Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Twitter Facebook YouTube Pinterest MeWe

RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

What role for small modular nuclear reactors in combating climate change?

Posted on 1 October 2021 by greenman3610

This is a re-post from Yale Climate Connections

Does the potential of small modular nuclear reactor technology make it a viable approach to helping solve climate change challenges not fully met by renewable energy sources such as wind and solar?

Experts interviewed in this Yale Climate Connections “This is Not Cool” original video in some cases hold out hope. But they also confront timing, economic, and communications obstacles that could be prohibitive.

Other Lab Chief Executive Officer Saul Griffith voices what he characterizes as “an extraordinary position … but hopefully not too extraordinary a postilion.” Nuclear energy, Griffith says, “has been pretty reliable and very safe and compared to other energy sources, all told, reasonably priced …. and good.” But he backtracks some: He readily acknowledges “huge political headwinds” and concerns about availability of adequate cooling water supplies, a view expressed also by water resources expert Peter Gleick. Griffith points to what many – among them proponents of nuclear energy – fear may be an Achilles heel: “It’s unclear if safe and reliable nuclear energy can compete with just where solar and wind are going …. That’s the reality.”

University of California Berkeley nuclear engineering professor Daniel Kammen says he’s hoping nuclear energy can fill some needs that renewables may not resolve. But he points to a stiff “learning curve.” In addition, Kammen says “There’s more work to be done on nuclear than on any other area for it to be a competitor.”

Less optimistic on the new nuclear technology is Arjun Makhijani of the Institute for Energy and Environmental Research. He says small modular reactors are attracting a lot of interest in part because “big ones have failed.” He is concerned by projections that the reality of small modular nuclear reactors may be close to a decade away. Too long a wait, Makhijani says: “We must have overwhelming momentum to zero carbon energy by that time.”

In the other corner, as one might say of a prize fight, is Microsoft founder Bill Gates, a bit more optimistic – or at a minimum more hopeful – than the others: “Nuclear power can be done in a way so that none of those nuclear failures of the past would recur because of just the physics” of small modular nuclear design.

“Convincing people of that may be just as hard as actually building it,” Gates tells CNN’s Anderson Cooper. But nuclear power “may be necessary because of climate change, so we shouldn’t give up.”

1 0

Printable Version  |  Link to this page

Comments

Comments 1 to 49:

  1. All nukes at any scale suffer from:

    1) solvable in principle but unsolved waste disposal in the US, 2) operational hazards due to operator error, 3) leakage of radioactives into the water supply due to maintenance failure, 4) the possibility of radioactive spills in transit, 5) the possibility of theft of fissionables to make a dirty bomb, 6) the possibility of theft of fissionables to make a nuclear bomb.

    All these issues will get much worse if we start to distribute lots of small reactors over the landscape. The resources of the companies involved will not be adequate to secure them, their operations or waste disposal.

    Waste disposal can be solved for a time by the right reprocessing and burial, as is going on in Sweden, Norway and France, but we have repeatedly failed to do this in the US for political reasons. Also we should be spending money to put together a reprocess that converts the fissionables and radioactives to safer isotopes using accelerators or nukes, powered by waste fuel and renewables, lowering required times of storage integrity.

    We should convert cooling from water to air. The technology exists and should be used as it is less prone to catastrophic failure. It would also free siting to be almost anywhere, not limited to vulnerable coastlines.

    Lots of mini-nukes is a bad idea. Put effort into improving what we have on a larger scale. If we build new large ones set the size to 500mwe or so and make them all to the same design to gain feature standardization, operating reliability and load following flexibility. Don't build mini-nukes.

    2 0
  2. Something on the alleged advantages of small modular reactors:

    www.energy.gov/ne/benefits-small-modular-reactors-smrs

     

    There do seem to be some moderate safety advantages in these reactors and they supposedly can't melt down. This is a big plus if it's correct, but I agree that with so many of these reactors you might end up with a proliferation of smaller but still troubling problems. It might be one step forwards and one step backwards.

    0 0
  3. Doing a little background reading on modular reactors I found this:

    "The Guardian reported in October 2018:22

    "Backers of mini nuclear power stations have asked for billions of pounds of taxpayers' money to build their first UK projects, according to an official document. … But the nuclear industry's claims that the mini plants would be a cheap option for producing low-carbon power appear to be undermined by the significant sums it has been asking of ministers.

    "Some firms have been calling for as much as £3.6bn to fund construction costs, according to a government-commissioned report, released under freedom of information rules. Companies also wanted up to £480m of public money to help steer their reactor designs through the regulatory approval process, which is a cost usually paid by nuclear companies. ...

    "David Lowry, a nuclear policy consultant who obtained the document, said: "SMRs are either old, discredited designs repackaged when companies see governments prepared to throw taxpayers' subsidies to support them, or are exotic new technologies, with decades of research needed before they reach commercial maturity.""

    The so-called Expert Finance Working Group on Small Nuclear Reactors in the UK laments "the financing sectors potential misunderstanding of nuclear specific risks and how such risks can be mitigated, and that nuclear specific risks aside, nuclear energy projects are no different to any other energy project."23 The finance sector might be in need of education on nuclear-specific risks, but its disinterest in SMRs suggests a clear understanding of the likelihood that they would be uneconomic."my emphasis source

    Nuclear reactors are not economic.  Baseload power will be of very low value is a renewable energy world.  Peak power on windless nights will be most valuable.  They do not address the lack of rare materials, like uranium, needed to produce a significant amount of nuclear power.  Most of the remaining problems in Abbott 2012 are also not addressed.  Without enormous government subsidies they cannot compete with renewables.

    0 0
  4. I have been designated as editor for a series of articles on small modular reactors. The focus is to be on the issues of safety, waste management, weapons proliferation, and cost.  We have the first article ready for review.  https://citizendium.org/wiki/Nuclear_power_reconsidered 

    This top article asks the questions. We have asked companies that are working on new reactor designs to answer these questions in an article that they will own.  Critiques and independent analysis will be included on a discussion page for each design.

    We have a response from one company, ThorCon Power LLC. The others are still just stub articles.  https://citizendium.org/wiki/ThorCon_nuclear_reactor

    Comments will be appreciated.

    0 0
  5. There are two main "political" arguments against nuclear reactors as an avenue to decarbonization of our electrical power supply: 

    1) They are too expensive and take too long to build, whereas solar and wind are cheap and quick. 

    2) They are dangerous because of the possibility of radioactive materials escaping into the environment. 

    Let's examine these arguments: 

    A modest wind farm costs about $15M, takes about 2 months to install and generates about 15 MW of power when the wind blows.  That's $1/W at best.  The installation is quick because wind turbines are being mass-produced in factories already.  It would take a lot longer if every wind farm had to be built "from scratch" the way reactors have been in the past.  The USA has been adding about 20 GW/year of wind capacity, and now has a net wind capacity of around 150 GW at a net cost of around $150 billion.  To reach the total national power requirement (490 GW) should take about 17 years and cost about another $340 billion.  We may want to increase the total capacity to account for windless days. 

    Prototypes of the proposed SMRs (Small Modular Reactors) are now under construction.  Once factories are built to mass produce them the way wind turbines are, proponents predict, a new 300 MW SMR can be turned out every 4 years (per factory) at a cost of about $1.5 billion each.  Thus it would take over a thousand new SMRs at a cost of around $1.7 trillion to take over the capacity now supplied by other means.  Worse yet, if there were only one supplier with one factory, it would take 4,000 years.  So obviously we'd need 100 such factories to get it done soon enough to help.  

    Of course, the operating lifetime of a reactor is at least half a century; wind turbines last at most half that long before they need replacing.  But my "back of the envelope" estimates tentatively agree with the RE claims.  Let's do both, and install appropriate power where needed. 

    Now, as to the hazards of radiation... please see https://citizendium.org/wiki/Radiation_Hazards

    1 0
  6. A recent paper published in PNAS titled: Nuclear waste from small modular reactors analizes the waste streams from small modular reactors.  The short answer is that SMR's produce much more nuclear waste than the large reactors currently running.  In adition, much of the waste is in the form of reactive molton salts and liquid sodium.  These reactive wastes have no methods of preparing them for long term storage.  

    Claims by the nuclear industry that SMR's will produce less nuclear waste are simply industry propaganda.  I was stunned to learn that no process exists to convert much SMR waste into materials that can be long term stored.  The DOE plans to entomb in place the molten salt reactor built in 1969 because they have not been able to develop a method of stabilizing the left over salt mix for long term storage at an offsite location.  

    This paper is very techical but the basics can be understood by a careful reader.

