Nuclear: difference between two and three degrees?

A week into the crisis at the Fukushima Daiichi nuclear plant, the situation seems to have stabilised – though with reliable power not yet restored to several of the damaged reactors, and fuel assemblies in units 1, 2 and 3 still not fully immersed in water, there is a long way to go before proper ‘cold shutdown’ is achieved. Even so, my earlier prediction that there would be no significant risk to any members of the public – and no radiation-related deaths or injuries amongst the workforce – seem to have been borne out by events.

Chinese shoppers panic-buy salt; blood pressures soar

My new prediction is that those who lost their nerve and panicked will end up when final judgement is made being seen to have made the most negative contribution to the sequence of events in Japan. Top of my list is the Swiss, who have apparently decided to move their embassy from Tokyo to Osaka because of fears of radioactive fallout. I do hope their staff have a safe journey: they will be exposed to vastly greater dangers from an accident on the road journey down to Osaka than if they had stayed put in Tokyo with its infinitesimally raised levels of radiation.

There have been breathless press reports about radioactive iodine being identified in milk and spinach produced in Fukushima prefecture, whilst a shipment of fava beans to Taiwan has also been discovered to be ‘contaminated’. I would personally quite happily consume any of the above: the risk is so small as not to be worth taking seriously. It is a measure of our shared preoccupation with all things radiological (except medical procedures, where people subject themselves to much higher doses of radiation without a second thought) that such tiny risks make headline news.

The political fallout from Fukushima will be far more dangerous than anything physically radiaoactive. In Taiwan, in shock because of its entirely safe consignment of fava beans, thousands have protested against nuclear power, whilst the government has decided to delay the start-up of a new reactor. In the UK, even the level-headed Chris Huhne has mulled over backing away from nuclear, whilst Switzerland has suspended plans for three new reactors. Reflecting the political clout of the Greens there, the most extreme action has been taken in Germany: the country has shut down seven of its oldest plants, and suspended plans to extend licenses on more.

Apart from Europe, the other big players in this debate are the US and China. For the former, it is unclear which direction the administration will tip. It has enough well-informed scientists to know perfectly well that the Fukushima accident says nothing much about the future of nuclear power in America, but public opinion must be bowed to – and West Coasters have been rushing out to buy iodine pills and seaweed in order to feel that they are doing something as the ‘radioactive plume‘ drifts their way (though I would rather breathe that than LA smog anyday).

For China, the regime has seemed to be very sensitive to public fears of nuclear danger – and the fears so far have been extreme, and entirely out of proportion to any danger. The authorities were unnerved by outbreak of panic-buying, as Chinese citizens stockpiled salt in the erroneous belief that it would protect them from any radioactivity spreading from Japan. Needless to say, this is not a public climate likely to be friendly to additional nuclear power in China. Its government has suspended work on 26 reactors under construction, and is reconsidering plans for more than 60 more.

There was some early talk about how the renewables industries would benefit from a shift away from nuclear, but the real benefits will fall – as I also predicted – towards coal and other fossil fuels. Having shut down its nukes, Germany is already importing much more coal from the US and other countries, as is Japan. “The market looks pretty good for Europe for the longer term,” one coal exporter told the Wall Street Journal. I’ll say. The market for coal in China looks pretty good too.

This is a good time, then, to try to make a first-guess numbers-based assessment of what running down nuclear and switching back to coal and gas will mean for carbon emissions going forward. Let us assume, therefore:

  • A German nuclear phase-out, producing another half-billion tonnes of CO2 by 2020
  • A US phase-out, replaced by an equal-parts mix of coal and gas by 2030, producing another half-gigatonne per year by then
  • 100 Chinese nuclear plants not built by 2030, each replaced by coal emitting 10 million tonnes per year (=1 gigatonne CO2/yr)
  • no nuclear renaissance elsewhere, and an additional half-gigatonne from other OECD countries (Japan, UK, rest of EU)
  • a business-as-usual baseline of mitigation pledges submitted by countries to the international climate negotiations
  • nuclear/fossil fuels are substitutable: both deliver baseload to densely-populated industrial societies, and renewables increase flat-out anyway to cover increases in demand

