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  • #1294
    AvatarBrian H
    Member

    Gates is now pushing a new fission “travelling wave” design, 300MW+, buried for about 50 yrs, 40x more efficient than standard designs, uses depleted uranium etc.
    http://www.theregister.co.uk/2011/12/07/bill_gates_terrapower_china/

    #11203

    I would love to know what they mean by 40X more efficient than conventional reactor designs. A conventional light water reactor is about 27% efficient (thermal to electricity). You can’t be 40 times more efficient than 27%. Mr Carnot does not approve in a thermal sense and neither does the second law of thermodynamics. I hope they mean fuel utilization i.e. burn up which would be a substantial improvement in fission systems. A high efficiency, low waste fission system is a real threat to the future of fusion. It’s hard to argue against injecting a few neutrons to start an easily sustained chain of reaction. Well, nothing is free so time will tell what the real costs (waste, insurance, regulation) really are.

    I’ve seen similar systems based upon thorium instead of uranium. If the reactor would burn thorium that would also be a game changer as there is ~100X as much thorium as uranium. Waste is a bit of a problem but the big problems of nuclear waster remediation is the heavy actinides. Thorium cycles are far less likely to produce plutonium which is reason that we don’t reprocess nuclear fuel. “We can’t take the risk that plutonium gets diverted and turned into bombs,” says the gov’t.

    #11205
    Avatarzapkitty
    Member

    asymmetric_implosion wrote: A high efficiency, low waste fission system is a real threat to the future of fusion. It’s hard to argue against injecting a few neutrons to start an easily sustained chain of reaction.

    ?

    It certainly would not be a threat to aneutronic units… steam and turbines and waste handling eat up any potential savings.

    And by the same token any of the smaller neutronic fusion projects such as General or Helion would do as well as the enriched U starter and would be safer to boot.

    In my opinion fission breeders would be a power source of last resort… after people realize what the oligarch’s half-assed response to Fukushima is actually doing to Japan [em]any[/em] fission plant is going to have a hard row to hoe no matter how much better it is technically.

    Aneutronic fusion should be the first priority and neutronic fusion the second string… and each should be funded accordingly simply because the relative potential payoff of each is worth the investment.

    #11206
    Avatardelt0r
    Member

    40x is meant to refer to the use of fuel. That is a LWR or BWR typically has a burn up fraction of 1-5% or thereabouts. While a burn and bread design can use 40% or more of both the fuel and fertile elements. Of course this is also the problem. No fuel element/pellet has ever been rated with such a high burn up fraction, where volume and gas build up can compromise the element. The cost of validating fuel elements is one of the bigger costs in terms of time and hence money for a new design.

    Otherwise the design seems like a good one. Uses depleted uranium as the main stock of fuel, gives the most of the benefits of reprocessing without the reprocessing.

    #11208

    zapkitty wrote:

    A high efficiency, low waste fission system is a real threat to the future of fusion. It’s hard to argue against injecting a few neutrons to start an easily sustained chain of reaction.

    ?

    It certainly would not be a threat to aneutronic units… steam and turbines and waste handling eat up any potential savings.

    And by the same token any of the smaller neutronic fusion projects such as General or Helion would do as well as the enriched U starter and would be safer to boot.

    In my opinion fission breeders would be a power source of last resort… after people realize what the oligarch’s half-assed response to Fukushima is actually doing to Japan [em]any[/em] fission plant is going to have a hard row to hoe no matter how much better it is technically.

    Aneutronic fusion should be the first priority and neutronic fusion the second string… and each should be funded accordingly simply because the relative potential payoff of each is worth the investment.

    I appreciate that there are more efficient energy conversion systems than steam and turbines but they are and will continue to be the backbone of electricity production for a while. They don’t “eat up” any savings compared to another fission power system. Yes, I am comparing to fission for one reason and one reason alone. Fission power is here and working. The problem of fusion for most folks that work in the power industry is that fusion has yet to produce more electricity than it takes in or even less restrictive, more power generated by the plasma than is required to initiate it.

    Fukushima was a disaster without a doubt but it placed a reactor in conditions that it wasn’t designed to operate in or deal with in shutdown. I would argue siting a nuclear power plant is critical and whoever sited it along a coast in a high earthquake area was nuts.

    Potential payoff and risk need to be assessed for all these technologies but practicality needs to be mentioned. Fission power works and has worked for over 50 years. Fusion should be the power of tomorrow but we need power now. Even if FoFu or others make a breakthrough tomorrow, it will take a decade to engineer it and start selling electrons. Countries like China and India refuse to wait that long. India is heavily investing in a thorium reactors because they see a path to electricity in less than a decade.

