This is a longer version of the December 2011 Forum. It began as an answer to Pinayur Rajagopal, and grew. Some additional information has been added to the main text. An appendix addresses a number of points raised in letters. I apologize for the length, but as I have learned over the years, among those who oppose nuclear power, there is disagreement about what is important, and letter writers present very different concerns. Much thanks to Martin Kelley for putting all of these on one (very long) web page.

The information that surprised me most is the answer to this question: How does the danger from the Fukushima Daiichi reactors compare to other health dangers, such as Tokyo pollution?

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It is long past time for Friends to begin a conversation on nuclear power and the much larger issue of how we know what to believe. Many among us insist that what is overwhelmingly the safest of the large sources of electricity should meet standards that no other energy source meets. Many Friends insist that the scientific community is lying about the safety of nuclear power. And overwhelmingly, we as a community insist that solutions to climate change be only the ones we like, even when scientists and policy experts find these solutions partial or even counterproductive.

Our simplicity testimony calls for removing obstacles to walking joyfully with God. At the best of times, this is a challenge. Today, there can be little joy in the most optimistic scenarios for climate change. Additionally, our integrity queries don’t seem to raise some vital questions: everyone’s wrong, a lot. When am I wrong? How would I learn that I am wrong, that like-minded people are wrong? A single standard of truth does not mean checking on the web to confirm our hopes and fears.

Several letters comment on information sources. As Marilyn Dell Brady points out, “truth exists…but we need to find ways to choose between conflicting accounts.” Since many sources seem to disagree, she selects those she identifies as independent of the nuclear industry, which has “a stake in minimizing risks.” Unfortunately, these sources ignore peer review, e.g., Union of Concerned Scientists, Beyond Nuclear, and Arnie Gundersen. She complains that “official statements are often vague and contradictory,” implying that her sources are clear and in agreement, a hard case to make, in my view. Louis Cox cites a report published in the NY Academy of Sciences Annals (NYAS), and identified there as not peer reviewed, “Chernobyl: Consequences of the Catastrophe for People and the Environment”, which Pinayur Rajagopal also wants addressed. Donna Williams compares the integrity of my sources with tobacco industry sources. When Big Tobacco suppressed their research to protect their interests, the public was protected by academic scientists, who published in sources like the ones I choose.

There is a mainstream academic scientific community with rigorous traditions for discernment and restrictive standards of evidence. The work of this community is essential for governments and industry to perform well. Advocacy groups may or may not rely on mainstream science, depending on how well it supports the dominant view of the group. Such groups, from Sierra Club to Fox News, may turn instead to a larger community of scientists, researchers and analysts, citing work which has not been submitted to or vetted by mainstream scientists, including the sources cited in the letters above.

I get my information from the community of scientists who begin with peer review, a necessary but not sufficient condition. I usually skip early stages of discernment and rely instead on major reports based on information and models that have survived challenge. Errors in these reports are discussed in journals likeScience—major errors of understanding such as the attack on the National Academy of Sciences report on protecting salmon, or smaller errors, such as one place in a several hundred page report from Intergovernmental Panel on Climate Change that said “very likely” instead of the more accurate “likely”. Disagreements among experts in this community are laid out clearly, e.g., predictions about sea level rise this century. Experts in the peer review community disagree far less than many in the public believe. The disagreement many in the public perceive around controversial science issues generally comes from self-styled experts who share directly with the public information that has not undergone scientific discernment. No one argues that science proves Truth, but it removes a number of possibilities from the list, for instance, the idea that somehow, without expanding nuclear power, catastrophic climate change can be averted.

If the mainstream scientific community disagreed with the International Atomic Energy Agency (IAEA)report on Chernobyl, Science or/and other major journals would have provided a forum for the discussion. They do not routinely do this for lower level reports and almost never address non-peer-reviewed reports. The lack of discussion in Science, etc., makes it clear that scientists don’t take seriously the NYAS report. NYAS is not unique in making embarrassing mistakes—Lancet took 12 years to apologize for an article on MMR vaccines which should never have been published.

We have heard many Friends accuse two United Nations organizations of lying (IAEA and World Health Organization, WHO), as well as many thousands of mainstream scientists who failed to criticize the IAEA report on Chernobyl. The appendix in the article, Earthquake, Tsunami, and Nuclear Power in Japan, devotes quite a bit of space to contrasting how scientists, versus those like Greenpeace, calculate the effects of Chernobyl on health, and I invite you to read more there. Peer review of either the Greenpeace or NYAS report would have caught deaths attributed to radioactivity which are not linked in any other study.

