Part 11 – Summary and Conclusions

Following through the analysis I’ve undertaken you can see that the alternative designs proposed to the LWR do offer some advantages, notably in the area of safety, but many of these designs come with other problems attached. It is also difficult to see how any of these designs could be built for a lower cost that the current crop of LWR or indeed be built substantially faster than them. This is largely an issue due to the materials it would be necessary to manufacturer them out of, which is itself an issue related to the high temperatures they would be required to operate at. While it is certainly possible to operate reactors at said temperatures, it will inevitably be more expensive – sufficiently so that one has to question whether such expense would be economically justifiable, a particular issue given that its questionable whether LWR’s are economically viable.

So while the supporters of nuclear energy are correct in saying that so-called generation IV reactors would be “better” than LWR’s and thus make a better case for future nuclear energy use, it also has to be said, we’re talking a fairly narrow level of improvement, at likely a considerable cost – both in terms of the development costs of these reactors and their likely higher construction costs, and in many cases higher decommissioning costs and more nuclear waste. Consquently it has to be questioned whether undertaking such costs are worthwhile.

The Verdicts

The CANDU does close off some of the safety loop holes associated with LWR, but it opens up new ones too and generally means higher rates of fuel consumption, lower thermal efficiency and increased amounts of nuclear waste being generated.

The High Temperature Gas Reactor (HTGR) offers an order of magnitude improvement in safety as well as potentially better fuel economy and high thermal efficiency. However, it will likely come at the expense of much higher construction costs (and probably a slower construction rate depending on material choices, which again depends on operating temperature), higher decommissioning costs and possibly higher volumes of nuclear waste (that last point I’ll admit is debatable, see the article for more on that one). While the HTGR is fairly safe from meltdown scenarios, one would have likely weathered the Fukushima Tnusmai with minor damage, it also opens up a host of other safety issues, notably the fire risk associated with that graphite core.

The Gas cooled Fast Reactor (GcFR) offers the intriguing possibility of being able to transmute stockpiles of nuclear waste into less dangerous forms. However, it likely comes with a very hefty price tag with a lot of R&D work still outstanding. Some geological storage facilities would still be necessary given the length of time it would take to develop and the build a sizeable number of said reactors, not to mention store the waste after it’s passed through the reactor. This, plus the hefty price tag associated with GcFR’s could well make the whole idea uneconomically viable. Also the GcFR comes with some safety issues (it is not nearly as safe as the HTGR) and a severe proliferation risk.

The MSR concepts do offer a number of unique options in terms of safety improvements and improved fuel economy, plus reduced waste streams. However, its ability to achieve these goals is often heavily overstated by its supporters. Any such reactor and its associated prcessing plant would likely be expensive to build and slow to construct (again given the narrow range of the materials choice the design enforces on us). The thermal efficiency of any MSR type plant would probably be not much better than that of an existing nuclear plant (even with a Brayton cycle turbine) making it difficult to see a credible economic case for them. Also while safer than a LWR in terms of meltdown risks and LOCA scenarios, the MSR comes with its own particular safety problems, notably that graphite core (fire!), the risks of a burst pipe in the CPP, or indeed a leak of potential toxic and highly lethal gases. So all in all there may be a case for MSR’s, but it’s unproven at the moment and likely a much narrower case that its supporters would have you believe. Indeed probably the biggest enemy of the MSR or LFTR design is its own nutty cheerleaders who badly need to stay off the Kool-Aid. I’m still half wondering if some are secretly working for Greenpeace as part of some elaborate 5th column scam!

Fusion power offers a number of unique opportunities, but technology is still in the early stages of development and we’re along way from being in a position to even assess accurately the economics of Fusion, let alone actually build fusion reactors or even work out a time table for such construction.  Also, the current D-T fusion method will produce some small volumes of nuclear waste and our global usage of such a fusion process will be constrained by our stocks of lithium fuel to run the reactors, such that at best we could probably only hope to produce 8-20% of global energy from D-T fusion.