    I’m not against fusion or pursuing it but you will not be able to convince people that are interested in the wall plug when fusion hasn’t produced any net power yet. Fission and fusion are on two different levels. Fission is into making it better. Fusion is still in a “we hope, we think and it should”.

    #11210
    Avatarzapkitty
    Member

    asymmetric_implosion wrote:

    A high efficiency, low waste fission system is a real threat to the future of fusion. It’s hard to argue against injecting a few neutrons to start an easily sustained chain of reaction.

    I appreciate that there are more efficient energy conversion systems than steam and turbines but they are and will continue to be the backbone of electricity production for a while. They don’t “eat up” any savings compared to another fission power system. Yes, I am comparing to fission for one reason and one reason alone…

    Errrrrrrrrrr… but you didn’t 🙂 You were speaking of TWR or similar fission breeders vs fusion.

    asymmetric_implosion wrote: Fission power is here and working.

    The fission power we have [em]now[/em] is unsustainable and continually creates severe waste problems that future generations will have to deal with… or that we may have to deal with ourselves depending on quakes, floods, wind and human error.

    asymmetric_implosion wrote: The problem of fusion for most folks that work in the power industry is that fusion has yet to produce more electricity than it takes in or even less restrictive, more power generated by the plasma than is required to initiate it.

    Which is analogous to the case for TWR etc until the first prototype goes live.

    asymmetric_implosion wrote: Fukushima was a disaster without a doubt but it placed a reactor in conditions that it wasn’t designed to operate in or deal with in shutdown.

    Fukushima is a continuing disaster and the radiation is spreading with various isotopes of extremely recent vintage popping up in the damnedest places.

    asymmetric_implosion wrote: I would argue siting a nuclear power plant is critical and whoever sited it along a coast in a high earthquake area was nuts.

    … that would be the same sort of people who sited various U.S. plants near faults and water and who will be siting any new fission breeder plants…

    asymmetric_implosion wrote: Potential payoff and risk need to be assessed for all these technologies but practicality needs to be mentioned. Fission power works and has worked for over 50 years. Fusion should be the power of tomorrow but we need power now.

    And any new type of fission breeder plant is… just how far away from commercial use?

    asymmetric_implosion wrote: Even if FoFu or others make a breakthrough tomorrow, it will take a decade to engineer it and start selling electrons.

    Why would you think that? Your estimate somewhat differs from the LPP estimate of 5 years from FoFu-1 feasibility to generator. Why would do you think it would take twice as long when there is no radioactive fuel nor nuclear waste nor even a steam loop to deal with?

    asymmetric_implosion wrote: Countries like China and India refuse to wait that long. India is heavily investing in a thorium reactors because they see a path to electricity in less than a decade.

    ? The soonest estimate I’ve seen from India is that they hope to have a prototype by “the end of the decade.” And I’ve not even heard that much from China…

    asymmetric_implosion wrote: I’m not against fusion or pursuing it but you will not be able to convince people that are interested in the wall plug when fusion hasn’t produced any net power yet.

    I don’t think so. People who are “plugging in” on any commercial scale have a very distinct self-interest in finding, and perhaps funding, the best potential power options. The challenge lies in making them aware of other options.

    asymmetric_implosion wrote: Fission and fusion are on two different levels. Fission is into making it better.

    Fission “as is” cannot continue and, honestly, fission right now is more into “Researching techniques for not adding to an existing potential disaster.”

    asymmetric_implosion wrote: Fusion is still in a “we hope, we think and it should”.

    And, aside from the deliberate tar pit that is ITER, the neutronic fusion contenders are on a time-scale competitive with any new fission breeders… and aneutronic fusion could steal a march on them all due to its very nature.

    Again, given that the <1% will starve all alternative energy options but the one that they figure will give them the best leverage for control, the rational research triage is aneutronic fusion research first and neutronic fusion research second. Preferably both at once.

    The breeders are now funded and might well become the <1% fallback option after fossil but rationally, as I said previously, even fusion-fission hybrid breeders would be the option of last resort.

    #11211

    Zapkitty…Fission vs. Fusion… This is clearly a personal issue to both of us and I don’t want to argue for the sake of arguing. My bias in this is two parts so I will state them both. First, I am a nuclear engineer. I will always support the development of fission power because I believe it can be a clean power source once certain perceptions about reprocessing are addressed and people are educated. This argument is a similar one to fusion and it has its down falls but I believe it is the faster path to carbon free power at low risk. If you are concerned about risk, ask how many major nuclear accidents have taken place since nuclear power started to produce power. I count 3. One in the US; Three mile island which was a design flaw. Two, Chernobyl. Don’t get me started with that idiocy. Three, Japan. Bad things happened after a very bad situation. I agree that the disaster is ongoing. I agree that siting needs to be better but accidents will only tighten regulations leading to stricter siting requirements. Fission needs to do better and the next generation designs are doing that. So-called Gen III reactors are being built (china, Japan) with Gen IV well into design. Some Gen IV designs have applied for design licenses in the US. The TWR is not that far along yet but a similar idea is being pushed by a US company. They are likely to apply for a license in the next 5 years if the last design exercises pan out. Breeders exist and are licensed to be built in the US but fuel reprocessing is illegal so why build one? A point of interest perhaps, fission cores in nuclear subs last 20 years or more. I don’t know the details, but that is proven technology that could help the TWR concept along should the military declassify the core designs.

