Some recent news stories have claimed that the amount of Cesium-137 released by the Fukushima disaster in Japan has been half what was released at Chernobyl. Some news sources have suggested that this is an encouraging figure, but it looks pretty terrible to me.
The Chernobyl disaster involved a reactor design that was deeply and fundamentally flawed, followed by a series of mistakes from a secretive government that cared little for the health and welfare of its citizens. By contrast, Japan’s government is supposed to be good, along with their building standards, oversight, and emergency preparedness.
If a nuclear disaster in Japan can be half as bad as Chernobyl, it suggests to me that perhaps nuclear energy is just too fundamentally dangerous to be made safe in the real world – a world in which companies and governments will always try to cover up their mistakes, and in which they will hesitate to spend billions of dollars to improve the odds of a nuclear plant getting through a disaster without contaminating the area around it and putting the human population in peril.
It is certainly possible that scaling back plans for new nuclear reactors will make it harder to deal with climate change. At the same time, we should recognize that the economic costs of nuclear are very high and largely hidden, even when everything is going well. Perhaps we can recognize the dangers of nuclear, and respond by redoubling our efforts to deploy safe and renewable forms of energy, while working to reduce the level of absolute energy usage globally.
“It’s unfortunate, but the radiation is clearly being carried on the air from the Fukushima plant,†said Yukio Edano, the chief cabinet secretary. “Because it’s raining, it’s possible that a lot of places will be affected. Even if people consume the water a few times, there should be no long-term ill effects.†There has been frequent rain in recent days and the watershed for Tokyo’s tap water lies almost entirely to the north and northeast of the city; the nuclear plant is about 140 miles to the north.
But it was not entirely clear why the levels of iodine were so high, said a senior Western nuclear executive, noting that the prevailing breezes seem to be pushing radiation out to sea.
“The contamination levels are well beyond what you’d expect from what is in the public domain,†said the executive, who insisted on anonymity and has broad contacts in Japan. “There is no way that stored fuel did not burn in a very significant way.â€
New Scientist has a decent article on the fallout levels http://www.newscientist.com/article/dn20285-fukushima-radioactive-fallout-nears-chernobyl-levels.html
FYI The Tokyo tapwater issues has, for now, reduced but, as New Scientist points out, ‘The amounts being released, he says, are “entirely consistent” with the relatively low amounts of caesium and iodine being measured in soil, plants and water in Japan, because so much has blown out to sea.’
You say above that, ‘By contrast, Japan’s government is supposed to be good, along with their building standards, oversight, and emergency preparedness.’
Though in terms of earthquake preparedness, Japan is foremost on the globe, unfortunately their nuclear regulator NICE and Tepco have been unhealthily close for years and so their government of their nuclear industry is far from as good. (Past scandals of Tepco covering up safety issues were resolved without removal of the staff involved, there were questions about the recommissioning of this particular old plant given the design’s known – since the 1970s – flaws, the limitations of retrofitting and the growing knowledge of the dangers of spent fuel if an incident compromised cooling.)
This has been extensively reported at the New York Times and elsewhere http://www.nytimes.com/2011/03/22/world/asia/22nuclear.html?hp or (not a source I usually use) http://www.wsws.org/articles/2011/mar2011/tepc-m17.shtml Leaving such appalling safety mendacity aside, there are inherent risks in leaving safety decisions to profit-making corporate concerns who may be over-preoccupied with company’s end of the risks rather than the wider issues at critical early stages in a disaster and also lack the power to make national crisis level decisions in the deployment of personnel in dangerous areas http://www.nytimes.com/2011/03/20/world/asia/20time.html?ref=science
March 25 (Tokyo time) update on reactor status http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301056350P.pdf
Of course, NISA spokespeople take a very different view http://online.wsj.com/article/SB10001424052748704050204576218470429152728.html ‘Mr. Nishiyama said Wednesday his agency—Japan Nuclear and Industrial Safety Agency—”remains steadfastly independent” from the larger trade and industry ministry.’ … “We think this ‘double-check’ mechanism we have set up to maintain a healthy regulatory environment with the second safety agency is working just fine.”