Small to medium sized modular reactors do offer a good deal more flexibility in terms of how nuclear power could be used and yet a further improvement in safety. However, it also comes with lower economies of scale and thus higher construction costs and worse a slower rate of reactor roll out (at least in the early days). We could claw back on these two issues by mass producing said reactors in large volumes but it is far from proven whether that would be economically viable and whether there is in fact a market for large numbers of small reactors.

As I outlined, it’s likely the case for small reactors is heavily overstated by its supporters and not nearly as large as they suggest. It would also require a major shift in public opinion which post-Fukushima is unlikely to be forthcoming. Most of the reactor designs we’ve reviewed would be wholly unsuitable for mass production (notably the MSR). Only a handful of PWR, BWR and HTGR designs would be feasible options.

Worse still, by and large mass production means “dumbing down” our reactor designs – and generally that means accepting a reactor that’s much cheaper to build but has a lower thermal efficiency, a higher rate of fuel consumption and produces larger volumes of nuclear waste. With the exception of a small number of narrow cases, it’s difficult to envisage how this would offer an improvement on the current status quo.

The Thorium cycle, as covered throughout these articles does offer the option of solving the long term fuel supply issues surrounding nuclear energy somewhat. But the level to which it will do this is fairly narrow, as Thorium fuelled reactors still need fissile isotopes (drawn from Uranium) for startup purposes, or they require the use of expensive (and generally uneconomic) fast reactors and reprocessing of spent fuel. So yes, while Thorium could help stretch things out, it can only help a little bit, not nearly as much as the supporters of Thorium reactors would have you believe. Thorium fuelled reactors would still generate substantial quantities of nuclear waste and come with a number of potential proliferation risks attached.

A proposal common to all Generation IV reactors, and some renewable power plant proposals (notably geothermal), is to use Brayton cycle instead of the Rankine cycle for power generation. This would offer a substantial improvement in terms of energy efficiency. However, there is still some work to do on this issue, and it’s entirely possible that cold hard headed economics could torpedo the whole thing. So I won’t write off the Rankine cycle just yet. Indeed from what I’ve recently heard about the proposed Chinese HTR-PM program, they are still wavering and may indeed install a Rankine cycle turbine in order to simplify matters.

Similarly, the higher material limits required to raise reactor operating temperatures up to the level necessary to utilize the Sulfur-iodine process could well render the whole idea uneconomic (if we want hydrogen that badly, build a reactor with a lower operating temperature out of cheaper materials, generate electricity and hook it up to a electrolyser!).

Future implications – curb your enthusiasm!

All in all my conclusion is that the case for future Generation IV nuclear reactors is much narrower than the supporters of nuclear energy would have you believe – even the case for Fusion doesn’t look that clear cut! And I would note that this last point about Fusion is important. The way the nuclear energy supporters, and indeed many politicians or members of the public go on you’d swear Fusion was already a slam dunk, nothing could be further from the truth!

The exact implications of these articles entirely depends on ones point of view. If you see nuclear energy as a small niche energy source that some nations with poor renewable potential might need to resort to using as a temporary crutch (while supplies of Uranium fuel hold out, or Lithium in the case of Fusion energy) while we get renewable resources up to speed, then this view is not seriously impacted by the above conclusions. Personally I see a global potential for nuclear energy no greater than its current market share of 1.9-5.1 % of global energy use ….but I also reckon that future energy use will probably have to be a lot lower post-peak oil, so on a kWh basis I see nuclear output going down substantially in the future not up (see my post here for more info on my thoughts on that). And of course any continued use of nuclear power will require the urgent tackling of the nuclear waste issue.

A reduction in global nuclear energy use would have numerous advantages. It would reduce the output of nuclear waste and stretch out fuel supplies for longer. The case for safer reactor designs (such as the HTGR or MSR) becomes stronger if the volume of power being generated is smaller as one can invoke the whole “its quality not quantity” argument. If we can get Fusion power cracked I reckon we might be able to get 10-15% of global energy output running off nuclear by the end of the century – thought I would immediately note that current global electricity consumption represents 14% of current global energy demand, so even that’s a pretty ambitious target.

