Post by joshuamaurice on Jun 23, 2015 10:32:05 GMT 9.5
I've become involved in an online debate regarding increased cancer rates around nuclear power plants, esp. childhood leukemia. At first, I dismissed the claims, and gave my explanation of dismissal as saying that the yearly average rate of radiation release is well below background levels, and thus cannot be the cause.
In short, the argument is that the radiation release from a nuclear power plant is not constant over time, and thus it's inappropriate to use the linear no-threshold model. In fact, the radiation release over time has very large spikes during refueling operations. These spikes occur on the order of once a year, and they might produce short-term doses that are far more severe than the mere yearly average dose rate. I don't know how to respond to that immediately. It actually sounds rather plausible. It's difficult to find any pro-nuclear sources that even discuss this, and I don't trust many of the anti-nuclear sources at all.
PS: The article also makes an offhand mention about the different proclivity to bio-accumulate the released radioactive compounds from nuclear power plants, say as opposed to a banana. I'm curious if anyone has any insight there.
Post by joshuamaurice on Jun 24, 2015 16:33:58 GMT 9.5
To Roger Clifton.
Thanks for taking the time to reply, but I am not satisfied.
I am familiar with the 100 mSv / year number. It's often quoted by nuclear proponents as the smallest annual dose rate for which increase in cancer has been detected in human populations. However, I feel that you quoting this number in this situation is an inappropriate extrapolation. A exposure of 100 mSv over a second is likely to be much more dangerous than a flat exposure of 100 mSv over a year. Your reply strikes me as using the linear no-threshold which IMHO should be a discredited model of danger to humans from radiation exposure.
Further, it's my understanding that in lab animals, we have seen significant impact on cell function at acute exposures of 10 mGy from external photon sources. If I understand these units right, that is the same thing as an acute 10 mSv exposure. For one example citation, see:
> Integrated Molecular Analysis Indicates Undetectable Change in DNA Damage in Mice after Continuous Irradiation at ~ 400-fold Natural Background Radiation
> Werner Olipitz,1,* Dominika Wiktor-Brown,1 Joe Shuga,1 Bo Pang,1 Jose McFaline,1 Pallavi Lonkar,1 Aline Thomas,1 James T Mutamba,1 Joel S Greenberger,2 Leona D Samson,1 Peter C Dedon,1 Jacquelyn C Yanch,3 and Bevin P Engelwardcorresponding author1
> Environ Health Perspect. 2012 Aug; 120(8): 1130–1136.
I remain concerned that citing yearly-averaged doses for radiation exposure from nuclear power plants is insufficient when a majority of the yearly radiation release happens in less than a day during refueling operations. Estimates of the acute exposure from refueling operations are all over the place, from 20x to 100x of the reported yearly-averaged releases. That means that emissions from a nuclear power plant during refueling might be around the same magnitude as background radiation rates, or even higher. I don't have enough numbers to work with now to dismiss the concerns.
Further, it's my understanding from several sources that embryos are especially vulnerable and susceptible to radiation exposure. My hunch at the moment is that the acute exposure from refueling is probably not dangerous to adults, but the situation changes for rare cancers like leukemia in embryos and young children which are especially sensitive to radiation exposure.
For a source for some of these other claims, please see:
> A hypothesis to explain childhood cancers near nuclear power plants
Please know that I am still strongly pro-nuclear as the only solution to global warming, energy security, reducing conventional air pollution, all while maintaining our current standard of living, raising the rest of the world out of poverty, and the only way of avoiding likely mass starvation in the future which would occur absent mass desalination. Even if these concerns are substantiated, it's a very small number of deaths, and the problems could be mitigated or completely solved.
Still, I would like to be better informed about this issue. I would note that even if this issue is true, from my minimal knowledge of nuclear engineering, it seems to be eminently solvable. Add an offgas system of some kind to capture the noble gases and some degree of tritium to prevent mass release from depressurizing the system during refueling. Would that be possible? What would the cost of that be? Would adding such a system be as simple as I imagine?