    0 0
  7. macquigg:

    The answers to questions about waste in your discussion section on the ThorCon reactor run the gamut from evasive to deliberately false.  ThorCon presents no plan to deal with 137Cs and says only that they will process most waste offsite.   I expect that you will add the information from the nuclear waste paper cited in comment 6 to your general post on MSR's.

    MSR's are uneconomic and the materials to build out a significant number of reactors do not exist.

    0 0
  8. Michael Sweet, what specifically is "deliberately false"? On Cs-137, did you read their section on safety? "The most troublesome fission products, including iodine-131, strontium-90 and cesium-137, are chemically bound to the salt." 

    I will add the paper you cite to the Bibliography page, but to include it in the Discussion page, we need specific challenges to this design, not general speculations about all MSRs.

    I started to read the article you cite, and it looks to me very similar to other general complaints that lead to endless arguments on FaceBook forums.  I read that there is some problem with neutron leakage, and it makes no sense to me.  Do any of these complaints apply tp this design?  I will then get a response from the company.

    On the question of cost, did you read that section?  It looks to me like they have done a thorough analysis.  They are saying they can deliver a complete nuclear plant, reactor, turbines, generators, switchgear, everything, for $1200 per kW, lower than the cost of a coal plant.  Anyway, it seems like a waste of time to debate cost.  If a vendor offers a product you want, at a price you like, don't tell him he is wrong about his own design, place an order.

    0 0
  9. There is a response to the PNAS article from NuScale, one of the reactors featured in the Citizendium series:   https://newsroom.nuscalepower.com/news/

    I think we might get a similar response from the other companies, but before I bother them, lets see how this one pans out.

    0 0
  10. A buch more responses. NAS not looking good.  neutronbytes.com/2022/05/31/stanfords-questionable-study-on-spent-nuclear-fuel-for-smrs/

    0 0
  11. From ThorCon: 

    "All fission reactors produce essentially the same amount of fission products per thermal energy produced. This is immutable physics. Designs with higher thermal efficiency produce less fission products per kWh electricity produced, but this difference is less than a factor of two from the clunkiest LWR to the fanciest paper HTGR."

    I am not a nuclear engineer, and I did not spend more than an hour trying to understand Krall's article, but it seems like the whole thing fails on this one point.  What is wrong with the peer review at NAS?

    0 0
  12. Macquigg,

    I am too busy to write a full reply to your posts right now.

    A paper printed in the PNAS has much more wieght than propaganda released by nuclear plant companies.  Who cares what paid shills say compared to nuclear reactor designers with decades of experience.

    The issue with Thor Cons whining is that the paper clearly says that one of the major problems with small reactors is the high neutron leakage.  In post 8 you say you do not understand this problem and that it is endlessly discussed on facebook.  We have an clear answer to the facebook arguments: scientists think neutron leakage is a major problem.  The fact that you  do not understand it does not mean that it is not a problem.

    ThorCons answer that you quote is deliberately evasive.  Yes, the amount of fission products is about the same.  The high neutron leakage of their design results in the rest of the reactor becoming much more radioactive than happens in larger reactors wiith low neutron leakage.  The final result is much more radioactive waste that has to be permanently disposed of.  Thor Con ignores the claims made in the paper and argues using an answer that everyone who is informed already knows.  The ThorCon argument has no merit.

     Where I come from that is deliberate deception.

    I note that no process exists to treat the leftover salt mix in the Thor Con reactor. 

    In addition, ThorCon has 12 mol% Beryllium in its salt mix.  There is only one large Breyllium mine in the entire world.  From ThorCons' numbers I calculate that a single 1,000 MW  plant would use approximately 2.5 tons of Beryllium to start up.   Since total world production of beryllium is about 260 tons/year and ThorCons have to be replaced every 4 years, 400 1,000 MW ThorCons (approximately current world nuclear reactors) would use up the entire world supply.  You forgot to include in your summary that there are many elements that do not exist in sufficient supply to build out more than an insignificant amount of nuclear power. (always take calculations that have not been peer reviewed with a large grain of salt.  You could do the calculation yourself to check my numbers, if you know how.)

    ThorCons 137Cs claims also do not stand up to scrutiny.  Much 137Cs is carried out of the salt in the noble gas stream.  They have to say what they plan to do with the 137Cs that is mixed with their radioactive noble gasses.  If it remains in the salt they have to explain how that occurs.

    I suggest that you find someone who understands nuclear reactor design to moderate your thread if you want to correctly deal with the nuclear industry propaganda.

    If the bleeting from the nuclear designers has any merit they can write a letter to the editor of PNAS and it will be answered in time.  Until their letter is published we have to figure that the paper is correct.  

    I note that the rest of the responses that you have linked did not address the issue of increased radioactive waste even though that was what the headline in the newspaper was.

    It is difficult to discuss nuclear power on line since the proponents of nuclear consistently make false claims.

    Nuclear power is too expensive and the elements to build out the reactors does not exist.

    0 1
  13. Michael Sweet, I understand that you are busy, and not enough time to thoroughly research these issues.  Me too. I know that the "propagandists" who are designing the new reactors are even busier than us, and I don't want to bother them with this debate.

    Let me suggest that we avoid a long debate with lots of ad hominem, argument from authority, etc., and just focus on a few of the most important questions.  I will get expert responses to any issues you care to pursue.  What I need from you is a short statement on each issue, exactly the way you want it to appear on one of our Discussion pages. I will give you the same control over your statement that the "propagandists" have on the content of the articles on their own reactors.  You will also have the opportuntity to modify your statement after you see their response. We need a short point-counterpoint on any unresolved issues.

    On the issue of increased nuclear waste from the ThorCon reactor, I understand you think the company's response is "deliberately evasive". It looks to me like they responded perfectly to the issue as stated. I quoted the criticism directly from the abstract of the Krall paper.

    Perhaps you would like to restate the issue, emphasizing what you think they are evading.  If you are worried about non-fuel waste, that is a separate question, already addressed on the Discussion page.

    1 0
    Moderator Response:

    [DB] Hotlinked URL.  Please learn to do this yourself.

  14. Macquigg,

    I applied to Citizendium but they have not sent me anything after a week.  On mature reflection, I do not have time to explain reactor safety to the entire internet.  I try to respond to people who post obviously false information on this website.  

    I have already stated above that Thor Cons' response to radioactivity in the paper is deliberately false.  Obviously you do not understand the facts of the case.

    In the abstarct of Krall et al 2022 it says:

    ""the intrinsically higher neutron leakage associated with SMRs suggests that most designs are inferior to LWRs with respect to the generation, management, and final disposal of key radionuclides in nuclear waste." (my bold)

    This means all the radionuclides in the reactor i.e. the fission products and the reactor components rendered radioactive by neutron bombardment from high neutron leakage.  The paper states clearly that reactor developers have not reported the amount of reactor components that become radioactive.  The paper then claims that the reactor components are a major part of the waste chain and must be calculated.  Obviously all radioactive waste has to be disposed of.

    This calculation should have been done by reactor designers but they have been negligent and not provided this data.  Why have the designers hidden this damaging information?

    According to you, Thor Cons' response is "All fission reactors produce essentially the same amount of fission products" (my bold). Thor Con deliberately ignors the entire point of the PNAS paper.  The extra waste is the irradiated steel and other reactor components.  Where I was raised that is deliberate falsifacation.  It is not my problem that you do not understand the quotes you post.

    In your discussion on Citizendum poster Lyle Elhaney posts a long comment claiming that iron does not become radioactive under neutron bombardment.  He concludes:

    "Other materials - some do become radioactive when drenched with neutrons for an extended time. One would need to know what materials to analyze what happens."

    Krall et al 2022 now tell us.  The other materials cause a great deal of problems.  For one example, 58Ni is present in large amounts in the 316 steel and is converted into radioactive 59Ni.  There are other problematic isotopes formed.  Analyizing the iron alone deliberately minimizes the problem.  The comment should be updated to reflect that peer reviewed scientists think this is a big problem.

    Roger Bloomquist states:

    "There are small concentrations of activated structural elements like cobalt. These typically have half-lives of years, not multiple decades"

    The 59Ni mentioned above as one of the major isotopes formed in the irradiated 316 steel has a half life of 72,000 years.  Since it will have to be isolated for over 10 half lifes to decay that is over a million years. Where I live that is way more than "years".   Bloomquists post is false and should be deleted.  A new post stating that the radioactive steel will have to be stored for over a million years should be put in its place.

    Nuclear designers have been claiming since 1950 that nuclear power will be cheap and safe.  They have failed to produce on their promises.  You are obviously new to this conversation.  I suggest that you carefully read Abbott 2012 (referenced on citizendium) which gives 15 reasons why nuclear power can never produce more than 5% of all power and Lyman 2021 "Advanced" isn't always better (white paper from the Union of Concerned Scientists).  I spent two weeks reading Lyman and several hours reviewing it for these posts so I am unsympathetic to your using an hour reading Krall et al. 2022.

