It seems that the ANS is dominated by professionals who benefit from the status quo. Excess fear of radiation benefits people who sell expensive solutions to non-existent problems, like lead shielding in the walls at my wife's veterinary clinic, to avoid public exposure more than 5 uSv per day. Other examples - radon remediation experts trying to tell us that typical levels in our basements (less than 200 Bq/m3) are harmful, when the clearest study (BL Cohen 1995) shows there is actually a hormetic effect.
I'm collecting the most effective arguments on each side of the LNT Controversy for the Debate Guide page of Citizendium's article on Fear of Radiation. So far, all I have on the pro-LNT side is ad-hominem and appeal to authority.
What he said. Of course, I would put it much more politely.
Perhaps the most egregious example is the Hanford "cleanup" where the taxpayer is blowing 2-3 billion dollars a year to move contaminated dirt around despite the fact that the dose rates are below background on large parts of the planet.
"LNT does a reasonable job of roughly predicting the harm when the dose is received acutely (over a very short period of time) such as the bomb survivors."
No, it doesn't. The LNT cannot predict the cancers observed after radiological examinations (mammography, CT scans, and other medical procedures).
It's possible that high enough dose rates could have a disruptive effect on our repair processes. But I dont think we saw that in the bomb survivors. How do the dose rates in a mammogram compare with the Hiroshima/Nagasaki dose rates? I mistrust any epidemiologic data I cant explain biologically.
Electrical arc flash safety regulations nearly made this same mistake. The long duration sparking of a 240V wire with no breaker was calculated to deliver the same total energy as a high voltage flashover that lasts a fraction of a second, so workers at risk of exposure to either would be required to wear heavy protective equipment.
Fortunately the difference in risk is so easy to see that this simple total energy model was amended.
I wonder if radiation safety regulations are what they are in part because radiation is hard to see. We have no intuition for it, so it is hard to see the failings of simple math models.
They are what they are because the nuclear establishment has decided that extracting money from the taxpayer is more profitable than providing low cost electricity. We have no natural intuition about electricity. We can't see electricity. Occasionally, we can see phenomena created by electricity. Exactly, the same thing is true of radiation.
Jack, I finally read your 1/7/2024 "SNT for the Non-Technical" presentation. It makes sense. Ironically, since I'm not much of a traveler, one of the few places globally that I've been to is Kerala, India, so that part really caught my eye.
I have what may be a dumb question: "Linear No threshold" is well named; any dose is considered dangerous - there's no threshold dose. But why is "Sigmoid No Threshold" named as such? Shouldn't it be "Sigmoid Threshold"? - because there apparently is a threshold - the rate of dosage that is beyond what our DNA can repair.
For that matter, "sigmoid" itself is a word I haven't been familiar with, and I have a modest math and science background, unlike the average congressman or bureaucrat. So maybe use "S-shaped"? Getting politicians to understand is the goal, right?
One of the reasons LNT has survived is anti-LNTers set up a false dichotomy, either threshold or no threshold. Once you set up that dichotomy, LNT is safe because the thresholders can't answer these two simple questions.
I purposely put No Threshold in the name to make it explicit that this model does not fall into that trap.
Much of life is sigmoid. If the word is not in your dictionary, it should be.
Haven’t you mentioned that anything less than 20mSv per day seems to have no harmful effect? So that could be a tentative threshold, much better than the present standard of zero threshold that the NRC demands.
I try to very careful and always say "no detectable harm". If you've found a place where I have slipped up, pls point it out.
We have not yet detected statistically significant harm below 20 mSv/day, but that does not mean we can be sure that we would not detect it if we had a large enough population which received 20 mSv/day for a long enough period. My own guess is that if you sent a million people to Mars and they received 20 mSv/day for their entire lives, you would be able to detect harm.
A well-defined threshold model not only need to tell us the threshold, but how we calculate the harm for any dose rate profile. LNT and SNT can do that. To my knowledge, no such model has been annunciated, let alone tested. You can be the first if you like, but until you do that I dont want any lectures about thresholds, I'm tired of handwavers.
I’m using the term ‘threshold’ to mean a reasonable point at which to draw a line for safety - not that there is zero risk below that. Government regulatory agencies and building codes allow a certain amount of leeway for risk; otherwise nothing would ever get built. For example, take the strength levels required for concrete. The requirements are in effect a threshold. Of course that doesn’t mean there is zero risk of failure, but simply that the risk is lessened to a degree that is balanced with the benefits of allowing the construction.