But the supporters of nuclear energy want to get 20-50% of current global energy from nuclear power now and 50-100% with Fusion later (or 100% right now if you listen to the LFTR fans!). I put it to any of them that such targets are at odds with reality. There is simply not enough Uranium, Thorium or Lithium fuel in the world to run such a vast fleet of reactors and it would be physically impossible to build that many power stations within a reasonable time frame (e.g current annual energy use is 144 Trillion kWh according to the IEA, that’s 16,500 GW’s of generating capacity (@ 100% capacity factor) to meet 20% of global energy output with EPR’s would require ((16,500×0.2)/0.9)/1.6 = 2,292 of them!). Such a vast network of plants (with very short operating lives given how quickly we’d burn through global fuel stockpiles) would of course be wholly uneconomic and an enormous waste of public money. Even building a smaller scale fleet of reactors, replacing our existing LWR fleet with Thorium burning HTGR’s for example would probably be too costly and too slow to be seriously considered. And the attitude to nuclear waste seems to amount to “well I’ve got these coffee cans here, lets just store it in those and forget about it”. That drastically needs to change. Some countries are building up a very large and dangerous legacy of waste that’s going to haunt them for generations to come.

Nuclear energy supporters need to curb they’re enthusiasm for nuclear energy and accept it will always only ever be a small bit player in a big energy market, at least as far as the current century is concerned. This of course means we’ll need to rely on renewables for substantially more energy than we currently get from it. Which means nuclear energy supporters need to overcome their pathological hatred of renewables (or CHP) and stop the various “dirty tricks” they are up using to torpedo renewables roll out. They only people who benefit from such skulduggery are the fossil fuel lobby and global warming deniers.

The people must be on board

 Indeed one of the biggest obstacles to nuclear energy is this democratic deficit. In almost every situation the nuclear question has made it on to a ballot paper and been presented to the will of the people the answer has been a firm NO! In the recent referendum in Italy it was No (or yes the way the referendum question was phrased) by a margin of 94%!

If nuclear power is to have a future then its supporters need to address this democratic deficit, and that means appealing directly to the people, not schmoozing and buying off a few naive (or corrupt) politicians in smoke filled rooms. It also means realising that the general public are much smarter than the nuclear industry often give them credit. There seems to me to be a very condescending attitude prevalent in the whole nuclear movement. A view that seems to regard the average guy in the street as too stupid to comprehend the issues and that he must therefore be manipulated, talked down to and in many cases lied too. Such tactics inevitably backfire.

Consequently exaggerating or over stating the case for nuclear is not only dishonest and unethical, but actually unwise in the long run. You will enviably be “found out” one day by the public and the case for nuclear will be worsened as if there one thing the public dislike its being lied to or manipulated. As the situation in Germany proves there is a tipping point to public patience on this issue and once you exceed it there is no going back. All the logical arguments (or scare tactics!) in the world will be useless beyond that tipping point.

If any alternative to the mega-LWR “death spiral” that the nuclear industry is currently caught in is to be realised, that will require public support as it will be the public’s taxes who’ll pay for the research and the public’s back yards that these new reactors will be built in (smaller size equals more reactors spread out over a wider area).

Pragmatic thinking

Of course opponents of nuclear energy would say, its seems like and awful lot of trouble to go to for a little bit of electricity. Given all the problems associated with nuclear won’t we be far better off focusing on upping the mass production rates of renewable systems?

While acknowledging they may well have a point here, indeed I noted in a prior post that more widespread use of CHP could in certain countries greatly reduce or eliminate the need for nuclear energy altogether. I would counter that it’s again the “quality” of energy not the “quantity” that’s important, i.e. the fact that a single nuclear plant can generate large amounts of baseload electricity (and heat) on a reliable basis with a low carbon footprint. I see nothing wrong with keep existing reactors of an acceptable safety level (in countries with a good safe track record) running for the remainder of their service lives (the damage has already been done by and large), subject to an effective and “stressful” stress test post-Fukushima (what worries me is that such stress tests are likely to be somewhat stress free). I’d also certainly see the benefits of keeping our options open in terms of a few small research reactors of some of the Gen IV designs I’ve just reviewed, just in case (run by government R&D departments and universities rather than corner cutting corporations of course). I’d also point out that a good deal of this associated R&D would be into material science and advanced manufacturing methods (which could benefit renewables roll-out), so it wouldn’t be a total write off if these reactors were never taken beyond the concept level (and my suspicion is, they won’t). Certainly Fusion power research, despite my misgivings should be continued. You won’t win the lottery if you don’t buy a ticket! But certainly even these modest goals I’ve outlined will only be possible if public support is forthcoming, the public finances can afford such projects and inevitably even in the best case scenario the vast bulk of future energy will have to come from something other than nuclear.

