"(b) The total inventory of thorium, uranium, and plutonium contained in the nuclear reactor or any individual nuclear reactor that is part of the nuclear plant must not exceed 10 metric tons." I do like the "any individual nuclear reactor" - each Can is a separate nuclear reactor and we are right at 10 tonnes per Can.
For the choir, "we" in this case is ThorCon. Lars is ThorCon's chief designer. So my back of the envelope was wrong. A ThorCon Can is normally rated at around 550 MWt and due to ThorCon's high temperature this goes to 250 MWe. But if you provide bigger pumps and bigger heat exchangers you can push that rating up a lot with the same reactor. The metric is even more elastic than I implied.
Jack - Thank you for reading through the nearly 500 pages and extracting the key bits. Someday you will be amply rewarded.
You gave me another opportunity to mention my favorite topic about external forces that like expensive, slow nuclear.
"The regulators will have plenty of help from the incumbents. The last thing they want is the kind of competition needed to drive nuclear’s does-cost back down to its should-cost."
The last thing that any incumbent energy source provider wants is to enable nuclear suppliers to drive their costs down to "should cost" levels. ALL of them stand to lose a great deal of wealth and power in that situation.
The ones with the most to lose are those whose quarterly PROFITS are in the $100M-$20B range. Most of those are involved in selling natural gas and oil. Some are NOCs and provide substantial shares of national income.
I think he means National Oil Companies such as ARAMCO even tho they are partly privately owned.. I'm tired of repeating myslef on this one.
Big Oil was a big supporter of nuclear during the critical 1965-1975 period. when nuclear's cost skyrocketed. Pls see https://jackdevanney.substack.com/p/big-oil-and-nuclear-power They took a very big hit when nuclear flopped. They are not the reason nuclear's does-cost is many multiples of its should-cost inthe US. They are one of its victims.
Big Oil's big buy in to gas in the very early 2000's did put them indirectly in the electric power business and they have lobbied against some nuclear subsidies and bail outs since then. But for the most part they are sitting on the side lines. my sense is they would jump back on the nuclear bandwagon if they thought they could make money there. They have the cash and big project capability. See Dow and XEnergy,
But they were so badly burned the last time it wil take a lot of convincing. See Dow and the Midland plant.
Jack - We will always disagree on this topic. On the scale of the companies involved, Big Oil's nuclear investments were more dalliances than any kind of effort to succeed.
They were "victims" of increased costs for nuclear development in the same way that they were "victims" of the oil embargo or the Iranian hostage crisis.
Regardless of our disagreements about events from 50 years ago, it seems that you MIGHT be willing to acknowledge that there are well motivated competitors to nuclear energy TODAY among the wealthy and powerful that are involved in one way or another with the hydrocarbon industry. (I have never said it was only, or even primarily "Big Oil." Coal, gas and little oil did their share and they were assisted by speculators, unions, railroads, and perhaps even tanker operators & builders.)
Hydrocarbon competitors are now joined by Big Wind and Big Solar. Those interests were too tiny to have any significant pull in the 1970s.
Here is one specific hydrocarbon interest that isn't involved with "Big Oil." There is a small group of Japanese trading houses that have been profiting in the billions of dollars per year from the LNG import business. Do you think it MIGHT be possible that those influential enterprises have anything to do with the completely irrational decision to keep Japan's 33 operable nuclear plants at drastically reduced operational capacity?
A query of Google's Gemini indicates that the profits in the Japanese LNG business exceeded $14 B in 2024.
The topic on the table is proposed Part 57, which is actually a very interesting document, possibly a breakthrough document. Does the use of "commercial grade" mean the end of "nuclear qualified" which would mean reactor designers could use the same technology as everybody else!
Twisted tubes are just one example, In a twisted tube heat exchanger
the tube are flattened into ellipses and then twisted. The resulting tube bundle is self-supported meaning much better vibration resistance. And the resulting helical flow produces heat transfer rates that are up to 50% better than round tube, Your Big Oil villains use twisted tubes through out their refineries.Yet US reactor designers can't use twisted tubes because no vendor has jumped through all the time consuming, expensive hoops required to become "nuclear qualified". The market's too small. And if one did, he would charge an enormous premium for the same product.
I can give you a bunch of other examples. Does part 57 end this nonsense?
The 10 tonnes HM limit is curious indeed. One can easily lower the heavy metal by reducing the fertile - an extreme example of this is a plutonium burner reactor such as explored in e.g. the MOSART MSR system. One can easily obtain GW level outputs this way while keeping HM under 10 tonnes. 10 tonnes of reactor grade plutonium is one heck of a lot of reactivity - more than the 6 tonnes of U235 in the EPR and that's 1700 MWe.