This gives us, by 2030, another two to three billion tonnes of CO2 per year. Given that the 2020 ‘gigatonne gap’ (PDF tech. summ.) identified by UNEP amounts to as little as 5 gigatonnes per year (this is the gap between projected emissions and what is necessary to stay below two degrees) the amount is substantial, enough perhaps to tip the balance between a 2-degree and a 3-degree scenario. As my book Six Degrees explained, above two degrees lie some very dangerous ‘tipping points’ which could take the biosphere in the direction of uncontrolled global warming.

It would be overstatement at this point to say that the world’s reaction to the Fukushima nuclear crisis could make the difference between controlled and uncontrolled global warming. There are too many needed assumptions to make this kind of prediction with any confidence, and electricity generation is only a part of the world’s dependence on carbon-based energy (don’t forget deforestation, transport, agriculture etc). But I think this exercise at the very least helps us face up to the reality of risk: and the risk facing the biosphere from climate change is many orders of magnitude greater than anything resulting from even a succession of worst-case-scenario nuclear accidents. Many greens point out that wind farms and solar panels are even less risky than nukes: this is debateable, but even if one is to accept it at face value, there is another risk at play here – that the anti-nuclear, pro-renewables strategy holds a higher risk of not sufficiently mitigating global warming.

Even a week after Fukushima, I still think a pro-nuclear, pro-renewables, pro-efficiency strategy is the least risky of all, at least as far as the future of the planet is concerned.


  1. Robin Smith

    Would it sound like conspiracy theory to suggest that the Swiss, through their banking “industry”, laundered Big Oil money to fund the anti nuclear movement, without anyone knowing it? All the motive is there for Big Oil to do this. You may have received some of it yourself before you went to the dark side. Who knows?

    The real opposition to nuclear power being Big Oil? And the kleptocracy that let it happen in the name of the people? (BTW ALL the leaders we have elected over the past 30 years)

    Maybe not conspiracy theory. Perhaps coincidence theory, I’m not sure. Just a thought.

    PS I’m neither socialist nor libertarian. I prefer freedom AND equality.

  2. david on formosa

    The delay in opening Taiwan’s fourth nuclear reactor probably has little to do with politics or the Japanese nuclear incident. The project has suffered from numerous delays and they are most likely due to problems with construction or systems testing.

    1. Tom Blees

      Actually, the construction delays were due to pest lawsuits, from what I heard about it. This ABWR design had already been successfully built (VERY successfully, the first two being built in just 36 and 39 months) in Japan. The delays, which were political, cost a lot of money since the interest clock keeps ticking, and drove the cost/kW up much higher than either of the plants that had been built in Japan. This is exactly what utility companies in the USA fear about taking on a project like that, one of the reasons why the price tag is so much higher (usually 3-5 times higher) than building the exact same design in the Far East.

  3. Caspar Henderson

    Thanks for a useful exploration of the numbers. I’d sketch a strategy for a less global energy mix as follows:

    1) pro-efficiency and demand management (this should be huge);

    2) pro-renewables and investment in energy storage technologies (this too should be huge);

    3) everything else, including both nuclear so long as the four 4 ‘stress tests’ as recently outlined by George Monbiot are met ( and fossil fuels so long as carbon capture and storage plus all other necessary measures such as protection of environment from heavy metals etc. are also fully implemented.

  4. BlueRock

    > Nuclear: difference between two and three degrees?

    Assuming we sit on our hands and don’t use the billions of $$$ saved to rapidly deploy clean, safe, never-ending renewable energy.

