Increasing evacuation zones actually increases risk in case of reactor accident

Carefully conducted analysis conducted over a multiyear study suggests that expanding evacuation zones around nuclear power plants may increase the risk of latent cancer fatalities (LCF) in the unlikely event of an accident that releases radioactive material.

This slightly counterintuitive conclusion is not news anywhere else, but I came across a nugget buried deep in a lengthy report that led me to decide to produce a short blog on the topic. This post more early morning musing than the result of any particular initiating event in world.

While researching a response associated with an Atomic Insights conversation thread, I reviewed the concluding paragraphs of the State of the Art Reactor Consequence Analysis (SOARCA) report that was issued by the US Nuclear Regulatory Commission as NUREG-1935 in November 2012.

Though I was looking for something else, this paragraph caught my eye.

Analysis of Figure 15 and 16 also shows that expanding the evacuation size from a 10 mile radius to a 20 mile radius results in increased LCF risk for people in the 0-10 mile area. SOARCA analyses show that an evacuation beyond the area closest to the plant will delay those most at risk, i.e., closest to the plant. The increased risk to the population within 10 miles of the plant is due to slower evacuation speeds because of additional traffic congestion and delays that result from evacuation of a larger population.


It is not hard to imagine how this kind of thing can happen if people panic instead of responding rationally and carefully evaluating potential risks. Think, for example, about how the world wide supply of potassium iodine tablets was strained after Fukushima because people on the west coast of North America decided that they needed to rush out and purchase protection from radioactive iodine that had no chance of reaching them in sufficient quantities to cause any harm.

The self-centered people who overreacted and assumed they were at risk may have added a small amount of risk for the people who were close enough to the place where the releases took place to be able to receive some benefit from taking the KI tablets to reduce exposure to their thyroids from I-131.

The SOARCA model result of the effect of a 20 mile evacuation zone would be even worse if the researchers had considered the possibility that panic driven politicians might decide to increase evacuation zones to 50 miles.

If moving the people within 20 miles causes slowdowns for the most affected population who are closest to an accident, just think what would happen if the government tried to force everyone within 50 miles to of any given location to start moving at the same time. Don’t forget the fact that a wider imposed panic circle also increases the amount of travel required before an evacuee can feel safe – at least according to the information provided by supposed experts who thought that a 50 mile evacuation was reasonable in the first place.

This situation provides more support for my contention that actions that some assume are “conservative” can have unintended consequences that harm more people than actions that are perceived to be more moderate.

Aside: Sometimes I go off on a diverting tangent and come across useful information that needs some kind of immediate documentation or note. Otherwise it will fall off of my already overloaded and aging bookshelf memory. I adhere to a partially formed theory that one reason for memory issues as we get older is that our brains are like bookshelves. They only have so much capacity – which can be stretched with creative stacking.

If you load them up, you might get to a point where adding a new block of information requires some of the existing stored information to fall to the floor. That does not mean that the information is lost, it is just a little more difficult to locate in the piles of stuff that active minds accumulate as life progresses. End Aside.

About Rod Adams

92 Responses to “Increasing evacuation zones actually increases risk in case of reactor accident”

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  1. Daniel says:

    Rod,

    I am just wondering when the new pro nuclear Japan PM is going to act and use some symbolism if I can use the expression.

    Now 2 years after the facts, I think he should setup a ministry – energy perhaps – right outside the safe 5 km radius of the damaged plants.

    Man. That would work. Clinton talked about having brass. Well …. he needs nobody”s permission. I would do it.

  2. atomic age says:

    How rational and altruistic you are, as opposed to those who irrational and self-centered people who fled, due to the fear of not only iodine, but also other radioactive materials falling, some of which will live over 100,000 years. Apparently, irrational and self-centered fish didn’t leave the nearby the accident scene is now found astronomical number of cesium. But you are not afraid, right? I wish that I were like you.

    • Rod Adams says:

      You’ve got it right. I am not afraid of a small amount of radiation or radioactive material. It does no harm; in fact, a little bit of radiation is required to enable life to continue.

      The irrational fish remind me of the irrational wolves who are thriving in the Chernobyl evacuation zone.

      http://video.pbs.org/video/2157025070/

      NONE of the radioactive material that was released from Fukushima will last anything close to 100,000 years. The iodine had a half life of 8 days; it is all gone. The Cs-134 has a half life of about 2 years. It will be completely undetectable in 10-20 years. (Its concentration was never high enough to hurt anyone.) The Cs-137 has a half life of about 30 years; it will be completely gone in 300 years. However, its biological half life in a human body is just 70 days.

      Information and knowledge enables life without fear and trembling about the unknown.

      • Dr. Marci Dietrich says:

        There is not a SAFE level of radiation. It is ludicrous to believe that only those in a 10mi
        evacuation zone would not voluntarily evacuate. Cancers especially in children near
        nuclear power plants are significantly increased. This is reality–not fantasy.

        • Rod Adams says:

          @Dr. Marci Dietrich

          I respectfully disagree. We have about 100 years worth of information and detailed studies regarding the health effects of low level radiation. The studies that you are referring to generally attempt to make the claim that merely living near a nuclear power station is a risk factor, even when there is no attempt to quantify the radiation doses that are supposedly the source of the risk. The studies also use cherry picking techniques and selectively publicize those areas where the statistics seem to support the claim, while ignoring studies of very similar areas near different nuclear facilities where the statistics do not support the claimed effects.

        • David says:

          @ Dr. Marci Dietrich,

          I also respectfully disagree. The measurable radiation around Nuclear power plants (NPP) is below normal background levels. For Cancers in Children to be caused by radiation from these NPP you would also expect to find cancers in children at the same rates from any natural radiation source. Our bodies don’t distinguish between man made and natural radiation. Not only this – but the amount of radiation a person is exposed to is inversely related to distance. That is to say, put just a few feet between you and a radiation source and the intensity drops drastically. Children are miles away from NPP’s and any release of radiation is closely tracked – because it can be.

          Cancer is the 2nd leading cause of death.

          http://www.cdc.gov/nchs/fastats/lcod.htm

          With this many deaths from cancer it will always be easy to correlate cancer deaths with anything. The real question is not correlation but causation.

          Many NPP are close to coal powered electrical generation plants. It may be that the correlation is between Childhood cancers and increased particulates. In other words, find the cause, not the correlation of those cancers.

        • Dr. Marci Dietrich says:

          Dear Rod,
          I can sympathize with you. Unfortunately, your training and occupational experience
          has in a way – educated you to believe your employers, past and present. When I was a medical officer in the USN, I had the pleasure of meeting and treating many
          Nuclear Officers. They went on to have financially superlative careers in “private”
          nuclear industry—that does include lobbying– after they retired from the USN. You
          sound so upset. You are right in that merely “living” next to a nuclear power station isn’t a problem; so true. But, making it operational and storing spent nuclear waste
          has many negatives. You may desire to research the advances in genomics. This
          capability will help us to qualify and quantify the “possible” increase in genetic mutations of the population in range of nuclear plants. This technology was not available 100 years ago; for that matter neither was nuclear power. I would like to view all the info you on the environmental radiation studies from 1913. I hope you do not delete your initial reply to me.
          Sincerely,
          Marci

          • Brian Mays says:

            Dear Marci,

            I’m sure that your training and occupational experience of roughly three decades in “family medicine” has made you an expert in genomics, epidemiology, and the storage of “spent nuclear waste” — so much so, in fact, that it entitles you to come here and lecture everyone as if Rod and his readers were children.

            Goodness knows, the US has so many general practitioners who know so much about this subject that we don’t even need to do research on it anymore. We can just take your word for it. Thank you for saving us so much time. Without you, we would actually need to think about this.

            Sarcastically,
            Brian

          • Dr. Marci Dietrich says:

            Dear Brian,

            I acknowledge that you seemingly feel threatened by my remarks. I will not ask to
            lecture you, since you believe you know everything about this subject. When someone believes they “know it all” they are a danger to themselves and perhaps to the human race.
            Sincerely,
            Marci

          • Brian Mays says:

            Dear Marci,

            And I acknowledge that you seemingly feel full of yourself and have a irresistible need to double down on your patronizing condescension.

            We all deal with our weaknesses in our own way. Some ways are just funnier to watch than others. Thanks for the giggles. ;-)

            Sincerely,
            Brian

          • Rod Adams says:

            @Dr. Marci Dietrich

            Why would I delete my initial reply? I stand behind what I write. Nuclear power may be relatively new, with our first operational power reactors being built in the 1950s, but we have been studying radiation and radiation health effects since before 1900.

            As you mentioned, the science of genetics has come a long way since Muller took advantage of his Nobel Prize acceptance lecture to press his ideology on the world by claiming that all radiation, down to the very lowest level, carries a probability of genetic damage and then encouraged people to believe that the linear no threshold dose assumption should be adopted as the basis for regulation.

            Studies conducted in recent years indicate that low dose radiation results in several adaptive response mechanisms that protect multi-cellular creatures from harm.

            http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2657485/

            Yes, I earn a good living. However, I have earned a good living for many years, often doing jobs that have nothing to do with nuclear energy. No one pays me to share my knowledge about nuclear energy with the world and I have never been a lobbyist.

            If I sound upset, it is because I see a great deal of harm being done in the effort to scare people way from the beneficial use of nuclear energy because the only alternative is an expanding dependence on a rapidly depleting endowment of hydrocarbons. They are a good fuel source, but they cannot do the job of improving the lives of 7 billion people because they are simply not abundant enough to last very long. They also carry some substantial negative health effects and are putting the stability of our climate at serious risk. That knowledge is certainly enough to upset anyone who also understands the benign nature of nuclear energy and the fact that the power source is clean enough to operate inside sealed submarines.

          • Phil P. says:

            Dr. Dietrich,
            There is no credible statistic to support your claim that children or anyone else around civilian NPPs have higher rates of cancer than anyone else. 10 CFR 20 limits the dose to the public from a facility’s operations to 100 mrem/year. This would result in an additional 3000 mrem over 30 years. This “doubling dose” is estimated to increase the rate of spontaneous mitochondrial mutation to double it’s norm (~ 3×10-5).

            I will not argue that SAFE is a relative term. The linear no-threshold dose model is the standard in radiation protection and single hit theory is an accepted theory for damage from radiation exposure.

            What I will argue however is that people who are against nuclear power, physicians included, fail to reveal the fact that the cells of the body undergo tens of thousands of damage/repair events every day and that the majority are caused by factors other than radiation. Most are caused by lifestyle, diet, exposure to every day contaminants, and genetics.