A more sensible standard would be the active core Cs137 inventory. Even better would be the total source term available for release, as this is rather different for various reactor and fuel types.
I’m not sure “maximum fission product inventory” is as self-evident of a standard as you claim. Yes, total heavy metal inventory is indeed a curious proxy to this end. But the means by which the inventory is contained seems more relevant.
To wit: the same activity of fission products in TRISO-loaded pebbles represents a substantially different potential release term as compared to say, metallic fuel. The worst-case release scenarios are far different. Same goes for molten salt operating at ambient pressure.
It doesn’t give a neat and clean heuristic, but that’s the point; I think a true risk-based regulation actually requires a technical assessment of potential failure pathways, not just arbitrary metrics.
There are situations in which you need a simple bounding case, for example setting the insurance liability cap. Provided you have adequate buffer zones, so practically all the heavy stuff will fall out within the buffer zone, I think you can use the max inventory of
Te132/I-131, I-132, Cs-134, Cs-137 and say a 95% worst weather pattern to estimate the max liability. That's the approach the NRA actually takes. I badly over-simplified in this post. This approach also allows you to make an estimate that the cap is exceeded. See 1.6.5 in
It's probably important to point out that under the NRA, the regulator does not do the risk analysis. The underwriters do when they set the premium. A design that is judged to be less likely to produce any given release including the max liability release will be rewarded with a lower premium.
Jack - You have some great insights here (such as the critique of total dose) that could really improve Part 57. Might I suggest you and/or ThorCon submit comments to the proposed rule? I think the comment period is open through July.
I retired from ThorCon at 80. i no longer have any official connection except as a shareholder.
The Gordian Knot Group of which I am the self-appointed Supreme Leader may comment.
btu I doubt it will have any impact. Youre right, LNT is so ingrained that most of these people do not understand that as soon as you start talking about total dose, you've accepted LNT.
"(b) The total inventory of thorium, uranium, and plutonium contained in the nuclear reactor or any individual nuclear reactor that is part of the nuclear plant must not exceed 10 metric tons." I do like the "any individual nuclear reactor" - each Can is a separate nuclear reactor and we are right at 10 tonnes per Can.
For the choir, "we" in this case is ThorCon. Lars is ThorCon's chief designer. So my back of the envelope was wrong. A ThorCon Can is normally rated at around 550 MWt and due to ThorCon's high temperature this goes to 250 MWe. But if you provide bigger pumps and bigger heat exchangers you can push that rating up a lot with the same reactor. The metric is even more elastic than I implied.
Jack - Thank you for reading through the nearly 500 pages and extracting the key bits. Someday you will be amply rewarded.
You gave me another opportunity to mention my favorite topic about external forces that like expensive, slow nuclear.
"The regulators will have plenty of help from the incumbents. The last thing they want is the kind of competition needed to drive nuclear’s does-cost back down to its should-cost."
The last thing that any incumbent energy source provider wants is to enable nuclear suppliers to drive their costs down to "should cost" levels. ALL of them stand to lose a great deal of wealth and power in that situation.
The ones with the most to lose are those whose quarterly PROFITS are in the $100M-$20B range. Most of those are involved in selling natural gas and oil. Some are NOCs and provide substantial shares of national income.
Rods, what does NOC stand for, and can you name some?
I think he means National Oil Companies such as ARAMCO even tho they are partly privately owned.. I'm tired of repeating myslef on this one.
Big Oil was a big supporter of nuclear during the critical 1965-1975 period. when nuclear's cost skyrocketed. Pls see https://jackdevanney.substack.com/p/big-oil-and-nuclear-power They took a very big hit when nuclear flopped. They are not the reason nuclear's does-cost is many multiples of its should-cost inthe US. They are one of its victims.
Big Oil's big buy in to gas in the very early 2000's did put them indirectly in the electric power business and they have lobbied against some nuclear subsidies and bail outs since then. But for the most part they are sitting on the side lines. my sense is they would jump back on the nuclear bandwagon if they thought they could make money there. They have the cash and big project capability. See Dow and XEnergy,
But they were so badly burned the last time it wil take a lot of convincing. See Dow and the Midland plant.
Jack - We will always disagree on this topic. On the scale of the companies involved, Big Oil's nuclear investments were more dalliances than any kind of effort to succeed.