  5. Pingback: Divergent Lessons from Japan's Calamity for McKibben, Monbiot -

  6. patsi baker

    What makes you so sure the Japanese are being open with information?

    with a record like this…

    1. G.R.L.

      New Scientist probably sees that history as useful pro-fossil-fuel propaganda, but to me it seems to record an adversarial relationship between the nuclear part of Japan’s power industry and the Japanese government.

      This could stem from royalty income on natural gas that is also used to make electricity there. Letting the nuclear sector burn a dollar’s worth of uranium means the gas sector doesn’t burn $15 to $20 (as I recall, haven’t checked prices recently) in natural gas. (Spectacular photos of how natural gas performed, safety-wise, in the recent earthquake here.)

      If its royalty take is typical, that means the Japanese government has lost hundreds of millions of dollars in gas royalty income for each life the nuclear sector has saved. This motivates them to do their best, in dealing with the nuclear mishap, to keep fear alive.

  7. Pingback: The 'Dread to Risk' Ratio on Radiation and Other Matters -

  8. patsi baker

    Physicians for Social Responsibility

    23 March, 2011

    Washington, DC – March 23, 2011 – Physicians for Social Responsibility (PSR) expressed concern over recent reports that radioactivity from the ongoing Fukushima accident is present in the Japanese food supply. While all food contains radionuclides, whether from natural sources, nuclear testing or otherwise, the increased levels found in Japanese spinach and milk pose health risks to the population. PSR also expressed alarm over the level of misinformation circulating in press reports about the degree to which radiation exposure can be considered “safe.”

    According to the National Academy of Sciences, there are no safe doses of radiation. Decades of research show clearly that any dose of radiation increases an individual’s risk for the development of cancer.

  9. K9T


    Then you won’t be taking any flights from LA to NY anytime soon, I hope. Or getting a CT-scan or mammogram for any reason. The extra radiation you receive from those two medical procedures alone are akin to spending 1 day ON SITE at the Fukushima Daiichi power plant (much more than 30 miles away – exposure falls off with distance squared). I also hope you don’t eat bananas. The radiation dosage you get from one banana is akin to what you receive for a full year living next to a nuclear power plant. Heaven help you if you live in Colorado (as I do). You’ll be sprouting new arms within a week!

    [Source: (author is not a nuclear scientist, but these ratios have been widely known by nuclear scientists for decades).]

    And elevated risk? Like a whopping DOUBLING from .00001% to .00002%? “Physicians for ‘Social Responsibility'”? Sure sounds official, doesn’t it? Like some sort of certified medical board. Hence, they have to be experts at radiation exposure! ANd note the article doesn’t explicitly say this “council” of physicians said that the increased levels posed a health risk. The Wash Post said that. All the physicians did was “express alarm about misinformation in the press reports”. Lesson: Don’t take everything you read at face value just because you want to believe it.

    Nuclear power is to coal like air travel is to driving: much safer, much cleaner, and yet a target of fear-mongering based on a relatively small number of events (while the less-safe option’s catastrophic events are swept under the rug).


  10. M

    Don’t forget the impacts of a switch from nuclear to coal on:

    air quality (particulate matter, sulfate/acid rain, etc.)
    mercury emissions
    radiation levels under normal operation (see the xkcd chart: living 50 miles from a coal plant results in 3 times as much radiation exposure as living 50 miles from a nuke plant. This doesn’t take into account disasters, of course)

    I don’t know if I’ve seen a good analysis of the tradeoffs on the mining and waste sides: obviously, coal is pretty bad for mining between miner deaths and mountaintop removal, but I don’t think uranium mining is pretty either, and I don’t know how that ratio looks per megawatt of power. On disposal, nuclear waste might be more disturbing and longer lived, but the slurry lakes from coal mining aren’t great either. It would be good to look at water use (see Fire on the Plateau for the use of water in Colorado for coal mining, but nuclear plants also rely on nearby rivers for cooling and have impacts that way).