            Do you have such a strong opinion on the Big Mac?

        • David says:

          Dear Dr. Marci,

          Would you mind defending your statement that there is NO SAFE level of radiation?

    • Cyril R. says:

      How rational and altruistic you are, as opposed to those who irrational and self-centered people who fled, due to the fear of not only iodine, but also other radioactive materials falling, some of which will live over 100,000 years.

      Natural uranium and thorium in the ground, and their even more dangerous decay daughters, will live over 100,000,000,000 years, in quantities trillions of times higher than all releases from Fukushima Daiichi.

      However, judging from your comment, stupidity, ignorance and innumerate hyperbole may outlive natural uranium and thorium.

      Apparently, irrational and self-centered fish didn’t leave the nearby the accident scene is now found astronomical number of cesium.

      And the effects of these “astronomic” quantities of cesium in fish are? Zero. You won’t find a single marine biologist claiming that a few hundred kBq/kg of radiocesium has any effect on the species, indeed on the individual fish.

      In actual fact, the fish population is thriving because there is less fishing. Fishing is extremely deadly to fish. Uhm, yes I’m serious. If a fish is caught, it dies and is eaten. Pretty dramatic when you think of it.

      This may sound obvious, and you’d think Greenpeace would be happy that there is less dreadful deadly fishing around Fukushima. Clearly Greenpeace is not happy about it. This is because they, like all anti-nuclear groups, are internally inconstent and prefer ideology and political expediency over science and reason.

    • Daniel says:

      @ Atomic Age,

      Knowledge is power. radio active .. blah blah blah … 100,000 years .. blah blah blah ! scary.

      Where were you yesterday when I ingested a scoop (or two) of Bepto Bismol. You could have saved my life. It’s too late for me as bismuth has a half life of roughly 20,000,000,000,000,000,000 years.

      This is much, much, much larger than the lifetime of the entire universe, which is thought to have an age that is on the order of magnitude of tens of billions of years.

      Now, atomic age, be careful with that knowledge of yours and sue the pharmaceutical companies when I am long gone and do some good with this money you’ll get.

      You must be one of those idquorenewablerdquo guys.

    • Atomikrabbit says:

      @Atomic Age

      My plea further down thread for a “massive and pervasive public education campaign” would have come in handy right now.

      Unfortunately, the nuclear utilities didn’t do enough of it when they were riding high, and with lower wholesale electric rates due to a (temporary) domestic glut of fracked methane, they now have a financial excuse to push public outreach even lower on their list of priorities.

      For some of the BWRs in merchant markets, already barely breaking even, the upcoming mandatory expenditures for hardened filtered containment vents may be the straw that breaks their back. The antis know this, and will push it hard.

  3. Atomikrabbit says:

    Emergency Action Recommendations are made to the state and county authorities by the site Emergency Director (usually a high ranking manager who was once NRC-licensed) taking into account gradations of distance and wind direction from the plant.

    They are only recommendations, however, and the government authorities can do what they want.

    I suspect in the actual (unlikely) event, the reality will be that breathless reporters speculating on they deadliness of every secondary-side steam release televised live from circling helicopters, compounded by predictions of Chernobylish doom from the studio Machio Kakus, will result in the public taking a lot of unwarranted individual actions. It will matter little what the ED recommends or what the authorities declare.

    The only way to prevent this, and the best long-term solution, would be a massive and pervasive public education campaign so that an educated citizenry could discern whether the media is once again crying radioactive wolf.

  4. Daniel says:

    This thread must be nuanced with the odds of a civil nuclear plant actually spewing up harmfull radio active materials are pretty slim.

    • Cyril R. says:

      Exactly. As much as I think that serious design mistakes were made in the Fukushima Daiichi plants, a 15 meter tsunami is not physically plausible in the locations of the vast majority of nuclear plants. So the initiating event simply won’t exist in the vast majority of nuclear plant sites, even if the same electrical design mistakes were made in other plants.

      In the few plant sites were there is a big risk there is usually a high design basis against flooding and station blackout. A good example is the Diablo Canyon plant:

      http://www.zimfamilycockers.com/DiabloCanyon.html

      • jmdesp says:

        Very interesting site. I have read recently about the fish problem, and I’m surprised to see there the claim that it’s only fish larvae that get inside the reactor.

        I would like to see more confirmation of that.

  5. James Greenidge says:

    If Indian Point survives Cuomo’s hatchet, there’s hope for reactors that needn’t be banished to the boondocks in the name of evacuation. Why Indian Point doesn’t cite the evacuation overkill that was Fukushima I’ll never understand — the fear horse is already out of the barn! Rein it in with proof and reason! I’d also like to see a comparative study of the hospitalization/health clinic stats of diseases or various afflictions borne by a population within ten miles of a nuclear, gas, oil and coal plant. along with white-glove wiping of cars and buildings to tally pollution effects and see who comes out top-dog in the clean department. Be even better if this is done in the wake of severe accidents (TMI is too late and Fukushima currently too remote to take such samples and tallies), but the results of such a chart would floor the pernicious reactor nightmares many have — and rightfully alarm those living near other plants.

    James Greenidge
    Queens NY

  6. James Greenidge says:

    Greetings!

    If Indian Point survives Cuomo’s hatchet, there’s hope for reactors that needn’t be banished to the boondocks in the name of evacuation. Why Indian Point doesn’t cite the evacuation overkill that was Fukushima I’ll never understand — the fear horse is already out of the barn! Rein it in with proof and reason! I’d also like to see a comparative study of the hospitalization/health clinic stats of diseases or various afflictions borne by a population within ten miles of a nuclear, gas, oil and coal plant. along with white-glove wiping of cars and buildings to tally pollution effects and see who comes out top-dog in the clean department. Be even better if this is done in the wake of severe accidents (TMI is too late and Fukushima currently too remote to take such samples and tallies), but the results of such a chart would floor the pernicious reactor nightmares many have — and rightfully alarm those living near other plants.

    James Greenidge
    Queens NY

  7. Rich Lentz says:

    As I have said on here before the one thing that ALL of the people doing these studies ignore is that just 3 miles away from TMI is Brunner Island Power Plant. At last count there were three coal burning power plants, the smallest of which is 600MW all dumping their toxins in the air. How can any study ignore the effects of this power station? Are they ignoring it on purpose? Most plants in PA burn PA coal which is high in Radon. Radon is so high in PA that one TMI worker had to get rid of all of his wool shirts and jackets as they held the radon on the fibers and set off the alarms when he came through the portal. How many tons of Mercury, Radon, etc., is this plant putting in the air?

    Look at this view of Brunner Island. Then follow the river north about three miles to TMI

    http://www.bing.com/maps/?v=2&cp=40.09653963863703~-76.68723581999235&lvl=14&dir=0&sty=h&form=LMLTCC

    • Cyril R. says:

      This is also why many “studies” done around nuclear plant populations have found higher leukemia rates there. It turned out it was because of benzene released in the same industrial areas where the nuclear plants were built (the nuclear plants provided power to refineries and such that released large amounts of benzene).

      Of course the “researchers” never bothered to seeve out spurious correlations… in fact it’s quite clear that they don’t know what spurious means.

      I can also show that there’s a strong correlation between the number of libraries in a city and the number of murders in the city. But before we conspire of theories that libraries are slaughterhouses, we might consider looking at the size of the city: the size determines both the crime rates and the number of libraries, to a very high degree.

      What anti-nuclear groups do is they look no further till they find something bad about nuclear. So they will forge ahead with accusing ms. librarian of being a murderer.

  8. jaagu says:

    I find the people who say the evacuation zones are nonsense must not have studied the Fukushima accident in any detail. Japan was lucky that the wind was blowing out toward the ocean for most of the time and carried the radioactive materials out to sea. The old Boiling Water Reators (BWRs) in the US are not all located by the ocean with favorable winds. Thus a Fukushima type core melt accident in the US would have serious consequences for the people and the land due to radioactive releases.

    Upgrading old Boiling Water Reators (BWRs) in the US:

    The NRC has calculated that for the current fleet of 31 old BWRs with Mark I and II containments in the USA, there is an 86.1 percent chance that they can operate for 25 years without experiencing a core melt event (like Fukushima). That means we have a 13.9 percent chance of having a core melt event in the next 25 years. The reason that these 31 old BWRs are such a concern to the NRC when compared to newer BWRs or PWRs is that they have a very small containments which are easily over-pressurized once a core melt starts. With a core melt event, these old BWRs must vent the containment to prevent containment failure like the old Fukushima BWRs.

    The NRC Staff and Commissioners have already instructed these 31 old BWRs to install hardened containment vents for venting the containment after a core melt event. However, after lengthy studies and hearings the NRC staff engineers and scientists have also recommended to NRC Commissioners that filters should also be installed in these containment vent systems, to preclude releasing the radioactive gases and aerosols in the containment directly to the environment, as happened at Fukushima. These filters would trap the most of the radioactive gases and aerosols. This would greatly reduce the contamination of land, the need for evacuation, and the cost of cleanup. Filtered containment vent systems are not a new idea; they are already in use in countries like Canada, Sweden, Germany, France, Switzerland and many others because they provide that extra safety to the people and land around a nuclear power plant.

    The US nuclear industry however, is currently fighting the NRC staff recommendation of requiring filters on these old BWRs. The nuclear industry is less concerned about the safety of the old BWRs and more concerned about the few million dollars of cost. Profit over safety is what we get with free market nuclear power.

    NRC Source: SECY-2012-0157
    http://www.nrc.gov/reading-rm/doc-collections/commission/slides/2013/20130109/lochbaum-ucs-20130109.pdf

    • David says:

      @jaagu

      Your claim that the utilities who own some nuclear power are fighting the NRC is amazing. Could you give some links that show this type of backbone? This is encouraging! Finally they are not accepting every single possible “safety” feature!

      Could you please link this for me?

      • jaagu says:

        @David

        Here are some arguments by EPRI and NEI for not installing filters on some old BWR containment vents depending on detailed plant specific accident analysis. Both EPRI and NEI instead recommend other avenues of scrubbing the containment venting.

        http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?ProductId=000000000001026539

        http://www.nei.org/resourcesandstats/publicationsandmedia/insight/Fall-2012/Vents-and-Filtering-Strategies-Come-to-Forefront-i

        • Rod Adams says:

          @jaagu

          That does not exactly qualify as fighting back, though it is encouraging to think that the NEI and EPRI are not rolling over to blindly accept the NRC regulator’s recommendation as gospel.

