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 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).
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.