I know my prodding to get you to keep posting this stuff gets tiresome, but frankly you have quite the knack for it. The balance between scientific fact and readability is a hard one to find, and it seems to come naturally for you. Very happy to see this post, and thanks for linking the one about Grammy.... Missed that one, and find the difference in our memory of her fascinating.

My friend says to look at it this way: What's the wildest place in Europe today? That's right, Chernobyl. The biosphere at large tolerates radiation better than we do, and lots of mutations make baby Darwin smile.

On its way to the center of the earth. As crappy as ALL the other safety measures were/are one could postulate that the reactor containment vessels don't contain under emergency conditions.

"and c) were culturally quite incapable of understanding what had occurred. After all, apparently it took TEN YEARS after the accident to gain even the most basic understanding"

It seems cargo cult science is pervasive in the industry. I sometimes suspect the employees are cherry picked for that specific talent.

Aaron, I think you are depressed because you only read panic-mongering anti-nuclear websites. If you would take the time to study the hard scientific findings on nuclear energy, radiation, Three Mile Island and Fukushima, they would allay your anxieties.

Yes, some Japanese officials have claimed TEPCO wanted to abandon the Fukushima plant, a claim TEPCO has denied (http://www.reuters.com/article/2012/06/08/us-japan-nuclear-shimizu-idUSBRE8570EQ20120608). Aside from competing retrospective claims, what we know for certain is that TEPCO did not abandon the plant.

One reason TEPCO stayed was that there was never any objective reason to abandon the plant—because workers there were never exposed to extraordinary risks. To see this, Let’s look at the exposure data and resulting risks as documented in the recent World Health Organization study. (I have the report, “Health Risk Assessment from the nuclear accident after the 2011 Great East Japan Earthquake and Tsunami,” but unfortunately the WHO link to the pdf seems damaged.) (http://apps.who.int/iris/bitstream/10665/78218/1/9789241505130_eng.pdf)

During the whole year beginning with the March 11, 2011 meltdown, the roughly 18,000 emergency workers at the plant got an average dose of 15.86 millisieverts or less (p.138-40). Applying the Beir-VII risk factor of 570 cancer deaths per 100,000 people exposed to 100 mSv, that average exposure would cause 16 cancer fatalities. WHO uses larger risk factors; their highest estimate is for 77 total cancers, so roughly 35 eventual fatalities. (p.66.) 9 workers got exposures over 200 mSv, the highest being 679 mSv. (p. 138-40) If all 9 workers got that much that would induce 0.34 to 0.7 fatal cancers over a lifetime, depending on which risk factor and scenario you use. (p. 66)

So the notion that the situation at Fukushima Daiichi ever required workers to abandon the plant is untrue. The work entailed modest risks from radiation, but talk of it being a “suicide mission” is just alarmist rhetoric.

Aaron, I think you are depressed because you only read panic-mongering anti-nuclear websites. If you would take the time to study the hard scientific findings on nuclear energy, radiation, Three Mile Island and Fukushima, they would allay your anxieties.

Yes, some Japanese officials have claimed TEPCO wanted to abandon the Fukushima plant, a claim TEPCO has denied (http://www.reuters.com/article/2012/06/08/us-japan-nuclear-shimizu-idUSBRE8570EQ20120608). Aside from competing retrospective claims, what we know for certain is that TEPCO did not abandon the plant.

One reason TEPCO stayed was that there was never any objective reason to abandon the plant—because workers there were never exposed to extraordinary risks. To see this, Let’s look at the exposure data and resulting risks as documented in the recent World Health Organization study. (I have the report, “Health Risk Assessment from the nuclear accident after the 2011 Great East Japan Earthquake and Tsunami,” but unfortunately the WHO link to the pdf seems damaged.) (http://apps.who.int/iris/bitstream/10665/78218/1/9789241505130_eng.pdf)

During the whole year beginning with the March 11, 2011 meltdown, the roughly 18,000 emergency workers at the plant got an average dose of 15.86 millisieverts or less (p.138-40). Applying the Beir-VII risk factor of 570 cancer deaths per 100,000 people exposed to 100 mSv, that average exposure would cause 16 cancer fatalities. WHO uses larger risk factors; their highest estimate is for 77 total cancers, so roughly 35 eventual fatalities. (p.66.) 9 workers got exposures over 200 mSv, the highest being 679 mSv. (p. 138-40) If all 9 workers got that much that would induce 0.34 to 0.7 fatal cancers over a lifetime, depending on which risk factor and scenario you use. (p. 66)

So the notion that the situation at Fukushima Daiichi ever required workers to abandon the plant is untrue. The work entailed modest risks from radiation, but talk of it being a “suicide mission” is just alarmist rhetoric.

@ Aaron,
As for the health effects for the general public from the Fuku spew, the scientific consensus is that they will be tiny to nil.

The WHO report estimates for the most radioactive areas and sensitive people an increase of 4 percent in lifetime solid cancer risk, and a 7 percent increase in leukemia risk. (p. 8) So for every 100 people who were infants during the spew, 1-2 may come down with cancer because of it over an 89-year lifetime, on top of the 40 who would normally get cancer. Risks for older children and adults, and anyone who lives in the area after the spew, will be drastically lower.