          Though the people at the NRC are usually pretty capable, we need to remember that some of them are not terribly experienced. They will sometimes lean towards what they consider to be a more politically acceptable position rather than one that is technically as good or better, but pays a little more attention to the cost, schedule and technical difficulty associated with implementation.

          • jaagu says:

            @ Rod

            The people I have worked with at the NRC have been very capable and typically know more than the utility owners and operators about safety of nuclear power plants.

            I have never seen NRC take a politically acceptable position rather than a position that is as good or better even considering cost, schedule and technical difficulty. The nuclear industry is not shy about telling the NRC about their concerns. The NRC is a regulator and must hold the nuclear industry to the highest levels of safety or else there will be no nuclear industry. Remember the nuclear industry is a for profit industry and thus will always try to cut corners where they think it will never be a problem (aka Japanese nuclear industry).

            Some times the nuclear industry puts so much pressure on the NRC staff – for less safety improvements. The nuclear industry has strong political allies in Congress that are used to beatup the NRC at times.

            But getting back to filters on containment vents – do you agree that this is a minor cost and significant safety benefit for the old BWRs?

            The Japanese are going to require filtered containment vents on their nuclear plants.

          • Rod Adams says:

            But getting back to filters on containment vents – do you agree that this is a minor cost and significant safety benefit for the old BWRs?

            No. I do not agree on either statement. The cost may not be minor at all; estimates are starting at $15 million per unit, but I suspect those estimates do not include planning, license amendments, installation testing, loss of production or ongoing maintenance & testing after installation.

            The safety benefit is remote at best. The time that a filtered vent will do anything of value is in the case of an accident that pressurizes the containment. If that accident does not include any substantial fuel melting, the reduction in radioactive material release from the filters is inconsequential.

            As someone else stated, a better investment of $15 million would be something that increases the reliability of the power supplies. You can purchase a pretty good sized diesel fuel tank for $15 million, for example.

          • Cyril R. says:

            I have never seen NRC take a politically acceptable position rather than a position that is as good or better even considering cost, schedule and technical difficulty.

            Please tell me you are joking. The NRC is not an expert on costing at all (that’s putting it lightly). They are politically driven and hire (or get pushed) people including their chairmen/women, based on being anti-nuclear and not knowledgeable about nuclear engineering and industrial safety. Furthermore, their schedules are terrible. They are completely incapable of risk-based assessment and prioritising. They take 20 years to license a slightly changed PWR. They take 2 years to license a tricycle for the nuclear engineers to drive around the plant.

            The NRC is a ground-down bureaucracy that is absolutely not making nuclear power safer. Quite the contrary is true. A bureaucracy prefers rules and codes over common sense thinking, takes a long time to do anything, produces thousands of pages of documentation that no one reads in common practise, and prefers bureaucrats that can work the system and are poltically expedient over expert knowledge.

            I see this all the time. I work in industrial safety analysis with a large number of industries. Institutionalizing a technology is hampering safety and innovation and only drives up cost.

            If you want to make an unsafe situation that is hostile to innovation, putting up an organisation like the NRC is exactly what you should do.

          • Rod Adams says:

            If you want to make an unsafe situation that is hostile to innovation, putting up an organisation like the NRC is exactly what you should do.

            That statement has always been true and well understood by people who are in the thick of things. That is why there was so much effort expended to break apart the AEC and establish the NRC.

            By the way, you conservatives out there, do you know that the Nixon Administration (perhaps pushed by supporters in California, which was either two or three in oil and gas production at the time) was solely responsible for that decision? It was a major component of his 1971-72 reorganization effort.

    • Cyril R. says:

      Thus a Fukushima type core melt accident in the US would have serious consequences for the people and the land due to radioactive releases.

      Boldly asserting that which remains to be demonstrated. Non-sequiturs are the hallmark of the anit-nuclear activist.

      If you use the linear no threshold model then evacuation makes sense pretty quickly because of small numbers that add up linearly over a large population. For example if I know that a population of 100,000 people has ingested 100,000 pills of aspirin, I might fallaciously assert that, given the fact that 100 aspirin is a lethal dose, 1000 people must surely die. Then I might assert further, following the line of non-sequitur argument, that aspirin is dangerous and must be banned from all stores immediately.

      If you actually look at data we have from comparable chronic exposures at Chernobyl, Three Mile Island, etc. you’ll find that 20 mSv is far too conservative a limit. In fact, looking at the ecological studies it’s clear that evacuating 100,000 people is more dangerous than exposing all of them to 200 mSv of ionizing radiation.

      The Fukushima evacuation was NOT based on risk. It was based on drawing a circle. It was not based on knowledge of wind direction and fallout deposition. It was based on drawing a circle. It was based on ignoring data from the SPEEDY model which clearly showed that only an elongated area northwest of F-D had fallout over 200 mSv.

      The evacuation was also not based on the IAEA’s recommendation, which is a 5 km evacuation zone.

      In fact, to anyone who has studied the accident in detail, the appalling design mistakes in the electrical design basis of the plant goes hand in hand with an appalling government overreaction that has done far more damage than the radiation ever will, by orders of magnitude.

      Evacuation is NOT a conservative precaution. It is a last resort, only to be applied when it is almost certain that staying will kill more than evacuating. At no point in the F-D accidents was this the case.

      • jaagu says:

        @ Cyril R.

        You do a lot of hand waving about evacuation but your argument is incoherent. The fact is that following a core melt accident like Fukushima there is massive amounts of Iodine, Cesium and other radioactive materials released into the atmosphere that would have caused much more than 500 mSv for people within a 10 mile radius.

        Your attack on the Japanese government for evacuating 100,000 people is silly since they were never prepared for such an accident. They thought it was impossible for that to happen to their nuclear power plants. The Fukushima accident showed that the whole nuclear industry in Japan and the government were all inept at dealing with a nuclear accident. They did not design their plants correctly, they did not incorporate lessons learned from other countries, and they did not know what to do after a major accident. So picking on evacuation in Japan is just silly – it was better than letting the people stay when they did not know what to do.

        I disagree with your statement that there was chronic exposure of the public after TMI-2 accident. That accident was able to hold the melted core and fission products inside of the containment. That was a PWR that had a large dry containment that was not susceptible to rapid over-pressurization like the old BWRs in Japan and USA. The TMI-2 containment withstood the hydrogen explosion whereas the Fukushima BWRs were damaged by the hydrogen explosions due to their containment failures.

        The NRC and the nuclear industry have agreed that evacuation is part of the emergency plans for nuclear power plants based on valid science. Hear is what NEI reports:

        After the accident at Japan’s Fukushima Daiichi nuclear energy facility, the plant operators and public officials executed plans to keep people nearest the plant safe from any release of radiation, utilizing an emergency planning zone that extended in a 6-mile and, later, 12-mile radius around the plant.

        Though the Japanese response proved effective in protecting its citizens while avoiding widespread displacement, some Americans questioned the adequacy of the 10-mile emergency planning zone used at U.S. reactors.

        About 4.6 million Americans live within 10 miles of an operating nuclear energy facility, in what is called an “emergency planning zone.” While evacuation plans are part of safety planning, emergency planning zones are not synonymous with evacuation.

        Most residents in an emergency may only be asked to stay informed by listening to emergency alert system messages from public safety officials. Some may be instructed to close their windows and stay indoors if there is a release of radiation.

        Sue Perkins-Grew, NEI’s director of emergency preparedness, said that the concept of emergency planning zones is “based on sound science and research performed by [the U.S. Environmental Protection Agency] and other federal agencies.”

        “Evacuation rarely calls for completely emptying the 10-mile zone around a nuclear power plant. In most cases, the release of radioactive material from a plant during a major incident would move with the wind, not in all directions surrounding the plant,” according to the independent U.S. Nuclear Regulatory Commission. “The [radiation] release also would … become less concentrated as it travels away from a plant.”

        For planning purposes, the NRC defines two zones around each nuclear power plant. The exact size and configuration vary from plant to plant, answering Sen. Casey’s question about the unique nature of each plant and its surrounding community.

        What the NRC calls the “plume exposure pathway” has a radius of about 10 miles where there could be an exposure to radioactive materials. The “ingestion pathway” is about 50 miles in radius to prevent potentially contaminated food, water and vegetation from being consumed.

        If evacuation or sheltering is required, the area might extend beyond the 10-mile radius, depending on local conditions.

        The EPZ, as it is called, defines the area for planning response to a radiological accident.

        During the highest-level general emergency, people closest to the facility would be evacuated first, then public safety officials would make additional decisions to either evacuate people in larger surrounding areas or to order them to stay indoors.

        “People living in the remainder of the 10-mile zone will most likely be advised to go indoors to monitor Emergency Alert System broadcasts,” the NRC fact sheet says.

        “The idea of the 10-mile EPZ,” said Perkins-Grew, “is to protect the communities that are closest to the facilities. Public safety officials would make decisions based on conditions to either shelter-in-place or to evacuate or a combination of both. Those same public safety officials have the flexibility, if the event were to be prolonged, to make the same decisions beyond the 10-mile emergency planning zone.”

        Cheers,
        jaagu

        http://www.nei.org/resourcesandstats/publicationsandmedia/insight/insightspring2012/emergency-planning-zones-help-ensure-nuclear-plant

        • Cyril R. says:

          I see lots of claims, and zero zero proof.

          You have absolutely no proof that more than 1000 people would have died if no evacuation had taken place (1000 is roughly the death toll due to the evacuation and resulting deprevation of lifelihoods).

        • Cyril R. says:

          I disagree with your statement that there was chronic exposure of the public after TMI-2 accident. That accident was able to hold the melted core and fission products inside of the containment. That was a PWR that had a large dry containment that was not susceptible to rapid over-pressurization like the old BWRs in Japan and USA. The TMI-2 containment withstood the hydrogen explosion whereas the Fukushima BWRs were damaged by the hydrogen explosions due to their containment failures.

          More nonsense from our NRC buddy. There was a tiny exposure, due to later venting of the containment. Primarily noble gasses but some iodine also.

          There was never an AC power loss at TMI so this is

          1. completely incomparable to Fukushima
          2. proving my point about the importance of having power.

          If your research skills were as strong as your opinions, we would be having a useful debate in stead of me poking giant holes in your nonsense arguments with no effort.