  11. patsi baker

    So now events now show your predictions to be wrong, Mark.

    you said “…no radiation-related deaths or injuries amongst the workforce – seem to have been borne out by events.”

    Ok so now there are at least two workers who have been hospitalised.
    Another 17 have received high levels of radiation (100 mSv).
    the radiation levels in the sea have skyrocketed.

    Looks like the reactors have been leaking

    the water in the basements is so contaminated they are having problems removing it – ( where are they putting it?)

    What say you now?

    1. Mark Lynas (Post author)

      Yes, I have also seen reports that two workers have suffered radiation burns to the legs as a result of contaminated water overtopping their boots. I am sure that, whatever our differing positions on this issue, you join with me in hoping that there are no more workers exposed to further hazards or injury during the continuing stabilisation and clean-up operation.

    2. tahrey

      Perhaps it would be more truthful to say “serious injuries”, then. Of the type you can’t easily or fully recover from, or spend a long time doing, for example. Rather than a simple “burn” which has much the same effects as lying out in the sun too long (that’s also a radiation burn – technically arising from the heat and drying of skin plus IR radiation or visible light, and even near-UV… but most comparably, from the ionising far-UV, which is what your sunblock aims to keep from penetrating too far) and is not even close to being radiation sickness or a risk to health. You *may* have a slightly increased risk of melanoma at that site (as you do with sunburns), so they should hopefully be warned to keep a look out for growing moles or lumps in the burn area, so they can be safely excised whilst still benign if they prove to be cancerous.

      100mSv, in the scale of radiation risk, is hardly anything. You still have about 900mSv of headroom before we reach the point where there’s a reliably measurable increase in the (already fairly considerable because of natural or “less risky” man-made causes) lifetime cancer risk. It’s double the normal, pretty-cautious radiation worker annual limit (they won’t be back on the job any time soon, I’d guess), and 5x that of the very cautious limits for more civilian staff who have to work with radioactive materials (e.g. hospital radiology staff)… but that’s sort of like saying you can lift a 100lb weight before you’re at risk of doing yourself any injury, so let’s freak out because you lifted a 10lb one… and that’s outside your normal 5lb or 2lb limits (…with the lifting limit for everyday folk being 0.1lb, and the weight of your hands (= average background exposure) being 0.3lb).

      It is, after all, only equal to the limit placed on staff rescuing “valuable property” – so maybe they reached 100.1mSv and got pulled out, given that the plant probably qualifies? – and a mere 40% of the limit for those doing jobs with lifesaving consequences. Presumably their on-site radiation protection officer doesn’t believe that they are any longer involved in work that has the life or death of other civilians or workers riding on it, and so isn’t prepared to risk THEIR health by allowing them to go to the higher exposure level.

      I do hope that a bit of mild skin irritation or possibly some peeling is all that the workers who were exposed suffer from, and there are no long term-effects – either from this or naturally. I can’t see it being any higher unless they’re very unlucky. There are radiotherapy procedures that have worse effects on some parts of your body, on purpose…

      However I am, and have been watching the proceedings at the plant – and reading the press releases etc – with somewhat horrified curiosity. They have both been, and continue to be very unlucky it seems, and the whole thing isn’t being very well managed. Even before the initial announcement it seemed pretty clear that there were cracks in the containment pools etc which is why low-level waste (exactly what level is unclear) was leaking to the sea, and collecting in troughs around the site. It’s by no means over yet… they’ve got to get the cracks plugged, the fuel properly cooled and as much as possible removed to safer storage, the molten parts broken up and removed, and the whole place decomissioned (it was almost at that point anyway). Then a replacement built somewhere safer, as the country is seriously hurting from a generator of that size having gone offline. They’re still in the middle of rolling blackouts to keep demand down (yes, even with everyone hopefully doing their best not to waste power, and some areas having been disconnected by the quake). I wonder how many serious injuries or even deaths may have occurred as a result of THOSE? The external environmental issues can probably wait until that’s done… the seawater contamination will disperse (do we even know if it’s worse/equal/not as bad as Windscale/3MI etc in terms of water release yet? I lost that particular thread)… the most troubling thing would be contamination of soil with heavy, long lived isotopes, as those don’t wash out all so easily and could hang around for years. But the scale of releases so far don’t suggest a wide area being significantly affected; maybe a small area, or a wide area being insignificantly contaminated, but not both.