The WHO deliberately overstates the risk to err on the cautious side. Other estimates from anti-nuclear scientists are lower still. (http://www.nature.com/news/fukushima-s-doses-tallied-1.10686). Princeton physicist Frank von Hippel, writing in the nuke-dreading Bulletin of the Atomic Scientists, reckons an eventual one thousand fatal cancers arising from the spew. (http://people.reed.edu/~ahm/Courses/Reed-POL-422-2012-S1_NP/Syllabus/EReadings/03.2/03.2.Hippel2011The-Radiological.pdf)

A peer-reviewed paper by Stanford’s Mark Z. Jacobson, a noted renewables advocate and anti-nuke, predicts remarkably few casualties. (http://www.stanford.edu/group/efmh/jacobson/TenHoeveEES12.pdf) They used a supercomputer to model the spread of radionuclides from the Fukushima reactors around the globe, and then calculated the resulting radiation doses and cancer cases through the year 2061. Their result: a probable 130 fatal cancers, with a range from 15 to 1300, in the whole world over fifty years.

We’ll probably never know whether these projected Fukushima fatalities come to pass or not. They assume that risk factors at high doses will extrapolate to low doses, but that’s open to debate. Radiation is such a weak carcinogen that scientists just can’t tell for certain whether it causes any harm at all below a dose of 100 millisieverts (100 mSv). (http://dels-old.nas.edu/dels/rpt_briefs/beir_vii_final.pdf) Even if it does, it’s virtually impossible to discern such tiny changes in cancer rates in epidemiological studies. Anti-nukes give that fact a paranoid spin by warning of “hidden cancer deaths. But if you ask me, risks that are too small to measure are too small to worry about.

The Stanford study relied on a computer simulation, but empirical studies of radiation doses support the picture of negligible effects from the Fukushima spew.

In a direct measurement of radiation exposure, officials in Fukushima City, about 40 miles from the nuclear plant, made 37,000 schoolchildren wear dosimeters around the clock during September, October and December, 2011, to see how much radiation they soaked up. (http://www.thejapannews.com/article/fukushima-city-says-radiation-dose-level-unlikely-to-harm-health-2012-01-13), also (http://en.wikipedia.org/wiki/Radiation_effects_from_Fukushima_Daiichi_nuclear_disaster) Over those three months, 99 percent of the participants absorbed less than 1 mSv, with an average external dose of 0.26 mSv. Doubling that to account for internal exposure from ingested radionuclides (http://whqlibdoc.who.int/publications/2012/9789241503662_eng.pdf.) p.44 gives an annual dose of 2.08 mSv. That’s a pretty small dose, about one third the natural yearly radiation dose in Denver, with its high altitude and abundant radon gas http://isis-online.org/risk/tab7, and many times too small to cause any measurable up-tick in cancer rates. At the time, the outdoor air-dose rate in Fukushima was about 1 microsievert per hour (http://radioactivity.mext.go.jp/en/contents/1000/667/view.html) or about 8.8 mSv per year, so the absorbed external dose was only about one eighth of the ambient dose. That’s because the radiation is mainly gamma rays emanating from radioactive cesium in the soil, which are absorbed by air and blocked by walls and roofs. Since people spend most of their time indoors at a distance from soil—often on upper floors of houses and apartment buildings—they are shielded from most of the outdoor radiation.

And radiation levels are declining fast—down 40 percent over the last year because of radioactive decay and weathering. (http://ajw.asahi.com/article/0311disaster/fukushima/AJ201303020041) also (http://ajw.asahi.com/article/0311disaster/fukushima/AJ201303090044) Contrary to the alarmist centuries-of-devastation trope, radioactive contamination clears from the land pretty quickly.

An extraordinary wrinkle of the Stanford study is that it calculated the figure of 130 fatal cancers by assuming that there had been no evacuation from the 20-kilometer zone around the nuclear plant. You may remember the widely televised scenes from that evacuation, featuring huddled refugees and young children getting wanded down with radiation detectors by doctors in haz-mat suits. Those images of terror and contagion reinforced the belief that the 20-km zone is a radioactive killing field that will be uninhabitable for eons. The Stanford researchers endorse that notion, writing in their introduction that “the radiation release poisoned local water and food supplies and created a dead-zone of several hundred square kilometers around the site that may not be safe to inhabit for decades to centuries.”

But later in their paper Jacobson and Ten Hoeve actually quantify the deadliness of the “dead-zone”—and it turns out to be a reasonably healthy place. They calculate that the evacuation from the 20-km zone probably prevented all of 28 cancer deaths, with a lower bound of 3 and an upper bound of 245. Let me spell out what that means: if the roughly 100,000 people who lived in the 20-km evacuation zone had not evacuated, and had just kept on living there for 50 years on the most contaminated land in Fukushima prefecture, then probably 28 of them—and at most 245—would have incurred a fatal cancer because of the fallout from the stricken reactors. At the very high end, that’s a fatality risk of 0.245 %, which is pretty small—about half as big as an American’s chances of dying in a car crash. Jacobson and Ten Hoeve compare those numbers to the 600 old and sick people who really did die during the evacuation from the trauma of forced relocation. “Interestingly,” they write, “the upper bound projection of lives saved from the evacuation is lower than the number of deaths already caused by the evacuation itself.”

That sure is interesting, and it points to the likelihood that anti-nuclear alarmism is way more dangerous than nuclear power, even when it melts down.

Aaron, on Three Mile Island: Could you please supply some evidence for the great dangers posed by TMI. (I hope you don’t trot out the Harvey Wasserman bit about children dying after the meltdown—his data prove beyond any doubt that no children at all were harmed.)

Here’s a paper that finds no increase in cancer rates in the population around TMI, (http://www.ncbi.nlm.nih.gov/pubmed/21855866), except for a marginally higher leukemia rate for very high-dosed men. (A small sub-sample and therefore possibly a fluke.)

