From the choir: I hate to ask you for more, but could you shift just slightly and put a little more meat on the bones of the ALARA nightmare? I understand in general, from what you and others have written, how it exhausts and bankrupts nuclear efforts, but can you share a little more detail about how this philosophical burden gets hardened into specific and burdensome regs, paperwork, spurious systems requirements, etc.?
It's not any specific regulation. The basic problem becomes satisfying a regulator whio
can do anything he wants and whose primary motivation is to prevent a release, rather than the normal problem which is build the cheapest plant that meets a fixed set of rules. It breeds an entirely different mindset and ends up creating inefficient incumbents whose survival depends upon supporting the system that allows them to be inefficient. But if you want a more long winded treatment of ALARA see
I do not share your enthusiasm for SMR's. Standard Light Water Reactor technology is already too safe, and can easily be cheaper than coal. More basically, there is no technological solution to the AKARA problem western nuclear faces. If SMR's truly are cheaper, which is highly doubtful and certainly not proven, that would just give more room for the regulators to push the cost up. And the last thign we need is small nucelar reactors everywhere. Nuclear power plants need buffer zones. If SMR's really are the way to go,
Unless cogen is allowed, in which case it becomes more useful to locate reactors within population centers as close as possible to the heat sink so as not to lose too much heat during transport. Electrical transmission and distribution would also be minimized.
The combination of electricity and heat can justify higher CAPEX of the smaller SMRs. My understanding is that SMR buffer zones are minimal if not zero, extending only to the plant property boundaries.
The economics of cogen are at best marginal. The condensate in a good steam cycle will be at 32C. Not even enough for a good bath. If you go higher in temp
you are reducing electrical output. The argument for buffer zones, preventing evacuations, does not depends on such marginal economics.
ThorCon has always billed itself as a BMR. Big Modular Reactor. We need the biggest reactors we can build in assembly line fashion. And that means the whole plant, not just the priamry loop lest we fall into the Nuscale trap. That means building in a shipyards. which means hull mounted plants, which means the buffer zones come pretty easily.
AFAIK, the concept of cogen is NOT to reduce electrical output rather to use the district heating loops as the heat radiator for the waste heat thus gaining value from energy otherwise emitted directly to the biosphere. Is that not a viable approach?
As for EPZs, has the NRC backed off it's assessment to potentially allow an EPZ limited to site boundaries?
Yes the ThorCon design of double 250MW reactors is almost double that of the accepted definition of SMR limit of 300MW but it seems SMR developers are planning muti-reactor packs so minimum plant size would be similar to a ThorCon unit output. So it seems the whole "SMR" definition is somewhat nebulous.
Short answer: rarely. Most district heating grids operate at 50 to 70C. If you set up your cycle to exhaust at those temperatures, youa re definitely cutting into your plant's electrical output. Heat at 32C is pretty much worthless. There is a concept where heat at this temperature is distributed to keep the earth warm in cold climates. This warmth is then used to improve the efficiency of ground heat pumps. I cant imagine the economics of building such a grid are very compelling.
Calling the SMR concept nebulous is being excessively polite. BS is closer to the truth.
The ThorCon prototype will be a 500 MW plant, but they have a 1 GW plant on the drawing board. Like I say, we need BMR's.
Bear with me here. If the nuke plant exhaust heat is say 300C and that coolant comes back to the plant at 50C, hasn't the district heating loop severed the same purpose of a cooling tower? Presumably there are heat exchangers that dispense with the high heat coolant into a much larger volume of district heating loop liquid medium which effectively would suck the heat out of the coolant thus lowering the coolant returned to the reactor. What am I missing here?
Minor but potentially confusing typo in 2nd to last sentence? " make sure that our harm model [does?] not under-estimate risk..."
This posting is helpful in understanding your message of LNT vs. SNT; but I suspect it will not end up being the "last word". If nothing else, it seems we need an SNT-2.0 model to more closely align with the radium dial data, etc.
But I do not yet really understand the relationship between this technical data/curve/ evidence and how that logically should be converted to relaxing the regulations for building or operating nuclear installations; or for gaging how to establish private or public sector "insurance" or insurance equivalents to reimburse an exposed population or mitigate the risks and liability for a given facility owner?
There is also a longer discussion of Underwriter Certification and SNT in the Flop book version at gordianknotbook.com
However, you have a point. This stuff is spread all over the place. A book length Underwriter Certification Manual is being prepared which hopefully will bring it all together.
Worth noting that acronym SNT means Sigmoid No Threshold[1], while LNT of course is the Linear No Threshold model.