    3. tahrey

      A minor retraction/apology having rechecked my sources:

      I could’ve sworn that 1Sv (aka 1000mSv) was the lower bound for cancer risk, not 100mSv… appears that was mistaken. I’m not sure where that came from, but probably memory-poisoning by dodgy BBC News reports or something. Possibly that’s the minimum level for prolonged radiation poisioning or something? (If the minimum for sickness is about 400 and that of severe poisioning is about 2000)

      So, they may well have a higher risk in this case. But it will be very minimal all the same, and stochastic – it’s RISK, not a guarantee of getting some smaller cancer. If any of them smoke, quitting will vastly reduce said risk out of all proportion to this event. Or getting more exercise and drinking less alcohol than they currently might. Moving to an area with less natural radon in the air. Etc. Changing job, certainly. And staying away from roads to reduce their overall risk of death. All these will offset it in spades.

      Please consider what I said about the doses a little differently in light of that. Presumably we consider a minimum-measurable increase in cancer risk acceptable for saving valuable property, or 2.5x that exposure (not sure if that’s 2.5x the risk then … or an extra 0.0025% (number pulled out of air) vs 0.0010%… or some other exponential factor is involved) for saving other’s lives – IE, those who would have a fair certainty of being killed outright by the incident or something related to it (e.g. falling slabs after another aftershock and “we” need to run through a super-high-dose-rate area to pluck them to safety) if we didn’t act in that way.

  12. Colin Wright

    The more I learn about Chernobyl, the scarier Fukushima seems. It wasn’t 4000 who died from Chernobyl as the WHO/IAEA claim but close to a million.

    Now consider Japan is a densely populated small island and what will happen if the plutonium reactor meltsdown. (A microgram breathed into the body is enough to cause leukemia.) Do we just sacrifice the population of Japan?

    The only answer is a WW2 mobilization for a massive renewable build out.

    1. Mark Lynas (Post author)

      I am surprised that Friends of the Earth participated in this conference comparing Fukushima with Chernobyl. Dr Yablokov’s comments on this are more far-out than anything the climate change ‘deniers’ say about global warming. You can’t just pick and choose your ‘science’ (or your scientists) when it supports you – that’s surely the lesson we have learned from the climate battles. Either we go with the consensus opinion or we support the contrarians, and in this case the consensus position is that 50 people died, 4000 more might over future decades. So Yablokov saying a million have died is very extreme indeed.

    2. Barry Woods

      Compare this with Caroline Lucas or Franny Armstrong or many other environmental activists that are stating that hundreds of thousands of people are dying of climate change now (man made)

      Yet the consensus amongst scientists, would NOT attribute any recent extreme weather event being attributable to any sort of climate change man made or natural. (ie the consensus amongst scientists would NOT attribute any current deaths to man made global warming)

      The scientific position is that these type of event MAY increase in frequency. Yet no one corrects these lobby groups alarmism.

      The russain heatwave for example was held up immediately as man made climate change, months later NOAA say it was not attributable (whilst saying these events may increase)

      The sad thing is most of the deaths in the world due to extreme weather event (which have always been with us) involve the poor. If the focus was on how to improve the infrastructure, etc how many of these would have been saved.

