Congratulations to David LeBlanc (ORNL)

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E Ireland
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Re: Congratulations to David LeBlanc (ORNL)

Post by E Ireland » Sep 15, 2016 10:26 am

Are the models of the reference DMSRs any use here?
They seem to indicate superior to LWR and possibly CANDU uranium utilisation with the reference 30 year core life.

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Kirk Sorensen
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Re: Congratulations to David LeBlanc (ORNL)

Post by Kirk Sorensen » Sep 15, 2016 11:32 am

The IMSR is not a DMSR. It has no thorium in the core. Just enriched uranium and any plutonium bred from it.

Also, a loan guarantee is not a loan. It's the federal equivalent of having your dad cosign a loan.

They'll still have to convince a lending institution that they will be able to repay a $800-1200M loan with the financial returns from a 190MWe reactor. At $50/MW-hr and 8000 hours per year of operation, that's $76M/year of gross revenue before you subtract any of the costs of the plant itself.

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Tim Meyer
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Re: Congratulations to David LeBlanc (ORNL)

Post by Tim Meyer » Sep 15, 2016 1:45 pm

Kirk Sorensen wrote:The IMSR is not a DMSR. It has no thorium in the core. Just enriched uranium and any plutonium bred from it.

Also, a loan guarantee is not a loan. It's the federal equivalent of having your dad cosign a loan.

They'll still have to convince a lending institution that they will be able to repay a $800-1200M loan with the financial returns from a 190MWe reactor. At $50/MW-hr and 8000 hours per year of operation, that's $76M/year of gross revenue before you subtract any of the costs of the plant itself.
So. That's how much a year net? Equivalent to 20 years of payments on a $1 billion-dollar loan? That period would shrink if they built more than one. Two to produce a little more than Langley Gulch Power Plant—that cost $401.4 million to build.

Duke Energy shows here $121 billion in assets. If I had their money, I throw mine away! Of course, that'd be a loss of $1.21, so. If Duke is on the TE board, who needs Uncle Sam?
Kirk Sorensen wrote:Molten-salt reactors offer much more potential when the fissile and fertile materials are chemically distinct. When they are the same (such as in the LEU case) they appear to run into real problems with their fuel cycle.
But TE IMSR™ appears to be going ahead so that in 2024, all parties will learn that it has "real problems with [the] fuel cycle." That's a bad plan.

Way up here in the peanut gallery, we're cheering for your LFTR, Kirk, that evidently does NOT have a problem with its fuel cycle. Another discussion we're having from the outside looking in is that if your thorium MSR gets a foothold and breeding gets going, all the uranium businesses would begin to lose business. That's a lot of big money that doesn't want thorium never mind carbon money. Unless they are part of a transition from uranium to thorium. Do you like nuts? Never mind. It's from a Planters TV ad.
Idaho Power wrote:To fulfill Idaho Power’s commitment to meet growing electricity demands, the company added a new generation resource in July 2012. The Langley Gulch Power Plant is a clean, quiet, highly-efficient, combined-cycle combustion turbine (CCCT). . . . The plant's generating capacity ranges from 300 megawatts in the summer and 330 megawatts in winter.

In addition to providing electricity for Idaho Power’s customers, Langley Gulch helps integrate intermittent and alternative resources such as wind and solar from area projects in our system. The plant is located on 137 acres in rural Payette County.
Langley Gulch Power Plant is about 4.5 hrs west of and opposite INL itself at Idaho Falls where Duke Energy will back along with the US DOE the TE IMSR™ at 190 MWe for a first-of-its-kind commercial molten salt nuclear reactor burning uranium? Ironically, INL is near Lemhi Pass—the place where "thorium and rare-earth deposits in Idaho and Montana are the largest known in the U.S. Entitled 'Mineralogy of the Lemhi Pass Thorium' the report says 100,000 tons of thorium oxide are 'reasonably assured . . .' "

INL includes the Center for Advanced Energy Studies. Seems one of those studies would be on nuclear fuel cycle problems. For example, how to get the Flibe Energy thorium MSR working so that we can avoid the nuclear fuel cycle problems inherent to the Terrestrial Energy Integrated MSR technology. That sounds like an advanced energy problem.