    My second bias is I actively research plasma focus devices as radiation sources. I am very familiar with LPP and other alternative fusion concepts. I’ve talked to Eric Lerner on a few occasions at meetings. He believes strongly in his work which is true of any serious researcher but his results haven’t gone beyond what other plasma focus devices can do or have done. In fact, the latest LPP yield results were first accomplished in the 1970’s at the 1 MA level. Now do you see my problem? This is not to say that 2012 won’t lead to a revolution at LPP or some other fusion group. My doubts about LPP arise from the nature of the problems they keep having. FoFu-1 is a ~1 MA plasma focus. Pulse power technology at the 1 MA level is straightforward one the time scale (~1 us) for LPP. In fact, two universities in the US have 1 MA drivers that have fewer problems. Sandia National Laboratory has a 1 MA module that can operate at 1 Hz at day long. The lack of pulse power experience at LPP leaves me concerned about the future of the system. Firing a 45 kV capacitor at 40 kV in a ringing circuit will lead to a very short capacitor life (<100 shots in some cases).

    Anyway, I guess this is my long way of saying that I disagree with you but I can agree to disagree. Perhaps I lack the foresight to see fusion for what it is; but I ask you to look at the complete history of alternative fusion concepts (non-tokamak or laser driven) and I think you will see they started the same as tokamaks and laser fusion (NIF). It will only take a few more tweaks and we will be there was the common line or more commonly stated “fusion is only ten years away”. Now fusion is 50 years away unless the Chinese invest their GDP in it. ITER will not work because at the latest meeting, it requires 80 MW of continuous heating. NIF has problems with symmetry that may or may not be overcome. FoFu-1 has problems and the ones I know of can be fixed. I hope the problems are fixed and I am proved wrong but I will remain skeptical until I see the data. And until I see fusion gain data, I will not consider fusion as a power source, but what it has been since it’s inception; a concept with a great deal of promise. I will admit that few valuable things are easy, but smart people have worked on the fusion problem for a long time and we still sit without a physics demonstration of fusion in a gain configuration on earth (excluding a nuclear weapon). Even if the physics barriers are overcome, the engineering needs to begin. Fission does not have a physics problem. It has engineering problems and materials problems.

    #11213
    AvatarTulse
    Participant

    Chernobyl and Fukushima were/are terrible events, but far more people have died from routine coal production.

    That said, aneutronic fusion is surely the holy grail of energy production.

    #11214

    Tulse wrote: Chernobyl and Fukushima were/are terrible events, but far more people have died from routine coal production.

    That said, aneutronic fusion is surely the holy grail of energy production.

    I agree 100%. The quest for the holy grail is fraught with challenges.

    #11215
    Avatarmchargue
    Participant

    Excellent thread, and good post, asymmetric_implosion. A good mix of hope, statement of fact, and crusty practicality.

    #11216
    Avatarbenf
    Participant

    Being less bad than coal makes you good? I’m not so sure….fission nuclear accidents, Wikipedia….An awful lot of millions are spent repairing what were “just” minor accidents (were there only 3 major ones?). Weren’t we supposed to have learned from the first accidents, back in the fifties or eighties? Is a body count the sole criterion? The thing about a DPF, as I understand it is that if something goes wrong it just turns off. No meltdown potential. Kind of like the way a lightbulb goes out. There would be no release of radioactive materials that takes years, decades or centuries to abate. Why not try our damnedest to get it to work? Yet it’s hard to come by the funds to pursue Focus Fusion research, the funds have all gone to clean ups, repairs and new designs for fission…and gigantic tokamaks…great. Is that Greenland I see rising over there Physorg.com?

    #11218
    Avatardennisp
    Member

    I suspect it would be instructive to see a similar accident list for fossil plants.

    I doubt there’s anyone here who wouldn’t agree that if focus fusion works, all forms of fission will be obsolete. Or that we should spend some billions on researching FF and other alternative fusion projects.