But the nuclear supporter will say, can renewables close the gap? Can we seriously power the world without fossil fuels nor nuclear power? I’m going to take the cowards way out and answer that I honestly don’t know! The answer to that question depends entire on the context in which one asks it (I’m planning a future article where I will tease this one out). While I’m quitely confident about the potential for renewables, I’m not going to make the same error of the many nuclear industry supporters and make promises or assumptions that I can’t back up with facts.

But clearly, as regards the current discussion, we cannot run the world on nuclear energy; indeed we’d struggle to meet a tiny portion of global energy needs, for any prolonged period (and I mean a lot less that we currently manage!) with nuclear power, neither generation IV reactors, nor Thorium, nor even Fusion power will help much on this point. Even the most optimistic nuclear energy program we can realistically conceive of still has a substantial energy gap that something else will have to fill. And given our limited fossil fuel supplies (long term at least) that inevitably means alot more renewable energy, which has to take priority over nuclear.

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About daryan12

Engineer, expertise: Energy, Sustainablity, Computer Aided Engineering, Renewables technology
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10 Responses to Part 11 – Summary and Conclusions

  1. Pingback: » A critical analysis of future nuclear reactors designs

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  3. dark says:

    I read a few comments you’ve made about LFTR.

    You state LFTR should not be cycled. My understanding is that the reaction self cycles up when you release heat the salt increases density increasing fission, and that this cycle functions on the order of 10 minutes to stabilize. This could be to slow compared to natural gas so perhaps natural gas would make a good supplement?

    You state LFTR units will cost more than LWR. I have to ask why? I understand the claim to cost savings due to the pressure reduction and using a less costly but less efficient turbine. Do the costs of higher operating at higher temperature add that much or the chemical processing equipment? How does this compare to the cost of equipment to produce new and store used fuel rods?

    You state LFTR must use a carbon core creating a fire risk. I’ve seen reference to neutron resistant alloys that have fewer problems than the carbon cores. Is there some problem with these metals?

    You state U233 can be separated easily from the materials that make it difficult to use as a weapon material. My understanding is that the production of U233 results in some U232 production which can’t be separated chemically which is the convenient way LFTR purifies its material. Do you know an easy way to isolate isotopes of the same element? My understanding is the U232 produces a hard Gama-ray emission is there a simple way to deal with that problem?

    I am a LFTR fan. I hope that LFTR works out. I know we’ll never solve the problems if we don’t try. I’d rather try and fail than give up and fail.

    • daryan12 says:

      Apologies for the delay in getting this post up, I’ve note checked out this blog in weeks and been away the last few days. Also note the main discussion page on this matter is in the link below.

      I bring this up because about a hundred spam’s followed in on your coat tails, so I might have to disable this comment string in future to stop me being snowed under (this happens all the time to a well trafficked site I’m afraid!)

      Anyway, the point I’m trying to make about LFTR’s is that it is in the early concept stage of design. Many of the supposed advantages of them are as of yet unproved, or indeed highly dubious. For example, you mention power cycling and stabilization within 10 minutes. And when was that proven for a 1 GW commercial scale reactor? Do you have a reference to back that up where someone has shown it’s theoretically a possibly? (Journal paper, mind not a youtube video!). Basing our entire future energy strategy on an as of yet unproven technology would be a fairly audacious gamble.