From the standpoint of one powerless partially-informed voting US citizen (a Weinberg "trans-scientist"?), it appears that these high-powered, highly-educated, very experienced, stakeholder industry wonks are missing the big picture. How does that happen? The US government needs a thorium declaration. This is nuts.
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TerjeP
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Re: Congratulations to David LeBlanc (ORNL)

Post by TerjeP » Sep 15, 2016 4:14 pm

He can claim that, but where's the evidence? What's the enrichment level of the reactor fluid? Is he withdrawing fluid as he adds fuel? Is the total core salt inventory increasing? In either case each individual unit of enriched fuel is getting less utilized.
1. Evidence is not in the public domain as far as I can see.
2. The interviews I have read imply that nothing is withdrawn from the reactor vessel until long after it has cooled (except perhaps off gasses).
3. There is no suggestion of extra salt being added. However there is a void at the top of the salt that allows extra fuel to be added without needing extra space.
Fuel homogenization is a great feature of any molten-salt reactor. But in the case of LEU fueling I am increasingly convinced that it works against you. In order to "refuel" you must add new fuel at a higher enrichment level than the average of the core, and the mixing immediately reduces the enrichment of the fuel added, meaning an immediate loss of separative work. And if you withdraw a unit of fuel at the same time you add one (in order to keep the chemical composition of the salt the same) then you lose a unit of fuel at the average enrichment of the fuel.

I haven't seen any serious treatment of this problem by any of the companies proposing an LEU-fueled MSR, particularly Terrestrial. And it has the potential to be an absolute show-stopper relative to existing solid-fueled reactors, since if you can't show greater fuel performance than those machines, no one will seriously consider buying one.
Moltex kind of addresses it by keeping the salt in separate batches (tubes). Although they don't explicitly claim that as their reasoning as far as I can see.

As for Thorium in the fuel mix for the IMSR David LeBlanc has talked about Thorium being a serious option for the IMSR and a good one. It does require a higher level of enrichment for the associated uranium (ie more fissile). I can track down the interviews where he says this if you want. However he also says they don't need to use Thorium if using higher enriched uranium is a problem. Although either way it is still technically LEU, just a different grade.

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Kirk Sorensen
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Re: Congratulations to David LeBlanc (ORNL)

Post by Kirk Sorensen » Sep 15, 2016 5:10 pm

Well, then they should probably explain, in the public domain, how this reactor is supposed to work, particularly if they think that it merits taxpayer support.

I have been wondering about a purely LEU-fueled MSR for at least ten years now, but I must admit, I have not given it a great deal of thought until recently. I have always been much more interested in the LFTR design or in a LFTR-variant that would burn transuranics in the fuel salt. In both of those cases, the fertile material is thorium and the fissile material is uranium or plutonium. They are chemically distinct from one another and are kept in separate salt circuits anyway. But even if they were mixed together, they could be kept chemically distinct.

But an LEU-fueled reactor with no thorium is almost certainly a one-fluid reactor. In fact, I really can't conceive of any other configuration for such a machine than a single fluid. And a natural question arises: what is the most fuel-efficient version of such a reactor that one could build?

Ondrej Chvala points out to me that the most fuel-efficient version of a one-fluid LEU-fueled reactor would be a fast spectrum design, where breeding would be possible and the reactor could eventually operate on an equilibrium salt formulation. In that case, plutonium would be the fissile species and uranium the fertile.

So I should modify my original query to say: what is the most efficient thermal-spectrum LEU-fueled reactor that one could build? And would such a reactor outperform either an LWR or an HWR from a fueling perspective?

We can safely conclude some things about such a reactor right at the outset. It can't breed, so no matter how much plutonium it generates from uranium, it won't be enough to compensate for the loss of reactivity due to the consumption of U-235. So enriched uranium fuel will be necessary to keep the reactor operating for any length of time.

In the particular case of the IMSR, I have been told that no material is planned to be withdrawn and that the salt composition remains constant. Given these constraints, the only logical conclusion is that the overall salt inventory must increase, and that each unit of fuel salt progressively contributes less to the power generation of the reactor as the operating period lengthens. After some duration (they say seven years) the reactor is shut down, presumably with considerably more overall salt inventory than they began with.

So how much is there? What is its isotopic composition, both of uranium and plutonium? How much natural uranium and separative work was required to get to this point, and how does that compare to an LWR or an HWR (which does not require any separative work)?

My strong supposition is that this machine and its fuel cycle will underperform an HWR and perhaps even underperform an LWR, in which case it becomes a lot harder to sell it as a superior reactor option.

David LeBlanc is fond of saying, "come for the thorium, stay for the reactor" but I think he may have discarded the central value proposition in his effort to design his IMSR.