Here’s another paper on the big ongoing cohort study of TMI from 1979 to 1998. (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1241392/pdf/ehp0111-000341.pdf). The abstract says “although the TMI cohort provides no consistent evidence that radioactivity released during the nuclear accident has had a significant impact on the overall mortality experience of these residents, several elevations persist, and certain potential dose-response relationships cannot be definitiviely excluded.” They do find higher-than-expected death rates among the whole cohort—mainly because of heart disease rather than cancer. But neither that trend nor cancer mortality correlate with TMI radiation exposure. There are some problems with the paper. For example, its comparison with general mortality rates did not control for income; people who live near TMI probably can’t afford to live elsewhere, so they may be poorer than the general population, a known risk factor for early death, heart disease and cancer.

Also, the paper shows that natural background radiation, and even the differences between natural radiation levels around TMI, are larger by an order of magnitude than the total exposre caused by the TMI spew. Background radiation near TMI is 5.7 to 8-7 micro-rems per hour, or 50 to 76 millirems per year. The largest total TMI dose they estimate is about 40-50 mrem and most were less than 20 mrem, or less than a single year’s worth of background radiation in that area.

So I don’t get it: why shriek in terror at a whiff of TMI radiation when we are all constantly washed in much larger surges of natural radiation?

--“No one can even locate the cores of the four nuclear reactors that melted down.”
Dude, seriously. First, no, it was three reactors that melted down. The core of Fukushima # 4 is quite intact in the spent fuel pool where it was before the earthquake. Second, everyone knows where the other cores are to within a distance of a few yards: they are either still within the reactor pressure vessel, or leaked onto the containment floor below. Where else would they go?

And yes, it will take years before engineers know the exact lay-out and extent of the damage in the Fukushima reactors, as at TMI. Nuclear meltdowns make a shambles. So what? The implication here is that engineers are playing with apocalypse if they lack perfect understanding of the minutiae of the reactors’ condition. But that’s just more groundless alarmism.

We’ve had three major nuclear spews now, and none of them have proved apocalyptic. Epidemiologists still can’t tell whether TMI caused any casualties at all. Chernobyl sure did, but the number that can actually be counted, as opposed to conjectured, is perhaps in the low hundreds. And the scientific consensus is that Fukushima casualties will also be too few to discern—perhaps even if there had been no evacuation. Melt-downs are actually low-stakes, low-impact events with consequences too small to matter or even measure in most cases. Compared with the immense toll of death and destruction wrought yearly by fossil fueled energy, or by traffic accidents, airplane crashes, eating cheeseburgers and any number of mundane risks that we blithely accept, nuclear power is one of the safest activities we undertake.

In the meantime, nuclear reactors are doing the crucial job of producing clean low-emission energy, abating deadly air and water pollution and fighting climate change.

So cheer up, Aaron. Nuclear power is not going to kill you—and it may just save your planet.

Will! There you are! I wonder, does it pay well trolling the internet for crimethink?

Look, a few years ago when we corresponded offline I offered to publish a long essay you composed on this topic on the front page here. Your essay, and your views, are strongly contrary to my views. The only condition was that you provide a short bio explaining why readers should accept your judgment as correct.

I never heard from you, as apparently you prefer to express your OCD in the comments section. This is your call, but I don't feel very motivated to respond. If you want my time, explain to me why you deserve it.

For other readers, I offer just this synopsis:

The linear dose model is extrapolated from high doses to low doses; there is very little to no experimental data underpinning this extrapolation. Therefore this model should not be regarded as scientific. (In fact, the best science, from the group of Elena Burlakova in Russia, indicates that the dose response is "biphasic" at the cellular level.)

It would still be all right to apply the model if the results it supplies were audited, but this does not occur. Instead, regulatory agencies and governments point to the calculated doses (lots of room for fudging there, by the way) and to the model (not scientifically grounded) to justify the decision not to perform sound audits. It's perfectly circular.

Example: Will, how many audits of TMI fatalities were performed, and how large a population did they cover? Furthermore, what health outcomes did those audits examine?

Bottom line: I don't believe that the WHO, NRC and EPA guidelines based upon the linear dose model are valid because I understand statistical mechanics. At low doses, the health effects are related to the power spectrum, not simply to the absorbed energy. The theory describing the shot noise power spectrum was fully worked out (in another context) by Walter Schottky prior to 1920.

I learned about this quite basic result in engineering graduate school; it fully invalidates the linear dose model for internally deposited alpha- and beta-emitters. It's a scandal that this knowledge isn't applied in radiation biology.

Will Boisvert: ALL THREE meltdowns are STILL spewing radiation. Games NOT over yet.
As Alice sez, " Don't count your cards before they hatch."

In an article roundly criticizing others' inaccuracies it's always best to double check one's own facts, especially in the punch line.

"...in Japan, two years after the far more severe accident at Fukushima Daiichi no one can even locate the cores of the four nuclear reactors that melted down."

Unless you have information I don't (and would like to hear) I think that should be three reactors.

What's a reactor core, more or less in the wide scheme of things, eh? They're STILL in a meltdown, STILL pumping radiation and hot particulates and STILL NO SOLUTION toward a clean up. Right now WE have fish being caught off California that are contaminated with Fukushima leakage. Factor in that hot tuna fish sandwich into those long term actuaries, see what ya get. Remember ALL that sea water that was used to "cool 'er down"? Where did that radioactive sea water go? I'm guessing its now runoff, pouring back into the sea. What about that pile-o-junk that that used to be a power station? Where does THAT hot, steaming turd fit into Fukushima land development? Bulldozed into the ocean? The cores are surely molten still so that would be quite an engineering problem for bulldozing and would most likely MELT ANY pumping system. SAFETY FIRST, Folks, & nukes ain't safe. Its corrosive at the sub-atomic level.

Hey, look at Hanford, Idaho, nuclear leakage going on there RIGHT NOW, probably for years up until now and for years to come.

Right Mike Meyer, the Fukushima plant is still leaking radioactive material into the sea—but not at a dangerous level.