        • Joris van Dorp says:

          “The fact is that following a core melt accident like Fukushima there is massive amounts of Iodine, Cesium and other radioactive materials released into the atmosphere that would have caused much more than 500 mSv for people within a 10 mile radius.”

          Is that true? I thought the WHO concluded that – in case there would have been no evacuation – the radiactive dose for Fukushima residents would still have been quite low, including the area inside a 10 mile radius. Which source says that it would have been more than 500 mSv?

          • EL says:

            Joris van Dorp writes: “Which source says that it would have been more than 500 mSv?”

            Okuma (population 11,515) had readings of 508 mSv.

            Based on data provided by MEXT, IRSN suggests estimates “in excess of 200 mSv” within 20 km evacuation zone.

            And most of the radiation from Fukushima was blown out to sea. CEREA and EdF atmospheric dispersion model (scroll down for animation), SIROCCO has a model for sea surface dispersion.

            Is there a document from WHO that suggests evacuation was not warranted? I’m not aware of one.

    • Cyril R. says:

      The US nuclear industry however, is currently fighting the NRC staff recommendation of requiring filters on these old BWRs. The nuclear industry is less concerned about the safety of the old BWRs and more concerned about the few million dollars of cost. Profit over safety is what we get with free market nuclear power.

      You are jumping to solutions and to conclusions without understanding the problem.

      That is a tempting, but all too dangerous habit.

      Before we discuss solutions and jump to conclusions, it is vital to understand the problem.

      Once you understand the problem, the solutions will present themselves.

      The problem at Fukushima wasn’t about lack of filters. It was that the operators decided to vent to late, and when they did decide to vent they found it took a lot of time to align valves, use instrument air compressors etc. which then caused containment bypass and uncontrolled release and hydrogen explosions that further helped to push radionuclides into the air. If venting had occurred through the wetwell (suppression chamber) there would be inherent scrubbing of cesium and iodine.

      The venting system is designed to work with powered valves, motor operated valves. What they really need was power.

      But if they had power they would have had core cooling, makeup water supply, containment cooling, instruments, communications. The whole core damage accident would not have happened with power.

      So there you have it. The solution has presented itself based on a better understanding of the problem. You need to make sure you have power. Investments in that area are far more productive than investments in filtered venting systems.

      • jaagu says:

        @ Cyril R.

        I am not jumping to solutions and to conclusions without understanding the problem. You seem to have very little knowledge about what the NRC and the nuclear industry have been doing since the Fukushima accident. They have studied the accident in detail and have already determined what modifications must be made.

        The lessons learned from Fukushima have been well documented on the NRC website. The NRC has ordered the 31 old BWRs with Mark I and II containment designs to install reliable hardened vent with valves that are remotely operable after an accident. NRC requires the valves to be accessible to plant operators and be capable of remote operation and control, or manual operation, during sustained operations. The NRC design requirements for the vent system are detailed in the following NRC Order:

        http://pbadupws.nrc.gov/docs/ML1203/ML12039A127.pdf

        The Japanese were inept and they did not have power operated vent valves nor easily accessible vent valves to vent the containment manually.

        Your silly argument about having AC power for extended period of time has already been shot down by NRC and even the nuclear industry. Loss of all offsite and onsite AC power is a credible event. US nuclear plants only have 4 to 8 hours of emergency battery life after a station blackout (SBO) event. So if a US nuclear plant has an SBO longer than 4 to 8 hours, the core can start melting. Fukushima also had only 4 to 8 hours of emergency battery life.

        A tornado, storm or flood can easily knockout all offsite power. The emergency diesel generators are prone to failure and have limited fuel supply. Therefore, the NRC has also order nuclear plants to improve their capability to withstand an extended SBO event.

        So the NRC and many experts have concluded that we need to have more reliable AC power at all nuclear power plants and we need filtered containment venting of the 31 old BWRs because of their tiny containment designs.

        If you need directions to the NRC documents I will be happy to provide links.

        • Cyril R. says:

          If you don’t lose power then you don’t need the venting system as you don’t have a lot of hydrogen about; steam can be condensed, it’s the hydrogen that is noncondensable and pressurizes these type of compact containments.

          You appear to lack basic understanding of the physics here. If you have cooling, you have little hydrogen, thus no need to vent containment. Prevention is better than mitigation.

          As for emergency diesels being prone to failure, that is simply wrong. You have to keep them high and dry because flooding causes common mode failure. Same for other critical electrical gear. All of the emergency diesels in Japan started just fine and ran just fine till the tsunami hit. The plants were robust against earthquakes, there was simply a design error in putting so much critical electrical infrastructure at or below grade.

          In addition these plants have steam driven condensers that you can upgrade with a generator to provide DC power, then you can use it indefinately without any onsite or offsite AC power.

          If the AC power loss is a credible event, I would argue that there are design mistakes and these must be fixed, so that it becomes a non-credible event. For newer plants these have full passive cooling so don’t need safety grade AC power.

          I do congratulate you on misreading my comment. The NRC probably couldn’t have done worse than you.

          • jaagu says:

            @ Cyril

            “In addition these plants have steam driven condensers that you can upgrade with a generator to provide DC power, then you can use it indefinately without any onsite or offsite AC power.”

            I must admit I have never heard of a “steam driven condenser”. I think you are referring to the Isolation Condensor System which did not work so well in Fukushima Unit 1. And upgrading the Isolation Condensor System for the old BWRs with generators to provide DC power also requires that makeup water be supplied to the system. It will not operate indefinetly without makeup water provided by some other system.

            The reactor core isolation cooling (RCIC) system, which is used in BWR/4s, BWR/5s, BWR/6s, and the Advanced Boiling Water Reactor (ABWR) is the better upgrade for the BWR/2s and BWR/3s.

            I have not seen the cost analysis of these type of upgrades for the old BWRs. Can you provide some cost numbers for your recommendation?

        • Rod Adams says:

          @jaagu

          So the NRC and many experts have concluded that we need to have more reliable AC power at all nuclear power plants and we need filtered containment venting of the 31 old BWRs because of their tiny containment designs.

          You provided accurate and credible information all the way up to that very last statement. This is a quote from an article dated January 9, 2013:

          At the NRC meeting on Wednesday, the nuclear industry will also present their less-costly proposals to filter contaminants out of the reactor’s containment in the event of an accident without the installation of costly external filters.

          “This is not a decision making meeting for the NRC. The different parties will present the pros and cons of installing filters. We’re basically at the beginning of the process … and will come away from this meeting with a lot more information,” Tom Kauffman, a spokesman at the Nuclear Energy Institute, an industry trade group, told Reuters.

          A spokesman at the NRC said the commission had not set a date to decide on the filtered vent issue but hoped to have something later this year.

          (Emphasis added.)

          The Commission has not yet concluded that we need filtered containment venting of the 31 old BWRs because of their smaller containment designs. Some members of the STAFF have made that recommendation, but the decision process is just beginning. This is the time when the industry and its vast operating and maintenance experience can be brought to bear to provide a more nuanced and effective approach that takes into account the specific situations at each plant.

          http://www.reuters.com/article/2013/01/09/us-utilities-nuclear-nrc-idUSBRE9080NY20130109

          • jaagu says:

            @ Rod

            You are correct about the final decision on filters not yet being final. Poor wording on my part. But I think it will come to pass.

            Interesting to note that Westinghouse and AREVA are both offering filtered containment vent systems for all nuclear reactors.

            I think the nuclear experts around the world have found that extended loss of all AC power (SBO) is such a vulnerability to all nuclear power plants that filtered containment vent will mandatory in the future. Even EPRI says that it makes sense for certain plants in the US. NRC has a Tier 3 recommendation to have filtered containment vents on all nuclear power plants.

          • jaagu says:

            @ Rod

            Frank von Hippel wrote an excellent article on containment design history and the containment of a reactor meltdown. I think you and your readers will find it informative on the past and present thinking regarding containment venting and filtering.

            http://thebulletin.org/web-edition/features/the-bulletin-archives-containment-of-reactor-meltdown

          • Rod Adams says:

            @jaagu

            Thank you for the link. I will read it with interest. I must admit before doing so that I have a rather negative immediate reaction to both the author – Frank Von Hipple – and the publication – The Bulletin of Atomic Scientists.

            Both have a loooong history of working hard to discourage the use of nuclear energy. I’ve worked hard to understand why that might be; both the writer and the publication cannot seem to understand that there is a vast difference between wanting to develop energy sources to serve mankind and weapons that might destroy mankind. Just because both enterprises use the same materials does not mean that they both bear the burden of the same original sin.

            The fact that fissionable materials can explode with incredible force under very specific design conditions should not stop us from taking advantage of the fact that they can also release vast quantities of emission free, reliable, affordable power for an almost unlimited period of human history.

          • Rod Adams says:

            @jaagu

            I’ve now read the article. As I suspected, Von Hipple has once again attempted to discredit the research done by people with experience in the real world of metal, physical components, and post event analysis while attempting to fully credit immaginative research scientists with great prescience.

            He starts his piece with a description of how good engineers believe in Murphy’s Law “If something bad can happen, it eventually will.” What he fails to understand is that really good engineers recognize that there is a corollary to that Law “If the predicted bad things DON’T happen, even after 50 years worth of opportunity, then they probably won’t.”

            Fukushima proved that even a massive core melting accident in which three operating reactors lost power for many days is not nearly as consequential as those dire, “worst case” scenarios that Von Hipple and his favored researchers have imagined. Reactor pressure vessels do not disappear, melted cores do not melt through pressure vessels, containments do not fracture, and most of the fission products really do plate out or never leave the pressure vessel in the first place.

            Yes, iodine and cesium isotopes are able to escape. Exposure to iodine can be readily mitigated; the measurements after Fukushima have shown that doses to even the most exposed children have such a tiny chance of causing any negative health effects that most reasonable people would round to zero, even if they believe in the LNT assumption. Cs-137 is the only long lived isotope of concern, but long studies after Chernobyl, where there was an uncontained release for several weeks, do not show any reason to be concerned about the negative effects of that material.

            The bottom line for me is the result of the SOARCA study, which is FAR more credible than a 1982 vintage paper from a guy with an agenda like Frank Von Hipple. According to that study, there will be few, if any off site health consequences from a fuel melt, even if the containment fails.