      Japan just suffered a massive earthquake and tsunami, does any one doubt if Japan wasn’t a 1st world country that had a lot of preparation and infrastructure and the wealth to deal with the afterment, that the number of death would have been far higher.

      ie if the same events had occured off the coast of Haiti, or any other developing country, the death toll would most likely been hundreds of thousands. And in the aftermath, disease poverty would add many more. In Japan a main road was rebuilt in 6 days, in Haiti it might be 6 years or never.

    3. M

      “Yet the consensus amongst scientists, would NOT attribute any recent extreme weather event being attributable to any sort of climate change man made or natural. (ie the consensus amongst scientists would NOT attribute any current deaths to man made global warming)”

      First sentence: mostly correct, in my opinion. Parenthetical: mostly incorrect, in my opinion. You don’t have to be able to attribute any specific weather event to global warming in order to believe that the best estimate of deaths caused by global warming is not zero. My understanding is that the majority of scientists working in the field have the opinion that human-induced climate change resulting from increased GHG concentrations has led to increased deaths, even if they can not point out a specific corpse whose cause of death was “AGW”.


    4. Barry Woods


      we have hundreds of years of records of weather events… There is nothing to show that the frequency or severity of extreme weather events are anything but within the realm of natural variability…

      If there were. I’m fairly sure everyone would agree in this ‘environment’, that the scientists, etc would be shouting it from the rooftops..

      so ‘believe’ what you like.. The scientific evidence is not there for the alarmist claims some NGO and environmentlist groups make.

      What may happen in the future is a fair discussion. But they make these false claims now.

      and use it to say, people are dying now, you must listen to us and do what we say..

      sorry no. Evidence please, not alarmist emotional ‘beliefs’

    5. Colin Wright

      Dr. Yablokov has over 400 published papers, 20 books, is a member of the Russian Academy of Sciences, was an advisor to Gorbachev and Yeltsin. He reviewed over 4000 papers in slavic languages that the WHO/IAEA ignored. Over 100,000 alone of the 800,000 clean-up workers died. His co-author who flew over Chernobyl died of cancer. These are facts that can be checked. The Chernobyl book is published by the NY Academy of Sciences. (Unfortunately, I can’t find any free access). But here he is:

      A crank? I doubt it.

      The consensus of the nuclear-governmental complex (regulatory capture, I suspect) will always be that nuclear power is perfectly safe and the only option for dealing with AGW. Let’s check the facts before throwing out the “outlier data”. Future generations will thank us.

    6. Colin Wright
    7. Jeff S

      “Over 100,000 alone of the 800,000 clean-up workers died.”

      But *did* they die because of Chernobyl? That’s the central problem with that report, as far as I know. I’ve seen some rebuttals of that report, which point out that in the report itself, the authors specifically claim that they have chosen not to use standard scientific tests, mathematics, and methodologies that are normally used to try to determine if the deaths are in fact a result of Chernobyl.

      They, in essence, counted up every death that has occured since Chernobyl’s meltdown, even those deaths from causes which have no known link to radiation exposure, and said that those must be a result of Chernoybl (at least, according the analysis I’ve seen of the report).

      One of your statements is very illustrative of this. . . “His co-author who flew over Chernobyl died of cancer.”

      A sample size of one, as any scientist will tell you, is useless. Without any exposure to radiation outside of natural background, people start with about a 20 percent chance of getting cancer, from the sources I’ve read. How can you say that hi co-author’s cancer was actually the result of flying over Chernobyl. I mean, how often did the guy fly over Chernobyl? Once, twice, hundreds of times? Was he flying in an airplane where he was only “over” Chernobyl for maybe a minute, or was he in a helicopter where he stayed suspended over it for maybe 1/2 hour? What was the actual radiation dosage he was exposed to – did he fly over it during the worst part of the meltdown when there was a highly radioactive smoke plume coming out, or are we talking about flying over it years later when there was virtually no radiation coming out of it anymore (because of the sarcophogus)?

      Your statement leaves out so many details, it’s useless in proving the point you’re trying to prove.