    Neither you nor Thor Con has addressed my point that there is not enough beryllium to build out more than a few Thor Con reactors.  I would like to see how they calculate that a disposable reactor that only lasts 4 years can compete on price with a wind generator or solar farm.  I note that they claim only that they can produce electricity as cheaply as coal while wind and solar today are cheaper than coal.

    Nuclear power is uneconomic and the materials to build the reactors do not exist.

    0 1
  15. Michael Sweet, thank you for your detailed response. I understand your reluctance to debate "the entire Internet", and I am OK working with you in this forum.  I will even put up with your personal attacks, if there is enough substance to your criticism to make it worth my time.  Your comment above is a mixed bag, but allow me to deal with one issue at a time, and we can come back to the others later.

    1) On the issue of fuel waste, we seem to be in agreement that all reactors have the same amount of fission products generated per unit of thermal energy. That seemed to me the main criticism, which I quoted from the abstract of the paper. Unless I got this wrong, let's move on to the next issue.

    2) On the issue of non-fuel waste, I've spent several hours trying to get a clear concise answer to the general question, and what we have is too much generality, not addressing the question head-on for this particular reactor.  I will relay your comments above to ThorCon, and to others on Quora.com, where I got the other answers I posted. I will ask ThorCon specifically - What happens to the "343 tonnes of irradiated steel (one of the 4 "cans") shipped out for refurbishment" stated in their article under the heading "Average per year for a 500 MW plant:" I don't think they are being evasive.  More likely, they just didn't see it as a big problem.

    3) On the issue of cost, again I think this issue can be left for buyers and sellers to resolve.  If ThorCon says they can deliver a complete plant at $1200 per kW, don't argue with them.  Place an order.  Don't talk about the cost of old PWR designs, and don't assume that other countries will have the same regulatory burdens as the USA. Don't compare costs to wind and solar without storage.

    4) On the issue of materials resources, specifically beryllium, I will ask ThorCon.  I did read a discussion on this forum about a point in Abbott 2012, on the supply of hafnium.  Most reactors, even the old PWRs don't need hafnium. That should have been caught by the reviewers of Abbott's paper.

    5) On Lyman's major point that all MSRs require online processing (thereby posing a proliferation risk) what happened here?  Either the MSR designers have made a major error, or Lyman's paper is another example of failed peer review.  Elysium says their FNR can go 40 years without reprocessing (fast neutrons are amazing).

    Skeptical Science has been an excellent forum on climate change, the best in my opinion.  I hope it will be the same on nuclear energy.  Put aside politics. Get to the facts.

    0 0
    Moderator Response:

    [DB] Please refrain from personalizing things and from false claims of ad hominems.  The moderators review every comment here, perhaps not always in real-time, but inexorably, like gravity.

  16. Macquigg,

    In general, nuclear discussions on the web often degrade into repetitive posts with no conclusion.  It seems to me that this discussion has reached that point.  The comments policy of SkS is to refrain from repeating yourself once you have made your point.  I will address your numbered points above.

    1) As I have described in post 14 above, you are mistaken about what the abstract of Krall et al 2022 says.  Please reread post 14.  Krall et al say that the total radioactive waste from modular reactors is greater than current reactors, not the fission products only, like Thor Con claim.

    2) Krall et al 2022 tell us that the issue of non fuel waste is a big problem.  They also tell us that the developers have hidden this problem from public view. 

    In order to address this problem the developers of the reactors must release a complete analysis of their nuclear waste production including a complete discription of how they did the calculation.   A new press release or email to the internet is not satisfactory.  Why would a press release mean anything when we already know that they have hidden this problem from us for years?

    3) Nuclear developers have lied about costs since 1950.  Why would you think that I will believe them now?  Why are you so trusting of people who have lied to us for your entire life and more?  The reactors currently being built in Georgia were projected to cost $14 billion.  They are now projected to cost $34 billlion and customers have paid additional billions of interest.  Tell me more about cheap nuclear reactors.  I note that 15 years ago all the small modular reactor developers said they would have designs by 2020, where are those plans?

    4) Reactor developers must provide tabulations of all rare materials used in their construction.  This data is currently kept secret.  I noticed the beryllium issue.  

    Apparently nuclear supporters on the internet say hafnium is not used in current reactors and discredit Abbott 2012 because of this issue.  The nuclear supporters are wrong here, not the peer reviewers of Abbott 2012.  Hafnium is used in the control rods of most or all current reactors. 

    Nuclear supporters have not accurately quantified the amounts of rare materials used in reactor construction so it is not possible to determine which materials will be the first to run out.  Supporters of renewable energy proved that the materials to build out an entirely renewable system exist after nuclear supporters claimed the materials did not exist.  Nuclear supporters cannot prove the materials exist since nuclear developers keep secret the materials they use.  Your claim that hundreds of years of uranium exist (on another site) is incorrect, read Abbott 2012 again until you understand the issue.

    Criticizing peer review makes you look very bad on a scientific site like Skeptical Science.  Especially since I have shown you to be incorrect on your issues where you criticized peer review.  I suggest that you stop with this argument since it makes you look like you don't know what you are talking about.

    5) Lyman only says reprocessing is required if the reactors want to reach the fuel efficiency that they claim.  You are wrong.  Since Lyman is a white paper it was not formally peer reviewed, although I am sure it was informally reviewed.  When you critize peer review you look like you do not know what you are talking about. 

    If you want to claim that Lyman says all MSR's require reprocessing state the page number where the claim is made.  I reread the entire section on MSR's and did not see the claim you suggest.

    In post 8 you say you do not understand neutron leakage.  That means that you do not know much about nuclear reactor design.  Then you criticize peer review by people who have devoted their entire lives to reactor design.  Does that really make sense? 

    0 1
    Moderator Response:

    [BL] Please try to tone it down a bit.

  17. Michael Sweet,

    My time is limited and I share your desire to avoid unproductive debate. I am an editor working with two warring camps, looking to find the best obtainable version of the truth. I am not a nuclear engineer, but I do have a lifetime of experience working against junk science in industry, academia, in Federal court, and in politics. I have even used this site as a resource in a debate with a sophisticated climate science denier
    groups.google.com/g/az-2-forum  Everyone could see he had lost the debate when all he could do is call the basic science on this site “propaganda”. Let’s not call these nuclear engineers liars, but instead focus on the issues and get to the facts.

    I’m still working on point number 2, waiting for a response from an expert who has actual experience working with irradiated steel from nuclear reactors. I will then add that to our Q&A on non-fuel waste.

    I have added your comments on Cs-137 to the section on Radioactive Gases and on Beryllium to the section on LImited Material Resources. Let me know if you want to change the wording and avoid any ambiguity. We are trying to distill the best possible pro and con statements on each issue from all the blather on the Internet.

    0 0
    Moderator Response:

    [BL] Thank you for sticking to the issues.

  18. Macquigg @17 , thank you for your "groups.google"  link.  It was rather a short discussion between you and your antagonist, in 2017.  Your antagonist was severely irrational & ill-informed, and showed a stiff-necked hubris, typical of the crackpot type of science denier.  But at least it all had a modicum of politeness !   And I must add that your antagonist produced nothing of value for the exceedingly erudite and rational readers here at SkS.     ;-)

    Returning on-topic . . . it seems to me that it is rather too early to spend much time debating the usefulness of Small Modular Reactors.  At present they are Vaporware.   Perhaps in a decade there might be a small number up-and-running ~ but there are many impediments to their becoming available in sufficient numbers to make a timely difference to the global warming problem of this century.

    0 0
  19. Eclectic, I'm still waiting for a response from ThorCon on Michael's questions, and I will hold off until I get more substantive answers.  Meanwhile, we can discuss the timetable for SMRs.  They are definitely not vaporware.  China has one already on their grid. powermag.com/china-starts-up-first-fourth-generation-nuclear-reactor/

    My understanding of the urgency of global warming and the status of the nuclear and renewable rollout is that both can now proceed at full speed while we wait for a solution to the storage problem for wind and solar and for the finishing touches on advanced reactor designs. The limit now is economic - how quickly can the world build more of each to upgrade the fossil fuel plants we have now.  China is taking the lead, and will probably dominate this multi-trillion dollar market.  The USA, Germany, Australia and a few others will lag behind due to intense anti-nuclear sentiment in those countries, but the impact on progress against global warming will be small, because the demand for zero-carbon power will stay ahead of supply for many years.  If you are worried about production rate on existing SMR designs, take a look at ThorCon's plans. "The scale up rate will not be limited by shipyard capacity, but by the rate at which the turbogenerators can be built."