High-end estimates are that the plant is leaking 3 tera-becquerels per month of radioactivity, mostly radio-cesium, into the ocean—that’s 3 trillion radioactive decays per second! (http://www.nature.com/news/ocean-still-suffering-from-fukushima-fallout-1.11823) Pretty scary, right?

Maybe not. What you have to remember is that the Pacific Ocean is already a colossal reservoir of natural radioactivity that dwarfs by many orders of magnitude whatever Fukushima could add.

Most of the natural radioactivity comes from potassium-40 in sea water, and it amounts to over 11,000 Bq per cubic meter of seawater, or 11 trillion Bq per cubic kilometer. The volume of the Pacific Ocean is 660 million cubic kilometers, with a total K-40 radioactivity of about 7 billion trillion becquerels.

So lets calculate how much of an increment of radioactivity the Fukushima leakage could add to the Pacific’s natural radioactivity.

Let’s assume the leakage continues at its present rate for 300 years. That would add about 11 quadrillion Bq of radioactivity to the ocean. Divided by the volume of 660 million cubic kilometers, that’s an extra 16.7 million Bq per cubic kilometer. But each cubic kilometer already has 11 trillion Bq of K-40, so the Fukushima leakage adds just 0.00015 percent to the ocean’s radioactivity. If we assume the radioactivity stays confined to just one one-thousandth of the ocean’s volume, the radioactivity of that hotspot would still be just 0.15 percent larger than it’s natural value.

But that calculation drastically overstates the true amount of added radioactivity. That’s because the radio-cesium is decaying away with a half-life of 30 years. Half of it will no longer exist in 30 years, and essentially all of it will be gone in 300 years. The extra cesium radioactivity will thus be only a tiny fraction of the already tiny quantities we calculated above.

One thing I wish people would remember is that the world is naturally a very radioactive place. We are exposed to natural radioactivity from the sea, from the sky, from the earth, from the bricks in our houses, from every bite of food we eat, from ourselves because we are all naturally radioactive. Since we are bathed in large amounts of natural radiation all the time, it just makes no sense to get hysterical about the tiny amounts of radiation that nuclear power plants add to the environment, even when they spew.

--And no, Mike, the cores are not still molten. They are submerged under water, so they have cooled and solidified. (The contact with the cooling water is why radioactivity is leaking into the Pacific, remember?)

Will Boisvert: What about The Japanese Current? Though comforting, 300 years of CONCENTRATED nuclear waste dumped on America's West Coast, does seem a bit long.

"I Got Depressed"

--me too...

to: Glenn Greenwald

I do beg pardon for the editorial lapse, re: my erroneous reply to your Floyd Abrams/NYT article comment ("check your facts, Dean!")...mea culpa

@Aaron- a long shot, but might this be the essay Will sent? http://slackwire.blogspot.com/2011/07/trying-to-be-for-nuclear-power-when-it.html

Right, Aric, that's my essay on slackwire.blogspot.com. I posted another one there as an update on the Fukushima situations, at http://slackwire.blogspot.com/2012/08/fukushima-update-how-safe-can-nuclear.html#comment-form That second one has a very long and spirited debate on nuclear power in the comment thread.

@Will- having found and read several of your essays, I'm curious your background? Seems you do more on tech in general than focus on just nuclear?

By which I suppose I mean why should I believe your stance over Aaron's? He's been quite up front about his background and qualifications, and even with a lengthy amount of Googling I've found nothing on you in that regard. Frankly what I have found lent itself more towards you being a writer rather than scientist or engineer, so I'm afraid I'd a bit suspicious.

Will Boisvert: At what point during the 300 years will those melted cores STOP emitting radioactive cesium into the sea?

Jon's comment thread isn't a peer-reviewed journal--well, maybe it is in a sense, but anyway, what would matter would not be qualifications but the quality of the arguments. If you can't judge Will's arguments on the merits, you can't judge Aaron's either. Me, I'm mostly just a bystander when it comes to people suggesting major paradigm shifts in some field of science.

Last time I recall this came up, I suggested that if shot noise was relevant, then basically one is suggesting that two or more hits are needed to trigger a cancerous cell. Which suggests a quadratic dose model (if two hits) and it's common in radiation biology to consider the possibility of such things. (Usually the proposed equation is a combination of a linear term and a quadratic term, multiplied by an exponential with another linear and quadratic term, representing a survivorship factor. Can't have a cancerous cell if it dies first.) In fact, there it is, with a constant added to the pre-exponential, right on page 52 of my copy of the old BEIR V report. And no, I haven't read it.

I'm afraid I don't agree on that, Donald. IMO knowing the background of the people pitching conflicting viewpoints is important, as it provides insight as to how their viewpoint developed. Case in point, when they're ill, people tend to seek out a medical professional rather than asking the crazy person down the street. After all, it's clear the medical professional has training in such things and the crazy neighbor is, well, crazy.

What Will's discussing IS a snapshot of conditions on the ground. The FATAL ERROR of his discourse is that WE are forced to watch the whole movie. Radioactivity effects are cumulative, a product of time and exposure. Bechtel Leakers and atom bombs produce a lot of hot aerosol particles that fly for a long, long time creating repeated exposures. In his cesium argument he neglects to mention those "300 years" only start once the source is removed. Since the source is STILL there, I suppose the Pacific Ocean will be more of a radiation source than a couple of years ago.

Aric, I write on a range of topics.

--I don’t have any academic credentials, and never claimed any. (I haven’t yet been committed to a mental institution.) If you think my lack of credentials disqualifies me from commenting on scientific issues, then feel free to ignore everything I say. But I hope you’ll give me a hearing.