Have you examined studies of background radiadion? A consensus does not seem to exist:
- A paywalled 2009 study "based on outdoor and indoor dosimetry of each household, taking into account sex- and age-specific house occupancy factors" finds "no excess cancer risk from exposure to terrestrial gamma radiation. The excess relative risk of cancer excluding leukemia was estimated to be −0.13 Gy−1 (95% CI: −0.58, 0.46)." [5]
- A paywalled 2013 study on childhood background radiation[2] says "There was 12% excess relative risk (ERR) (95% CI 3, 22; two-sided P=0.01) of childhood leukaemia per millisievert of cumulative red bone marrow dose from gamma radiation; the analogous association for radon was not significant".
- A 2015 occupational study says[3] "The estimated rate of mortality from all cancers excluding leukaemia increased with cumulative dose by 48% per Gy (90% confidence interval 20% to 79%), lagged by 10 years."
- A paywalled 2020 review of childhood studies [4] opines "no firm conclusions can be drawn from the studies that have been published to date. Further data and perhaps pooled studies offer a way forward."
I must have read several hundred papers on low dose rate radiation. And yes for every paper that finds an increase in cancer at tiny dose rates, you can find a paper that claims the opposite. For example, study after study finds that the high background American states have lower cancer rates than low background.
Here's the problem. Low dose rate radiation --- and here we are talking about differences of the order of a few millisieverts per year or less --- is such a weak carcinogen that any of a multitude of confounding factors can overwhelm the effect of radiation. Unless you somehow correctly account for all these confounding factors, you are going to incorrectly attribute whatever differences you end up with to radiation.
For an extreme example of this, some studies have shown an increase in childhood leukemia for kids living in the vicinity of nuclear plants. Some have not. Typically distance from the plant is used as a proxy for dose rate.
But the dose rates involved are miniscule, of the order of micro-sieverts per year. The biology backed up by a vast number of laboratory experiments including experiments where thousands of beagles were 'sacrificed', says there is no way we could detect any effect at these dose rates. The observed differences in cancer when divided by the tiny differences in dose rates results in preposterously high incidence per millisievert, This is sometime trumpeted to show how dangerous radiation is; but what it really shows is the tiny differences in radiation could not have caused the differences in cancer. Radiation is everywhere. If those micro-sievert per year differences could really have caused this much cancer, none of us would be here.
The observed effect could be due to any number of possibilities. The composition of the population around the plant is never the same as the control group. Plants tend to be in low income, rural or industrial areas. There's evidence that viruses are an important cause of childhood leukemia. One theory is that the population mixing during the construction of plants leads to increased infections due to interactions between infected and vulnerable groups.
Radiation is such a weak carcinogen, if we want to reliably see its effect, we much search out populations which have received large doses, doses of 100's of millisieverts or more. Only when we do that, can we clearly see the impact of radiation. And what we find is that impact is determined by the dose rate, as we would expect from our knowledge of the repair process.
Fig. 1 is excellent for people like myself who are good at math and like to understand this topic thoroughly. But for non-technical readers, like the journalists we want to reach at Citizendium, I still favoring the simple bar chart of the Kerala data. I've put this on the Discussion page of our article on Fear of Radiation. https://citizendium.org/wiki/Talk:Fear_of_radiation#Another_very_large_study_debunking_LNT
along with Jack's comment emphasizing the key point of the figure.
The next step is to solicit comments from the anti-nukers on the Internet, and distill from the noise, the best arguments they have to offer. I will then get Jack's rebuttal, and not waste his time with the noise. See the section just above that for what I have collected on the topic of LNT and Radon.
I've gotten myself heavily involved in advocacy, which is compromising my position as Editor at Citizendium. I am hoping there is a member of this forum who will step up and be the advocate, saving Jack's time, and my neutrality.
To be a good advocate, you have to be patient with people who are smart and well meaning, but simply caught up in their belief system. The guy I was debating was a radon remediation expert. I never did convince him that low levels of radon were not harmful, but I consider the debate a success. Journalists reading it should come to the right conclusion.
Harm dose rate important perspective thanks for sharing
From the choir: I hate to ask you for more, but could you shift just slightly and put a little more meat on the bones of the ALARA nightmare? I understand in general, from what you and others have written, how it exhausts and bankrupts nuclear efforts, but can you share a little more detail about how this philosophical burden gets hardened into specific and burdensome regs, paperwork, spurious systems requirements, etc.?