      You mention costs, as I point out several times the whole nuclear industry is currently geared towards building LWR or Gas cooled reactors out of more conventional materials. Furthermore as I point out in section 10 if you want to reduce the costs and speed up production of any product the strategy is usually to simplify the design and use cheaper materials, the LFTR amounts to doing the opposite, a more complex design using more exotic materials.

      The point I make about non-proliferation is that it is as much a political matter as a technical issue. The Fast reactor program in America remember was killed because of the proliferation issue (at least officially anyway!). It would be foolish and naive to ignore this. Also this hard gamma emissions of U232 creates technical problems for the LFTR reactor and separation plant design. One of the things that they’ve been trying to do with conventional reactor design recently is reduce the use of any potential hard gamma emitting elements as they are a bit of a bugger to dispose of.

      I would note that I also do state at the end (section 11) that I see nothing wrong with continued research into the LFTR, although I’ll admit that my suspicion is that said research will merely confirm my worst fears are true and allow us to confine the LFTR to the text books of history (as well as generating useful science that can be recycled and used by other fields, Molten salt solar systems or Brayton cycle Geothermal plants for example).

      Finally, the most damning indictment of the LFTR I’d say is the attitude of the mainstream nuclear industry. I know people who work in the industry and they are if anything even more hostile as regards LFTR’s than I or any environmentalist! While they are keen on the Thorium cycle they would prefer to focus on using it in Gas-cooled reactors and existing HWR or LWR’s instead. Of all the so-called generation IV designs the LFTR seems to be the one furthest from commercial maturity and the one with the least amount of investment in it by the nuclear industry. Now I wonder why? Is it perhaps because they worked out what I’ve said in this post along time ago?

  4. fireofenergy says:

    You say, in regards to LFTR, “there is not enough thorium”. Untrue (I thought you were scientifically adept at this debate).
    I found it true that LFTR parts would most probably need frequent replacements, however, that should not prevent the best way to power planetary populations into the tens of billions as the reduction of wastes (per unit of energy) is reduced to like below 1% of that of the water cooled reactors which I do NOT agree with.

    Solar is the only other source that could power 10 billion people living at near Western standards using about 2% of the land area (just1% if GaAs fresnel arrays were used). But only through advanced machine automation could it ever be cheap enough!
    We DO need such robotic factories to make the LiFePO4 battery (or better) so as to electrify the fleet (and thus address the valid concerns over XSCO2). Both nuclear and solar ambitions REQUIRE that.
    Wind can power a planetary population too, but it also needs the batteries.
    All the other RE schemes can not… except possibly, algae. Thus their contribution should only be considered as a requirement for furthering the scientific knowledge base (and for off grid applications)
    Cellulostic is a loser (cell u lose) because once initiated on the large scale, entire forests could be wiped out into the conversion of “just some more” liquid fuels.
    FF’s obviously are a dead end
    And, again, conventional nuclear pits opposing physical forces within INHERENTLY unsafe constraints among other disadvantages such as very low fuel efficiency and very high waste streams.
    Fusion is not here yet and cold fusion is just a hoax, so…

    “What is the best way to power growing planetary populations”?
    LFTR and its kind, of course…
    Why? Because only about 5,000 tons of thorium would displace the many Billions of tons of FF’s and the 85,000 tons or so of uranium needed to power humanity every year.

    Thus THIS is LFTR’s major downfall. Why would any profit seeking entity want that!

    • daryan12 says:

      Apologies for the delay in getting this post up, I’ve been fairly busy the last few days. Also note the main discussion page on this matter is in the link below.

      “not enough Thorium” I refer you to the pro nuclear Prof David Mc Kay. He gives two sets of figures, one involves the known reserves of Thorium, a smaller figure supported by the World Nuclear Association estimates on Thorium, and another speculative ones based on “possible” future technologies, which don’t yet exist. His realist figure of 4 kWh/person/day is about 3.2% of UK energy demand, and even the highly optimistic 24 kWh/p/d is but 19% of UK energy demand, where does the other 96.8-79% of the energy come from?…oh! and Americans consume about 2-3 times more energy than the average European so even these numbers are likely to be overly optimistic!