    But until somebody actually achieves net power using fusion, it looks to me like the best option for building new power plants today is fission. It’s way better than letting hundreds of thousands of people die every year from coal emissions. By comparison, we have:

    Three Mile Island, which didn’t hurt anybody,

    Chernobyl, which was an ancient design with a horrible positive feedback and no containment dome, and

    Fukushima, which was a 1970s plant hit by a 9.0 earthquake and tsunami. Another fission plant right next door was built ten years later with improved safety features, and got through the same challenges just fine.

    And that’s our record with GenII reactors, using active safety systems. GenIII+ is a lot better, and when you get into things like liquid thorium reactors, safety goes to a whole different level. There’s no meltdown potential there either, or anything that could cause an explosion.

    Bottom line: the world is going to spend tens of trillions of dollars over the next several decades, replacing and expanding our energy infrastructure. It’s crazy not to spend mere billions now researching every advanced energy source we can.

    But until we have better stuff available, I’d much rather build GenIII+ fission than fossil plants. As for cost, France is 80% nuclear with complicated old non-modular GenII plants, and has the cheapest electricity in Europe.

    #11220
    AvatarTulse
    Participant

    benf wrote: Is a body count the sole criterion?

    It’s an objective criterion, and the one people most often cite.

    The thing about a DPF, as I understand it is that if something goes wrong it just turns off. No meltdown potential. Kind of like the way a lightbulb goes out. There would be no release of radioactive materials that takes years, decades or centuries to abate. Why not try our damnedest to get it to work?

    Absolutely! I wasn’t intending to imply at all that FF wasn’t the best option, or that we shouldn’t be pursuing it as vigorously as possible.

    My only point was that people tend to focus on the possibilities of fission plant accidents, and fail to account for the accepted negative impacts of other forms of power generation. Regarding coal specificially, more than 100,000 US coal miners have been killed in accidents over the past century, and in modern times roughly 30 die [em]every year[/em]. That’s just deaths from mining, and not the more difficult to quantify impacts of emissions from coal plants (which includes natural radioactivity and other substances such as mercury). When arguing against fission power, I think it is important to compare apples to apples, and overall deaths involved in producing power seems like a reasonable criterion.

    #11221

    The message is that every energy producing system to date has problems. They have safety that needs to be addressed and we are learning from our mistakes. The mistake at Three Mile Island was a return signal. That was corrected. Chernobyl was a flaw from its design and should never have been built. The USSR had different safety standards than the west. Fukushima started because of a once in two lifetimes event. Errors made after the fact made the situation worse. Why didn’t they design the plant for a 9.0 earthquake and a tsunami? It has to do with risk analysis and cost. All engineered systems have to address these issues as the final product or during production. For example, solar is very clean once the panels are built but building the panels requires toxic chemicals.

    I’m not saying that nuclear waste isn’t a problem. In fact it is the biggest problem of fission power. I believe it is a problem within our ability to solve using reprocessing and either fast reactors or particle accelerator driven systems to burn up the waste. There are plenty of systems that can burn the waste and produce energy. If you are asking for a perfect system with no impact it doesn’t exist. Even p-11B will have some by-products that will be undesirable. The one that come to mind of great concern is diborane and other boron containing materials; bad stuff from the chemical side.

    The PF can continue to fire after the fuel is expended which is useless but relatively safe. The key questions about a pulse power system are less safety and more about reliability. One might argue that a unreliable power source can cause as many deaths as a power source that produces waste. Imagine losing traffic lights at rush hour because the pulse power failed on a PF. Good news, it produces little waste; bad news, it only works some of the time. I think the pulse power can be overcome but again, like gain from a p-11B fusion reaction, it needs to be demonstrated. I support funding p-11B systems and other fusions systems. If fusion is to be practical, an aneutronic solution is required. The DT reaction produces almost as much waste as a fission plant when you consider the replacement rate of wall materials and other structures.

    I know tokamak bashing is popular on this site and I agree that the tokamak is far from ideal, but one should look at the history and compare to the plasma focus. The tokamak is a stable pinch device designed to eliminate the end loss problem of linear pinches (like the plasma focus). Stuff squirts out the ends and the tokamak was supposed to solve it. It sort of solved the problem but introduced new problems. The PF took the other path which is fast pinch devices. Fast pinches have a number of problems which I have mentioned in this thread. They can be solved but the biggest problem remains the net energy problem. I feel safe in saying that those of us that support fission don’t do it because we think it is the best option that could be done, but rather it is the best option we have right now.

    Of course, dennisp said the same thing as I’m typing. A thousand curses upon your fast fingers. 🙂

    #11222
    Avatardennisp
    Member

    Heehee…I think, given that focus fusion would be a large number of small reactors (50MW and below), and they’ll be really cheap to build, we’ll have plenty of redundancy to smooth out any downtime.

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