It is very hard to hear how serious climate change is today, very hard to listen, in part because the most optimistic scenario is awful. Some of us, perhaps those who fly or drive a lot, may have feelings of guilt which interfere with listening. I suspect that most eyes glaze over when reading what is happening and likely to happen due to climate change, such as dustbowls on every inhabited continent, or that flooding is likely to increase dramatically, killing many thousands each year, making hundreds of thousands homeless, and leading to mass starvation.

Even when Friends grasp the seriousness of climate change, even when we accept the overwhelming scientific consensus that its causes include human activity and its effects include widespread illness, death and social disorder, as well as species extinction, some cling to preferred solutions, rejecting nuclear power based on incomplete information, unreliable reports, and long-held convictions. This response is only human, but climate change requires us to reach beyond.

It is time to hold ourselves in the light, to lovingly examine why so much of Friends discussion is counter to scientific understanding, and to the solutions so vital to addressing climate change.

Appendix—Other concerns raised in responses to the article

Physical half-life of cesium is 2 years for Cs-134 and 30 years for Cs-137. However, even in the absence of remediation, ecological half-life is less. In real ecosystems, cesium disappears more rapidly, at a rate that depends on soil characteristics. A recent report from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) found, “a relatively fast decrease with a half-life of between 0.7 and 1.8 years (this dominated for the first 4–6 years after the [Chernobyl] accident, and led to a reduction of concentrations in plants by about an order of magnitude compared with 1987); and (b) a slower decrease with a half-life of between 7 and 60 years.” In some areas, no decline was found after the first 4–6 years. (pp 76-7) At the end of one year, from 37 – 65% of the cesium remains. After 4 – 6 years, from 3 – 20% of the cesium remains.

Now to the letters.

On the non-peer reviewed report published for a while by NY Academy of Sciences

New York Academy of Sciences has posted a highly critical review by M. I. Balonov; his sources are primarily United Nations organizations. According to Balonov, two of the three authors of the original report, V.B. Nesterenko and A.V. Nesterenko, encouraged the use of pectin to reduce radionuclide content in children, although there is no evidence that this works.

Neither Alexey V. Yablokov, the first-listed author of the NYAS report, nor his organization Center for Russian Environmental Policy, can be found at Wikipedia. Sourcewatch says that Yablokov was a member of the USSR parliament, and environmental advisor to Yeltsin, and that “he pioneered the application of ‘phenetic’ marks (the smallest differences in anatomical structures such as the difference in ear shape on the two sides of a person) to the detection of animal population structure and environmental stress.” Yablokov has published as well on the effects of pesticides, showing perhaps an astounding breadth of scientific expertise, but more likely, a willingness to publish outside his field of expertise.

We don’t know that the Sourcewatch accusation is accurate, nor is it easy to find information in English to establish Yablokov or other authors as particularly trustworthy. While those invited to join the U.S. National Academy of Sciences are highly respected, in the former Soviet Union, entire fields of research ranked from among the most respected in the world (in some fields of geology) to not taken seriously outside the highly politicized Soviet hierarchy (much of biology). None of the authors is well known to us in the West, and it is a poor assumption that a small group of who avoid peer review is more trustworthy than the scientific establishment.

Dangers of Climate Change

• Paul Manglgesdorf, Jr, in a letter that I otherwise agree with, says that I “identify “climate change” as the simple total of deaths due to disease, floods, landslides, and starvation” and ignore a constant baseline.

Intergovernmental Panel on Climate Change Working Group 2 addresses the effects of climate change. Inchapter 8, section 8.4.1.2 they discuss the World Health Organization report I mention:

“The World Health Organization conducted a regional and global comparative risk assessment to quantify the amount of premature morbidity and mortality due to a range of risk factors, including climate change, and to estimate the benefit of interventions to remove or reduce these risk factors. In the year 2000, climate change is estimated to have caused the loss of over 150,000 lives and 5,500,000 [disability adjusted life years] (0.3% of deaths and 0.4% of DALYs, respectively). The assessment also addressed how much of the future burden of climate change could be avoided by stabilising greenhouse gas emissions. The health outcomes included were chosen based on known sensitivity to climate variation, predicted future importance, and availability of quantitative global models (or the feasibility of constructing them):

• episodes of diarrhoeal disease,

• cases of Plasmodium falciparum malaria,

• fatal accidental injuries in coastal floods and inland floods/landslides,

• the non-availability of recommended daily calorie intake (as an indicator for the prevalence of malnutrition)

Limited adjustments for adaptation were included in the estimates.”

