit the nuclear plane, with the LFTR that none of these articles online include in the picture about the past project. Certainly LFTRs are different animals than LWRs. Perhaps if some effort is put into it, there is a solution in there somewhere.

    I had thought that there was no way to actually get sufficient thrust out of a reactor-driven jet engine. It seems others thought there was.

    The crash problem I also knew about.

    In lieu of both, I was satisfied that a nuclear plane is not an option. I think that is still a valid position. I think it is more secure and more reliable to use LFTR energy to produce electricity and store it on board to drive propeller craft. There still would remain the problem of storage batteries, of course. This hasn’t been solved for ground vehicles, but perhaps it might be different for airplanes. Perhaps not.

    But for civilian use, LFTRs seem to be able to do everything else. If jets and plastics were the only uses for petroleum, we’d still be ahead of the game.

  7. I was wondering how small a LFTR reactor one could build and what are the specs for using thorium as radiation sheilding? I have looked at the different salts one could use, and I think Zr fluoride in place of Be fluoride might be a better choice. The primary reasons are two fold, Zr is cheaper than Be, and far less toxic. Zr might not meet the criteria that Be achieves, but getting a LFTR built will require one to prove out the actual technology in the most economic manner.

  8. Curran –

    I approved your comment that reads:

    “Thorium reactor can produce material for a bomb. One just has to wait for the protactinium isotopes to decay by 20 half life’s.”

    Right now it isn’t showing up. I don’t know why, so I popped this in as a replacement.

  9. Now I’d like to comment on your comment that “Thorium reactor can produce material for a bomb.”

    You are busted, as follows:

    The decay chain is laid out at

    You mention “Protactinium isotopes” – but we don’t have to deal with any Pa isotopes besides Pa-233. Thorium-232 only converts to Pa-233, not any of the other Pa isotopes.

    We find the following are ALL the isotopes in the Pa-233 decay chain, after Th-232 absorbs a Beta particle in the nuclear core jacket and becomes Pa-233. The chain divides (there are basically 5 chains in total), so this list is more or less the order from top to bottom:

    U-233 (used in the reactor)

    There ARE no others.

    None of these are used in nuclear weapons. The only isotopes that I can find that are used in nuclear bombs are U-235 and Pu-239.

    Also: There ARE no Protactinium isotopes in the decay chain other than the Pa-233 which is created in the jacket around the reactor core and is then removed until it decays in ~27 days to U-233.

    It appears your assertion is incorrect.

    It is possible that I am being foolish and taking the word of a website that calls itself – but I don’t think so.

    PLEASE: Correct me if I am wrong – and if you do, please provide your references/sources. Thanks!

    [Edited 2:37am Nov 10, 2013 – corrected the phrasing of the paragraph before the list of isotopes.]

  10. Hello,
    You are correct. I just reread the section about U-232 contamination in the June 1969, U.S. Atomic Energy Commission report, “The Use of Thorium in Nuclear Power Reactors,” and on page 108 it states “the n,2n takes place only with high-energy neutron.” Given that the LFTR is in the thermal spectrum, there should only be Pa-233 produced. You are correct, and thanks for challenging to dig deeper.

    • As for material for a nuclear bomb, it is my understanding that U-233 can be used for such a purpose, but given that all the fissionable uranium will be needed to keep the reactor critical, it really is a mute point.

  11. Curran –

    Can I ask where you found the report? That is cool.

    Also, the U-233 is specifically NOT bomb material. That is the reason LFTRs were abandoned. Yes, U-233 is fissionable, but I understand that it irradiates so intensely that it ruins the structural materials around it if stored as warheads (which for many missiles has been decades), plus it gives off so much radiation that bomb facilities are easily discovered and targeted. The reasons there I am doing off the top of my head, so if they are off a bit, sorry.

    But the bottom line is that the U.S. government dropped LFTRs because they couldn’t make bombs out of U-233.

    The U-233 itself, though, is why the LFTRs are such a probable godsend for a world desiring more and more energy (and clean energy, too), as more countries have developed. LFTRs are able to use over 99% of the energy available in the Thorium first seeded into a reactor. Current LWRs only use about 0.7% of the available energy in the Uranium-235. The nuclear waste has to be handled afterward. LFTRs not only produce much, much less waste, but they can also have LWR waste included with the U-233 fuel, enabling the LFTR to ‘burn up’ the currently existing stock – and making more energy from the waste than the LWRs got out of the fuel in the first place.

    The main problem that I’ve heard with LFTRs is that the fluorides are tough on the materials used in the piping and valves, but it is a problem the engineers are dealing with. I haven’t read any of the reports from the experiments back in the ’60s, but it is my understanding that they dealt with those problems well enough for the prototype that ran for thousands of hours.

    There is every reason to hope that LFTRs will be successful and give us the promise (made in the 1950s) of cheap and abundant nuclear energy.

    Also, as to how small a reactor might be made – that was the purpose of the LFTR in the first place: to make a reactor small enough that they could build nuclear aircraft. Given the design that I have seen, it looks quite easy to make a reactor quite small – but how small I don’t know. They are talking about ones that might be able to fit on the back of a semi-trailer. Also, it is strongly suggested that small towns and even industrial plants can have their own reactors – especially since the reactors can NOT produce bomb materials.

    If any of this is wrong, correct me.

  12. Steve,
    I guess my last post didn’t go through. I haven’t been able to find the PDF on-line but Google Books list it in one of their searches; strange they don’t have an electronic copy of the document.
    Getting back to the idea of hard radiation, I believe the radiation is coming from U-232, not U-233. It is one of the reason they dropped 233 as material for making a bomb. I can only guess that they used a fast reactor to make their U233, and one will get problems with U-232.
    As for the diagrams in the book, I am looking at making 3D cad drawings of the reactor for a three dimensional printer. I thought it would be great to have a small scale model of the Original Oak Ridge reactor.

  13. Curran –

    I have a vague memory of U-232 being involved, but I am certain that the LFTR runs on U-233 converted from TH-232.

    They didn’t NEED to use “a” fast reactor to make the U-233 – the LFTR does that. The LFTR is DESIGNED to do that.

    Have you seen any of Kirk Sorensen’s Youtube videos? Look at one of the longer ones; he goes into more detail. He is also pretty entertaining – especially for a nerdy physicist.

    3D printing one sounds good. What 3D software do you use? Solidworks?

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