Post by Roger Clifton on Jun 24, 2015 18:07:52 GMT 9.5
Actually, I did mean 100 mSv in a single exposure.
My reply echoed the reiterated reassurance by Professor Yamashita, the radiation risk adviser for Fukushima prefecture, to mothers that there was no risk of their children developing thyroid cancer unless they had received at least 100 mSv. Which they hadn't. But he became unpopular for failing to indulge their fears. (*)
The measure of 100 mSv has history. Early studies of the survivors of the two Japanese bomb flashes (including Yamashita's mother) revealed significant increases in certain cancers in people who had received a high dose, and it was thought (1960s) that with the passage of time more cancers would appear in proportion to the dose. That is, that there would be no threshold. However since then the emergence of cancers above expectation arose in proportion to the bomb-day dose only down to a minimum dose of 100 mSv, where cancer increase was barely above the significance level.
Plenty of people agree with you that a dose extended over time is not so injurious. Spread smoothly, quite high dose rates can be sustained long-term, as at Ramsar, Iran. There's Wade Allison's "relatively safe" recommendation for 100 mSv per month. There is a real recovery time after a high acute dose too, though estimating it must be nuanced. Radiation oncologists prefer not to give their patients two doses (massive, but localised) per day, but rather to bring them back the following day for the next massive dose, so it seems that it takes about a day for our bodies to respond, repair and restore our reserves. And on BNC...
However the relevant question remains, how big a dose was received by someone downwind of a refuelling operation? Unless it was more than 100 mSv, it's a fuss about nothing. Whoever cried wolf had some other reason for frightening innocent people than their health. Come to think of it, why did you put the old bogey of "childhood leukaemia" in the title?
Post by joshuamaurice on Jun 26, 2015 6:43:11 GMT 9.5
I decided to try to educate myself better in this topic.
It seems that there is a wide agreement in the scientific literature on the following points. Double-strand breaks in DNA are a very significant indicator (or cause) of later cancer development. There is an inherent error rate in the biological repair mechanisms of double strand breaks. A single electron track of ionizing radiation can cause double-strand breaks. On this mere basis, LNT seems to immediately follow.
I have not previously looked into this in so much detail. I'm glad I have now.
That argument looks pretty airtight.
However, I stumbled across this paper, which has an explanation of why the above argument might not hold. In the interests of full disclosure, even the paper itself says that this explanation is speculative.
The authors of the paper have observed that cell cultures after irradiation, and the results are highly suggestive of the following: In cells with a very low number of double-strand breaks, the biological repair mechanism for double-strand breaks does not turn on. In growing cell cultures after irradiation, the cells with persisting double-strand breaks die, and are replaced by division from their neighbors without DNA damage. The (speculative) conclusion then is that this could be the cause of a threshold-like relationship between real cancer risk and radiation. Below a certain threshold of radiation, double-strand breaks are uncommon in the cell population, and rather than using error-prone repair mechanisms, the cells with DNA damage are simply left to die.
If this speculative conclusion is true, their data indicates a threshold dose is around 1 mSv for acute exposure.
> Evidence for a lack of DNA double-strand break repair in human cells exposed to very low x-ray doses
> Kai Rothkamm and Markus Lobrich*
>Fachrichtung Biophysik, Universitat des Saarlandes, 66421 Homburg, Germany
Post by joshuamaurice on Jun 26, 2015 6:54:41 GMT 9.5
To Roger Clifton
I hope to consider it well-accepted that epidemiological studies, including the nuclear bomb survivors, do not have a sufficient sample size to detect possible linear effects at small population sizes. Thus, an acute exposure of 100 mSv may be the smallest dose for which we have hard evidence from actual humans, but that is not evidence of a lack of effect at lower acute doses. (Further, there seems to be some controversy on that topic, with some papers I'm finding that claim measurable cancer rates in real humans as low as 10 mSv or 50 mSv.)
epidemiological studies, including the nuclear bomb survivors, do not have a sufficient sample size ... not evidence of a lack of effect at lower acute doses
The sample size is quite adequate. The hibakusha who received the vicinity of 100 mSv were in a wide annulus in a densely populated city. So there are plenty of dosed humans in the sample. Similarly they have been studied for decades, so the study extends well over time. However, what would be difficult would be discerning a significant correlating bump amid the noise of all the other irritants in the same people. Geoff Russell has pointed out (elsewhere on BNC) a greater variation in the irritants for other Japanese cancers, and their incidence. It is meaningless to assign causes below the noise level.