Climate change is responsible for <1% of deaths and DALYs from these causes in 2000. For example, some 600,000 deaths occur yearly due to weather-related natural disasters, 95% in poor countries. You can link directly to the study from the WHO site, which includes a map of increased deaths per million. These range from 0 – 2 in much of the Northern Hemisphere and Australia, to 60 – 120 in parts of Africa.

Many believe that we in the rich world will really hear that climate change is killing people when it becomes a more important cause of death, and closer to home. Perhaps. After 2000, climate events have occurred in areas we pay more attention to, such as the European heat wave of 2003, “likely linked to climate change”, which killed 35,000 (IPCC WG2, Box 8.1). The extreme heat wave in Moscow in 2010, which killed thousands, is given an 80% chance of being caused by global warming.

Deaths due to climate change will continue to increase. By 2020, rice productivity in parts of Asia may decline 10% due to higher nighttime temperatures (rice is the single most important source of calories worldwide), and food productivity in parts of Africa that depend on rain-fed agriculture may decline 50% (IPCC Working Group 2). Temperature and precipitation extremes, such as drought leading to a 99% decline in rice production in Australia, a major rice exporter, are expected to become increasingly important.

Cost of nuclear power, and cost of the Fukushima accident

• Brady says that “the cost of the disaster will be astronomical.”

The following information comes from the World Nuclear Association, Fukushima Accident 2011 page. The numbers they provide are mainstream thinking, all on one page, and easier to follow than IAEA. WNA updates their information regularly—this information was posted November 1, 2011.

The cost of the accident is expected to be many tens of billions, including compensation to those who evacuated. Tokyo Electric Power (Tepco) will borrow $62 billion, and repay it over 10 – 13 years; other nuclear utilities will help a little. Tepco expects the cost of electricity to increase $13 billion/year over the next decade due to greater use of fossil fuels. (Other utilities must bear an increased cost for electricity production as well, due to reluctance to restart reactors shut down during the earthquake; the increased cost of electricity appears to be the majority of the accident costs.) Additionally, Japan has committed to spending $1.2 billion over 30+ years, primarily to provide health care to the 2 million residents of Fukushima prefecture, but also to conduct a long-term epidemiological study.

• Mary Gilbert makes a number of economic assertions. “Huge cost overruns are standard. The old reactor at Vogtle… cost more than 400 times the original estimate. I have read that high cost will be the factor that stops the growth of nuclear power.” Yes, the old method of separately approving construction and licensing stretched out the process during the time Vogtle Units 1 and 2 were built; reactors of that era suffered delays from protests, and even longer delays as Nuclear Regulatory Commission (NRC) improved regulations after Three Mile Island. The cost of money was high during the late 1970s and early 1980s, and the price of many plants was much more than projected. Additional costs were added over the years as NRC required new concerns to be addressed. Overall, NRC’s focus on safety led to nuclear reactors operating much more of the time, and industry profited from regulations imposed for safety. I assume by 400 times, Gilbert means 400% (4 times). The final cost for Units 1 and 2 was $8.87 billion, and an initial estimate of $10 million each is doubtful, even accounting for high inflation rates which doubled or tripled apparent costs between proposal and completion.

It is true that if nuclear reactors cost significantly more or take longer to produce than manufacturers predict, or if quality is poor, demand for new nuclear will fall. Yet even in the well-publicized case of the Areva Generation III+ reactor being built in Finland, with very public discussions of cost overruns and delays for Unit 3, Finland in 2010 approved Areva for Unit 4.

• Gilbert says, “Commercial insurance companies will not underwrite [nuclear reactors]. All accident costs are absorbed by the public, namely us.” I assume she is referring to the Price-Anderson Act, which was addressed in some detail in a previous article, A Friends Path to Nuclear Power. Basically, companies must buy maximum insurance on their reactors (in 2011, this is $375 million per reactor). After that, all companies are responsible for a nuclear accident anywhere; in 2011, Price-Anderson liability for the utilities in event of any U.S. accident anywhere is $12.6 billion (up to $111.9 million per reactor). After that, government is responsible, or Congress can retroactively increase the nuclear industry’s liability. To date, the public has contributed no money.