  13. shaun burnie

    On the issue of health risks from the Fukushima accident I would draw attention to the French government’s IRSN – hardly a bunch of anti hysterics, and the Austrian In the case of the IRSN their estimation covering reactors 1 – 3 and the time period between 12.03.2011 and 22.03.2011: 90,000 TBq j-131, 10,000 TBq Cs-137 (plus specification covering other nuclides); in the case of ZAMG – they have published estimations covering the total release of J-131 and Cs-137 in the first four days. This estimation has been specified on the 23.03.2011: 400,000 TBq J-131, 85,000 TBq Cs-137. The conclusion of Dr Helmut Hirsch advisor to the Austrian Government, and former advisor to the Government of Lower Saxony is that:

    1 – the releases so far are 500,000 TBq iodine equivalent;
    2 – that the Fukushima accident (ongoing) is already a level 7 on the INES;
    3 – that it may actually be 3 level 7 events;

    Chernobyl was until now the only level 7 INES.

    The consequences for the long term health of the Japanese population may indeed be more serious – there is no graphite fuel at Fukushima – so no high altitude release – but that is the problem – it means the radioactivity venting from the plant will be concentrated over a smaller land mass – namely the densely populated land mass of central Japan (to date perhaps 90% of the releases have ended up over and in the North Pacific) with wind changing daily/hourly deposition in the Kanto region will expose 42 million people to elevated levels of radiation. Population density comparisons highlight the risks – Belarus where largest % of Chernobyl deposited – 40 persons per sq/km; Japan average 700 psq/km; metropolitan Tokyo 1200 psq/km.

    Would be interested to hear how this squares with radiation not a problem beyond 1km from the plant ?

    I’ve worked for over 20 years in Japan, including at Fukushima. My thoughts are with the people and the workers battling to bring the situation under some control. Hyping the threat is irresponsible – but dismissing them all together is deeply disrespectful to the people of Japan.

    1. tahrey

      OK, first of all, writing Iodine 131 as “J-131” doesn’t help your cause much.

      Secondly, want to give us any kind of indication as to what the severity of contamination – either individually or comparitively – the release of 400 petabequerels of I-131 and 85 petabeqs of Caesium 137 over a 96 hour period actually entails? I’ve worked in a hospital handling tracer sources for injection, sometimes including I-131 (with individual activities tens- or even hundreds-of-Megabeq range) and I’d have a hard time telling you; partly because I can’t remember the exact specs and am having trouble finding examples online (I have a feeling that the much faster decaying Tc99m tracers were a few hundred MBq per dose, and I-131 was a little under 100M). You sound pretty knowledgable, please, fill me in.

      ….actually let’s have a crack at this now my googling has had some success.

      Administered dose for a diagnostic I131 thyroid scan (as in, one that is imaging only and judged to have an overall beneficial risk-benefit ratio) ranges from 37 to 370MBq, though about 74Mbq is more typical.

      So, that’s a dose of Iodine 131 with a total rate of 74,000,000 disintegrations per second at point of administration being put INSIDE a human being – in their bloodstream in fact. Concentrated in about a cubic metre of organic material, and ultimately in as little as a few CC’s, as the idea is for the thyroid (or in the case of the test in question, any remaining cancerous thyroid tissue subsequent to surgery and/or radiotherapy) to take it up as strongly as possible and make a nice bright glow on a gamma-camera screen (…and the rest of it generally passing out through the kidneys – another few cc’s – and the bladder… a couple hundred cc’s much of the time).