          • Brian Mays says:

            Rod – Personally, I loved von Hipple’s argument that “reactor containment buildings today are not designed to contain a reactor core meltdown accident,” because Three Mile Island was not a reactor core meltdown accident. ;-)

            Of course, we know better today. The accident at Three Mile Island melted roughly half of the core. In hindsight, von Hipple’s ancient BAS article seems very foolish indeed. It’s as out of date as Jane Fonda’s legwarmers, another relic from 1982.

          • Cyril R. says:

            In hindsight, it seems to me that the whole concept of a high pressure tight containment is flawed. It costs a lot of money, drives the construction schedule up, and keeping structures airtight in the face of high temperatures and pressures for weeks during accidents, is really difficult. In some ways it can make a situation more dangerous, as containment leaks become more likely with higher pressures.

            In the chemical industry, much smaller lower cost high efficiency filtered confinement type buildings are used as containment. Some of the chemicals handled in such buildings are more dangerous than I-131.

            The buildings have a very safe operating principle: all air that is removed from containment is filtered with extreme high efficiency filters. This offers a high reliability controlled filtered leak path. Since it has such filters, our friend Jaagu must like them too. During a nuclear accident any activity is simply filtered out and the residual cleaned steam and air is vented.

            This is a far lower cost and safer approach. Unfortunately the focus on getting rid of every microsievert has resulted in not allowing this approach. The trace activity release frequency is greater, so we’ve gone for the approach that has a much larger, uncontrolled release risk in stead (from containment bypass).

            If we were to design new nuclear plants from the ground up, clearly the filtered confinement approach is the way to go.

          • Rod Adams says:

            @Cyril R

            I wholeheartedly agree.

            Jaagu might not understand my nuanced position, but I tend to agree that Fukushima pointed out a weakness in our decades old containment strategy. I just do not think that the lesson should result in expensive retrofit requirements on existing containments. They do a reasonable job of protecting the public from harm as is; if money is to be spent on upgrades for existing plants, it is far better to spend it on making the power supplies more reliable.

            For new construction projects, a more useful and ultimately far cheaper path is to design low pressure, filtered confinement buildings from the very beginning. Provide a continuously open path to the environment that passes through simple filtering media like water and sand to scrub out the vast majority of any released contaminants. Take advantage of the fact that hydrogen does not want to accumulate in a vented building because it is so light and let it escape without building up.

            Cal Abel and I had a conversation here about vented confinements quite a few months ago. If I am not mistaken, he has even filed some paperwork with the PTO on the topic.

            PS – It turns out that the vented containment discussions here were conducted during the period between Nov 2011 and Jan 2012.

          • David Andersen says:

            @Cyril
            For a Pressurized Water reactor the concrete portion of the containment is for shielding,the steel liner is for vapor containment. The containment only stays pressurized for a short period of time because the pressure increase is caused by the water in the RCS flashing to steam, this steam is rapidly condensed by either a spray down system or by fans and heat exchangers. After a period of time the containment is vented through filters.

    • donb says:

      jaagu wrote:
      The NRC has calculated that for the current fleet of 31 old BWRs with Mark I and II containments in the USA, there is an 86.1 percent chance that they can operate for 25 years without experiencing a core melt event (like Fukushima).

      What the NRC does not calculate is harm caused by generation of replacement power by more dangerous power plants if this new regulation should be enough to push a nuclear power plant owner to close a plant.

      Nuclear power plants should be safer than the alternatives. But if we make nuclear power plants so safe that few are built, and other more dangerous power generation technologies are used instead because they are easier to build, we are not making progress in safety.

      • jaagu says:

        @ donb

        Fukushima accident caused great economic harm to Japan. It will cost over $500 billion to cleanup the nuclear damage over a 40 year period.

        No other type of power generation system except maybe for some giant hydro project can cause such economic harm in an accident.

        $15 million per reactor for filtered containment vents is peanuts to a utility. They generate over $1 million per day in revenue from their nuclear plants. I think it is a small price to pay for not have a potential $500 billion accident.

        • Daniel says:

          @jaagu,

          500 bilions really. You should know that most of this money Will serve to handle non dangerous dust.

          What a shame !

        • Cyril R. says:

          $15 million per reactor for filtered containment vents is peanuts to a utility. They generate over $1 million per day in revenue from their nuclear plants. I think it is a small price to pay for not have a potential $500 billion accident.

          Again, that filtered vent won’t prevent core damage. You still have a 10-20 billion dollar cleanup on your hands. You still have a Three Mile Island (actually worse because you still get no power). If you spend 15 million on improved AC and steam driven cooling systems that are not vulnerable to common mode failure you get to avoid the entire accident altogether. It is pure common sense that prevention is better than mitigation. If you can prevent, then prevent in stead of mitigate.

          Think of it this way: even with a filtered vent, you still have to restore power and closed loop cooling at some point. This is what they did at Fukushima. Why not skip the accident and add the robust cooling system, flood-proof, in the first place?

          Keep in mind also that filters can fail, just like cooling systems. Often a passive cooling system like isolation condenser (with noncondensables pure lines) gives you more safety, as proven by probabilistic risk analysis.

          The problem with safety is that you can always invest more. The filter may fail, so let’s add a redundant filter. But what if that fails too? Add another filter. And add more valves too in case these fail. And add… you can continue this excersise indefinately. 15 million here, 30 million there. 100 million there. Pretty soon you’ve priced nuclear out of the market and get more coal, which is dangerous.

          This is why you have to prioritise. What is most useful to prevent the accident?

          • jaagu says:

            @ Rod

            I recommended the Von Hippel article to give some history behind containment design concepts. Most of it was written in long time ago and revised immediately after the Fukushima accident. It does not include the benefits of the investigations and analysis done after the Fukushima accident.

            The point is that we should design our reactors containments for complete meltdown of the reactor core. This has been thought about a long time ago and has been adopted at some nuclear facilities in US. The Department of Energy has typically used filters as the last ditch method of preventing releases of radioactive materials to the environment.

            In the early days of nuclear plant designs, GE and Westinghouse were always trying to make their nuclear plants as cheap as possible to compete with fossil fueled power plants. So they went whole hog for small containments and more safety systems. In hindsight, they could have built much cheaper plants with less active safety systems if they would have built larger containments and provided more passive systems like natural recirculation and filtered containment vent systems.

            The NRC and nuclear industry have recognized the potential need to vent Mark I and Mark II containment designs to cope with severe accident conditions since at least the early 1980s. In 1983, the NRC approved Revision 2 to the Boiling Water Reactor Owners’ Group Emergency Procedure Guidelines, which included guidance for operators to vent Mark I and Mark II containments in response to containment overpressure conditions.

            With regard to the $15 million estimate for filters, it comes from the NRC report SECY-2012-0157 for Option 3.

            I highly recommend SECY-2012-0157 for current NRC thinking on filtered containment vents. They present 4 Options including detailed backup on their analysis and investigations. It was issued late last year.

            http://www.nrc.gov/reading-rm/doc-collections/commission/secys/2012/2012-0157scy.pdf

            You keep saying Fukushima did not have dire consequences because the radioactive materials blew out toward the ocean. That is not true. A $500 billion dollar accident with extensive contamination is dire.

            If you put the Fukushima accident at Peach Bottom, Limerick or Oyster Creek the consequences would be even more dire than Fukushima.

            The SOARCA study you cite is very preliminary with many non-conservative assumptions.

            “According to that study, there will be few, if any off site health consequences from a fuel melt, even if the containment fails.”

            I would not be relying on that preliminary study for your basis. It does not explain how mass evacuation assumptions would be accomplished. It does not estimate the economic impacts of the accident – which would be much greater than Fukushima due to the higher population and industrial density surrounding some US BWRs.

            Thanks for being a rational listner to my thinking.

          • Rod Adams says:

            You keep saying Fukushima did not have dire consequences because the radioactive materials blew out toward the ocean. That is not true. A $500 billion dollar accident with extensive contamination is dire.

            Actually, you’ve not been reading here very long. I’ve been trying to say that the only reason the estimates for Fukushima range even remotely close to $500 billion is because the Japanese government reacted in a completely irrational way to a radioactive material release that would have had NO negative health consequences.

            The total quantity of long lived radioactive material was less than 100 kg spread over a very large area. I’m pretty sure that the max dose to any individual could have been kept to less than 10 rem per year with very simple and low cost mitigation strategies.

            The real cost could have been limited to the economic loss of 4 reactors with a little more to compensate the public for minor impacts.

            Unfortunately for the victims here, there’s been a sustained, multi-decade effort to teach people to fear small quantities of radiation.

          • Rod Adams says:

            @jaagu

            SOARCA is not a preliminary work. It was completed in June 2012 and issued as NUREG-1935 in November 2012.

            http://pbadupws.nrc.gov/docs/ML1233/ML12332A057.pdf

            The research was conducted over a 6 year period. The draft report was ready by the summer of 2011, but delayed for what I believe were political reasons. I’m guessing that the then serving Chairman did not like its conclusions.

            http://atomicinsights.com/2011/08/spreading-calm-certainty-and-reassurance-about-nuclear-energy-counteracting-focused-fud.html

          • Brian Mays says:

            The SOARCA study you cite is very preliminary with many non-conservative assumptions.

            As Rod points out, this study is not “very preliminary.” Personally, I welcome a study with “many non-conservative assumptions.” To this experienced ear, that means that the study might actually have a slight chance of reflecting reality.

            Let’s save the unrealistic, “conservative” worst-case scenarios for Hollywood disaster movies, where it should be clear that the content is pure fiction.

        • Rod Adams says:

          @jaagu

          You were the one who linked to a 1982 vintage paper by Von Hipple in which the cost estimates for filtered vents for containments ranged from $1 to $20 million, IN 1982 DOLLARS.

          Your claim of $1 million per day in revenue from a nuclear plant is also obsolete and incorrect. If the wholesale market price for electricity averages $30 per MW-hr (which is the case in some markets for some periods of time) and the plant has a maximum power capacity of 600 MWe (also a reasonable number for some of the smaller plants that might be affected by the filtered vent requirement) the GROSS revenue is just $432,000 per day. There are a lot of expenses that need to be covered by that figure, including an NRC operating license fee of $4.7 million per year no matter what size the reactor is.

          How confident are you in your estimate of $15 million for all of the operating plants? What is the real probability that a reactor in the United States, with B5B equipment, FLEX, and other mitigation efforts will experience ANYTHING close to what happened at Fukushima?