• Gilbert says, “The plants are very slow to get on-line, along the lines of 10 to 15 years.” If this turns out to be true, the cost of new nuclear power will be much higher and it will not be an attractive option. Construction is expected to begin for the new Vogtle plants in early 2012, and commercial operation is expected in 2016 (Unit 3) and 2017 (Unit 4). (They are the first Gen III+ plants built in the U.S. and delays may occur.) Southern Company began with an application, submitted in 2004. (The paper-shuffling portion of the process will definitely speed up after NRC gains confidence and experience with Gen III+, and utilities gain experience.) In August 2009, excavation began after Southern received a limited work authorization. Technically, Vogtle Units 3 and 4 will be under construction for 4+ years (from 2012 to 2016 for Unit 3); perhaps the 2 years of safety and excavation work could be included as well. Counting the paper work may be unfair.

• She also says, “Huge amounts of energy are needed, both to extract materials used to build them, and to do the building itself. The financial and environmental costs of mining uranium to fuel the plants continues as long as the plants run. Once we have committed to building them we are locked into a very expensive infrastructure, yielding profit for the few.”

All three statements are correct. However, the life cycle costs of energy, greenhouse gas emissions/kWh, and the environmental impacts of the mining are comparable to or smaller than the GHG and other environmental impacts of other sources of energy. (Life cycle costs are calculated from mining to decay, hundreds of thousands of years from now.) There was a long discussion of these points in another Friends Journal article, The Nuclear Energy Debate Among Friends: Another Round. Readers may also wish to listen to Per Peterson’s talk comparing inputs needed for nuclear, coal, natural gas, and wind, or link to the data summary on my blog post.

The final statement contains two truths. First, nuclear has very expensive infrastructure (not nearly as expensive /kWh as wind and solar, however). Second, investors expect to make a profit. Customers’ bills are lower with nuclear power compared to natural gas, so we can perhaps say that while only a few make a profit, many profit from the use of nuclear power.

• Gilbert finishes by saying, “Money diverted to these plants is not available for other uses,” and then advocates that the money for nuclear power instead fund research and development for, and subsidies of, various renewable energy sources, and replacing and retrofitting buildings, and funding public transportation. I am puzzled by the idea that unsubsidized nuclear is too expensive, but subsidized renewables are not. Renewables are also part of the climate change solution; some of their costs and limitations are discussed in other articles such as The Nuclear Energy Debate Among Friends: Another Round. Bottom line—enormous amounts of low-greenhouse gas electricity are needed in the U.S. and the world, even if efficiency is introduced at the high pace policy experts recommend, and neither nuclear nor more expensive renewables will be sufficient, alone or together.

New reactors in the U.S.

Along with the cost question I often hear confusion about whether new U.S. nuclear power is planned. Nuclear build seems to be occurring below the public radar. Tennessee Valley Authority (TVA) finished Unit 1 in Browns Ferry in 2007 at a cost of $1.9 billion, and saved $800 million the first year. TVA began construction in 2007 on Watts Bar 2, which had been abandoned in 1988 as demand for electric power increased more slowly than expected. When construction is complete, likely in 2012, TVA plans to begin construction on Bellefonte 1, where construction was also abandoned. These two plants never operated, so are considered new reactors. All three reactors are the same generation as other U.S. nuclear power plants, generation II. Vogtle Units 3 and 4, the first two Gen III+ reactors in the U.S., are expected to begin construction in 2012, and to begin operation in 2016 and 2017, although there may be delays for first of a kind. Construction of Gen III+ reactors for Virgil C. Summer Units 2 and 3 are expected to begin next year as well, with commercial operation expected in 2016 and 2019. Because these reactors are Westinghouse AP1000, more of the work is done at the factory, and delays are likely to be fewer. While these are first-of-a-kind reactors for NRC, they are not for Westinghouse, which has already shipped units to China.

Many wondering whether to go with nuclear power will be watching to see whether a high-quality reactor is produced close to the cost and time Westinghouse announced.

The AP1000 has a number of advantages over Gen II reactors. By doing so much of the construction at the factory, costs are expected to be lower and quality higher. New reactors use more passive safety mechanisms. For example, if the reactor becomes too hot, cooling begins automatically, and can continue 72 hours without operator control.

Living lighter on the planet

Williams “unplugged [her] drier to hang [her] laundry in the sunshine which is plentiful, cheap, local, and adds nothing to the carbon footprint”. Muriel Strand is looking at her “fossil fuel addiction”, trying to live more consciously, and reconsidering choices. Good!!! to both, and to all attempting to live in a manner consistent with our values. I, too, never use a dryer. I don’t fly, and I am in a car about 200 miles/year. I do this for myself—I want my life to testify to my values, and believe climate change is important.