      (In fact … there’s a thing … how can we have XXX terabequerels released “over four days” – it’s a measure of instantaneous activity, not total received dose. Is that material being released such that its overall activity averaged 400,000TBq over that 4-day period? If it stayed absolutely steady during that time I’d be amazed… an uncontrolled release altering such as to accomodate for the vagaries of the immediate environment as well as the comparitively rapid decay of I131 (8 day half life)…. I’m beginning to think your/their figures are a load of crap)

      ANYWAY, moving on…

      400,000 TBq divided into 74 MBq gives… a dose equivalent to 540 million patient injections. Which, yes, is quite a lot. But it would be very spread out, and also largely external to the body, where it does FAR less (potential) harm than if ingested. Only the desperate, stupid, or drastically ill-informed would eat anything potentially touched by the OMG SO DANGEROUS radiation cloud in the days after the release.
      For the whole lot to decay to the level of a single patient dose (an amount that’s quite happily allowed to roam around unsupervised in public, and to be passed out and flushed down the toilet) would take about 29 half-lives, or 232 days. So this year’s growing season is probably off the cards, if it wasn’t already largely ruined anyway, just in the name of utterly paranoid public safety.
      But after that, little lasting or even detectable effect.

      540 million cubic metres (i.e. the volume into which you’d have to pack the stuff to have the same spatial activity density as that patient’s blood, which is considered mildly hazardous for about a week, tops) represents a space 815 metres on a side, by the way. Or if you expanded it to the inner 20km-radius circular exclusion zone, it’s an air layer 43 centimetres thick, or about 18 inches. Across the 30km zone, 19cm / 8 inches. A week after the end of this release event, presuming it hadn’t dispersed any further, 4 inches (or to put it another way, equivalent of 1/20th that patient’s dose if you were 2 metres tall and ingested and absorbed into your bloodstream/bodily tissues ALL the air that your body displaced in the midst of that stuff).

      My word I am SO scared. Avoid that thick cloud of radioactive death with all your might, guys!

      Its easy to make things sound amazingly terrible when you chuck out some enormous numbers but don’t make any reference to what they actually represent, isn’t it…

    2. tahrey

      BTW, therapies that actually harm the thyroid on purpose, by burning it away with intense beta-particle exposure – and may cause some damage to the reproductive organs – and require isolation in a clean-room for 2-3 days, but otherwise have a low risk to the patient?

      Administered dose can be up to about 3.7 GIGAbequerels. Ingested. Or 50x that of the typical scanning dose used above (and, let’s say, 10 million times less than the supposed release; a cube 215 metres on a side, or a slab 2 x 2km and about 2m high…). That’s the level at which you have to be properly worried about the health effects, IF you’ve taken that much into your body either by breathing, eating or drinking. Externally it’s still not so bad. Your Radiation Protection Officer would freak to see your fortnightly film badge results, but 100mSv would be pushing it, particularly if you adhered to a normal hygeine schedule.

      It’d be pretty good going. These things are usually a series of gelcaps or fairly large injections, specially prepared for the treatment (the master sources delivered on a weekly or monthly basis aren’t so much higher than that once they’re considered spent, and have to be handled very carefully – lots of shielding and distance, minimum contact time, to keep the civvie worker doses within safe limits). The conditions “in the wild” required to concentrate down a dispersed cloud of radionuclides to that strength, particularly where people can breathe it or it can get into the food or water supply chain, would be flukey in the extreme… and isotope supply companies would end up studying the area to see if there’s something they can learn or take advantage of, rather than laboriously churning this stuff out of industrial acclerators or refining it from reactor waste.
      (Hmmm … I wonder how the global Tc99m supply is doing right now? It’s a far safer and more useful tracer-isotope, and one that was already suffering a shortfall as some big reactors of the particular kind that produced a lot of its precursor (radioactive Molybdenum) had shut down … I wonder if Fukushima was one of the other remaining suppliers, given its age?)

      And of course it exponentially dies down just the same…

    3. tahrey

      Uh … 476m on a side… finger must’ve slipped. Which thanks to the exponentiality of cubes, is a fogbank 1.5 metres deep pervading a 4.8km (3.0 mile) radius exclusion zone to be at that instantaneous activity.

      37.5 cm at 6 miles … about 9.5cm (<4") at 12 miles.

      Still not worried.

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