I don’t think it solves anything to just decide whom you should trust based on their “background.” On the topic of global warming, for example, you can find PhD meteorologists at good universities who are global warming deniers, and not all of them are hired lackeys of Big Oil. Whom do you trust when well-credentialed people are arguing both sides? To be responsible citizens, laypeople can’t escape the burden of thinking hard about issues and exercising independent judgment.

The worse problem is that what we really end up trusting isn’t someone else’s background and expertise, but our own biases—whichever expert echoes back our untutored preconceptions is the one we believe. That gives us an excuse to ignore voices that challenge the conventional wisdom we’ve grown comfortable with. And I’m afraid that among many greens the belief that nuclear power is a satanic evil has indeed hardened into an unshakeable dogma that brooks no debate.

But a lot of leftists like me have started questioning that conventional wisdom. We have studied the science--all the science, not just the alarmist redaction of it--and we’ve come away persuaded that nuclear power is remarkably safe, even when you take account of once-a-generation spews. Since it’s a prodigious, really unrivalled source of clean low-carbon energy, we want more of it, to abate pollution and fight global warming.

All I’m hoping to do is prod people into taking a second look at these issues and doing their own research—because the more people understand nuclear power, the more they tend to like it. (Plus, it’s a fascinating subject in its own right.)

@ Donald Johnson,

The exact shape of the radiation dose-response curve—linear or linear-quadratic—is important for medical radiology, where they deal with people who get huge doses. It’s less relevant for the low doses people are exposed to by Fukushima-like spews. Below 100 mSv it’s imponderable anyway, since the cancer effects, if they exist, are too small to detect against the background incidence.

That said, if the curve is linear-quadratic then that implies that LNT overstates radiation risks at low doses. (Linear-quadratic is now incorporated into LNT by way of DDREF, the Dose-rate Dependent Risk Factor, which divides LNT by 1.5 or 2 at low chronic doses on the grounds that a dose spread out over time is less toxic than an instantaneous dose, an effect that’s well-documented at high doses.)

What LNT is good for is to set an upper bound for the public health risks from radiation. In the case of Fukushima, the upper bound is still low enough as to be essentially conjectural—too small to measure in epidemiological studies.

That result is not an estimate based on extrapolation; it has the status of an empirical observation. When studies try to measure radiation risks for doses below 100 mSv, they find no significant elevation over background—the confidence intervals straddle zero excess risk.

That’s why I feel that Aaron’s theory, positing low-dose radiation risks that are much higher than LNT predicts, cannot be right. It’s not that it violates an imponderable theory of low-dose LNT, it’s that it runs afoul of the bald empirical finding of no statistically significant effects at low doses. There might be a mouse hiding in the grass, but not an elephant. (Though I must admit that I just don’t understand the shot noise business, so maybe I’m missing something.)

The Burlakova theory that he’s now espousing, positing a sharp spike in cancer risk at low doses, seems exceedingly doubtful. It implies that over a certain range a decrease in radiation exposure results in a dramatic increase in cancer risk. (Oddly, it’s formally indistinguishable from a pet theory of pro-nukes called “radiation hormesis,” which argues that a little radiation is good for you.)

The notion that radiation has a threshold below which doses are innocuous seems much more sensible to me. Just about everything we know of has a lower-bound toxicity threshold. Drugs, vitamins, even water—marathoners and radio-contest doofuses have occasionally killed themselves by drinking too much water. Even gravitational acceleration has a non-linear risk threshold. One man falling 1000 feet equals one fatality, but 1000 men falling one foot equals zero fatalities.

Will Boisvert: I for one welcome YOUR comments no matter what the credentials. I, myself, am a motorcycle mechanic therefore no expert on nuclear power. On the other hand my Dad and my Brother were/are millwrights and spent many a year building nuclear power plants in the south and I have a cousin who is an operator in a plant. So around family gatherings I hear much about the industry. I've been to TMI but never in, but I believe its a LEAKER because my family told me so, and the FACTS on the ground agree.
WE are not JUST getting low dosages from Fukushima, WE ARE JUST GETTING MORE DOSAGES FROM FUKUSHIMA. WE passed low dosages in the dayz of ABOVE GROUND TESTING.

@Will- so would "hobbiest" be an accurate term then?

Before July 1945, there was water on this planet that was NOT radioactive, earthquakes were just earthquakes, not world wide disasters, and leakers were the tires on a car. Steel was just steel with NO contamination from fallout. Diseases&conditions from radiation exposure almost nonexistent and basically unknown.
Ah, the benefits of low dosage.

Mike Meyer, I’m glad to hear you have relatives in the nuclear industry—that’s a noble calling indeed.

Mike, no one knows know how long it will take to stop the leakage at Fukushima. The point of the calculation I did above—I guess I didn’t make it clear enough—was to lay out a worst case scenario: what if they can’t stop it and it just goes on leaking for 300 years? How bad would that get? The answer I came up with is that it would not be bad at all—it would have an utterly negligible effect on the radioactivity of the Pacific Ocean, so tiny that it could not possibly harm anyone.

Why did I choose a 300 year time span? Because that’s how long it will take the Cesium-137 and -134 at Fukushima, which is virtually all of the leaking radioactivity, to decay away to nothingness. Remember Mike that cesium-137 has a half-life of 30 years. That means that, 30 years from now, half of the cesium-137 in the reactors will simply no longer exist, and after 60 years 75 % will no longer exist—not at Fukushima, not in the ocean, nowhere. Scientists count ten half-lives as the time needed for a radionuclide to decay to background radiation, so in 300 years, no more Cs-137 to worry about, anywhere. Cesium 134 has a half-life of 2 years, so in 20 years it will all be gone. Right after the spew the Cs-137 and 134 was about half-and-half, so by now about 30 % of the total has decayed away, in 30 years 75 % of the total will be gone. So no, Mike, the 300 year countdown does not start after the source is removed, it’s going on now, incessantly depleting the radiocesium.