Unfortunately, people in energy policy say that behavior change will be as important a solution to climate change as voluntary smog checks were to cleaning up Los Angeles air. This is because few are motivated to sacrifice much for the common good. (Luckily, many of us don’t see our choices as sacrifices, but reflections of our values, and we often see our choices lead to greater health and happiness, independent of any benefit to the environment.) Also, the details are confusing (is fish better than meat? How much of a difference will this flight make?) and the flesh may be weak. Many want solutions to be what they want solutions to be, but how important to climate change is eating organic? Locavore? Buying green?

Looking at our own behavior is an important unit in my classes and workshops, but I see no reason to doubt policy experts on their pessimism that this will help much. For every person I know who no longer flies, I know several who fly long distances for short vacations. And as much as I have reduced my own greenhouse gas emissions, it isn’t enough—the goal is to reduce by 2050 per capita emissions worldwide below 5% of current U.S. levels.

What happened at Fukushima? How dangerous was it?

We should know more soon about actual exposures to the public—Japan is examining the thyroids of all residents of Fukushima Prefecture under 18 at the time of the accident (360,000), and testing all residents of Fukushima Prefecture (2 million) for exposure dose. Additionally, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) plans a report in late 2012 on how much radioactivity was released to the atmosphere and ocean, and exposures to both workers and the public.

• Brady says, “The reactors were damaged by the quake itself, not merely from the tsunami. Their cores experienced meltdown and fuel pools were damaged. Bits of plutonium were found 45 miles from Fukushima.” Gilbert says, “The plant has released 15,000 terabecquerels of cancer-causing Cesium, equivalent to about 168 times the 1945 atomic bombing of Hiroshima. The radioactive core in one of the reactors has melted through the floor of the reactor, and I have seen photos of radioactive steam pouring out of the ground nearby. This means there is radioactive pollution of the groundwater. Emissions from Fukushima have lessened but are ongoing, and no-one knows how to clean it up.”

According to Fukushima Accident 2011, and other sources I have read, the reactors appear to have survived the earthquake (a postmortem in a decade+ may show this is not true). The cores of all three operating reactors did melt, and much of the gases (volatile fission products) escaped; the rest was contained. Significant radioactivity was released. Radioactivity can cause cancer, as can air pollution. Unit 4 fuel pool experienced damage to both building structure and plumbing during the earthquake. Some fuel rods may have been damaged. Radiation release from the spent fuel pools was small. (One team found evidence of extensive radiation release from Unit 4 fuel pool, but other evidence, such as the appearance of the fuel rods, appears to contradict this conclusion.) Most of the melted corium (fuel and control rods) is assumed to be at the bottom of the reactor pressure vessels, although in Unit 1, melted corium may have reached containment drywall. Small amounts of strontium and plutonium were also released, though most plutonium at all sites comes from atmospheric testing of nuclear weapons.

It is not clear how Gilbert knows that the groundwater has been polluted or that the steam is radioactive. One challenge of writing on a current event is that information is out of date almost as soon as it is typed. As of November 2, “Temperatures and pressures at all the damaged reactors at Fukushima have been stable and declining for several months, and all are now far below the target temperature of 100ºC: units 1, 2 and 3 are at 59.4ºC, 76.3ºC and 71ºC respectively. Airborne radioactive emissions from the site have dropped to within normal operating limits.” In April, a roadmap was created for the first 6-9 months of cleanup; with revisions, of course, the expectation is that the first stage of cleanup will be completed this year. Many of the details of the long-term cleanup will be a challenge, but “no-one knows how to clean it up” may overstate the case.

• Brady says, “radiation releases were much larger, more widespread, and more dangerous than the Japanese government or the officials of the plant initially revealed… Food and water are contaminated. Ocean radiation is triple what we were told.”

There is no question that the release of radiation was larger, more widespread, and more dangerous than the Japanese government or Tepco initially announced. Some of this was the challenge of learning what is happening in a confusing situation when the government has other concerns (>20,000 dead and >100,000 homeless), mistranslations (“white smoke” is the Japanese term for “steam”, “undeniable” means “can’t prove one way of the other”), and slower reporting of data than we are used to.

How radioactive is the area near the Daiichi reactors? How dangerous is it? How does the danger compare to other health dangers, such as air pollution?