Scientist at Work
Countering Radiation Fears With Just the Facts
By DENISE GRADY
Published: March 26, 2011
As soon as David J. Brenner heard about the undersea earthquake and subsequent tsunami that devastated northern Japan on March 11, he checked a map of the region’s nuclear power plants. One, because of its coastal location and reactor design, looked particularly vulnerable: Fukushima Daiichi. He hoped he was wrong.
Less than a day later, ominous reports of failed cooling systems and radiation leaks at that plant began to emerge. Dr. Brenner, director of the Center for Radiological Research at Columbia University — the oldest and largest such center in the world — found himself called on repeatedly to explain what was happening with the failed reactors and to assess the radiation risk to public health, both in Japan and around the world.
Dr. Brenner, 57, a native of Liverpool, England, is a physicist who has spent his career studying the effects of radiation on human health. He has published research showing that CT scans increase the cancer risk in children, and he recently testified before Congress, saying that the widespread use of whole-body X-ray scanners at airports would produce 100 extra cases of cancer each year in the United States.
He thinks CT scanners and the people who use them need more regulation to make sure the scans are medically needed and the doses of radiation as low as possible. He believes that even low doses increase the risk of cancer, and that there is no “safe†level or threshold below which the risk does not rise — even if that risk cannot be measured statistically.
On Friday, 25 March, Japan’s nuclear regulator announced that a breach had likely occurred in the containment vessel of the No. 3 reactor (containing mixed oxide fuel), which officials suspected may be cracked and leaking radiation. World wide measurements of radioactive fallout released from reactors were reported by New Scientist to be “nearing Chernobyl levels”. It reported that the Comprehensive Test Ban Treaty Organization had measured levels of iodine-131 at 73% and caesium-137 at 60% the levels released from the Chernobyl disaster. Contamination in the local region led to bans on the sale of food grown in the Fukushima area up to 100 km (65 miles) from the plant and on tap water in the Tokyo area being given to infants. The government distributed bottled water. Subsequent sampling has shown safe levels in the Tokyo region and the ban has since been lifted.
Last week, the Institute for Energy and Environmental Research, an independent think tank in the United States, said that since the quake and its aftermath, the plant has already released far more radioactivity than the 1979 Three Mile Island accident. The institute, based in Takoma Park, Maryland, said that by March 22, the Fukushima reactors had released about 2.4 million curies of iodine 131, about 160,000 times the best estimate of the amount released at Three Mile Island, and about 10 percent of the amount released in Chernobyl in 1986. Fukushima Daiichi has also released half-a-million curies of cesium-134 and cesium-137, which have longer half lives, also about 10 percent the amount released in Chernobyl.
Of course, the radiation exposure from the Chernobyl disaster was vastly higher than the radiation leaks in Japan – so far. But there is a twist to the potential long-term radiation exposure that should be considered. Even though the radiation intensity is very low, the fission product particles that have leaked into the Japanese landscape might hang around for days, years, centuries or even eons.
Consider these fission product half-lives, the time it takes for 50 per cent of the substance to dissipate: for iodine-131, eight days; cesium-137, 30 years; molybdenum-99, 200,000 years; zirconium-93, 1.5 million years; palladium-107, seven million years.
To gauge the effect of medications on human health, doctors consider two key elements – dosage and duration. If a doctor prescribes an antibiotic, say a tablet of 500 milligrams once a day for a week, a patient may experience side effects. But we know that the medication will be completely washed out of his system in a matter of days.
Now consider the time frame of radioactive particles. What happens if a doctor prescribes another pill, say a low dose of only one milligram a day, but this time for 30 years, or perhaps seven million years? It is this potential for low but super-long exposure that is worrying.
There are hundreds of manufacturing cycles in the human body that can be affected by chronic low radiation exposure. For example, it takes just the right biological steps over 75 days to make sperm, one month to make new skin, nine months for a baby and one year to renovate 10 per cent of your bone mass. Such processes can be derailed or deranged by ever-present radiation.
Japan raised the severity level of the crisis at its crippled nuclear plant Tuesday to rank it on par with the 1986 Chernobyl disaster, citing cumulative radiation leaks contaminating the air, tap water, vegetables and seawater.