David,
Assume you have seen
https://jackdevanney.substack.com/p/alara and
https://jackdevanney.substack.com/p/how-can-nrc-style-regulation-be-so
It's not any specific regulation. The basic problem becomes satisfying a regulator whio
can do anything he wants and whose primary motivation is to prevent a release, rather than the normal problem which is build the cheapest plant that meets a fixed set of rules. It breeds an entirely different mindset and ends up creating inefficient incumbents whose survival depends upon supporting the system that allows them to be inefficient. But if you want a more long winded treatment of ALARA see
https://gordianknotbook.com/download/alara-is-a-showstopper
@jackdevanney, speaking of what, as another commenter put it, "exhausts and bankrupts nuclear efforts..."
your perspective on this proposal for a DIFFERENT type of "nuclear effort" to ban energy poverty, that's also based on the facts you expose here, would be REALLY appreciated: https://mfioretti.substack.com/p/a-nuclear-power-offer-that-you-cannot
Marco,
I do not share your enthusiasm for SMR's. Standard Light Water Reactor technology is already too safe, and can easily be cheaper than coal. More basically, there is no technological solution to the AKARA problem western nuclear faces. If SMR's truly are cheaper, which is highly doubtful and certainly not proven, that would just give more room for the regulators to push the cost up. And the last thign we need is small nucelar reactors everywhere. Nuclear power plants need buffer zones. If SMR's really are the way to go,
we would put a bunch of them on one site,
Unless cogen is allowed, in which case it becomes more useful to locate reactors within population centers as close as possible to the heat sink so as not to lose too much heat during transport. Electrical transmission and distribution would also be minimized.
The combination of electricity and heat can justify higher CAPEX of the smaller SMRs. My understanding is that SMR buffer zones are minimal if not zero, extending only to the plant property boundaries.
Incidentally isn't your Thorcon reactor an SMR?
Ike,
The economics of cogen are at best marginal. The condensate in a good steam cycle will be at 32C. Not even enough for a good bath. If you go higher in temp
you are reducing electrical output. The argument for buffer zones, preventing evacuations, does not depends on such marginal economics.
ThorCon has always billed itself as a BMR. Big Modular Reactor. We need the biggest reactors we can build in assembly line fashion. And that means the whole plant, not just the priamry loop lest we fall into the Nuscale trap. That means building in a shipyards. which means hull mounted plants, which means the buffer zones come pretty easily.
AFAIK, the concept of cogen is NOT to reduce electrical output rather to use the district heating loops as the heat radiator for the waste heat thus gaining value from energy otherwise emitted directly to the biosphere. Is that not a viable approach?
As for EPZs, has the NRC backed off it's assessment to potentially allow an EPZ limited to site boundaries?
Yes the ThorCon design of double 250MW reactors is almost double that of the accepted definition of SMR limit of 300MW but it seems SMR developers are planning muti-reactor packs so minimum plant size would be similar to a ThorCon unit output. So it seems the whole "SMR" definition is somewhat nebulous.
Short answer: rarely. Most district heating grids operate at 50 to 70C. If you set up your cycle to exhaust at those temperatures, youa re definitely cutting into your plant's electrical output. Heat at 32C is pretty much worthless. There is a concept where heat at this temperature is distributed to keep the earth warm in cold climates. This warmth is then used to improve the efficiency of ground heat pumps. I cant imagine the economics of building such a grid are very compelling.
Calling the SMR concept nebulous is being excessively polite. BS is closer to the truth.
The ThorCon prototype will be a 500 MW plant, but they have a 1 GW plant on the drawing board. Like I say, we need BMR's.
Bear with me here. If the nuke plant exhaust heat is say 300C and that coolant comes back to the plant at 50C, hasn't the district heating loop severed the same purpose of a cooling tower? Presumably there are heat exchangers that dispense with the high heat coolant into a much larger volume of district heating loop liquid medium which effectively would suck the heat out of the coolant thus lowering the coolant returned to the reactor. What am I missing here?
Minor but potentially confusing typo in 2nd to last sentence? " make sure that our harm model [does?] not under-estimate risk..."
This posting is helpful in understanding your message of LNT vs. SNT; but I suspect it will not end up being the "last word". If nothing else, it seems we need an SNT-2.0 model to more closely align with the radium dial data, etc.
But I do not yet really understand the relationship between this technical data/curve/ evidence and how that logically should be converted to relaxing the regulations for building or operating nuclear installations; or for gaging how to establish private or public sector "insurance" or insurance equivalents to reimburse an exposed population or mitigate the risks and liability for a given facility owner?
Thanks. Will fix unfortunate typo.
See https://jackdevanney.substack.com/p/snt-versus-lnt-at fukushima
https://jackdevanney.substack.com/p/snt-for dummies
https://gordianknotbook.com/download/replacing-lnt-with-snt
https://gordianknotbook.com/download/compensating-radiation-harm
https://gordianknotbook.com/download/draft-compensation-pamphlet
There is also a longer discussion of Underwriter Certification and SNT in the Flop book version at gordianknotbook.com
However, you have a point. This stuff is spread all over the place. A book length Underwriter Certification Manual is being prepared which hopefully will bring it all together.
Worth noting that acronym SNT means Sigmoid No Threshold[1], while LNT of course is the Linear No Threshold model.