So over the next few decades the radiocesium leakage from Fukushima will decline sharply because most of the radiocesium will no longer exist—the laws of physics dictate that. And the concentration of radiocesium in the Pacific will also decline sharply because the leakage rate will drop and because the radiocesium already in the ocean will also be decaying away.

That’s one of the mitigating aspects of radioactive waste—it is constantly decaying away to nothingness, so over the long term it’s a problem that solves itself. That’s not true of the lead, mercury and other heavy-metals generated by coal plants and solar panels and batteries and the like—that toxic waste is here permanently.

Now Mike, to err on the side of caution, the worst-case calculation that I did above assumed, counterfactually, that the radiocesium would not decay away at all. I assumed that the radiocesium dumped in the Pacific today would still all be there in 300 years, whereas in fact most of it will have decayed away after 30 years. On that basis I calculated that the total radiocesium concentration after 300 years (the endpoint when there will be no more radiocesium in the reactors to leak) would be 0.00015 % of the natural radioactivity that always exists in the Pacific. But of course that 0.00015 % figure is hundreds of times larger than the actual radioactivity will ever be even at a maximum, because it doesn’t take into account the constant ongoing decay of the radiocesium.

What about the Japan Current taking the radioactivity straight to California? That will not be a problem, Mike. Remember, the Japan Current carries an enormous volume of water, millions of cubic kilometers. The Pacific Ocean is so big that even a small part of it is also incomprehensibly large. Diluted in that vast volume, the radio-cesium will add an utterly negligible amount to the Japan Current’s natural radioactivity.

I actually included a Japan Current scenario above, by calculating what the additional radioactivity would be if the radiocesium were confined to a hotspot of just one one-thousandth of the Pacific Ocean’s total volume, which is smaller than the actual Japan Current’s volume. The number is 0.15 % of the natural radioactivity—and again that figure is hundreds of times higher than the real value would be, because it doesn’t take into account the decay of radiocesium.

So even if the Japan Current grabs every bit of Fukushima leakage and whisks it straight to California, the additional radioactivity will be far too tiny to make any difference. (Of course, the Japan Current is not Fed-Ex, so most of the radiocesium transported by it will not land in California but just swirl around in the deep ocean.)

The radioactivity from Fukushima leakage will never amount to more than a hundredth of a thousandth of one percent of the natural radioactivity of the Pacific. It doesn’t matter if some tuna fish or Malibu surfer soaks in it all their lives: the tiny extra bit of radiocesium cannot possibly have any discernible effect, especially when compared to the colossally greater natural radioactivity they are exposed to anyway.

Mike, radiation is not black magic. It works like any other potentially toxic substance: a big dose can hurt you, but an infinitesimally small dose cannot. It just doesn’t make sense to be afraid of an absurdly small increment of man-made radioactivity when the natural radioactivity we all get all the time is literally millions of times higher.

That’s about as clear as I can put it, Mike. If that still doesn’t convince you, I guess we’re at an impasse.

Will- I agree with that logic completely. Sadly it's missing one key point- recriticallity and the accompanying release of more (and poss

Will- I agree with that logic completely. Sadly it's missing one key point- recriticallity and the accompanying release of more (and possibly longer lived) isotopes. Data I've seen shows Fukushima has done that several times in the past 2 years, which kinda blows a hole in the "it's cooled, contained and stable" arguement, as well as the "radiation from it will naturally subside over the next century or three" arguement. Let's not forget, there's ample evidence for naturally occurring pockets of radioactive material to go critical on its own, so IMHO it's foolish to assume a man-made witches brew of recently-critical material is safe for the long run.

Will Boisvert: Cesium WILL be created from the breakdown of the uranium core as long as there is uranium. THAT'S how fission works.(190 metric tons uranium, per core)

Mike- Absolutely. This is quite a fundamental fact of life to overlook, isn't it?

Will- So, hobbiest or....?

Will- Nevermind; Google knows all, and I found my answer re: "hobbiest or...?".

Aric, no, there has been no “recriticality” at Fukushima. That’s an anti-nuclear urban legend.

There’s been a lot of speculation about “recriticality,” i. e., that chain reactions might re-ignite in the damaged Fukushima reactor cores. Claims that this has happened have proven false.

For example, a major recriticality furor started after TEPCO detected Xenon-135 in the Unit 2 reactor on Nov. 1, 2011. Xenon-135 has a half-life of about 9 hours, so people argued that it couldn’t be left over from the chain reaction that shut down on March 11, 2011; therefore a new chain reaction—recriticality—must have been producing the Xenon-135.

But then on Nov. 4, 2011, TEPCO issued an analysis saying that the traces of Xenon-135 resulted from “spontaneous fission”—heavy radionuclides spontaneously breaking apart in the absence of a chain reaction, a well-known process. Their argument was that the Xe-135 traces were smaller by orders of magnitude than the known production rates in chain reactions, and that they persisted after the core was smothered with borate. (http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/111104e19.pdf)

Furthermore, recriticality is essentially impossible. Here’s why:

People have the impression that fission chain reactions are always champing at the bit to start up and can only be restrained with great difficulty. That’s not really true. It’s extremely difficult to get a CR started or to sustain it; the art of nuclear engineering is the precise assemblage of reactor parts and operating conditions to coax to life a CR that would prefer to fizzle out.

For example, in light-water reactors like the Fukushima ones, the fuel has to be covered with water, which is the moderator. Neutrons slow down when they bounce off hydrogen atoms in water, and that makes them easier for U-235 nuclei to absorb during the chain reaction. If cooling water boils away, the chain reaction instantly stops.