There are 4 ways in which radioactivity is treated with excessive caution.
(1) Assuming LNT is correct. As noted here, this is difficult to disprove because of such small health impacts are impossible to distinguish from background noise.
(2) Ignoring the time dimension. This is easily proven, as pointed out in this post.
(3) Setting a 'safe limit' (1 mSv/year) that implicitly values a life lost to radioacitivity at least 100 fold higher that a life lost to other harms, such as air pollution from PM2.5 particles. This is easily proven using widely accepted data. See https://www.ft.com/content/e76cd8f6-f4bb-498f-bb22-8e692d1a6133
(4) Treating those radioactivity safe limits as sacrosanct. Air pollution safe limits (5-15 ug/M^3 for PM2.5 particles, WHO) are something to aspire to, and do not induce mass evacuation when exceeded by large amounts. In contrast, radioactivity limits are treated as something that should never been exceeded and they provoke permanent compulsory evacuation of large areas or highly expensive clean up operations.
Given how much more conservative the safe limits for radioacitivity are than for air pollution, and how easy this is to prove (see 2 and 3), would it not be sensible to focus on having (4) changed?
It is not asking much just to have existing radioactivity 'safe limits' treated in the same way as the 'air pollution' safe limits - as something to aspire to under normal operation, rather than limits that should never be exceeded.
Strongly disagree with (1). You don't test radiation harm models by looking at situations where the harm is so small that the difference inpredictions is practically untestable, You find situations where the difference in predictions is easily visable. In this case, that means looking at groups which have received very large doses, both acutely and chronically. LNT fails the latter test miserably. LNT makes predictions that are wrong by orders of magnitude.
Excellent. If the dosage is low and spread over enough time for DNA repair, then obviously the cumulative dose is not a problem.
> professional society which feeds off LNT to admit it.
What does this mean?
It seems that the ANS is dominated by professionals who benefit from the status quo. Excess fear of radiation benefits people who sell expensive solutions to non-existent problems, like lead shielding in the walls at my wife's veterinary clinic, to avoid public exposure more than 5 uSv per day. Other examples - radon remediation experts trying to tell us that typical levels in our basements (less than 200 Bq/m3) are harmful, when the clearest study (BL Cohen 1995) shows there is actually a hormetic effect.
The one society that seems to be breaking with this orthodoxy is the Health Physics Society. https://hps.org/hpspublications/historylnt/episodeguide.html
I'm collecting the most effective arguments on each side of the LNT Controversy for the Debate Guide page of Citizendium's article on Fear of Radiation. So far, all I have on the pro-LNT side is ad-hominem and appeal to authority.
https://citizendium.org/wiki/Fear_of_radiation/Debate_Guide#LNT_Controversy
Gary,
What he said. Of course, I would put it much more politely.
Perhaps the most egregious example is the Hanford "cleanup" where the taxpayer is blowing 2-3 billion dollars a year to move contaminated dirt around despite the fact that the dose rates are below background on large parts of the planet.
https://gordianknotbook.com/download/you-want-nuclear-waste-ill-show-you-nuclear-waste
but there are scores of other examples.
LNT and the fear that it creates is a key element in keeping this ripoff going.
"LNT does a reasonable job of roughly predicting the harm when the dose is received acutely (over a very short period of time) such as the bomb survivors."
No, it doesn't. The LNT cannot predict the cancers observed after radiological examinations (mammography, CT scans, and other medical procedures).
https://danielcorcos.substack.com/p/radiation-the-other-conspiracy-of
It's possible that high enough dose rates could have a disruptive effect on our repair processes. But I dont think we saw that in the bomb survivors. How do the dose rates in a mammogram compare with the Hiroshima/Nagasaki dose rates? I mistrust any epidemiologic data I cant explain biologically.
Some women had dose rates comparable to mammograms, but there were not sufficient numbers to assess the effect.
https://pubmed.ncbi.nlm.nih.gov/286106/
Radiological examinations were widely used in Japan at that time.
Electrical arc flash safety regulations nearly made this same mistake. The long duration sparking of a 240V wire with no breaker was calculated to deliver the same total energy as a high voltage flashover that lasts a fraction of a second, so workers at risk of exposure to either would be required to wear heavy protective equipment.
Fortunately the difference in risk is so easy to see that this simple total energy model was amended.