Anyway, your title gives casual readers the impression that there is a connection between childhood leukaemia and nuclear electricity generation. What is it ?
Post by joshuamaurice on Jun 26, 2015 14:17:22 GMT 9.5
To Roger I will look the purported sample size problems further.
As for your question: "Anyway, your title gives casual readers the impression that there is a connection between childhood leukaemia and nuclear electricity generation. What is it ?", I believe I explained myself sufficiently already. I cited several articles and papers with a hypothesis, and I came here to ask about the plausibility of the hypothesis. I have received several answers, some of which I need to follow up on and consult the literature.
Post by Roger Clifton on Jun 27, 2015 12:12:56 GMT 9.5
A hypothesis without a measurable threat is just an empty nightmare. However there is something more nasty involved here. By proposing that there might possibly be a threat to worry pregnant mothers, these authors and perhaps yourself are terrorising pregnant mothers with baseless fears.
I am not exaggerating here. After Chernobyl, thousands of pregnant mothers in neighbouring countries underwent voluntary abortions. This was not due to evidence of damaged embryos, but to fears that had been spread wide by cynical scaremongers, who subsequently claimed the butcher's bill of damaged lives as proof of the need to be afraid. Those would-be leaders are still around. Check – aren't you spreading their propaganda for them?
If you really are concerned for our children and our children's children, you could alert your neighbours to the damage carbon-based fuels are doing to our greenhouse and the climate they will inherit. If renewables enthusiasts are persuading you that 100% renewables can power the world's heavy industries, check your facts. Then when you discover that RE can't do without carbon-based fuels backup, it is time to dismiss those empty fears of nuclear. And tell your neighbourhood scaremongers where to get off.
Post by joshuamaurice on Jun 27, 2015 17:11:58 GMT 9.5
To Roger The linked article and paper cite several studies which purport a real danger, such as the infamous KiKK study. AFAIK, it's the largest study of its kind, which means that other much smaller studies may lack the statistical power to detect the same effects. Of course, I've also heard other people say that the KiKK study was badly done for several reasons. I've looked into the matter a little bit, but it's still hard to make out what's right and what's not, especially because of publication bias.
Also, when someone presented this hypothesis to me, the first thing I said that even if it's true, the number of deaths are miniscule relative to workable alternatives, and we should still pursue nuclear. I also mentioned that my understanding of the issue is that there's relatively simple and cheap equipment to capture a lot of that released gas to prevent this hypothetical problem.
I agree that nuclear is still the answer, and I often evangelize for nuclear offline and online, but I don't think that's a legitimate reason to shy away from asking a simple question based on seemingly a reputable study like the KiKK study, plus when combined with a reasonably plausible mechanism namely the spike from refueling, etc. I'd rather chase the truth no matter where it leads.
I resent the strong implication that because I'm asking these questions I'm some sort of silly "green" "renewables" proponent. I'm not. For example, I'm currently in another forum doing some basic math for someone. They said that this new project in South Australia would make wind and solar work. I did the math for them and showed that it doesn't even come to 0.1% of the total energy capacity requirement to cover the intermittency of wind and solar.
Still, I have to thank you for your input, which forced me to reexamine some of my positions and see if I can find evidence for them. I now realize that LNT is a little more complicated than I thought. It's still probably wrong (IMHO), but I'm less sure about the actual safe acute dose. I need to look at the atomic bomb survivor data and statistics myself.