    0 0
  20. Macquigg @ 19 , thank you also for the info on those Chinese demonstration SMR's coming online later this year (2022).  A pair of SMR's of (electrical generation) approx 100 MW output each.  Not quite sure whether I would class them as Small MR or Medium MR size.

    I kind of take back my "Vaporware" comment ~ if I had written more slowly & thoughtfully, perhaps I might have found a more precise term.  Still, we must await the case when SMR/MMR's are coming off the production lines and are "hitting the streets" in the necessary large numbers, and at a commercially viable cost.  Remembering that the world's present electrical generation is roughly 3,000,000 MegaWatts and will need to increase about eight-fold by year 2050.  (Would a quarter of that have to be from SMR's ?)

    The Chinese reactors are described as using helium.  So they are not quite the low-tech / low material cost type that I was expecting.  Helium availablity & cost could be a big problem.

    0 0
  21. Macquigg:

    Krall et al have responded to NuScales' letter  (at the end of the article).  It appears that NuScales' letter is completely without merit.  I guess the reviewers at PNAS know more about nuclear reactor analysis than Nuscale does.  I am not surprised.

    You state somewhere that you want to post "what scientists think" and not nuclear propaganda.  It seems to me that you consider anything that shows nuclear weaknesses to be propaganda and accept false claims from industry as what scientists think. 

    I do not have time to respond on other forums to baseless complaints that scientists are biased against nuclear power.

    "What scientists think" is documented in the peer reviewed literature.  If you want to discuss nuclear rationally you need to consider and post what the peer reviewed literature says.  Krall et al 2022 is state of the art scientific thought. 

    Lyman 2021 is a 135 page, very well referenced report that summarizes what many scientists think about small modular reactors.  It is grim reading.  I suggest that you read it entirely, as I did, so that you know more about what you hope to moderate.  At least it should be linked prominently on your pages.

    On page 96 Lyman discusses MSR's that do not require reprocessing.  On page 97 he discusses the Thor Con MSR reactor which also does not require reprocessing.  Anyone who discredits Lyman with claims Lyman says MSR's require reprocessing is wrong.

    On page 91 Lyman discusses the accumulation of 137Cs in the noble gas stream of molten salt reactors.  Cite his discussion on your pages.  Lyman claims that there is too much radioactive noble gas to trap and store it as Thor Con claims they will do.  I will have to see peer reviewed calculations (the NRC is ok) that show it is possible to trap all the noble gasses before I will believe Thor Con.  I note that Thor Con keeps this data secret and refuses to say what they will do with the 137Cs that will accumulate in the noble gas waste stream.

    Abbott 2012 should be prominently discussed on your pages.  People who discount Abbott using claims that hafnium is not used in commerical reactors are wrong.

    Good luck in your efforts.  

     

    There is not enough uranium (and other rare elements) to build out a significant amount of nuclear power and the reactors are too expensive.  I note Eclectic's concern about helium.

    0 0
  22. Michael Sweet and Macquigg :-

       if you have time, please briefly educate me on the SMR choice of helium as a cooling medium.  Helium is expensive and finite in supply.  And so there must presumably be a good technical reason for its choice (as opposed to using the cheap and abundant noble gas Argon).

    Is it that the large size of the argon nucleus absorbs too much of the fissionable fuel's neutron flux, and thus reduces the SMR's fuel efficiency?  Or does the neutron flux convert the argon into undesirable radioactive potassium . . . or cause the argon to fission into other undesirable elements?  Or some other reason exists?

    (The mandatory 3-minute googling has failed me ! )

    0 0
  23. Eclectic:

    I found this:

    "Helium is an inert and transparent gas that eliminates most of the problems associated with the interaction of the refrigerant with the structural materials. In addition, it has no moderating effect on fast neutrons, which makes the GFR neutron spectrum the most resistant among fast reactors," source (there are several articles at this cite).

    The gas must be non-corrosive, stable at very high temperatures and low neutron cross section.  Carbon dioxide is also used but it is very high pressure (about 200 atmospheres versus 70 atmospheres for Helium) and decomposes over 700 C.  

    Gas cooled reactors are designed to breed more fissile material.  Since enough uranium does not exist to fuel large numbers of once through reactors, breeder reactors are designed to produce more fissile material.  There are many technical and proliferation problems with breeder reactors.

    In general, reactor designers are limited in the materials that have the exotic properties needed in the reactors. Rare and costly materials are widely used in nuclear reactors.  That is why I try to always put "the materials to build the reactors do not exist" at the end of all my posts on nuclear reactors.

    Nuclear power is uneconomic and the materials to build the reactors do not exist.

    0 0
  24. Michael, thank you.  As I feared, using argon as an SMR coolant is quite impractical, owing to the neutron-damping property of argon's large nucleus.  And using high-pressure CO2 limits the operating temperature range of an SMR (and I gather hot elemental carbon gas would degrade an SMR's structural materials).  So, a shortened life for an SMR.

    A dilemma.  Helium is "mined" from a finite reservoir of subterranean gas ~ with a supply from USA of about 40m cubic meters of gas, and a similar amount from Russian wells (at time of writing, a daunting political problem).   And a daunting political problem, to divert helium supplies away from usage by hospitals' Magnetic Resonance Imagers & the various other liquid-helium usages for cooling superconductors (unless someone invents the long-sought high-temperature superconductors).

    Back-of-envelope  :-  Present world energy usage about 180,000 TWh annually.  Roughly equivalent to 20,000 GigaWatts continuous, of which 15% is presently electrical generation (mostly with fossil fuels).

    For full electrification by year 2050 : say 30,000 GW generation, requiring 300,000 of the above-mentioned "demonstration" Chinese SMR's of 100 MW generation each.   

    Obviously we would struggle to produce 10,000 Chinese SMR's annually for the next 30 years, quite apart from the helium deficiency.  The nett-zero-carbon electric generation target would blow out past 2060 and 2070 . . . and beyond.   Even allowing these my wild guesstimates to be discounted by 75% of the total generation that may come from wind & solar generation.  (And maybe some biomass-derived fuels.)

    An uncomfortable situation, dollar costings aside.  Ignoring the helium question, it would seem that the future role of SMR's is likely to be tiny.

    0 0
  25. Michael Sweet @21: I will respond to your issues one at a time when I have some good information, so this may take a while. To keep track of where we are, I will continue the previous numbering, adding two more issues.

    2) Non-fuel waste.  I have a call in to an engineer who has had hands-on experience decommissioning reactors. What I am hearing from reactor designers is that irradiated steel is a trivial problem compared to the much more radioactive spent fuel.

    4) Material resources. I have posted your question on beryllium to our Discussion page. On the hafnium question, do we really need to worry about this?  Do you really think reactors can't be built with some other material in the control rods? Are you aware that some MSRs don't even have control rods?

    5) Lyman's statement about all MSRs requiring on-site processing. See below.

    6) The NuScale controversy. Looks to me like a miscommunication over an issue that doesn't really matter. They are arguing about maybe a factor of two at most in a volume of waste that is easily managed.

    7) Cs-137. I have included your critique on the Discussion page for the ThorCon reactor. Watch this space. [Link]

    ========

    Here is one issue I think we can be done with:

    5) Lyman’s claim that all MSRs require on-site chemical processing.
    Here is a fresh cut-and-paste from the Executive Summary of Lyman’s 2021 paper:
    “All MSRs chemically treat the fuel to varying extents while the reactor operates to remove radio-active isotopes that affect reactor performance. Therefore, unlike other reactors, MSRs generally require on-site chemical plants to process their fuel.”
    This statement is contradicted on page 102 with the statement “Some MSR concepts, such as ThorCon, would not have on-site reprocessing, but the company assumes that spent fuel salt would be sent off-site for reprocessing to recover unused fuel.”
    The point of this statement about on-site processing is to emphasize the risk of diversion of fissile materials from operating reactors. Reprocessing at a secure central location does not have this risk.
    It looks to me that Citizendium's handling of this controversy is correct. Most readers of Lyman’s paper will not get as far as page 102. They will be left with an incorrect understanding of MSR proliferation risk.
    [Link]

    ======

    I am having difficulty getting nuclear engineers to participate in this forum. One of them said he doesn't engage with belligerent sophomores. Another says they just ignore the greenies, they have no influence in the countries they are dealing with.  If you want this forum to continue its excellent tradition of good science above politics, please stop accusing nuclear engineers of hiding problems.  Assume that everyone is acting in good faith. Let's focus on the message, not the messenger.  Peer review is a plus, but honest mistakes are possible.

    0 0
    Moderator Response:

    [BL] Links activated.