      “solar….only through advanced machine automation” You’re point is countered by looking at the modern world. Everything around us, including the computer in front of you represents the enormous power of mass production and its ability to run off a product, at an affordable price by the tens of millions. One of the nice things about many renewables technologies is that they are very conducive to mass production – solar pv riding on the coat tails of the electronics industry. This is why output of renewables topped 100 GW’s of new installed capacity in 2010 (nuclear only ever managed a maximum of 30 GW’s back in the 70’s, currently nuclear is fighting to build reactors globally as quickly as they are decommissioned). Solar energy installation capacity almost doubled in a year with no reason to doubt it won’t do this again next year.

      Click to access REN21_GSR_2010_full_revised%20Sept2010.pdf

      By contrast, as I point out in chapter 10, nuclear reactors aren’t easy to mass produce. An important step in making something ready for mass production, is to compromise the performance for the sake of increased production at cheaper rates. That’s why a Ferrari costs you £250,000+ while a Nissan Skyline costs £40,000 even tho the Skyline’s top speed is only about 25% less than the Ferrari’s. You’re paying thro the nose for only a modest improvement in performance.

      You could maybe “in theory” mass produce a smaller nuclear reactor, I speculate on a civilian versions of a military PWR or BWR or a HTGR and how they could be mass produced in chapter 10. But crucially, you’d have to sacrifice performance for reduced costs and increased production volumes (meaning you’re reactor would be less efficient than existing plant and ultimately produce more nuclear waste not less!). Unfortunately the LFTR, with its complex network of pipes in the CPP and use of exotic materials (various Nickel alloys, again issues here discussed in Chapter 3) would be very difficult to mass produce, if not impossible…and that assumes the technology actually works to begin with!

      Incidentally, current mass production theory strikes a balance between automation and human operators, as heavily automated plants often cost more and have lower production efficiencies compared to other plants that strike a balance – too many robots spoil the broth it would seem!

      “FF’s obviously are a dead end”
      I wish what you’re saying was true, but unfortunately there’s still ample supplies of fossil fuels in various “unconventional” deposits worldwide. The major point the “peak oil” theorists are getting across isn’t that we’re “running out”. its that supply may no longer be able to match demand, forcing us to down size our FF energy use…but there’s still enough of them left to do a lot of damage! I’d gladly take bets with you that we’ll still be using FF’s in 300 years time…if either of us would be around for me to collect! That’s why I favour being realistic and promoting energy efficiency, CCS and CHP technologies as we may as well make the best of a bad situation.

      “5,000 tons of thorium would displace…”
      IF LFTR technology actually works as well as its online supporters believe it will! As an academic with access to scientific journals I see a distinct difference between the “MSR’s” proposed by “real” scientists working on this technology and the bloggers online promoting LFTR’s. The academics are much more cautious about the potential of such reactors (they recognise its still a blue sky idea and that they need to prove the concept) and the pace at which it can be realised. Over selling an idea is the one sure fire way to make sure no corporation nor research institute will ever fund you!

      Even Thorium doesn’t rate highly for the mainstream nuclear industry. Even the NNL seem to pour cold water on it here.

      Click to access nex__1294397524_Thorium_Fuel_Cycle_-_Position_.pdf

      And the head of the NNL goes further and pooh-poohs the LFTR itself here!

      One pro-nuclear energy supporter here in the UK let slip to me awhile ago their mood as regard Thorium (HTGR’s being their preferred choice rather than the LFTR….notably because they actually work and the technology was proven, with Thorium powered runs by the Germans back in the 1980’s). To him its an “insurance policy” in case Fusion doesn’t turn out to be as clean and cheap as they thought.

      “Why would any profit seeking entity want that!”
      As I point out in section 4 on PWR’s many of the conspiracy theories dreamt up by LFTR fans regarding Weinberg and the favouring of LWR’s over LFTR’s simply do not add up to rational scrutiny. I know people who work for investment firms and major energy utilities and believe me if LFTR’s actually worked as well as you claim, they’d be trying to build them. Clinging to and promoting such conspiracy theories merely makes LFTR fans look like cranks and all but guarantees nobody in a position of authority will ever take you seriously, so take my advice and drop the martyr routine!

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