          Will the requirement for filtered vents be the straw that broke the economic camel’s back for 1, 2, 9, or even 31 of our operating reactors? If the owners decided that it is more economical to shut down and turn in their operating license (as Dominion has already announced that it is planning to do with Kewaunee, even without a filtered vent requirement and as Exelon has indicated that it might do with Oyster Creek in the case of ANY unplanned expense), has that resulted in a safer grid or one that carries more potential for harm to people?

          There is no doubt in my mind that our nuclear plants are far safer than any replacement plant, even if they do not install any additional equipment.

  9. Bill Hannahan says:

    For decades I have believed that station blackout combined with full meltdown should be a design basis accident. Had the Fukushima reactors been designed to this standard, they would have passively vented at low pressure through filters, resulting in negligible release of radioactivity on the surrounding land. There would have been no hydrogen explosions. That would have demonstrated that nuclear plants can absorb a worst case (China syndrome) accident without disruption of the surrounding community.

    More importantly, for the human race, we would now be in the midst of a strong nuclear renaissance with the support of most people.

    Under this standard, the need to prevent a meltdown at all cost is reduced from a human safety issue to an economic analysis. The elaborate and extremely expensive to design build and maintain safety systems can be greatly simplified.

    Under this strategy the probability of a meltdown increases from extremely small to very small, yet public safety is improved, and the cost to build and maintain nuclear plants goes down. Ultimately the cost of nuclear kWh’s is reduced.

    • jaagu says:

      @ Bill Hannahan

      “For decades I have believed that station blackout combined with full meltdown should be a design basis accident.”

      I agree with you and I think the nuclear experts around the world will come to the same conclusion.

      The Westinghouse AP1000 is getting closer to that concept, but it still has a way to go. Westinghouse should add filters to their containment vents.

      • Cyril R. says:

        I agree with you and I think the nuclear experts around the world will come to the same conclusion.

        Agreed.

        I agree with you and I think the nuclear experts around the world will come to the same conclusion.

        The AP1000 does not need venting. It has passive containment cooling. Even if you can’t add makeup water to the PCCS pools, the pressure stays below failure pressure with air cooling alone when the PCCS pools run out (after about 3 days).

        The AP1000 looks to me as being especially robust to station blackout, with fail-open valves on loss of power for the PCCS, natural circulation cooling, gravity drain…

  10. Cyril R. says:

    Okuma (population 11,515) had readings of 508 mSv.

    This gives a similar risk to living in Tokyo. Tokyo is very dangerous with all that air pollution (not to mention crime and traffic accidents).

    So why aren’t you suggesting we evacuate Tokyo? By this reasoning, it would be safer to evacuate Tokyo and put them in Fukushima district.

    • EL says:

      Similar … by what measure.

      http://www.mlit.go.jp/common/000987248.pdf

      Tokyo readings: 0.29 mSv – 0.46 mSv/year.

      You appear to be suggesting we take no extra precautions above a level of 500 mSv/year. What irrational world do you live in … and you wonder why nobody takes pro-nuclear advocates seriously when they say such things?

      Last time I checked, you commit a crime in Tokyo you go to jail.

      • Cyril R. says:

        You appear to be misreading my comment. With such reading skills, it’s no wonder we take you anti-nuclear renewables zealots seriously.

        I am saying exactly this. No more no less.

        1. Air pollution in tokyo is very dangerous. This is not because of nuclear power; in fact it is caused by not having nuclear power powering Tokyo’s cars, factories and powerplants.

        2. No one has yet suggested we evacuate Tokyo, despite 13 million being at risk from the constant fossil pollution. This appears strange to me as the air pollution cancer risk alone is greater than the evacuation limit of 20 mSv/year.

        3. Precautions? I have said nothing of precautions. Here is what I have to say about it. If the exposure is from radioidine, the reasonable precaution is iodine pills, but only for younger people. If from cesium, no action is required. Certainly not evacuation, which is much more dangerous than 500 mSv of ionizing radiation, and we are not evacuating Tokyo despite high air pollution risks. What’s interesting is that the lowest dose at which someone has been known to be killed by cesium and iodine radiation is around 4000 mSv.

        Residents in Taiwanese appartments exposed to highly radioactive cobalt that accidentally made its way into construction steel, turned out to have no negative effects even in the 4000-5000 mSv total dose cohort. Radiocobalt is a more dangerous nuclide than radiocesium.

        Tokyo, much like the rest of Japan, is actually deprived of radiation, with a much lower background radiation than the global average. It is well known that such populations have insufficiently stimulated biological defence mechanisms, resulting in poor health.

        Your response… that 500 mSv is so dangerous in your mind that no one should take me serious… shows you have not read any of the ecological studies on chronic doses of this level. It shows your bias towards wanting to believe that ionizing radiation is infinitely dangerous, unlike anything else, unlike coal that kills 2 million a year.

        • EL says:

          Cyril R. wrote: “Residents in Taiwanese appartments exposed to highly radioactive cobalt that accidentally made its way into construction steel, turned out to have no negative effects even in the 4000-5000 mSv total dose cohort.”

          Please come back from the cliff edge, Cyril? Nobody wants to lose you from the world of unreason and irrationalism when it comes to health physics and nuclear power. That would be a very significant loss indeed.

          http://en.wikipedia.org/wiki/Radiation_hormesis#Effects_of_Cobalt-60_Exposure

          I guess you haven’t seen any of the follow-up research on exposed residents in Taiwan apartments to Cobalt-60? It appears the original study didn’t control for age (lots of old people skews your results) or socioeconomic status (who generally lead healthier lifestyle)? Later studies show a correlation between exposure dose and increased health risk (especially for leukemia in men and thyroid cancers in women). And DNA anomalies have been common and elevated in population (especially among the young).

          Cancer risks in a population with prolonged low dose-rate γ-radiation exposure in radiocontaminated buildings, 1983 – 2002” (International Journal of Radiation Biology, 82(12):2006)

          Estimates of Relative Risks for Cancers in a Population after Prolonged Low-Dose-Rate Radiation Exposure: A Follow-up Assessment from 1983 to 2005” (Radiation Research, 170(2):2008).

          And an average dose of 47.7 mSv is not the same as 500 mSv. I think most people know this.

          Ecological studies, huh? I suppose you mean the work by Bernard Cohen (physicist). You are aware that epidemiologies view ecological studies as much lower in reliability than cohort studies or case-control studies. If you don’t control for individual exposures, causal relationships are much harder to infer. WHO puts it this way:

          Such descriptive studies are the weakest form of epidemiological investigation because the cumulative exposure of individuals cannot be estimated, nor can important confounding factors such as smoking be controlled for at the individual level. Ecological bias, namely the difference between associations seen at the group level as opposed to the individual level (Piantadosi, 1994; Morgenstern, 1995), has long been recognized as the principal limitation of geographical correlation studies.

          And they discuss the work of Cohen thus:

          The weight of evidence is that the ecological analyses of Cohen can be rejected.

          • Cyril R. says:

            What a pathetic attempt of a rebuttal.

            Here’s what Wikipedia says:

            A subsequent study by Hwang et al. (2006) found the incidence of “all cancers” in the irradiated population was 40% lower than expected (95 vs. 160.3 cases expected), except for leukaemia in men (6 vs. 1.8 cases expected) and thyroid cancer in women (6 vs. 2.8 cases expected), an increase only detected amongst those exposed before the age of 30. Hwang et al. proposed that the lower rate of “all cancers” might due to the exposed populations higher socioeconomic status and thus overall healthier lifestyle, but this was difficult to prove. Additionally, they cautioned that leukaemia was the first cancer type found to be elevated amongst the survivors of the Hiroshima and Nagasaki bombings, so it may be decades before any increase in more common cancer types are seen.[46]

            Besides the excess risks of leukaemia and thyroid cancer, a later publication notes various DNA anomalies and other health effects among the exposed population:[48]

            There have been several reports concerning the radiation effects on the exposed population, including cytogenetic analysis that showed increased micronucleus frequencies in peripheral lymphocytes in the exposed population, increases in acentromeric and single or multiple centromeric cytogenetic damages, and higher frequencies of chromosomal translocations, rings and dicentrics. Other analyses have shown persistent depression of peripheral leucocytes and neutrophils, increased eosinophils, altered distributions of lymphocyte subpopulations, increased frequencies of lens opacities, delays in physical development among exposed children, increased risk of thyroid abnormalities, and late consequences in hematopoietic adaptation in children.

            6 cases in both leukemia and thyroid is not signficant (because n is so much smaller than N). If you understood anything about statistics, you would not use this as an argument.

            Furthermore, the quoted argument about socio-economic status is a theory; not a rebuttal. There is no evidence of this at all. It is countering a real statistical result with a hypothesis that can’t be proven by the author. That’s pathetic and not constructive.

            Certainly higher socio-economic status helps to prevent cancer; but when you expose a group of people, young or old, wealthy or poor, to 4000 mSv of ionizing radiation, the cancer incidence predicted by LNT is so large it will show up. Furthermore, consider that higher socio-economic status has a higher average age (wealthier people are usually older) and you would actually expect this to negate itself somewhat. Consider also that higher socio-economic status will typically mean larger appartments with more contaminated steel, therefore greater exposure… the net effect may well be positive with socioeconomic status, or at least it should be, and it isn’t.

            I am fully aware of the criticisms to the Taiwanese work; none of these criticisms explain why the cancer incidence is so low, nor why it DECLINED over the years (ie become lower with increasing exposure). They don’t even have a theoretical explanation of the latter effect!

            Same for rejecting Cohen’s work: certainly ecological studies have their downsides, and you can’t infer a model from them, with all the spurious factors, but you can, however, test other models with it. LNT would show up huge cancer rates with all these chronic type exposures, yet the ecological studies don’t show this… it means LNT is bullshit at least for chronic exposures of which Fukushima is a type. It means that further investigations are warranted. Cohen has, by the way, provided rebuttals to these critiques of him that you can google and some of it is also found here:

            http://www.phyast.pitt.edu/~blc/

          • Bill Hannahan says:

            EL, you make it sound as if there is a superior cohort study that actually measures the carcinogenic risk of radon at low levels and finds it to be consistent with LNT. Please provide a link.

            What do you think explains the dramatic difference between Cohen’s results and LNT at low level, yet consistent results at high levels.

          • EL says:

            Cyril R. wrote: “What a pathetic attempt of a rebuttal.”

            I take it you read through those quotes before posting them? I don’t see how they discount anything I have said. Yes, there is an elevated risk among those under 30, and “it may be decades before any increase in more common cancer types are seen.” Thank you for providing that detailed and informative clarification.