    The web software here does not automatically create links. You can do this when posting a comment by selecting the "insert" tab, selecting the text you want to use for the link, and clicking on the icon that looks like a chain link. Add the URL in the dialog box.

    Also note that the specialty here at SkS is climate - and more specifically rebutting false claims about climate science. We have several people well-versed in climate science, but we do not generally have access to many people with backgrounds in nuclear power engineering. Your expectations of SkS expertise (an all-volunteer group) need to be kept reasonable

    To get an idea of the history of nuclear energy discussions at SkS, you can look at this post. This is not intended to cast aspersions on you, but to help you understand the path that nuclear "debate" has often taken, and why SkS regulars may respond the way they do. (The post is short; much of the history knowledge comes from reading the comments.)

    https://skepticalscience.com/NuclearEnergy.html

    Assuming that everyone is acting in good faith must a struggle when you find it difficult to get nuclear engineers to participate in your forum and they use phrases such as "belligerent sophomores" and "ignore the greenies", n'est pas?

  26. Michael Sweet @21: I will respond to your issues one at a time when I have some good information, so this may take a while. To keep track of where we are, I will continue the previous numbering, adding two more issues.

    2) Non-fuel waste.  I have a call in to an engineer who has had hands-on experience decommissioning reactors. What I am hearing from reactor designers is that irradiated steel is a trivial problem compared to the much more radioactive spent fuel.

    4) Material resources. I have posted your question on beryllium to our Discussion page. On the hafnium question, do we really need to worry about this?  Do you really think reactors can't be built with some other material in the control rods? Are you aware that some MSRs don't even have control rods?

    5) Lyman's statement about all MSRs requiring on-site processing. See below.

    6) The NuScale controversy. Looks to me like a miscommunication over an issue that doesn't really matter. They are arguing about maybe a factor of two at most in a volume of waste that is easily managed.

    7) Cs-137. I have included your critique on the Discussion page for the ThorCon reactor. Watch this space. https://citizendium.org/wiki/Talk:ThorCon_nuclear_reactor#Radioactive_gases

    ========

    Here is one issue I think we can be done with:

    5) Lyman’s claim that all MSRs require on-site chemical processing.
    Here is a fresh cut-and-paste from the Executive Summary of Lyman’s 2021 paper:
    “All MSRs chemically treat the fuel to varying extents while the reactor operates to remove radio-active isotopes that affect reactor performance. Therefore, unlike other reactors, MSRs generally require on-site chemical plants to process their fuel.”
    This statement is contradicted on page 102 with the statement “Some MSR concepts, such as ThorCon, would not have on-site reprocessing, but the company assumes that spent fuel salt would be sent off-site for reprocessing to recover unused fuel.”
    The point of this statement about on-site processing is to emphasize the risk of diversion of fissile materials from operating reactors. Reprocessing at a secure central location does not have this risk.
    It looks to me that Citizendium's handling of this controversy is correct. Most readers of Lyman’s paper will not get as far as page 102. They will be left with an incorrect understanding of MSR proliferation risk.
    https://citizendium.org/wiki/Talk:ThorCon_nuclear_reactor#Risk_of_proliferation

    ======

    I am having difficulty getting nuclear engineers to participate in this forum. One of them said he doesn't engage with belligerent sophomores. Another says they just ignore the greenies, they have no influence in the countries they are dealing with.  If you want this forum to continue its excellent tradition of good science above politics, please stop accusing nuclear engineers of hiding problems.  Assume that everyone is acting in good faith. Let's focus on the message, not the messenger.  Peer review is a plus, but honest mistakes are possible.

    0 0
    Moderator Response:

    [BL] Contents of duplicate post deleted. I assume that you did this by accident.

  27. Michael Sweet @21: I will respond to your issues one at a time when I have some good information, so this may take a while. To keep track of where we are, I will continue the previous numbering, adding two more issues.

    2) Non-fuel waste.  I have a call in to an engineer who has had hands-on experience decommissioning reactors. What I am hearing from reactor designers is that irradiated steel is a trivial problem compared to the much more radioactive spent fuel.

    4) Material resources. I have posted your question on beryllium to our Discussion page. On the hafnium question, do we really need to worry about this?  Do you really think reactors can't be built with some other material in the control rods? Are you aware that some MSRs don't even have control rods?

    5) Lyman's statement about all MSRs requiring on-site processing. See below.

    6) The NuScale controversy. Looks to me like a miscommunication over an issue that doesn't really matter. They are arguing about maybe a factor of two at most in a volume of waste that is easily managed.

    7) Cs-137. I have included your critique on the Discussion page for the ThorCon reactor. Watch this space. https://citizendium.org/wiki/Talk:ThorCon_nuclear_reactor#Radioactive_gases

    ========

    Here is one issue I think we can be done with:

    5) Lyman’s claim that all MSRs require on-site chemical processing.
    Here is a fresh cut-and-paste from the Executive Summary of Lyman’s 2021 paper:
    “All MSRs chemically treat the fuel to varying extents while the reactor operates to remove radio-active isotopes that affect reactor performance. Therefore, unlike other reactors, MSRs generally require on-site chemical plants to process their fuel.”
    This statement is contradicted on page 102 with the statement “Some MSR concepts, such as ThorCon, would not have on-site reprocessing, but the company assumes that spent fuel salt would be sent off-site for reprocessing to recover unused fuel.”
    The point of this statement about on-site processing is to emphasize the risk of diversion of fissile materials from operating reactors. Reprocessing at a secure central location does not have this risk.
    It looks to me that Citizendium's handling of this controversy is correct. Most readers of Lyman’s paper will not get as far as page 102. They will be left with an incorrect understanding of MSR proliferation risk.
    https://citizendium.org/wiki/Talk:ThorCon_nuclear_reactor#Risk_of_proliferation

    ======

    I am having difficulty getting nuclear engineers to participate in this forum. One of them said he doesn't engage with belligerent sophomores. Another says they just ignore the greenies, they have no influence in the countries they are dealing with.  If you want this forum to continue its excellent tradition of good science above politics, please stop accusing nuclear engineers of hiding problems.  Assume that everyone is acting in good faith. Let's focus on the message, not the messenger.  Peer review is a plus, but honest mistakes are possible.

    0 0
  28. Sorry for the duplicate posts. I have had several interruptions today, and apparently closing my laptop causes the unfinished comment to post.  I wish there was a way to delete or edit a just-posted comment, but I will be much more careful in the future.

    0 0
  29. I will also be more careful about links. Please delete # 26,27,28 and this post. There doesn't seem to be any private message feature like in FaceBook forums.

    0 0
  30. Moderator @25, Thank you for you helpful comments. I apologize to anyone on this forum who may have mistaken my statements intended as constructive criticism of the forum, to be a disingenuous swipe at anyone here. I repeated some phrases I have heard from nuclear experts who could make a valuable contribution to this forum, but decline because they see too much personal bickering. In future comments, I will avoid criticism of this forum or any debate with other members, and stick to my original purpose, which was to collect the best critiques I can find for some Citizendium articles on nuclear power. Michael’s comments have been very helpful. I will pass the substantive parts on to the engineers who designed these reactors and get their response. Please think of me as a neutral editor at Citizendium, not a pro-nuclear partisan. If I am pro-anything, it is pro-science.

    I understand the specialty at SkS is climate, not nuclear engineering. My suggestion was to encourage nuclear engineers to join and contribute. You have won the battle with climate science deniers. The big question now is how to solve the CO2 problem - renewables, nuclear, or both. I would love to see SkS play the same role in resolving this question as you played in resolving the climate debate.

    I have read some of the comments on your earlier nuclear energy post, the first hundred two year sago, the last dozen or so just now. I am seeing the same problem with too much personal animosity. This will discourage experts from participating. You might want to take a look at the FaceBook forum Renewable vs. Nuclear Debate for an example of excellent moderation. OK, no more criticism after this. It’s your forum.

    0 0
  31. BraveNewClimate was blog that discussed nuclear issues and had that focus. It attracted people with the appropriate expertise which contributors did not have. Sks has been about refuting denier arguments with published science. Arguments about nuclear energy potential seldom focus on any published science so it would be hard to see how Sks could work in that space effectively. Moderation is rather informal - moderators are people who read Sks and skim the new comments. If you arent interested in the nuclear debate, then probably skimmed too quickly for effective moderation.

    0 0
  32. scaddenp, the battle against climate science deniers has been won, and SkS played a major role. Even the oil companies are now promoting wind and solar. The war against global warming is much bigger than that one battle.  Climate scientists should play a major role, even if they don't understand the technical details of nuclear power. Very few of the critical issues require that level of understanding. e.g. a civil engineer building inspector could verify the safety of many of the new designs. SkS should expand its role in this debate.