The chain reaction also requires that the fuel be in a “critical geometry” that has a sufficiently low ratio of surface area to volume. Without a critical geometry, too many neutrons leak out through the surface of the fuel elements before fissioning another nucleus, and the chain reaction cannot sustain itself. The critical geometry also has to have water channels running through it, so the neutrons have a chance to be moderated. But if the fuel melts, it loses its critical geometry.

Also, all the Fukushima reactors were shut down before the tsunami by having boron control rods inserted into them. Boron is a neutron poison; it absorbs the neutrons before they can fission a nucleus. You can’t have a chain reaction with boron in the fuel.

So when the water boiled away in the reactors, recriticality was impossible because there was no moderator and because the boron control rods were there. After the meltdown what you had was a shapeless corium melt without a critical geometry but with lots of boron mixed in. Nowadays the fuel is covered with water again, so the moderator is there, but it’s water laced with boron—boron everywhere and no critical geometry. There’s just no way you can get a chain reaction out of that. If by some miracle it started up again, it would fizzle out as soon as it boiled away the moderating water. But that could never happen anyway. Those reactors are dead.

--longer-lived isotopes are less radioactive than radiocesium, and therefore usually less of a health risk. Remember, the radioisotopes with half-lives in the thousands of years are long-lived precisely because they are not very radioactive and thus not very toxic.

Well, Will, good buddy, when I see you on an episode of House Hunters International on the HGTV scouting out your dream house right down the coast from the former Fukushima Nuclear Power Plant, I might listen to your loquacious spewings with more attention. But until then, I'm going with Aaron, Mike, and Aric. For now, I'm treating your argumentation with circumspection, as is its due.

Will- Seriously? No recriticallity at Fukuhsima?

Ok, I'll bite... how else do you explain intermittent clouds of radioactive cesium wafting over the US by way of the jet stream? Which, I might point out happens to draw a nice wavy line from Japan to the US?

Let me put it this way, Will... Saying something has been proven false is not the same as proving it false. Saying that there are PhD meteorologists on staff at good universities who don't buy into global warming doesn't mean they actually exist.

Frankly I'm still on the fence about "(misguided) hobbiest or paid nuclear energy shill", but frankly you're quacking, so it doesn't really matter which. Either way you've got way too many of the fundamentals wrong, so not worth listening to.

Case in point (among many), for you to ponder, while downing a capsule of plutonium: "Remember, the radioisotopes with half-lives in the thousands of years are long-lived precisely because they are not very radioactive and thus not very toxic."

Erm, should probably explain that a bit... It strikes me quite odd that a self-professed leftist environmentalist with anti-tech leanings who mainly writes/edits a Chicago-based Socialist newsletter would suddenly go pro-nuclear upon hearing about the Fukushima disaster, and suddenly posses such a (seemingly) deep (yet ultimately flawed) understanding of nuclear physics and the effects of exposure to radiation. Just doesn't fit, and as I said earlier, Google knows all.

OK, if you're implying that he's an industry flack, that seems like possibly a reasonable point to make. I was starting to feel that repeatedly harping on his lack of formal credentials seemed sort of dickish. And that's all I've got to say about any of this.

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Good point Aric, most plutonium isotopes are a bit more toxic than cesium-137. Some other long-lived isotopes like Cs-135, half-life 2.3 million years, are less toxic. (http://www.evs.anl.gov/pub/doc/cesium.pdf) I shouldn’t have generalized.

Can you give me a link to that data on intermitten clouds of cesium 137? And can you show how the intermittent clouds prove recriticality? Because any process that lofts any cesium-137 into the air can potentially spread it around the world. For example, cleanup efforts in Japan that loft Cs-137-contaminated dust into the air might do it. Or if for example, the cores of the Fukushima reactors became uncovered by water, they might heat up and volatilize existing Cs-137. That would result in more Radiocesium spew, but it wouldn’t be coming from recriticality.

Aric, Richard Lindzen is a professor of meteorology at MIT and a global warming denier. So they do exist. (http://en.wikipedia.org/wiki/Richard_Lindzen#Third-party_characterizations_of_Lindzen).

I don’t write/edit a Chicago-based Socialist newsletter. I live in New York. I don’t have anti-technology leanings, but I am a against lousy, harmful, ineffective technology. There’s no sinister agenda behind my support of nuclear power. I’m an environmentalist who is concerned about global warming. Nuclear power is a prodigious, reliable source of clean, low-carbon energy. I think it’s indispensable if we’re going to fight climate change. Having studied up on the issue, I’ve found that anxieties about the risks are simply not warranted; the science shows that the health effects of nuclear spews are modest to nil, and otherwise nuclear power is the safest energy source bar none. Lots of leftists are coming around to that view, and I hope you’ll consider it, too.

One more issue is really that video gaming has become one of the all-time largest forms of fun for people of any age. Kids enjoy video games, and adults do, too. Your XBox 360 is probably the favorite gaming systems for people who love to have hundreds of games available to them, in addition to who like to experiment with live with other people all over the world. Many thanks for sharing your ideas.

@Godoggo- Dickish? Perhaps. But reading over his posts here and elsewhere it seems he's familiar with the subject well beyond what someone who merely reads blogs and regurgitates would be, which implies either academic training or working in the industry. For me "reading all the science" doesn't cut it, and I find his refusal to actually say what his background is suspicious.

@Will- Sorry if I'm incorrect about who you are, but posts of yours elsewhere pointed you to being an editor at In These Times, which is in fact a Socialist magazine based in Chicago that lists Will Biosvert as a Contributing Editor.

Aric, could you please provide some links to the data you have referred to that demonstrate recriticality in the reactors? Some evidence that we could look at that can’t be easily explained by other causes? Or could you explain how a fission chain reaction can restart in reactors that lack a critical geometry and are smothered in boron, a neutron poison? If you can’t do these things then it’s time for you to reconsider your belief that recriticality has occurred at Fukushima.