They were "victims" of increased costs for nuclear development in the same way that they were "victims" of the oil embargo or the Iranian hostage crisis.
Regardless of our disagreements about events from 50 years ago, it seems that you MIGHT be willing to acknowledge that there are well motivated competitors to nuclear energy TODAY among the wealthy and powerful that are involved in one way or another with the hydrocarbon industry. (I have never said it was only, or even primarily "Big Oil." Coal, gas and little oil did their share and they were assisted by speculators, unions, railroads, and perhaps even tanker operators & builders.)
Hydrocarbon competitors are now joined by Big Wind and Big Solar. Those interests were too tiny to have any significant pull in the 1970s.
Here is one specific hydrocarbon interest that isn't involved with "Big Oil." There is a small group of Japanese trading houses that have been profiting in the billions of dollars per year from the LNG import business. Do you think it MIGHT be possible that those influential enterprises have anything to do with the completely irrational decision to keep Japan's 33 operable nuclear plants at drastically reduced operational capacity?
A query of Google's Gemini indicates that the profits in the Japanese LNG business exceeded $14 B in 2024.
You've taken us way off topic. If you want to continue this counter-productive digression from the real problem, do it over at
https://jackdevanney.substack.com/p/big-oil-and-nuclear-power
The topic on the table is proposed Part 57, which is actually a very interesting document, possibly a breakthrough document. Does the use of "commercial grade" mean the end of "nuclear qualified" which would mean reactor designers could use the same technology as everybody else!
Twisted tubes are just one example, In a twisted tube heat exchanger
the tube are flattened into ellipses and then twisted. The resulting tube bundle is self-supported meaning much better vibration resistance. And the resulting helical flow produces heat transfer rates that are up to 50% better than round tube, Your Big Oil villains use twisted tubes through out their refineries.Yet US reactor designers can't use twisted tubes because no vendor has jumped through all the time consuming, expensive hoops required to become "nuclear qualified". The market's too small. And if one did, he would charge an enormous premium for the same product.
I can give you a bunch of other examples. Does part 57 end this nonsense?
Now that's a really interesting question.
I apologize for the detour.
No problem, It's always fun,
but we have to focus on the real problem.
The 10 tonnes HM limit is curious indeed. One can easily lower the heavy metal by reducing the fertile - an extreme example of this is a plutonium burner reactor such as explored in e.g. the MOSART MSR system. One can easily obtain GW level outputs this way while keeping HM under 10 tonnes. 10 tonnes of reactor grade plutonium is one heck of a lot of reactivity - more than the 6 tonnes of U235 in the EPR and that's 1700 MWe.
A more sensible standard would be the active core Cs137 inventory. Even better would be the total source term available for release, as this is rather different for various reactor and fuel types.
I’m not sure “maximum fission product inventory” is as self-evident of a standard as you claim. Yes, total heavy metal inventory is indeed a curious proxy to this end. But the means by which the inventory is contained seems more relevant.
To wit: the same activity of fission products in TRISO-loaded pebbles represents a substantially different potential release term as compared to say, metallic fuel. The worst-case release scenarios are far different. Same goes for molten salt operating at ambient pressure.
It doesn’t give a neat and clean heuristic, but that’s the point; I think a true risk-based regulation actually requires a technical assessment of potential failure pathways, not just arbitrary metrics.
Prof
There are situations in which you need a simple bounding case, for example setting the insurance liability cap. Provided you have adequate buffer zones, so practically all the heavy stuff will fall out within the buffer zone, I think you can use the max inventory of
Te132/I-131, I-132, Cs-134, Cs-137 and say a 95% worst weather pattern to estimate the max liability. That's the approach the NRA actually takes. I badly over-simplified in this post. This approach also allows you to make an estimate that the cap is exceeded. See 1.6.5 in
https://gordianknotbook.com/download/underwriter-certification-of-nuclear-power/
It's probably important to point out that under the NRA, the regulator does not do the risk analysis. The underwriters do when they set the premium. A design that is judged to be less likely to produce any given release including the max liability release will be rewarded with a lower premium.
Jack - You have some great insights here (such as the critique of total dose) that could really improve Part 57. Might I suggest you and/or ThorCon submit comments to the proposed rule? I think the comment period is open through July.
Power,
I retired from ThorCon at 80. i no longer have any official connection except as a shareholder.
The Gordian Knot Group of which I am the self-appointed Supreme Leader may comment.
btu I doubt it will have any impact. Youre right, LNT is so ingrained that most of these people do not understand that as soon as you start talking about total dose, you've accepted LNT.