    0 0
  33. nuclear waste is a non issue  when compared to any other power source.  Power density is orders of magnitude higher so the ecological footprint is much smaller. 


    Good rebuttal about SMR waste argument at 10:12

    Fossil fuel burning creates climate change and aerosols

    hydro creates mercury in the food chain

    solar and wind have short lifetimes and their manufacturing stream has a significant chemical waste footprint.

    0 0
  34. Macquigg,

    You are mistaken.  Scientists overwhelmingly oppose nuclear power.  The last group studying future energy systems that supported nuclear power gave up on nuclear in 2021.  The debate is over.  Abbott 2012 is accepted by the scientific community.

    2) Krall et al 2022 have shown that small reactors generate much more radioactive waste and it is a disastrous problem.  We have not even discussed  Krall's claim that the fuel waste from many modular reactors cannot be processed and stored in currently planned long term repositories (no long term repositories exist).  You cannot find anyone who can contradict a paper in the PNAS written and peer reviewed by experts with over 200 years of experience designing reactors.

    4) There are many elements that are in short supply besides beryllium.  Helium and uranium come to mind immediately.  Your reference on uranium is incorrect.  Abbott 2012 shows that the energy used to mine low grade ores is greater than the energy you get from the reactor.

    5) You claim that when Lyman says "MSRs generally require on-site chemical plants" he means "all MSRs".  Generally doesn't mean all.  Generally means most of the time, not all.  You are completely wrong.

    It is impossible to have a rational discussion when you insist generally means all.

    6) Nuscale accused Krall et al of having an error in their paper.  That is a very serious claim in science.  Nuscale was completely incorrect.  Their error was massive.  Their letter was not written in good faith.  I note that the Nuscale letter would not have passed peer review.

    0 0
  35. Michael, I have said nothing about the scientific consensus on nuclear power. Please stop trying to make me your strawman. This debate is not about me. I am here to collect critiques for the Discussion pages on some articles in Citizendium. To avoid long, inconclusive debates we are summarizing the best statement from each side, focusing on just one issue at a time. If you want to raise new issues, like “no long term repositories exist”, please make that a separate issue. I will add it to our numbered list.

    5) Lyman's statement about all MSRs requiring on-site processing. See my last statement on this issue at post 27. I did NOT claim that generally means all. Another strawman.
    I will assume from your response at post 34 that we agree, the quote from Lyman’s paper is complete, accurate and not taken out-of-context, and that the response from ThorCon’s engineer is factually correct.
    https://citizendium.org/wiki/Talk:ThorCon_nuclear_reactor#Risk_of_proliferation
    We disagree on how to interpret Lyman’s words “All MSRs chemically treat the fuel”, and “generally require on-site chemical plants”.
    Even if we alter the quote, changing “all” to “generally”, the ThorCon response is still correct: “ThorCon does no chemical processing online to remove fission products or anything else.” Also, I think the altered quote would still be untrue. I am familiar with three MSRs (ThorCon, Elysium’s FC-MSR, and LFTR). Only LFTR uses on-site chemical processing. I think we should leave the quote on Citizendium as is, and let the reader decide what it really means.

    2) Non-fuel waste
    https://citizendium.org/wiki/Talk:ThorCon_nuclear_reactor#What_about_non-fuel_waste
    I have just added this:
    Answer from World Nuclear Association discussion of Recycling and reuse of materials from decommissioning:
    Decommissioned steam generators from Bruce Power in Canada
    "These steam generators were each 12m long and 2.5m diameter, with mass 100 tonnes, and contained some 4g of radionuclides with about 340 GBq of activity. Exposure was 0.08 mSv/hr at one metre." This compares to a chest x-ray (0.02 mSv) or the minimum exposure to show a measurable increase in cancer risk (100 mSv) XKCD Radiation Chart

    I am still trying to get numbers on the ThorCon reactor. I have talked to engineers at ThoCon and one who was in charge of decommissioning a big PWR. They tell me that the irradiated steel is not a big problem. Cutting is done underwater, and the pieces are handled the same as spent fuel. Nobody is being evasive here. We just can’t get experienced nuclear engineers to jump only a few days after kerfuffle in academia.

    You said I “cannot find anyone who can contradict [the Krall] paper in the PNAS written and peer reviewed by experts with over 200 years of experience designing reactors.” I gave you two links in comments 9 and 10 above. Here is another:
    https://www.terrestrialenergy.com/wp-content/uploads/2022/06/Letter-to-PNAS-22-06-03-final2.pdf - response from David LeBlanc, Chief Technology Officer, Terrestrial Energy; “IMSR’s actual predicted thermal neutron flux at the reactor vessel is over 1,000 times lower.” than Krall assumes.

    Who are these reactor designers you say reviewed the paper? Apparently not the engineers familiar with the designs. The reviews are still rolling in, and Dan Yurman is updating his webpage:
    Stanford's Questionable Study on Spent Nuclear Fuel for SMRs | Neutron Bytes

     

    4) Material resources. I have posted your question on beryllium to our Discussion page. On the hafnium question, do we really need to worry about this? Do you really think reactors can't be built with some other material in the control rods? Are you aware that some MSRs don't even have control rods? Helium is not an issue for this reactor.
    Uranium supply should be a whole separate issue. WNA has a section on Uranium Resources: https://world-nuclear.org/information-library/nuclear-fuel-cycle/uranium-resources.aspx

    6) The NuScale controversy. Looks to me like a miscommunication over an issue that doesn't really matter. They are arguing about maybe a factor of two at most in a small volume of waste that is easily managed. Let’s put this question aside until we resolve #2, and let’s stop calling people dishonest.

     

     

    0 0
  36. macquigg - Sks space is refutation of myths with peer-reviewed science. Other sites dealt more effectively with political and economics. To my mind, a useful site for discussion of nuclear is one where nuclear scientists and engineers contribute and back their claims with peer-reviewed paper not references to blogs and opinion pieces. The opinions of practitioners vested in the industry are difficult to evaluate without peer review.

    The climate controversies were not helped by people without any domain knowledge (and often wikipedia-level physics) making wild speculations and theories. I dont think an accurate evaluation of risk and benefits of nuclear power is going to come from atmospheric physicists.

    0 0
  37. Macquigg,

    Rereading you post at 27 it appears to me that you are using the terms "chemically treat" and "reprocessing" as equivalent.  They are not equivalent.  Chemically treating the fuel can be a number of different actions, many small, that change the chemical composition of the fuel.  Reprocessing is extensively repurifying the fissile compounds in the fuel to put back into the reactor.  According to you Lyman says: 

    "All MSRs chemically treat the fuel to varying extents while the reactor operates to remove radio-active isotopes that affect reactor performance. Therefore, unlike other reactors, MSRs generally require on-site chemical plants to process their fuel."

    That means that all plants chemically treat their fuel but only some reprocess the fuel.  For example, Thor Con chemically treat the fuel to remove the noble gasses from the fuel.  Thor Con does not reprocess the fuel on site.

    At 27 you say:

    "The point of this statement about on-site processing is to emphasize the risk of diversion of fissile materials from operating reactors. Reprocessing at a secure central location does not have this risk."

    You are saying that chemically treating the fuel is the same as reprocessing the fuel.  This is incorrect.  Lyman says all MSR's chemically treat the fuel since they remove the noble gasses from the fuel.  Some plans call for on site reprocessing but others, like Thor Con, call for off site reprocessing.

    It is not my job to teach you the vocabulary of nuclear plants.  Your claim that Lyman was wrong is incorrect. 

    It is not clear to me what post from Thor Con you refer to.  Most of what I have seen from Thor Con is deliberately deceptive.

    The peer reviewed literature says that uranium is extremely limited.  Nuclear engineers would not be looking at breeder reactors, thorium and obtaining uranium from sea water if they were not resource limited.  From your post at citizendum "As for the cost of fuel, the World Nuclear Association says it is essentially unlimited" my emphasis.   It is not economic to have a fuel with unlimited cost.  Wind and sun are free.

    Nuclear plants are not economic and the materials needed to build them do not exist.

    0 0
  38. Michael, you keep treating me as an advocate. My role here and at Citizendium is as a neutral editor. I have what I need from this forum, a list of critiques of our articles from the anti-nuclear side. Even if I wanted to argue with you on the points I have copied to CZ, I am not the expert.  Also, any such debate should be done in a neutral forum, like Renewables vs Nuclear Debate, or perhaps on Quora.com.  As I said before, this forum is a bit too hostile for the nuclear experts I have invited.

    I am not following this forum (and there does not appear to be a notififation feature) so if you expect a response from me, please notify me via gmail, username macquigg.