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TerjeP
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Re: Congratulations to David LeBlanc (ORNL)

Post by TerjeP » Sep 15, 2016 5:17 pm

Here is the interview where David talks about fuel options. Although he clearly wasn't getting pinned down on the specifics. Still worth a read if you have not seen it before.

http://www.daretothink.org/david-leblan ... scenarios/

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Re: Congratulations to David LeBlanc (ORNL)

Post by TerjeP » Sep 15, 2016 5:39 pm

Also, you're a computer guy. What do you know about modeling systems? Especially as applied to nuclear engineering. Thanks. I ask because not having the knowledge and experience, I wonder if its possible to simulate close to the actual working of a fluid reactor enough to predict salt compositions in various regions of the reactor.
Tim - this is not really my area. However the following software might be worth a look. You might want to also hire somebody who knows how to drive it.

http://www.ansys.com/Products/Fluids/ANSYS-Fluent
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Re: Congratulations to David LeBlanc (ORNL)

Post by TerjeP » Sep 15, 2016 5:44 pm

http://www.daretothink.org/david-leblan ... scenarios/

Here is the relevant extract regarding thorium. David LeBlanc is here talking about the IMSR-80. The smaller version of the reactor.
GZ Let’s make a big jump here. You started out with 3-4% enriched uranium, meaning there’s 100 to 150 KG of fissile U235 on a total of 3 to 5 tonnes of uranium. After seven years, what do we find in the nuclear soup within the IMSR?

DL In those seven years, we have added small amounts of makeup fuel, so we started with about three cubic meters and we’ll end up with a bit more. That’s no problem: there is adequate space within the reactor vessel for the salt volume to expand. In this fuel salt are fission products, of course, there will be some fissile uranium left and there will be very small amounts of transuranics, most of which will be plutonium. What exactly will be in there depends on certain choices we still have to make. We have the option of adding thorium fluoride. One big choice is whether or not we will add this thorium. That especially is a very complex decision.

GZ What makes it complex?

DL Having thorium in the fuel salt or not has effects on about a dozen aspects. Unfortunately, I cannot completely uncover them at the present time, but I can assure you it’s a very interesting set of pro’s and con’s. I can say this: if we use thorium, we will want to use a higher grade of low enriched uranium, depending on what is commercially available and what the law will allows us. We may be able to obtain uranium with an enrichment grade of 9 to 10 per cent. But even at that percentage, the majority of the fuel will then be the thorium in the salt. After 7 years of operation if we have employed thorium, the remaining uranium in the salt will be a very attractive mix which will have modest amounts of U233, and a very small remainder of U235, and that uranium will be very attractive to recycle – I’ll come back to recycling in a minute.

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Re: Congratulations to David LeBlanc (ORNL)

Post by macpacheco » Sep 15, 2016 10:31 pm

Kirk Sorensen wrote:I don't think the IMSR can outperform a CANDU in terms of energy extracted from a unit of natural uranium. Refueling of the IMSR will inevitably lead to a large loss of separative work, and extraction of equilibrium fuel will also result in a loss of separative work.

Solid fueled reactors can remove uranium fuel at enrichments below the average enrichment level of the core. Molten salt reactors, at least those with a single fluid, do not appear to be able to do this. Thus a lot of uranium will be wasted in an IMSR.

Molten-salt reactors offer much more potential when the fissile and fertile materials are chemically distinct. When they are the same (such as in the LEU case) they appear to run into real problems with their fuel cycle.
1 - The most critical aspect with new nuclear is cost / MWe until the revenue starts coming and and time until the revenue starts coming in. If IMSR costs 1/2 of an LWR and 1/3 of a CANDU, most of your arguments are quite mute from a real world business perspective, and we all know, fuel costs are tiny compared to initial investment.
2 - How much make up fuel will be added / year vs startup fuel ? Depending on how much / how little, that loss of separative work could be quite acceptable
3 - How about all of those neutron efficiency gains with having far less neutron poisons in the reactor core, the advantage of having a fairly homogeneous fissile to fertile ratio throughout the operational life of the reactor ? Those advantages help all MSRs. Why wouldn't those advantages offset the disadvantages you claim would be show stoppers ?