There are still disagreements about the total amount of radiation released. One team produced an estimate twice that of the Japanese government for Cs-137, explaining that the Japanese paid less attention to the radioactivity blown into the ocean (if they are correct, radioactivity released into the ocean may be more than triple early estimates). Yet, “[t]he differences between the two studies may seem large, notes Yukio Hayakawa, a volcanologist at Gunma University who has also modelled the accident, but uncertainties in the models mean that the estimates are actually quite similar.” The xenon-133 release mentioned by the team makes sense; according to one author at a UC, Berkeley discussion page, 100% of noble gaseswere likely released. (The Xe-133 numbers were ignored in media accounts because they have no biological effect.) No matter how large the total release, the only sites with important levels of radioactivity are within a few miles of the Daiichi reactors.

Radiation in and near the Evacuation Zone

Map from nature.com; go here for a bigger map. For more data, go here. To convert from microsievert (µSv)/hour to millisievert (mSv)/year, multiply by 8766 hours/year; divide by 1,000 to change µSv to mSv. (See appendix in the article for an explanation of units and radioactivity; sievert is a measure of dose equivalent.) Then, take half-life into account. Since half of the cesium is Cs-134, the ecological half-life should be short. If it is one year, half will be gone at the end of the year, so multiply by 72% (0.72) for cumulative exposure for the year. For example, Namie town, 24 km (14.5 miles) northwest of the reactor, had the highest reading outside the 20 km exclusion zone, 33 µSv/hour. If this rate remained constant, a person would receive a dose equivalent of 290 mSv/year. The actual dose equivalent will be closer to 200 mSv. This is clearly too high. At this level, 1% of victims of Hiroshima/Nagasaki ended up dying from cancer (see article appendix for the controversy about low dose rate).

Discussions of contamination danger are challenging because motivations for standards vary. Sometimes there is a health standard—EPA reduced allowed levels of arsenic in drinking water so that in the population drinking that water, fewer than 0.1% (1 in 1,000) die from cancer as a result. Some standards are As Low as Reasonably Achievable: radioactivity from nuclear power plants is regulated because it is cheap. EPA does not regulate coal power plants, which produce 100 x as much radioactivity/kWh, because of cost. No health effects have been detected at these levels. (If EPA did regulate radioactivity release from fossil fuels, the main effect would be reducing emissions of much more serious pollutants.)

So action levels depend on a number of factors, including cost, but also public concern. Japan is cleaning up areas far less radioactive than Denver and much of Finland which have above average but not particularly high levels of radioactivity (>10 mSv/year). Japan had planned to reduce the extra radioactivity from Fukushima to as little as 1 mSv/year (to a total of about 4 mSv); IAEA suggests instead “realistic and credible limits”. See appendix to the original article for more on natural background radiation around the world.

Tokyo water reached 210 becquerel/liter, and children drank bottled water for a few days. The European standard is 1,000 Bq/liter. In Tavistock, UK, drinking water can be as much as 6,500 Bq/liter. (Becquerel is a measure of decay rate, see appendix to article.)

I don’t know how Japanese standards compare on food, although, as the appendix to the original article notes, it would require quite a bit of banned spinach to get to CAT scan levels. For those wishing to read more, the Japanese government has provided information on drinking water, seafood, milk, and meat and eggs. There is a summary here; in Fukushima prefecture, 12,375 food samples were tested and 472 rejected due to radioactivity. Nationwide, 48,773 food samples were tested and 862 rejected. More information can be found here.

• Brady says, “Radiation rates were far above acceptable levels miles beyond the 12-mile evacuation zone. Children outside the evacuation zone have received dosages above those acceptable for nuclear workers.”

The numbers affected are high; tens of thousands have returned home, tens of thousands won’t be allowed home until the end of 2011 (when the reactors will be in cold shutdown), and thousands live in areas proposed for long-term evacuation. Since the Japanese limit to members of the public is 20 mSv, I’m not sure why Brady believes anyone has already received dose equivalents above 50 mSv, except perhaps farmers near the plant who refused to evacuate. We will know more after the Japanese survey.

How does the 20 mSv limit compare to living in Tokyo air pollution?

Here I will ignore fear of radioactivity, which IAEA deems more of a danger to public health than the radioactivity itself. When Chinese, who live in one of the most polluted nations on Earth, search for protection from tiny amounts of radioactivity, when people across the Pacific Ocean do the same, it is important to find ways to communicate actual numbers and their importance.

Iodine is in a category by itself, as discussed in the appendix to the original article. The largest radioactivity release that has a biological effect is I-131. It targets the thyroid, which weighs less than 1 ounce—the dose equivalent to many thyroids after Chernobyl was enormous.