I feel that your energies would be better spent researching the substance of these issues rather than investigating the “backgrounds” of people who have the temerity to disagree with you. You could then make a more enlightening contribution to the debate, rather than wasting everyone’s time flinging false and utterly baseless insinuations at others, like the conceit that I am a “paid nuclear energy shill.”

The anti-nuclear position you hold clearly advances the interests of coal and natural gas-fired power plants, which are commercial competitors of nuclear power. You are also blogging under a pseudonym, rather than using your real name as I have done. Should we therefore conclude that you are a covert paid operative of the coal and gas industries? Of course not, and you wouldn’t like it if I did.

So please, stop with the McCarthyite smear tactics. Argue your case on the merits and present evidence to support it, or else leave the forum to other people who can.

Will, I'm sorry of you feel my wanting to know you background in order to better judge your position is McCarthyesque. As I've stated before it's important to know where someone is coming from to fully understand their position. For whatever reason the idea of a pro-nuclear leftist environmentalist freelance writer with such a seemingly deep knowledge of things nuclear makes little sense to me, except when said person works in the industry. I'd very much like to take you assertion that you "read all the science" at face value, but for the average person to assimilate this sort of thing to this depth without at least a background in engineering or the sciences? I don't know about that, which is why I'd like to know how it happened for you.

As for the requested links, afraid I'm going to have to pass as you've already stated your position on the matter above. Same goes for recriticallity and neutron poisoning as well... It's all covered above and no need to hash it out further. Your belief is the cores are contained and cooled, my belief is they are not and are subjected to groundwater infiltration. Truth is neither of us really knows for certain, but until you can provide direct evidence of containment, the fact that emissions are ongoing suggests that you're wrong.

Btw, my name actually *is* Aric, and no, I am not a fan of coal or gas. Or even hydro and most types of solar for that matter. Not that any of that makes a difference.

A finite amount absorbs ONLY a finite amount of neutrons. Once "full" the boron itself becomes a neutron emitter, same as water.

AND "geometric configuration" is for a CONTROLLED reaction. For the regular uncontrolled reaction one only needs CRITICAL MASS.

"That said, if the curve is linear-quadratic then that implies that LNT overstates radiation risks at low doses."

Yeah, I know. I'm not doing too well making my points succinctly or clearly in either this thread or the other.

OK Aric, since you flat out refuse to cite any, we’ve established that there is no evidence at all to support your claim of recriticality at Fukushima.

I never claimed that the Fukushima reactors were contained. In fact, the calculation I did upthread explicitly assumed that they would continue leaking without containment for 300 years. Aric, it’s wrong to misrepresent what other people say, and stupid to do so when readers can just check upthread to verify the truth.

The business about my “background” is the oldest trick in the propagandist’s playbook. When you can’t answer the arguments a man makes, then attack the man—attack his background, smear him with lies about his motives, question his right to speak at all. That kind of bullying insinuation tells us nothing about its target—and everything about the person hurling it. It is clearly meant to distract attention from the fact that you have nothing cogent to say about nuclear power, and no evidence to back up your position.

Aric, it’s not going to work. No one cares about my background and credentials, or yours. What people care about is the quality of substantive reasoning and information that commenters can add to the debate. So come back when you’ve learned something about nuclear power and can participate intelligently, without stooping to name-calling and innuendo.

Jeez Will, got your panties in a bunch or something? Seems my post a bit ago got rejected as spam due to too many links, so here's a new one.

Simply owning a copy of Physicians Desk Reference doesn't make you a doctor, as reading doesn't necessarily lead to understanding. You said you "read all the science", and I'm asking how that lead to understanding. Quite the fair question in the context of supporting your arguement, as your expertise clearly goes beyond simply being someone that's read a couple blogs and formed an opinion.

Secondly, saying that my not citing any proof of recriticallity is proof it didn't happen is quite the logic fail. if you recall, I specifically said I was not going to cite anything because you clearly have your mind made up on the matter, so there's no point to it.

But since you insist, for the links that got booted simply go to Google and type in "Fukushima recriticallity". Then scan a couple articles, note some dates and then head over to Radnet. Not hard to do.

Alternatively, the folks at Potrblog.com did a decent job of covering the topic, but I fear you'll dismiss them as "alarmist".

Now, kindly tell me something about yourself... :-)

Ok, perhaps I've taken the wrong tack with you, Will, and for that my apologies. From the other direction, as a ditch digger/housewife (actually true, as is my name on the post), given two seemingly equly valid arguements which should I pick as true? The one where the guy takes the time to pay out his credentials, or the one who doesn't (and may well believe Jesus rode a triceratops)?

Seriosly now... I've *never* run into a freelance writer who didn't at least include a little "lives in NYC and enjoys fishing", yet here you are taking an authoritative stance on everything from a biography of Lincoln to slamming the MIT Media Lab over their work with Kindle (iirc, Not that it matters) to the effects of liability insurance on nuclear power plants. Seriously? Not even going to give us a little nibble as to your background? Not even a passing mention of working for In These Times or The Baffler? Or enjoying long walks in Central Park? Seriously, not even a little bit to humanize your story to make it believable?

Frankly it doesn't take a rocket surgeon to see someone with a paid agenda.

Wow, what happened here? This is fantastic!

Maybe I should read it.

What happened is I found out that the only credential Will has is that he's a friend of a friend of a friend of the site owner, and is playing that as a means to expand his movie reviews into nuclear stardom.

Will, face it.... You're a fanboy, not a nuclear engineer. And have drank the Kool-Aid. I'm sorry for labeling you a shill.