PS: I'm not claiming an IMSR will actually cost 1/3 of a CANDU and/or 1/2 of an LWR, but since you took the job to attacking Terrestrial by questioning the data they can't publish since they feel its valuable, I think somebody should suggest some data point at some more optimistic to balance the argument.
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TerjeP
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Re: Congratulations to David LeBlanc (ORNL)

Post by TerjeP » Sep 15, 2016 11:00 pm

The following two articles attempt to compare the cost of the IMSR to alternatives. Each has their own logic and they don't seem to correlate much. I'd take them with a big pinch of salt.

http://analysis.nuclearenergyinsider.co ... ssil-fuels
http://www.nextbigfuture.com/2013/04/co ... trial.html

E Ireland
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Re: Congratulations to David LeBlanc (ORNL)

Post by E Ireland » Sep 16, 2016 5:32 am

Whilst a HWR does not require seperative work to work - calculations by various people in Romania show that it is a good idea.

21GWd/t from 1.2% SEU is rather better than ~7GWd/t from 0.7%

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Tim Meyer
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Re: Congratulations to David LeBlanc (ORNL)

Post by Tim Meyer » Sep 16, 2016 10:10 am

E Ireland wrote:Whilst a HWR does not require seperative [sic] work to work - calculations by various people in Romania show that it is a good idea.
US nuclear evidently does no separative work in the present uranium fuel cycle with a growing inventory of SNF assemblies cooling off in pools and casks. Leslie Dewan never joined this forum?

Thank you, Terje, for the link and the answer on your experience in modeling. Also, the blog link. Who is Gijs Zwartsenberg and is this person here? No matter.

David L: Where'd you go? You used to post here. You support public education to reduce public fears of nuclear energy and get nuclear going again. Lars (Jack et al.), too?

Of course, nuclear engineers to discuss IP in the open is likely?
Kirk Sorensen wrote:Well, then they should probably explain, in the public domain, how this reactor is supposed to work, particularly if they think that it merits taxpayer support.
In the US, nuclear law requires public hearings. That's usually where SNAFU turns into FUBAR.

The inventor of the molten salt reactor made important clarifications that ought to be regarded ("Science and Trans-Science").

If Duke Energy is convinced and apparently they are, then they can marshal their ample in-house resources and circumvent taxpayer funds and keep all these juicy nuclear details hush hush. But that won't happen because they can't justify the high-level of first-mover costs of this historic effort to get at the atomic nucleus for running our nations without fossil carbon burned up with our abundant atmospheric oxygen!

Why not hire all the MSR startups in a group effort like Panama, Boulder on the Colorado, Manhattan, the interstate highway system, Apollo, others? I agree with Jim Kennedy, ThREE Consulting, on the inability of free market competition to get the job done. He correctly points up how China is operating as a nation would attempting such a big project.

ThorCon's (Martingale in Florida) urgency on climate change is not shared by powerful carbon interests. The only MSR company that is honestly facing the true case for this form of energy technology is Kirk's Flibe Energy in Huntsville, AL.

The scientist who is best qualified to deal with trans-science, Alvin M. Weinberg, inventor of this technology, intended to control what happens in the region of neutron flux by virtue of the fine control of a hot molten salt solvent that is IMPOSSIBLE with solid-fueled reactors and REQUIRES a very sophisticated chemical processing system for a TWO-FLUID NOT A ONE-FLUID reactor and the host of demanding nuclear engineering requirements that fall out of that central requirement.

Working with high-gamma rad field quantities of U-233/U-232 is exactly how the job gets done for full thorium utilization and scares the bejesus out of people who think bombs can be made of it—Kim Jong Un is NOT nor will EVER use thorium for making a bomb. To let the fear of U-233 stop the only available energy response to climate change and stagnant economic growth is stupid—not particularly edifying for the people of such greatness compared to the rest of the not-so-greats. A gram of neutrons costs tens of millions of dollars, yes? They're just too precious. Terrestrial and Martingale and who else? want a short cut. There is no short cut. Nuclear has no place for cowards. Alvin Weinberg worked with Captain Rickover. That's brave!

The MSR was correctly called the chemists' reactor. Engineering needs to ignore the false argument on weapons risk and focus on continuous control of the core fluid and how to use the off-gas handling and the chemical processors to get the job done right. Fluid and gas allows for continuous processing and that is a gargantuan advantage in nuclear engineering for commercial power. Period.