    I have collected one more critique from your last comment, a challenge to the WNA statement that nuclear fuel is essentially unlimited. If you have any good sources on this, please notify me.

    As for your argument about what was really meant about on-site chemical processing, I repeat: the statement from the UCS report Executive Summary is accurate, complete, and not taken out of context. Your interpretation that they meant to include the collection of gases bubbling out of the molten salt as a "chemical treatment" and a proliferation risk (that is the context of their statement) seems to me like a crazy stretch. The company's response, that they do no chemical processing online, addresses the critique as stated. 

    As for your critiques on Cs-137 and beryllium, they remain open points on our discussion page. ThorCon has not responded, but they probably will when I submit the article for final review. They have stated that the Cs is chemically bound to the salt, but we could use some data on how much ends up in the gas, and whether they use some kind of getter to remove it, as they do with tritium.

    It's been a while since I took chemistry, but as I recall cesium is in column one, like sodium. If a few disgruntled cesium atoms take their electrons and leave the party, they will probably be followed by some hungry chlorine atoms, and end up as salt on the reactor walls. There are some chemists at Quora.com who could take up this debate. 

    Sodium and Chlorine

    0 0
  39. Macquigg,

    You have acted as an advocate of nuclear here so I have responded in kind.   The Renewables vs Nuclear Debate forum on Facebook seems to me like a lot of nuclear advocates slamming the "greenies".  You frequently state there that you support nuclear power.  I see little informed discussion.  The nuclear proponents who come here to post usually have little knowledge about reactors.  One poster, Ritchieb1234, was very informed and we had a good discussion.

    As I have previously told you, Abbott 2012 describes the issue with uranium.  He shows that with low uranium concentrations in the ore it takes more energy to mine the uranium than you get from using it in a reactor.  Your WNA article assumes that future engineers will develop mining processes that are orders of magnitude more efficient than any currently known processes.  I doubt that is possible.  Nuclear supporters would not work on breeder reactors or thorium if they thought there was enough uranium.  We could get unlimited supplies of hydrogen simply by syphoning off the surface of the sun, but that is impossible.  I note that you said "the cost of uranium is unlimited", not the supply.

    Thor Cons statement that they do not process the salt is obviously false since they remove the noble gasses from it.  That is a chemical process by definition.  You do not understand the difference between a chemical "process" and "reprocessing" nuclear fuel.  Thor Con is misleading.  That is not my problem.  Chemical processing the fuel is not a proliferation risk.  Reprocessing the fuel is a proliferation risk.  It appears to me that you are decieved by misleading information from Thor Con.

    137Cs.  As stated clearly in Lyman 2021, which I linked for you at least twice about this issue, giving you the page number (91) to read here, Thor Con would remove 137Xe, a noble gas, from the salt as part of their scheme to remove the noble gasses.  The Xenon then decays into 137Cs in whatever storage system they have for the noble gasses.  It would coat the inside of all the piping and the pumps.  Thor Con has to answer the question of how they plan to deal with radioactive cesium-137  formed in the noble gas stream.  Read the reference I have given for you to get the question that you are seeking.  Lyman stated (in advance) that Thor Cons answer is misleading.

    Your statement about Cesium being in column one is uninformed.  If you had read the citation I gave you, you would know that the cesium is formed in the gas stream from radioactive decay, it does not evaporate from the salt.  Since I am a professional chemist and I have read much, much more about reactors than you, I understand the chemistry of reactors better than you.  If you framed your statments as questions I would be more helpful and less irritated.

    Keep in mind that I have been having this debate with nuclear supporters for 15 years.  From your posts I understand that you are a newbie.  I researched most of your points years ago.  Nuclear supporters online repeat the same old tired arguments that were already false 15 years ago.  Back then renewables were more expensive than nuclear and there was a debate.  Now renewables are much cheaper than nuclear.  Informed debate ended several years ago, you have just not learned enough about nuclear and renewable energy yet to realize you are barking up the wrong tree.  Read Abbott 2012 about 15 reasons why nuclear cannot work.  His arguments have not been answered by nuclear supporters.

    This discussion has become very repetitive.  Since you do not read the references that I give, you do not understand the questions and answers.  I note that I have read your citations, read your Facebook site and read your Citizendium posts.  I have read Abbott, Krall and Lyman entirely and the response to Lyman on Facebook (the response is completely worthless).  Why don't you come back when you have done your homework and can address the issues that I raise.

    I have authored three posts on Skeptical Science about producing all the world's energy supply using renewable energy.  Read them here here and here.  All three say nuclear power is not necessary or economic.  That is what scientists think about future energy supplies.  You could use them as a basis of your renewable post.  Dana Nucitelli also authored a post about renewable energy powering the world.

    Nuclear power is not economic and the matrerials do not exist. 

    0 0
  40. Doing background reading I found this report about the NuScale reactor that they hope to build in Montana.

    NuScale’s Small Modular Reactor
    Risks of Rising Costs, Likely Delays, and
    Increasing Competition Cast Doubt on LongRunning Development Effort

     

    This report is written by the Institute for Energy Economics and Financial Analysis.   They describe themselves as "The Institute for Energy Economics and Financial Analysis (IEEFA) examines issues related to energy markets, trends, and policies. The Institute’s mission is to accelerate the transition to a diverse, sustainable and profitable energy economy."

    The report is very grim reading for nuclear supporters.  The first line in the Executive Summary is "Too late, too expensive, too risky and too uncertain."  It is easy to read if you are interested in seeing why the NuScale reactor is a terrible investment and is unlikely to ever be built.

    On the issue of vaporware discusssed upthread, I note that in 2008 NuScale said they would have operating reactors by 2015-2016  (7-8 years).  They now plan to have working reactors by 2019-2020 (7-8 years). 

    They have decided to change the design they submitted to the NRC for review.  They plan to submit their new design to the NRC in December 2022 and hope to have an operating reactor by December 2029.  This report shows that timeline is not credible.  Their cost estimates are also not credible and all the risk is set on the buyers of the reactors if the timeline slips or the costs overrun.  There are many other very serious issues.

    That sounds like vaporware to me.

    Apparently buyers are starting to wise up.  The subscriptions for buying power have fallen from 213 MW in October 2020 to 101 MW.  Since the current design of the plant calls for producing 462 MW of power they are a long way from their targets.

    MacQuigg,  this paper will probably be easier for you to read.  I suggest you read the entire 39 pages like I did.  There are a lot of diagrams.  It should be added to your discussion of modular reactors.

    It is clear that these analysts think the debate around nuclear is over, nuclear is not economic.

    Nuclear power is not economic and the materials do not exist.

    0 0
  41. Michael: Quoting from my comment #38 "from your last comment, a challenge to the WNA statement that nuclear fuel is essentially unlimited." This is referring to the supply of fuel, not the cost. It is also not my statement. I am simply reporting on what WNA has said. Please stop misquoting me. Thank you, however, for pointing out a possible misunderstanding of the WNA statement. I have changed "it" to "the supply of urantium".

    Thank you also for the substantive challenges to ThorCon's article and correcting my misunderstanding of the origin of Cs-137 in the gases. I wish I could get some nuclear engineers to participate in this forum, but it seems the world is divided into pro-nuclear and anti-nuclear "safe spaces".  You are right about the FB forum being too pro-nuclear. I report comments I see there that are too disrespectful, even when the anti-nuclear visitor is just repeating what she heard about Fukushima, or whatever. The moderators have been very good at deleting inappropriate comments.  Still, the forum is heavily pro-nuclear.

    You are also right that I have taken the pro-nuclear side in some debates. Honest debate is a good way to get to the truth, and for the last year I have been engaging in these forums to learn more about the nuclear option. My participation in these debates does not mean I am "pro-nuclear".  I am pro-science, and I try to avoid advocacy. My current belief, which has changed in the last 12 months, is that nuclear is going to be an essential part of the solution. That belief will change again if I see good evidence to the contrary. I have read Abbott 2012 and parts of the other anti-nuclear articles in our bibliograhy. I am not convinced.

    I will be following up on your critiques by quoting from your comments in other forums, but only as "a discussion at SkepticalScience.com" not using your name. My goal for Citizendium is that it becomes the neutral forum we really need, where both sides can make their best case.  Citizendium is what Wikipedia should have been, no mob editing, no industry shills or other advocacy groups "piling on", authors by invitation, based on their knowledge of the subject, like a tradional publishing company.

    Again, please notify me at gmail, name macquigg, if you have anything further to say. There is no notification feature in this forum.

    0 0
    Moderator Response:

    [BL] This debate is getting increasingly counter-productive.,

    I do not think that "discussion by proxy" is a viable mode of continuing this debate. The process of "I heard this said over here, I am repeating it over there. Bring stuff from there back here" is time-consuming, subject to error in interpretation, and subject to irritation. People will tend to think that what you say here is your own view - and what you select to repeat here will undoubtedly be affected by your own view (intentional or not).