Post by Roger Clifton on Jun 27, 2015 19:04:16 GMT 9.5
Josh, I might well be wrong in implying that you see alternatives to the nuclear solution. However you are indulging in an innuendo that damages that hope. There is no such effect - you are unable to quote statistics of people being dangerously dosed, with significant injuries resulting. Wittingly or not, giving airtime to your whimsy is spreading fear about nuclear. At least, would you be willing to remove the name of that ugly disease from the title of this thread?
Post by joshuamaurice on Jun 28, 2015 10:59:55 GMT 9.5
@roger You're being unreasonable.
Again, I am not claiming it's true. I'm asking a question. I don't know the answer.
I provided citations to several pieces of evidence, most noteworthy is the KiKK study. It is unreasonable to dismiss this evidence out of hand because I didn't provide this other form of evidence. The KiKK study, if done properly, is sufficient evidence on its own to reasonably conclude that nuclear power reactors are causing increased rates of cancers. Now, maybe you think that the study is bad - ex: publication bias, failure to account for confounding variables, etc. - but that's a separate discussion which you have not yet done.
I also think it entirely unreasonable to avoid the discussion because you think it will be bad PR. We should seek the truth no matter where it leads us, because only by knowing the truth can we make proper public policy. That should be the advantage we pro-nukers have over the greens. Please stop disappointing me here.
Would you be happier if I added a question mark to the thread name?
Post by joshuamaurice on Jun 28, 2015 11:50:33 GMT 9.5
I will say this: The more I look at this Ian who postulated the hypothesis, the more he looks dishonest. I've been looking over several of the studies which he has cited, and thus far all the ones I've look at have had severe methodological problems.
Post by Roger Clifton on Jun 28, 2015 12:19:10 GMT 9.5
"I provided citations to several pieces of evidence"
Well, no. You have provided citations, but not evidence. Since you haven't been able to quote relevant evidence from them, there is no reason for us to read them. They might as well be tracts of religious literature handed out at the airport.
"I'm asking a question"
Sure, and I have provided the answer over and over – without evidence it's just nonsense, offensive nonsense.
It might be more helpful to you, if one or two of the many other readers were to contribute a comment to the thread. They have a variety of backgrounds and knowledge that would make knowledgeable assessments of your concern, quite independently and maybe even contradicting my own.
On the other hand, their silence may be telling us something too.
Post by Roger Clifton on Jun 29, 2015 8:13:28 GMT 9.5
To be taken seriously, the idea that an event (refuelling) had caused an increase in the incidence of a certain disease (leukaemia) needs to be supported with facts that describe cause, effect and coincidence. Write the numbers out for us to read instantly, followed by the link to where you got them from.
We need to see measurements that show that members of a certain group of people had received an acute dose over 100 mSv; a significantly increased incidence of the disease in the same group; and that the rise and fall of the pattern of exposures preceded the rise and fall of the disease by the appropriate lag in time.
On BNC we have discussed similar speculations before, but they have always fallen short of providing us with adequate evidence.
Because I am repeating myself in saying that, it would help both of us if a third reader would comment. Either to help you with facts or to tell me what is going on here.
Post by John ONeill on Jun 30, 2015 17:37:51 GMT 9.5
Hi, I've been following your discussion - like Roger, I was looking forward to a major increase in nuclear power as an alternative to coal, and also like him, regard the KiKK as an obstacle to that happening, and worrying in itself. I know there have been other studies in France and England, and I think in the US, which didn't find such an effect, but not having a background in either statistics or epidemiology, it's a case of your expert against my expert. I was listening yesterday to a radio item about an area round a radio telescope, where broadband wifi and cellphone towers are discouraged to avoid the radio equivalent of light pollution. Apparently the place has become a haven for ' radiosensitives ', who claim to suffer health effects from EM emissions. Are the Germans being similarly precious about nukes? If someone could point out the alleged errors in the design of the KiKK it would help. In a similar vein, I've seen hormesis proponents claiming that radon is actually linked to lower lung cancer rates, but if you follow wikipedia-type links, it definitely increases cancer among smokers, possibly also for passive smokers, and for virgin lungs it's maybe too low to figure.