            And is there a reason why you keep citing 4000 mSv? High-contamination cohort received >15 mSv/y (11%), moderate-contamination between 5 – 15 mSv/y (9%), and low-contamination cohort between 1 – 5 mSv/y (80%).

            Cyril R. wrote: “Cohen has, by the way, provided rebuttals to these critiques of him”

            Odd … a non specialist who’s research has been rejected by WHO (and other health physics professionals) has a rebuttal. Funny world we live in, eh?

          • EL says:

            EL, you make it sound as if there is a superior cohort study that actually measures the carcinogenic risk of radon at low levels and finds it to be consistent with LNT. Please provide a link.

            Radon and Lung Cancer in the American Cancer Society Cohort,” Cancer Epidemiology, Biomarkers & Prevention, 20(3):2011.

            Article cites “confounding by cigarette smoking” and “cross-level bias” (typical of ecological studies) as reasons for different result and negative correlation in Cohen.

          • Cyril R says:

            The study provided by EL is very interesting.

            This one, available without paywall, shows similar results, but is more useful in the explanations:

            http://www.ehjournal.net/content/10/S1/S4

            Notice the huge spread of data point! 95% confidence interval shows anywhere between 0% risk and 28%!

            So which is it, no risk or a big one? Big variations in the studies!

            The author claims very strong evidence, but a 95% CI of 28% all the way down to 0% is not strong evidence. To the contrary, it shows the need for further controlling variables.

            Fortunately the article contains a graph that sheds some light on this enigma. Notice there’s a big influence of age: younger people are positively affected by radon concentration, whereas old folk are at risk.

            http://www.ehjournal.net/content/10/S1/S4/figure/F2

            Now this is all very interesting, but radon’s biological danger isn’t such a big mystery; it accumulates in one organ, the lung, where it concentrates its alpha damage, and its decay daughters are known to be very dangerous and bioaccumulating.

            There’s no radon involved in Fukushima. There’s only cesium right now, which is closer to cobalt-60 in term of emitter type (no alphas), dose type (chronic full body dose), non-bioaccumulating.

          • Cyril R. says:

            Yes, there is an elevated risk among those under 30, and “it may be decades before any increase in more common cancer types are seen.” Thank you for providing that detailed and informative clarification.

            Actually the study I linked to about radon risk shows a lower risk among those under age of 55. Furthermore, the decades you are talking about… similar to the decades that have gone by since Chernobyl, and still no massive death rates seen… as agreed upon also by the WHO, who you and I both consider health expert?

            Oh, those decades. Well, they’re great decades. They’ve shown us we needn’t fear people like you who tell us radiation of any dose and type is bad.

            And is there a reason why you keep citing 4000 mSv? High-contamination cohort received >15 mSv/y (11%), moderate-contamination between 5 – 15 mSv/y (9%), and low-contamination cohort between 1 – 5 mSv/y (80%).

            4000 mSv is total dose. A quite long time is involved. See the original study, table 1:

            https://docs.google.com/viewer?a=v&q=cache:MWA74HChNecJ:www.ecolo.org/documents/documents_in_english/low-dose-Cobalt-taiw-06.pdf+&hl=en&gl=nl&pid=bl&srcid=ADGEESjRHBWXNJY0hBVlxsRFUFwI8LyNfPTcoDDpcP1AAUT9EE4wZIdK3Rq4A243RG4TtKXZSrOQlE1kvqJInDrqKccVuibvxrUCH0JAbWkjVCnBsd37gHbxd0qnW8VXu0uw7UlnKqs7&sig=AHIEtbSh-IDC5Q85kLCsajEVfnZmAiEM2g

            Odd … a non specialist who’s research has been rejected by WHO (and other health physics professionals) has a rebuttal. Funny world we live in, eh?

            You mean the WHO who agreed that Chernobyl radiation has had tiny radiation health consequences? You mean the same WHO who claims that 1-2 million people are being killed every year by fossil fuels – of which you renewables folks will need lots and lots to cope with intermittency?

            Yes, I agree. It is a funny world, EL.

          • Brian Mays says:

            EL – The radon study that you have cited is more of a semi-ecological study than a true cohort study. The risk model was based on ecological indicators — namely, the zip code of the participants when the study began. (Apparently there was no effort to track whether the participants moved between 1982 and 1988.) If you’re going to criticize studies for ecological inference, then you should recognize that it is a major weakness of this study too.

          • Brian Mays says:

            And is there a reason why you keep citing 4000 mSv?

            EL – The 4000 mSv figure comes from figures for the “high” cohort in Chen et al. (2004).

            I acknowledge that Chen et al. has some serious issues, but the paper that you have cited, Hwang et al. (2006), has some ugly warts too. Its conclusions are not adequately supported by the analysis.

            The main problem with the paper is that it purports to draw conclusions about “low dose-rate” radiation exposure, but it uses data for a cohort that includes exposures up to 2363 mSv at rates as high as 1413 mSv per year. I’m sorry, but 2.4 Sv does not qualify as low-dose exposure (it’s about half the LD50 dose with no medical intervention) and 1.4 Sv per year is not a low dose rate!

            In other words, they’ve included data that is roughly 25 times higher than the upper limit of what is typically considered low dose and low dose rate into their study of low dose rate exposure. They are well into the range of the well-studied high-exposure Japanese atomic bomb survivor data, so it should come as no surprise if more-than-expected cancers are observed in some of the numbers.

            If the authors were genuinely interested in studying low dose rates, they could have easily excluded data for individuals who had received more than 100 mSv of estimated cumulative exposure, but they did not. Why is that? I suspect that they ran the numbers and didn’t find anything interesting. They already acknowledge that, when the entire cohort is taken as a whole, the risk (in SIR’s) for the exposed population is lower for all cancers, all solid cancers combined, etc. They explain this by a hand-waving argument of speculating that this is due to the exposed population having a “higher socioeconomic status” than the general population. That might be true, but it is hardly a rigorous, convincing argument.

            To get an estimate of the increase of risk with dose, they calculate a hazard ratio that compares the group that received less than 1 mSv of dose to the group that received more than 50 mSv. The former group is probably a reasonable control group, but the latter group still contains the people who received very high exposures.

            What was the distribution of exposures in the 50+ mSv group? We don’t know, because the authors don’t provide any information about this, not even a simple histogram. All we know is that there are 590 people who received somewhere between 50 and 2363 mSv of dose and who are responsible for a marginally significant result that allows the authors to claim that low dose-rate radiation exposure appeared to increase the risk of certain cancers.

            Why was the limit set at 50 mSv? Why not pool everyone with >1 mSv? I suspect that this particular value was chosen because it is low enough to qualify as low-dose radiation, but high enough such that the really high exposures included in the group are able to pull up the numbers up to get a marginally significant result that matches the preconceptions of the researchers.

            It’s a shame that the reviewers of this article never asked these questions.

          • EL says:

            Brian Mays wrote: “The main problem with the paper is that it purports to draw conclusions about “low dose-rate” radiation exposure, but it uses data for a cohort that includes exposures up to 2363 mSv at rates as high as 1413 mSv per year.”

            You’re talking about this study, correct? Chen, et. al. (2004).

            http://www.jpands.org/vol9no1/chen.pdf

            Nobody received doses as high as 4000 mSv or 1413 mSv in a single year. These are cumulative doses for the period 1983 – 2003. And cobalt-60 has a half life of 5.3 years.

            I’m looking at this quickly, but am I missing something. Highest doses were for first year (1983). Mean annual dose for high cohort in first year was 525 mSv/year (11% of population). Mean annual dose for low cohort in first year was 16 mSv/year (80% of population).

            The study is pretty loose with methodology for arriving at doses, averaging doses, and creating an impression that doses were consistent over time. I could look at it closer later, and Hwang too, but this is what jumps out at me quickly tonight. I feel like I could be missing something (but I thought it was worth providing a link to study … so others could see for themselves).

          • Rod Adams says:

            @EL

            Yes, people did receive cumulative doses as high as 4,000 mSV. Look at table 1 in the study to which you linked.

          • Brian Mays says:

            You’re talking about this study, correct? Chen, et. al. (2004).

            EL – No. As Rod points out, the 4000 mSv figure comes from Table 1 of Chen et al. (2004).

            The majority of my comment, however, including the part that you quoted, concerns Hwang et al. (2006) and doesn’t have anything to do with Chen et al. (2004).

          • Cyril R. says:

            The really interesting part about the Chen et al study, is not so much the lower initial cancer rate – this is explained in part by the lower age (students). It is the fact that cancer rates from the irradiated group declined, while average Taiwanese rates increased. And the decline matches the decay curve of cobalt-60 very well. In other words, cancer incidence reduced with increasing exposure. The improvement is quite dramatic, as you can see from figure 1 in the study. It is virtually impossible to explain this by confounding factors such as socioeconomic factors (which Chen et all explicitly stated did not deviate enough from the Taiwanese average to be a major explanation). But hormesis explains it perfectly.

          • EL says:

            Cyril R. wrote: “It is virtually impossible to explain this by confounding factors such as socioeconomic factors (which Chen et all explicitly stated did not deviate enough from the Taiwanese average to be a major explanation). But hormesis explains it perfectly.”

            Cyril … you’re too funny. They study is not yet complete. You provided a quote yourself indicating further study is needed, and follow-up for common cancer types might not be seen for decades after exposure. We do get higher risk for some cancers (when we control for age of population).

            And I don’t know why people are having such a hard time reading the dose measurements for this study. Nobody received yearly dose of 4000 mSv or 1413 mSv (as indicated by some above). Mean doses for the first year were as follows: 525 mSv/year (1,100 people), 60 mSv/year (900 people), 18 mSv/year (8,000 people). In fact, the study averages these dose rates over the entire period and describes it this way:

            The dose evaluations were used to classify the apartment dwellers into three cohorts, based on contamination level (average dose rate), for government remedial measures and care: The high-contamination cohort (~11%) received >15 mSv/y. The moderate-contamination cohort (~9%) received between 5 and 15 mSv/y. The low-contamination cohort (~80%) received between 1 and 5 mSv/y.

            It seems to me some folks here wish to say a 4,000 mSv annual dose (or even 500 mSv annual dose) is a perfectly fine based on this particular study (and discounting other studies with same population). I see no evidence to merit such a claim, and folks here should stop making one.

          • Cyril R. says:

            Cyril … you’re too funny. They study is not yet complete. You provided a quote yourself indicating further study is needed, and follow-up for common cancer types might not be seen for decades after exposure.