People ought to listen to the man who invented the whole program: Alvin M. Weinberg. He seems from his interviews such a gentle yet firm fellow. I doubt he was interested in ego and fame. He just saw an avenue for getting the energy we need by converting mass to pure energy instead of the dirty chemical energy. It made sense to him (and every member of Sapiens) considering that fossil reserves would eventually be exhausted thousands of years before thorium. And neutron flux is doable whereas overcoming the coulombic barrier for plasma energy is an even bigger challenge than the already daunting challenge of fission.

All the nuclear engineers evidently agree that the THERMAL (excellent emphasis, Kirk) neutron flux for thorium burning is better than U/Pu in an ideal breeding environment. It's a natural fact? Just as the only primordial fertile elements amidst the star dust that is our lifeblood is just two elements on the periodic table (excluding traces)? That is science. NOT trans-science. Public domain? Are you kidding? This subject is not the exclusive domain of Duke Energy or any company with deep pockets. Thorium is a major issue. What will President Putin do when his thorium report arrives March 1, 2017? Sputnik is a chump next to thorium.

The composition of the core salt leaving the reactor core zone where the neutron flux is optimized for fission must be fully processed to the correct composition for return to the core flux. The salt composition in the neutron flux has an optimum requirement.

The whole reactor requires the second region for transmuting the thorium with it's own chemical loop requirements, and the fueling of the reactor by the immense and way-too-understated virtue of hexafluoride chemistry. This is a marriage of a completely separate industry—uranium enrichment which is huge and entrenched—with the nuclear reactor industry. Another massive challenge ill-suited for cowards. I know cowardice very well from direct experience.

Kirk, you are right. Public funds are certain to be needed and this means the whole nuclear program has to be vetted in the public. So Terrestrial and others will have to be very specific about their designs in public—or not and take a chance that their machine will fail to perform next to the existing solid-fueled fleet.
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Kirk Sorensen
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Re: Congratulations to David LeBlanc (ORNL)

Post by Kirk Sorensen » Sep 16, 2016 1:17 pm

Tim Meyer wrote:Kirk, you are right. Public funds are certain to be needed and this means the whole nuclear program has to be vetted in the public.
I never said this. Flibe Energy has a plan that is entirely privately-funded.

The reason all these companies don't "get together" is because they all see the go-forward strategy differently. That's ok. But that's why they don't "join forces" and that's why there are so many disparate concepts.

Terrestrial Energy USA has changed things by asking the US government to back a billion-dollar loan. If they want to hang around in Canada and do their thing, fine. But when they come over here wanting my government to back their ideas, they had better be ready to explain why they're not crap, because increasingly that's what they're looking like to me.

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TerjeP
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Re: Congratulations to David LeBlanc (ORNL)

Post by TerjeP » Sep 16, 2016 3:07 pm

I'm not a US taxpayer. But I would feel much the same way as Kirk does if I was. The US government already has a tonne of debt and really shouldn't be looking for new ways to be giving away cash or putting themselves on the hook to do so if a particular enterprise does not work out.

That said if Terrestrial Energy is following the rules as set down by the DOE, including rules regarding technical disclosure, then I can't blame Terrestrial Energy for putting their hand out. The major criticism ought to be directed at those that are taking money from taxpayers and giving it away. Not those who play by the rules and qualify to receive it.

Kirk seems quite concerned that the IMSR has some deep technical flaws and won't work as advertised. I'm not qualified to say. I've done a lot of reading about this design, and I regard myself as a technically literate person, but I'm not a nuclear physicist and there is a lot that is not known about the design. If it does prove to be false advertising then it will have hoodwinked a lot of investors and government officials. One would expect that those people would have done their technical due diligence. But if they haven't then I suppose it would not be the first time in history.

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Re: Congratulations to David LeBlanc (ORNL)

Post by Kirk Sorensen » Sep 16, 2016 3:13 pm

TerjeP wrote:Kirk seems quite concerned that the IMSR has some deep technical flaws and won't work as advertised.
I'm not sure I would call it a technical flaw. I'd call it a performance flaw. If you want your reactor to be adopted in the market then it had better be a LOT better than the technology it replaces. From a fuel consumption perspective, it is not difficult for me to see that the IMSR might actually be worse than an LWR from a fuel consumption basis.

Yes, I know that there's a lot of other things to think about than just fuel. But fuel consumption is a pretty significant metric for nuclear reactors, not so much from a cost basis as from a waste generation basis, and an LEU-fueled reactor, because of the constant core homogenization (which is such an advantage in so many other aspects), might be underperforming existing solid-LEU-fueled reactors that can discharge their fuel at enrichments far below the core average.

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