People in public health use a number of very different units to describe health dangers. Fortunately, a 2007 report in BMC Public Health, Are passive smoking, air pollution and obesity a greater mortality risk than major radiation incidents?, uses similar metrics, allowing us to compare health risks. Most of the information that follows comes from that report.

We are exposed to radioactivity all the time. The model used in Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII predicts that natural background radioactivity worldwide has a 1% mortality rate (230 out of 1,000 Americans die from cancer, and 10 of those die from natural radioactivity). Note: all attempts to find a higher cancer rate in areas with high background radioactivity have been unsuccessful to date; for example, the 2.7 million in Denver receive a dose equivalent of >10 mSv/year, >700 mSv over 70 years. Using Table 1 from the BMC report, cancer mortality would be predicted to be 2.5% higher in the Denver area (cancer deaths would be about 255 out of 1,000) than in areas where background is closer to 3 mSv/year, 210 mSv over 70 years. But both cancer rate and mortality are lower in the Denver area. The increase in Denver, about 500 mSv over 70 years, is double the exposure of those who evacuated from the Chernobyl exclusion zone and then returned. The discrepancy between prediction and observation occurs because the risk from low doses or low dose rates are overstated or/and because other factors, such as the number of smokers, are more important.

The BMC report looks at effects of air pollution, particularly PM2.5, particulates smaller than 2.5 microns (one millionth of a meter). (Other important pollutants, such as ozone, are ignored; a recent study shows that decreasing U.S. ozone levels 35% would save 4,000 lives each year.) Central London (12.9 microgram/m3 air) is more polluted than Inverness (6 µg/ m3), and, according to Table 2, an estimated 2.8%, 28 more out of every 1000 people, die from air pollution in Central London. In Los Angeles(population 13 million), PM2.5 levels vary from 5.2 to 26.9 ?g/m3, with a mean of 20.3. In Tokyo, the PM2.5 level is 23 µg/ m3, so 4% more of the population, 40 more out of every thousand, die from air pollution in Tokyo than in Central London, 68 more than in Inverness. This means that if a person receives a dose high enough to get acute radiation syndrome, 1,000 mSv in one burst, and doesn’t die from it, the increased risk of dying from the exposure is less than from Tokyo air pollution. This is an apples and oranges comparison, a one-time accident and a lifetime of living in a polluted city.

To compare apples and apples, a year in Tokyo air pollution (PM2.5 only) is predicted to have the same effect on human health as 24 mSv dose equivalent (assuming that low dose rates are dangerous at this level; it is known that PM2.5 has important health effects well below levels found in Central London). The most polluted areas of LA, compared to the least polluted, have a health effect similar to 31 mSv/year.Large swaths of the world have PM2.5 levels between 50 and 80 µg/m3; compared to Inverness, one year in such an area is predicted to have an effect on human health equivalent to 65 – 110 mSv/year.

The BMC report conclusion: “The increased mortality rate of the populations most affected by the Chernobyl accident may be comparable to (and possibly lower than) risks from elevated exposure to air pollution or environmental tobacco smoke. It is probably surprising to many (not least the affected populations themselves) that people still living unofficially in the abandoned lands around Chernobyl may actually have a lower health risk from radiation than they would have if they were exposed to the air pollution health risk in a large city such as nearby Kiev.”

Since Japan has laws to reduce Tokyo air pollution, clearly the 20 mSv standard does make sense. The most radioactive areas in the 20 or so miles outside the Daiichi plant may take a few years, in the absence of remediation, to become as safe as Tokyo. The great majority of the evacuated zone is already less dangerous. Since 36 million live in Tokyo, the effects of Tokyo pollution are far greater.

Disasters such as we are seeing at the Daiichi plant create temporary dangers, and we feel particularly unhappy when human failings are partly or wholly responsible. However, the intense focus on nuclear dangers distracts us from attending to other dangers, and can help us feel safe with our other choices, from fossil fuel to hydropower.

And then there is climate change. Besides the cost of coal and natural gas, a coal power plant requires one metric ton coal /2,700 kWh, and produces about 3 metric tons carbon dioxide. If the 6 reactors at Fukushima Daiichi, 4,700 MW, assuming a capacity factor 80%, were replaced with coal power, 12 million metric tons of coal would be burned each year, and >35 million metric tons of carbon dioxide released. Liquefied natural gas kills fewer members of the public and workers from direct pollution and accidents, and produces about half as much carbon dioxide, but it is much more costly.