Post by David B. Benson on Jul 1, 2015 11:55:39 GMT 9.5
radiation is about a thousand times safer than suggested by current international safety standards www.radiationandreason.com/ Physicist Wade Allison knows what he is writing about. I encourage exploring his website.
Post by joshuamaurice on Jul 1, 2015 14:28:11 GMT 9.5
@roger Clifton You triggered one of my pet peeves, and I'm sorry that I'm going to go into excruciating detail.
I would not have to show you the evidence which you ask for in order to conclusively demonstrate beyond all doubt that nuclear power plants cause cancer in children. (For clarity, I am still undecided.)
Of course, I will say that if I had evidence of the kind which you are asking for, then that would be much more compelling. However, it's not required. Evidence of the kind of the KiKK study, mere correlational evidence, would be enough on its own to show causation, in the right circumstances.
However, the KiKK study has not yet been replicated, the statistical confidence level was rather low, publication bias is rampant, and several other studies have been published showing the opposite result, which means we don't have strong evidence for it. However again, imagine a world where the other studies confirmed the KiKK results, new studies were coming out all the time, and they were accounting for economics, social background, and other possible confounding variables. Imagine the world where we do much better than a pithy 95% confidence level, and where publication bias was a much less severe problem. In that world, it would be unreasonable to doubt that nuclear power plants in some way cause childhood cancer.
What you wrote spreads a fundamental misunderstanding of science, and it really irks me.
We all know the t-shirt: "correlation does not show causation". While cute, it's wrong. It does contain a kernel of truth in there, but almost every time I've seen it used, it's used wrongly or misleadingly. The only way that we can show causation is by showing correlation - plus accounting for confounding variables. That's all there is to even a cliche control-group experimental-group lab experiment.
AFAIK, Hume said it first and best. He called this idea "constant conjunction". The only way that we ever learn about causation is by observing As then Bs, always As then Bs, always in constant conjunction. When we sees As then Bs in constant conjunction, we infer causation. Again, that's all there is even to a cliche control-group experimental-group lab experiment.
In this case, if I had the evidence you asked for, you might ask me "ok, now show me that acute doses 200 mSv causes cancer". I might answer that in terms of biology. You might ask me to show that these claimed facts about biology are true. I might then resort to chemistry. You might question chemistry. I would then resort to particle physics, and you could again question basic particle physics. At that point, you might say "give me evidence that magnets actually cause that attraction which pulls them together". That's akin to asking the infamous question "how do magnets work?". I have no answer for that question, and frankly no one does. Sure, a modern quantum field theorist might give an answer in terms of interacting quantum fields, but you could just ask "why do these quantum fields interact in that way? And how do they interact?". No one has the answers for that question. Not yet at least.
Reductionistic explanations of causation are wonderful, and they have allowed us to make great progress in understanding the world around us. However, reductionistic explanations have to end at some point, such as basic particle physics, and all we have to show that basic particle physics is right is correlation, plus good demonstrations that there are no confounding variables. That's all physics is. That's all physics has. That's all physics probably ever will be. We might have reached 5-sigma level of confirmation of the Higgs boson, but that result is entirely correlative. It's just seeing As then Bs in constant conjunction and no more. (Technically, the evidence for the Higgs boson is slighly more complicated and interesting, but for the purposes of our discussion here, it can be accurately described as using the model of constant conjunction to infer existence and causation.)
If you want to dispute the KiKK study on other grounds, please have at it. I can totally understand that. You can dispute it on the grounds of a relatively low statistical confidence level. You can dispute it on the grounds of purported biased authors. You can dispute it on the grounds that there are plenty of confounding variables left to check out. You can dispute it on the grounds that other studies have contradicted it, plus publication bias, and thus the KiKK study might have been just a literal fluke - if you deal poker for long enough you'll eventually get a royal flush. However, please don't dispute it on the grounds that this kind of evidence is never good enough.
Further, please see your own hypocrisy - perhaps accidental. You yourself have said that you are relying on the Japanese atomic bomb survivor data to make your arguments, data of exactly the same kind as the KiKK study, so don't give me this wrong-headed arguments that evidence like the KiKK study will never be enough.