Have you examined studies of background radiadion? A consensus does not seem to exist:
- A paywalled 2009 study "based on outdoor and indoor dosimetry of each household, taking into account sex- and age-specific house occupancy factors" finds "no excess cancer risk from exposure to terrestrial gamma radiation. The excess relative risk of cancer excluding leukemia was estimated to be −0.13 Gy−1 (95% CI: −0.58, 0.46)." [5]
- A paywalled 2013 study on childhood background radiation[2] says "There was 12% excess relative risk (ERR) (95% CI 3, 22; two-sided P=0.01) of childhood leukaemia per millisievert of cumulative red bone marrow dose from gamma radiation; the analogous association for radon was not significant".
- A 2015 occupational study says[3] "The estimated rate of mortality from all cancers excluding leukaemia increased with cumulative dose by 48% per Gy (90% confidence interval 20% to 79%), lagged by 10 years."
- A paywalled 2020 review of childhood studies [4] opines "no firm conclusions can be drawn from the studies that have been published to date. Further data and perhaps pooled studies offer a way forward."
[1] https://jackdevanney.substack.com/p/snt-for-dummies?utm_source=profile&utm_medium=reader2
[2] https://www.nature.com/articles/leu2012151
[3] https://www.bmj.com/content/351/bmj.h5359/
[4] https://www.tandfonline.com/doi/abs/10.1080/09553002.2020.1867926
[5] https://journals.lww.com/health-physics/abstract/2009/01000
David,
I must have read several hundred papers on low dose rate radiation. And yes for every paper that finds an increase in cancer at tiny dose rates, you can find a paper that claims the opposite. For example, study after study finds that the high background American states have lower cancer rates than low background.
Here's the problem. Low dose rate radiation --- and here we are talking about differences of the order of a few millisieverts per year or less --- is such a weak carcinogen that any of a multitude of confounding factors can overwhelm the effect of radiation. Unless you somehow correctly account for all these confounding factors, you are going to incorrectly attribute whatever differences you end up with to radiation.
For an extreme example of this, some studies have shown an increase in childhood leukemia for kids living in the vicinity of nuclear plants. Some have not. Typically distance from the plant is used as a proxy for dose rate.
But the dose rates involved are miniscule, of the order of micro-sieverts per year. The biology backed up by a vast number of laboratory experiments including experiments where thousands of beagles were 'sacrificed', says there is no way we could detect any effect at these dose rates. The observed differences in cancer when divided by the tiny differences in dose rates results in preposterously high incidence per millisievert, This is sometime trumpeted to show how dangerous radiation is; but what it really shows is the tiny differences in radiation could not have caused the differences in cancer. Radiation is everywhere. If those micro-sievert per year differences could really have caused this much cancer, none of us would be here.
The observed effect could be due to any number of possibilities. The composition of the population around the plant is never the same as the control group. Plants tend to be in low income, rural or industrial areas. There's evidence that viruses are an important cause of childhood leukemia. One theory is that the population mixing during the construction of plants leads to increased infections due to interactions between infected and vulnerable groups.
Radiation is such a weak carcinogen, if we want to reliably see its effect, we much search out populations which have received large doses, doses of 100's of millisieverts or more. Only when we do that, can we clearly see the impact of radiation. And what we find is that impact is determined by the dose rate, as we would expect from our knowledge of the repair process.
Fig. 1 is excellent for people like myself who are good at math and like to understand this topic thoroughly. But for non-technical readers, like the journalists we want to reach at Citizendium, I still favoring the simple bar chart of the Kerala data. I've put this on the Discussion page of our article on Fear of Radiation. https://citizendium.org/wiki/Talk:Fear_of_radiation#Another_very_large_study_debunking_LNT
along with Jack's comment emphasizing the key point of the figure.
The next step is to solicit comments from the anti-nukers on the Internet, and distill from the noise, the best arguments they have to offer. I will then get Jack's rebuttal, and not waste his time with the noise. See the section just above that for what I have collected on the topic of LNT and Radon.
https://citizendium.org/wiki/Talk:Fear_of_radiation#LNT_and_radon,_Controversy_over_Figure_4
The final summary of these debates will appear on the Debate Guide page.
As you can see from the Radon debate https://www.facebook.com/groups/2081763568746983/posts/3204596069797055
I've gotten myself heavily involved in advocacy, which is compromising my position as Editor at Citizendium. I am hoping there is a member of this forum who will step up and be the advocate, saving Jack's time, and my neutrality.
To be a good advocate, you have to be patient with people who are smart and well meaning, but simply caught up in their belief system. The guy I was debating was a radon remediation expert. I never did convince him that low levels of radon were not harmful, but I consider the debate a success. Journalists reading it should come to the right conclusion.
"The guy I was debating was a radon remediation expert. I never did convince him that low levels of radon were not harmful ..."
But of course his job depends on radon being harmful ...