            I’m not funny, I’m dead serious. Yes, more research is warranted – especially regarding age control. I was simply pointing out that you can’t reject a study like Chen on some hypothesis, which is both unproven and even if true won’t explain the reduction in cancer incidence as time passes on.

            Decades, you say? Decades is exactly what have passed already in the study timeframe. If there was an effect, it should show up. Certainly we can’t explain a lower incidence of cancer with time, even if no extra cancer shows up you’d expect a straight line. Not a very strongly declining line! It’s just bizarre.

            And I don’t know why people are having such a hard time reading the dose measurements for this study. Nobody received yearly dose of 4000 mSv or 1413 mSv (as indicated by some above). Mean doses for the first year were as follows: 525 mSv/year (1,100 people), 60 mSv/year (900 people), 18 mSv/year (8,000 people).

            You appear to be quite oblivious. What part about cumulative dose do you not understand? Do you understand this word, cumulative? Do you understand why the LNT uses cumulative doses? Do you understand the word linear? Do you understand that in a linear effect presumption, doses can be simply summed up?

            Can’t you put 2-n-2 together? Sheesh.

            And do you know what the sign “>” means? >15 mSv/year means from the peak 500 something mSv to 15.1 mSv/year.

            It seems to me some folks here wish to say a 4,000 mSv annual dose (or even 500 mSv annual dose) is a perfectly fine based on this particular study (and discounting other studies with same population). I see no evidence to merit such a claim, and folks here should stop making one.

            We never said anything like this! You misunderstood us because you don’t understand simple concepts such as cumulative exposure in a LNT model, even when explicitly pointed out to you.

          • Brian Mays says:

            And I don’t know why people are having such a hard time reading the dose measurements for this study. Nobody received yearly dose of 4000 mSv or 1413 mSv (as indicated by some above).

            Do you not bother to read the studies that you cite? (Note: this is a rhetorical question; I already know the answer.) The 1413 mSv/y figure is taken directly from the text of Hwang et al. (2006): “When the exact exposure duration for each individual was taken into consideration, the estimated dose-rate of excess exposure was 10.5 ± 50.2 mSv/year on average (< 1 to 1,413 mSv/year), including 63% with less but close to 1 mSv/year, 16% with 1 – 5 mSv/year, and 21% with more than 5 mSv/year.”

            Mean doses for the first year were as follows: 525 mSv/year (1,100 people), 60 mSv/year (900 people), 18 mSv/year (8,000 people).

            Why are you talking about mean doses? If 1100 people are exposed to a mean dose of 525 mSv/year, that doesn’t mean that every one of those 1100 people received that exact same dose. Some received substantially less, and some received substantially more. Because the 1100 people represent a “high dose” group, there is a lower bound to the distribution of exposures (namely the cutoff between this group and the “medium dose” group). Thus, to have a mean of 525 mSv/year, there must be a considerable subpopulation of this group who received doses that were substantially higher than this mean value, because of the way that averaging works.

          • EL says:

            Cyril R. wrote: “Certainly we can’t explain a lower incidence of cancer with time, even if no extra cancer shows up you’d expect a straight line.”

            You mean the higher incidence for certain age groups, right?

            Again, quoting from Hwang, et. al. (2006):

            “In this study, we were able to note significant exposure-dependent increased risks in individuals with initial exposure before age 30 but not beyond this age, especially for all cancers combined, all solid cancers combined. Due to relatively small numbers of cancer cases, it was difficult to observe exposure- dependent associations for these cancers” (p. 856).

            And regarding follow-up:

            “The average follow-up period since initial exposure was still too short to observe the development of the whole spectrum of cancers in this cohort. Further follow-up of the study cohort is necessary to corroborate our findings and identify other types of cancers that may also be related to the protracted and low dose-rate ionizing radiation” (p. 857).

            Despite a single individual who received a dose of 1,413 mSv/year, 63% of the population received doses of less than 1 mSv/year, 16% less than 5 mSv/year, and 21% more than 5 mSv/year. We have a regulatory guideline of 20 – 50 mSv/year for many power plant workers in many countries. I don’t see where anything in this study causes us to think this regulatory guideline (especially given that many exposures to gamma radiation in this study were below this amount)?

          • Cyril R. says:

            You mean the higher incidence for certain age groups, right?

            No, the total. I’m talking about the Chen et al study. See figure 1 of that study.

          • Brian Mays says:

            EL – I agree. Hwang et al. (2006) is nearly worthless for drawing any conclusions, because the researchers seem to be so interested in obtaining a (marginally) “significant” result that they looked at the wrong things.

            Guidelines are guidelines. Whether they are too low or not and whether they reflect the genuine risks is simply not answered by such a poor study. Then again, the epidemiological literature on cancer risks from radiation is plagued with an overabundance of such poor studies.

  11. Cyril R. says:

    I must admit I have never heard of a “steam driven condenser”. I think you are referring to the Isolation Condensor System which did not work so well in Fukushima Unit 1. And upgrading the Isolation Condensor System for the old BWRs with generators to provide DC power also requires that makeup water be supplied to the system. It will not operate indefinetly without makeup water provided by some other system.

    The reactor core isolation cooling (RCIC) system, which is used in BWR/4s, BWR/5s, BWR/6s, and the Advanced Boiling Water Reactor (ABWR) is the better upgrade for the BWR/2s and BWR/3s.

    Yes, isolation condenser (IC) and reactor core isolation cooling (RCIC) are the systems I was referring too.

    The IC of F-D unit 1 did not work well because of hydrogen gas accumulating in it after core melt had occurred. This was a design flaw as modern ICs have noncondensables vent lines to passively purge these insulating gasses to the wetwell.

    It is true that RCIC has the advantage of easier makeup water addition. But it is also the more complicated system, with a steam driven turbine, controls, governors, electronics and required DC power… whereas IC has no moving parts and needs only power to activate it initially. At F-D unit 1 the IC was not fail-open and was motor operated. Another design weakness as one of the prime reasons the IC is needed is during station blackout…

    I prefer the IC system. It is far simpler with no moving parts and electronics. Makeup water can be added with standard fire engines, the water mains, a generator powered pump, or the standard safety grade makeup and cleaning lines. With IC you can boil off this water to atmosphere, whereas with RCIC you reject heat back to the wetwell, pressurizing containment… so you still need a containment cooling system on top of the RCIC, whereas the IC is all you need as long as the primary loop is intact (this was the case at Fukushima – the earthquake ruptured no pipes).

    • jaagu says:

      @ Cyril

      “I prefer the IC system. It is far simpler with no moving parts and electronics.”

      So are you recomending that all the old BWRs install an IC system with DC generators?

      Personally I think the old BWRs owners would object to this fix more than they would to the $15 million for filters on the containment vents. Again have you come up with the cost of adding an IC system with DC generators to the old BWRs as I asked before?

      • Cyril R. says:

        A well designed IC doesn’t deed DC power. It can be designed as fail open (into operation) on station blackout. Using normally closed motor operated condensate return valves, fail open by a spring upon loss of power.

        Some BWRs have these ICs already so in some cases the solution may be as simple as replacing a single valve. In other cases a noncondensables vent line would have to be added.

        Other BWRs have the RCIC. These could install DC generators attached to the RCIC turbine. But RCIC cannot be used for weeks because steam conditions will degrade, tripping the turbine. So I like the IC system better. It won’t trip.

        An isolation condenser is not complicated. It is a rack of stainless steel tubes in a tank of water. BWRs already have pools of water available for flooding the core during refuelling, so we’re talking about installing some stainless steel racks and two valves.

        Cooling is far more important than filtered vents. Even if you have filtered vents, you still need cooling. You always need cooling. It’s the tricky thing with decay heat – it can’t be shut off.

  12. Bill Hannahan says:

    @Rod… “Will the requirement for filtered vents be the straw that broke the economic camel’s back for 1, 2, 9, or even 31 of our operating reactors?”

    Excellent point Rod. This is a problem with all government regulatory agencies. I call it BOX MENTALITY. They are only interested in improving safety inside their box, with no consideration for external impacts.

    Imagine you have a daughter away at college. She wants to fly home and surprise you on your birthday but she cannot afford the fare. She goes on the internet and buys an unused ticket for 70% off. Wait, she cannot do that because of the photo ID law, so she gets into her car after the last class of the day, drives through the night, falls asleep at the wheel, rolls into a ditch, and dies.

    We know that any group that can build a semtex bomb into a working transistor radio can make a fake ID or buy a real ticket under any name. I wonder how many people die each year in traffic accidents so that Bill Clinton could have a talking point after a terrorist attack.

    My general solution to this problem is to give every regulation a lifespan, and require the regulating agency to present a high quality benefit/cost analysis, covering the total impact of the regulation on society, not just inside the box. It would be published on the internet for public review and comment. They would have to respond to substantial comments. The Code of Federal Regulations would shrink to a continuously evolving streamlined set of cost effective regulations.

    My specific recommendation in this case is to give the utility the opportunity to present a benefit/cost analysis for any regulations they choose, and that they be relieved of those requirements with a very low or negative ratio in exchange for installing accident rated filters. In this way safety can be improved while cost goes down.

  13. Cyril R. says:

    For a Pressurized Water reactor the concrete portion of the containment is for shielding,the steel liner is for vapor containment. The containment only stays pressurized for a short period of time because the pressure increase is caused by the water in the RCS flashing to steam, this steam is rapidly condensed by either a spray down system or by fans and heat exchangers. After a period of time the containment is vented through filters.

    The concrete containment of PWRs is usually prestressed concrete, which is designed to bear internal pressure. The liner is only for hermeticity as concrete isn’t completely vapor tight. The liner on its own wouldn’t have the strength to contain an accident.

    The spray system requires power… hence is not available in station blackout. A filtered confinement can be designed so that it doesn’t need power. If you’re going to vent later on anyway, you might as well start with a low pressure filtered confinement. If high pressure containment were a good idea, high pressure chemical reactors would use them. They don’t.

    • David Andersen says:

      @Cyril
      For PWRs I know of at least 4 different containment designs. Older small ones like Yankee Rowe had only a steel shell, Ice Condensers to allow for smaller containments, large containments without prestressed concrete because the accident pressure was low enough to not require the additional strength, and the smaller containments with prestressed concrete. All of these designs would use a concrete wall for shielding, but not necessarily for structural strength.
      I realize that this discussion was primarily about BWRs which function in a different manner.

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