Japanese nuclear regulators said the rating was being raised from 5 to 7 – the highest level on an international scale overseen by the International Atomic Energy Agency – after new assessments of radiation leaks from the Fukushima Dai-ichi plant since it was disabled by the March 11 tsunami.
…
The new ranking signifies a “major accident†with “wider consequences†than the previous level, including widespread health effects, according to the Vienna-based IAEA.
However, Japanese officials have played down any health effects of radioactive releases so far from the Fukushima plant. They said the leaks amount to only a tenth of the radiation emitted in the Chernobyl disaster, while acknowledging they eventually could exceed Chernobyl’s emissions if the crisis continues.
Some 370,000 terabecquerels of radioactive iodine and cesium have been released at Fukushima — more than officials originally thought. (A terabecquerel equals 1 trillion becquerels, a measure for radiation emissions.) Most of it spewed into the atmosphere in the early days of the crisis, and radiation levels have generally been declining.
Though Fukushima and Chernobyl are both level 7 nuclear accidents, the health consequences in Japan to date are much less severe. In part, that’s because far more radiation was released at Chernobyl. So far, Fukushima Dai-ichi has released about one-tenth of the amount of radioactive material that escaped Chernobyl, according to an official from the International Atomic Energy Agency.
At Chernobyl, an entire reactor exploded, sending up a massive fire and radioactive plume that dispersed radiation over a wide area. The reactor at the Soviet plant was not surrounded by any containment structure, so radiation escaped freely.
People near Chernobyl were not warned against drinking contaminated milk, and many residents later developed thyroid cancer. Two Chernobyl plant workers died on the night of the accident, and 28 more people died within a few weeks from radiation poisoning. Over the long term, several thousand more people were put at risk for cancer.
But there are very important differences between Fukushima and Chernobyl. The biggest, in my mind at least, is the timescale over which the accident occurred. When Chernobyl’s reactor number 4 exploded in 1986, it scattered debris over a wide area and sent radioactive fallout high into the atmosphere. Entire villages near the reactor had to be evacuated in a matter of hours, and many residents had to leave personal effects behind. A fire burned at the site until 5 May, spewing tones of radioactive material over 200,000 square kilometres. By November, workers had successfully completed a concrete sarcophagus around the core, effectively sealing it off. In the short period following the explosion, the accident spewed some 14 million terabecquerels of radiation into the environment.
The Fukushima accident has unfolded much more slowly. The damaged reactors exploded over a period of days, and after a modest initial release, radiation has fallen off. So far, the reactors have spread about half-a-million terabecquerels into the air. I haven’t been able to find hard data on the first month after Chernobyl, but I’m willing to bet my lunch that it put out a lot more in that period.
The problem is that Fukushima’s slow bleed of radiation is going to continue for a good period of time to come. Reactors are normally kept cool by recirculated water, but at Fukushima, the circulation system has been heavily damaged, and the only solution is to simply dump tons of water onto the cores. The water absorbs radioactive isotopes like caesium-137, and itself becomes a big waste problem. Moreover pictures from as recently as 10 April show steam continuing to rise from the reactors.
A new study posted for open peer-review suggests that the nuclear reactors at Fukushima Daiichi released far more radiation than the Japanese government initially estimated. The study [PDF] uses global radioisotope and meteorological data to calculate the size of the release from the plant. Nature News reports that, contrary to official claims, the model shows that fuel being stored in a pool at unit 4 released a significant amount of cesium-137, a long-lived contaminant that has spread across the countryside. It also says that some Xenon-133 may have been released early on in the accident, suggesting that the plant was already damaged before it was hit by a tsunami. Overall, it estimates that Fukushima released about twice as much cesium-137 as the government claims and half as much as Chernobyl.
“The total amount of radiation released into the air after the colossal earthquake and tsunami was variously estimated to have been between 18 and 40% of the quantity released during Chernobyl in 1986”
m.guardian.co.uk/environment/gallery/2013/mar/11/fukushima-abandoned-towns-in-pictures