Nuclear Regulatory Commission

• Brady asks, “Why haven’t nuclear power plants been assessed regularly for their vulnerability to earthquakes as other types of buildings are? Why aren’t plants inspected more regularly and thoroughly and why aren’t the problems which are found resolved?” Asked differently, how often does Nuclear Regulatory Commission (NRC) update its regulations on nuclear power plants? How effective is NRC?

NRC updates regulations periodically— in response to new information (such as Three Mile Island and Fukushima), problems that appear in nuclear reactors over time, and concerns that arise from ongoing analysis. For example, NRC “began assessing the safety implications of increased plant earthquake hazards in 2005 when the staff recommended examining the new CEUS earthquake hazard information under the Generic Issues Program (GIP). The NRC staff identified the issue as GI-199 and completed a limited scope screening analysis for the seismic issue in December 2007, to decide whether additional review is needed. The screening compared the new seismic data with earlier seismic evaluations conducted by the NRC staff. This analysis confirmed that operating nuclear power plants remain safe with no need for immediate action. The assessment also found that, although overall seismic risk remains low, some seismic hazard estimates have increased and warrant further attention. In September 2010, NRC issued a Safety/Risk Assessment report and an Information Notice (http://www.nrc.gov/reading-rm/doc-collections/generic-issues/gis-in-implementation/) to inform stakeholders of the assessment results.” (Bold from NRC)

North Anna’s two reactors in Virginia shut down during the earthquake August 23. All reactors are designed for worst-case scenarios in their local area, and then overdesigned. (In recent years, as mentioned in the previous paragraph, awareness has increased that in some areas, maximum shaking might be worse than expected.) NRC responded to its own question in a blog post, How Long Will the NRC Keep North Anna Shut Down?, “The short answer is: The North Anna nuclear power plant in Virginia will remain shut down until the NRC is satisfied the plant’s operator, Dominion, has proven the plant’s two reactors can operate safely.” This behavior is typical. Because North Anna is the first U.S. operating nuclear reactor to experience shaking exceeding design specifications, NRC is doing a thorough review although there is no evidence of problems.

In a recent example in another area, flood production, NRC directed Omaha Public Power District in 2010 to provide written procedures for worst-case flood protection, and OPPD improved flood protection, after protesting that it was unnecessary, in time for the longest duration flood ever of a U.S. nuclear power plant.

All three reactors at the Browns Ferry plant were closed by NRC in 1985 for a variety of non-compliance issues. It took 6 years before TVA was allowed to restart Unit 2, another 4 years to restart Unit 3. The decision to rebuild Unit 1 was made in 2002, and it began operating in 2007.

Similarly, Millstone units 1 and 2 were closed in 1996 because of a leaking valve. NRC conducted a thorough study and found a number of other problems.

NRC mandated a number of upgrades to the Mark 1 containment system well before Fukushima, some after Three Mile Island and some because ongoing analysis showed potential problems. Etc.

Sometimes I hear concerns that NRC doesn’t implement new regulations yesterday. Here a nuclear criticcomplains that NRC cuts back on solutions that don’t work (and replaces them with solutions that do work). Others of us like NRC’s style: enough analysis to make sure of proposed solutions.

Nuclear power can and will be made safer

Nuclear power is not perfectly safe, and cannot be made perfectly safe. The Fukushima meltdowns revealed a number of flaws that will be addressed, and nuclear power will be safer. Some solutions have been long understood, such as the need for a strong, independent regulatory agency, like NRC. Newer concerns include a need to space reactors so that an explosion in one doesn’t create problems in another. Japan’s initial insistence on dealing with the problem on its own has led to calls for an international emergency response team “with pre-staged equipment that is interoperable both domestically and internationally”. For more suggestions, see the article appendix (the section called Follow Up), the September 16, 2011 Science, Preventing the Next Fukushima, and the World Association of Nuclear Operators.

The U.S., like other countries with strong regulatory agencies, will implement most/all recommendations. Additional international solutions that help with governance are also needed. As Bunn and Heinonen say, “Some nuclear countries, or countries now planning their first plant, struggle with regulatory ineffectiveness, corruption, and political instability. The IAEA, states and companies selling nuclear power facilities, and nongovernmental organizations must work together to help these countries put in place and sustain effective safety and security measures.” Since nuclear power is so much cheaper than alternatives (except hydro and coal in countries with those resources), the use of nuclear power will expand independent of climate change, and effective national and international structures promoting safety are needed.

However, if critics of nuclear power succeed in stalling expansion of the industry in the U.S. where it is well regulated and safer than our other major sources of energy, they will cause great harm. Currently, the path we are on is likely to lead to a 6°C increase.