    You seem to be characterizing this space as "anti-nuclear". The bits you have selected to display in this context seem to fall into the category of complaints characterized by "it would be easier to discuss this with those poopy-heads if they'd stop calling us poopy-heads". It smacks of tone trolling.

    As for the bias towards peer-reviewed science, the climate science area has been long subject to dishonest and biased "reporting" from industry. This is not a case of "both sides deserve equal respect".  Fossil fuel interests made considerable effort to hide their activity behind apparent "third party" and "independent" groups. The Tobacco Institute was also not a good source of information on the links between cancer and smoking - this is a long-established approach to protect financial interests. Industry in general has a long history of denying science where it suits them.

    Attempting to be an "honest broker" is a difficult role. Certain individuals have claimed this position with respect to climate science, while essentially acting on behalf of climate denial. Read this blog post over at Eli Rabett's to get the gist of how this plays out in climate science.

    To keep a long story from getting too long, the nuclear industry in general has frequently gone over budget, overdue, etc. There are good reasons to be very skeptical of claims that "this design won't run into that problem" - especially when those claims come from industry or industry trade groups.

    Please take a bit of time to decide what you want to accomplish. What is happening here will not be allowed to continue much longer.

  42. Notice: I have started a discussion on the Cs-137 problem at:  

    www.facebook.com/groups/2081763568746983/posts/3217689965154332

    If you disagree with an argument, attack the argument, not the person making the argument.

    I will not be commenting further in this forum, other than these notices encouraging your participation in the discussions.

    I know that being an honest broker is difficult, and not at all possible in this forum. Still, it is worth the effort on an important issue like what is the best solution to our climate crisis. I can assure you I am not acting on behalf of anyone.

    0 0
    Moderator Response:

    [BL} Accusations of dishonesty deleted.

    While telling others to not attack the person, you continue to personalize disagreement of the material you post.

    Regarding future activity, simply posting links is not acceptable. Skeptical Science is not a place to put advertising material. I refer you to the Comments Policy, which you should review before continuing to post anything here.

    No link or picture only. Any link or picture should be accompanied by text summarizing both the content of the link or picture, and showing how it is relevant to the topic of discussion. Failure to do both of these things will result in the comment being considered off topic.

  43. BL, I did NOT accuse anyone of dishonesty. My response was defending my honesty against your earlier comment that others claiming to be honest brokers were actually acting on behalf of someone else (i.e. shills).  I appologize for any lack of clarity in my statement above and in other statements where I am attempting to defend myself while not accusing others. Search this discussion for ten instances of "deliberate", and I think you will see who is on the offense here.

    Enough of this battle.  I came here in my role as a neutral editor to collect critiques of our Citizendium artcles on nuclear power, and sifting through all the hostile verbiage, I have some good ones. I will continue to follow up on these, getting responses from the other side, and summarizing the arguments from both sides on our discussion pages.

    My link above was not "advertising", but an offer to anyone on this forum to continue the discussion in a more neutral forum where there are actual experts with years of experience in nuclear engineering. I have tried other ways to communicate with you, including your contact form, but gotten no response.

    Hey, does anyone here have a sense of humor? You might enjoy this confession from a pro-nuclear advocate revealing her secret payment for shilling. thoughtscapism.com/climate-and-energy/#jp-carousel-41157

    0 0
    Moderator Response:

    [BL] You accused an entire site of being incapable of allowing an honest broker. My earlier moderation comment was intended to try to help you understand why people are reacting to you in a particular way.

    Enough. Further moderation complaints will be deleted in their entirety.

  44. Macquigg,

    I noticed that you have edited your post at Citizendum.   My orignal quote was cut and pasted from your site.  An interesting Freudian slip.  The WNA do not address the cost of their supposed "unlimitted"  supply.  In the real world cost is a critical factor.  Nuclear engineers have not learned that lesson yet.  You might want to consider cost more closely.  Read the article about NuScale, the modular reactor closest to building.

    0 0
  45. Michael, Quoting from your comment #39: "you said 'the cost of uranium is unlimited', not the supply." I did NOT.

    I did edit the article in Citizendium. I told you that I did (in comment #41), and I thanked you for pointing out a possible misunderstanding of the WNA statement. You did not just "notice" some sneaky edit.

    The original text from "my site" (I assume you mean the article in Citizendium, not my site) is "As for the cost of fuel, the World Nuclear Association says it is essentially unlimited.[22]"  This seems pretty clear to me. The statement makes no sense if you think "it" refers to cost. To make that even more clear, I changed "it" to "the supply of uranium".

    Please stop these attacks. You won the debate. I am bowing out.

    0 0
    Moderator Response:

    [BL] You are not behaving well.

    "I noticed" carries no implication of notorious intent on the part of the editor. You are over-interpreting the writing of others - in exactly the way you are accusing others of acting.

    Regarding the quote "As for the cost of fuel, the World Nuclear Association says it is essentially unlimited", the subject of the sentence is "the cost", not "the fuel". Changing the subject of the sentence mid-sentence is bad writing. Better writing would improve readability, reduce ambiguity, and reduce mis-interpretation. Quoted from another source or not, you are the one posting it.

     

  46. If anyone here would like to continue the discussion of Cs-137 leakage, or any other substantive criticism of the Citizendium articles, please join us on the other forum. We have a reponse to Michael's point from a nuclear engineer, but so far it is rather dismissive. I am pressing him for more detail. This is a rare opportunity to bring together people who are technically smart, but on opposite sides of this issue.

    0 0
  47. @23:  The statement that helium "has no moderating effect on fast neutrons, which makes the GFR neutron spectrum the most resistant among fast reactors," confuses me.  Neutron moderation is achieved specifically by kinetic energy loss in elastic collisions, so the lighter the target nucleus the more effective the moderation.  That's simple undergraduate kinematics.  Therefore the only coolant more effective than helium as a moderator would be hydrogen, as in water molecules, or deuterium in heavy water.  Since water or heavy water is widely used as a coolant, I suppose helium looks heavy by comparison; but argon would hardly slow the neutrons down at all. What am I missing here?

    0 0
  48. JHBrewer @47

    I found this information:

    Some common light nuclei for comparison (the tables are hard to read each time to consult):H - scattering 4,24 barns at 1 MeV, 20,4 barns thermal, capture 332 millibarns thermal D - scattering 2,87 barns at 1 MeV, 3,4 barns thermal, capture 0,5 millibarns thermal He - scattering 7,06 barns at 1 MeV, 0,77 barns thermal, capture impossible C - scattering 2,58 barns at 1 MeV, 4,74 barns thermal, capture 3,86 millibarns thermal O-16 - scattering 8,15 barns at 1 MeV, 3,85 barns thermal, capture 0,19 millibarns thermal

    Reference: https://www.physicsforums.com/threads/helium-as-moderator.637730/

    Apparently the cross section of Helium is low for thermal neutrons.  It is also interesting that helium-4 cannot absorb neutrons at all, the only element with this property.  It seems to me that the main reason the helium has low effect on the neutron energy is its low density since it is a gas, but I could be incorrect.  I did not find any references to using argon as a coolant.  I guess argon might absorb too many neutrons.

    I suggest yiou read the papers summarized in the link of post 23.  Here is another link.  That source has a number of peer reviewed articles about high temperature gas reactors and the materials they require.   

    Reading some of the abstracs it seems to me that it is a waste of time to discuss  high temperature gas reactors.  They are described as needing very large amounts of R&D to build.  They are unlikely to be designed before 2050 and will be of no use building out a completely non-carbon energy system in that time frame.

    Nuclear power is not economic and the materials to build the reactors do not exist.

    0 0
  49. A new article in Energy Policy reviewes current plans to builod nuclear reactors and future possible builds.  They find that the contribution of nuclear before 204 0will not be significant (less  than 5% of all energy).  They find that the supply of uranium is too small to support additional reactors.  They find breeder reactors to be unreliable and unlikely to be developed before 2050.

    The highlights read:

    Highlights:

    Nuclear power's contribution to climate change mitigation is and will be very limited.

    Currently nuclear power avoids 2–3% of total global GHG emissions per year.

    According to current planning this value will decrease even further until 2040.

    A substantial expansion of nuclear power will not be possible.

    Given its low contribution, a complete phase-out of nuclear energy is feasible. (my emphasis)

    They have a good review of the extremely limited supply of uranium and why the WNA article referenced by MacQuigg is incorrect (with references).

    0 0

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.



The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2022 John Cook
Home | Translations | About Us | Privacy | Contact Us