I wonder if radiation safety regulations are what they are in part because radiation is hard to see. We have no intuition for it, so it is hard to see the failings of simple math models.
v,
They are what they are because the nuclear establishment has decided that extracting money from the taxpayer is more profitable than providing low cost electricity. We have no natural intuition about electricity. We can't see electricity. Occasionally, we can see phenomena created by electricity. Exactly, the same thing is true of radiation.
Well, probably half of their membership dues are paid for by selling fear.
Jack, I finally read your 1/7/2024 "SNT for the Non-Technical" presentation. It makes sense. Ironically, since I'm not much of a traveler, one of the few places globally that I've been to is Kerala, India, so that part really caught my eye.
I have what may be a dumb question: "Linear No threshold" is well named; any dose is considered dangerous - there's no threshold dose. But why is "Sigmoid No Threshold" named as such? Shouldn't it be "Sigmoid Threshold"? - because there apparently is a threshold - the rate of dosage that is beyond what our DNA can repair.
For that matter, "sigmoid" itself is a word I haven't been familiar with, and I have a modest math and science background, unlike the average congressman or bureaucrat. So maybe use "S-shaped"? Getting politicians to understand is the goal, right?
Al,
What is that threshold? I need a specific number. What is that number? And why is it
that number, and not some other number?
Pls read https://jackdevanney.substack.com/p/zero-risk-or-negligible-risk
One of the reasons LNT has survived is anti-LNTers set up a false dichotomy, either threshold or no threshold. Once you set up that dichotomy, LNT is safe because the thresholders can't answer these two simple questions.
I purposely put No Threshold in the name to make it explicit that this model does not fall into that trap.
Much of life is sigmoid. If the word is not in your dictionary, it should be.
Haven’t you mentioned that anything less than 20mSv per day seems to have no harmful effect? So that could be a tentative threshold, much better than the present standard of zero threshold that the NRC demands.
I try to very careful and always say "no detectable harm". If you've found a place where I have slipped up, pls point it out.
We have not yet detected statistically significant harm below 20 mSv/day, but that does not mean we can be sure that we would not detect it if we had a large enough population which received 20 mSv/day for a long enough period. My own guess is that if you sent a million people to Mars and they received 20 mSv/day for their entire lives, you would be able to detect harm.
A well-defined threshold model not only need to tell us the threshold, but how we calculate the harm for any dose rate profile. LNT and SNT can do that. To my knowledge, no such model has been annunciated, let alone tested. You can be the first if you like, but until you do that I dont want any lectures about thresholds, I'm tired of handwavers.
I’m using the term ‘threshold’ to mean a reasonable point at which to draw a line for safety - not that there is zero risk below that. Government regulatory agencies and building codes allow a certain amount of leeway for risk; otherwise nothing would ever get built. For example, take the strength levels required for concrete. The requirements are in effect a threshold. Of course that doesn’t mean there is zero risk of failure, but simply that the risk is lessened to a degree that is balanced with the benefits of allowing the construction.
There are 4 ways in which radioactivity is treated with excessive caution.
(1) Assuming LNT is correct. As noted here, this is difficult to disprove because of such small health impacts are impossible to distinguish from background noise.
(2) Ignoring the time dimension. This is easily proven, as pointed out in this post.
(3) Setting a 'safe limit' (1 mSv/year) that implicitly values a life lost to radioacitivity at least 100 fold higher that a life lost to other harms, such as air pollution from PM2.5 particles. This is easily proven using widely accepted data. See https://www.ft.com/content/e76cd8f6-f4bb-498f-bb22-8e692d1a6133
(4) Treating those radioactivity safe limits as sacrosanct. Air pollution safe limits (5-15 ug/M^3 for PM2.5 particles, WHO) are something to aspire to, and do not induce mass evacuation when exceeded by large amounts. In contrast, radioactivity limits are treated as something that should never been exceeded and they provoke permanent compulsory evacuation of large areas or highly expensive clean up operations.
Given how much more conservative the safe limits for radioacitivity are than for air pollution, and how easy this is to prove (see 2 and 3), would it not be sensible to focus on having (4) changed?
It is not asking much just to have existing radioactivity 'safe limits' treated in the same way as the 'air pollution' safe limits - as something to aspire to under normal operation, rather than limits that should never be exceeded.
Anton,
Strongly disagree with (1). You don't test radiation harm models by looking at situations where the harm is so small that the difference inpredictions is practically untestable, You find situations where the difference in predictions is easily visable. In this case, that means looking at groups which have received very large doses, both acutely and chronically. LNT fails the latter test miserably. LNT makes predictions that are wrong by orders of magnitude.
By any coherent logic, LNT must be rejected.