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D'coda Dcoda

"Ecological Half Life" of Cesium-137 May Be 180 to 320 Years? [23Aug11] - 0 views

  • A Wired Magazine article dated December 15, 2009 cites a poster session presentation of the research of the Chernobyl exclusion zone at the American Geophysical Union conference in 2009, and says radioactive cesium may be remaining in the soil far longer than what the half life (30 years) suggests. To note: it was a poster session presentation, and I'm looking to see if it has been formally published in a scientific paper since then.
  • From Wired Magazine (12/15/2009): SAN FRANCISCO — Chernobyl, the worst nuclear accident in history, created an inadvertent laboratory to study the impacts of radiation — and more than twenty years later, the site still holds surprises.
  • Reinhabiting the large exclusion zone around the accident site may have to wait longer than expected. Radioactive cesium isn’t disappearing from the environment as quickly as predicted, according to new research presented here Monday at the meeting of the American Geophysical Union. Cesium 137’s half-life — the time it takes for half of a given amount of material to decay — is 30 years. In addition to that, cesium-137’s total ecological half-life — the time for half the cesium to disappear from the local environment through processes such as migration, weathering, and removal by organisms is also typically 30 years or less, but the amount of cesium in soil near Chernobyl isn’t decreasing nearly that fast. And scientists don’t know why.
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  • It stands to reason that at some point the Ukrainian government would like to be able to use that land again, but the scientists have calculated that what they call cesium’s “ecological half-life” — the time for half the cesium to disappear from the local environment — is between 180 and 320 years.
  • “Normally you’d say that every 30 years, it’s half as bad as it was. But it’s not,” said Tim Jannik, nuclear scientist at Savannah River National Laboratory and a collaborator on the work. “It’s going to be longer before they repopulate the area.”
  • In 1986, after the Chernobyl accident, a series of test sites was established along paths that scientists expected the fallout to take. Soil samples were taken at different depths to gauge how the radioactive isotopes of strontium, cesium and plutonium migrated in the ground. They’ve been taking these measurements for more than 20 years, providing a unique experiment in the long-term environmental repercussions of a near worst-case nuclear accident.
  • In some ways, Chernobyl is easier to understand than DOE sites like Hanford, which have been contaminated by long-term processes. With Chernobyl, said Boris Faybishenko, a nuclear remediation expert at Lawrence Berkeley National Laboratory, we have a definite date at which the contamination began and a series of measurements carried out from that time to today. “I have been involved in Chernobyl studies for many years and this particular study could be of great importance to many [Department of Energy] researchers,” said Faybishenko.
  • The results of this study came as a surprise. Scientists expected the ecological half-lives of radioactive isotopes to be shorter than their physical half-life as natural dispersion helped reduce the amount of material in any given soil sample. For strontium, that idea has held up. But for cesium the the opposite appears to be true. The physical properties of cesium haven’t changed, so scientists think there must be an environmental explanation. It could be that new cesium is blowing over the soil sites from closer to the Chernobyl site. Or perhaps cesium is migrating up through the soil from deeper in the ground. Jannik hopes more research will uncover the truth.
  • “There are a lot of unknowns that are probably causing this phenomenon,” he said. Beyond the societal impacts of the study, the work also emphasizes the uncertainties associated with radioactive contamination. Thankfully, Chernobyl-scale accidents have been rare, but that also means there is a paucity of places to study how radioactive contamination really behaves in the wild.
  • “The data from Chernobyl can be used for validating models,” said Faybishenko. “This is the most value that we can gain from it.” Update 12/28: The second paragraph of this story was updated after discussion with Tim Jannik to more accurately reflect the idea of ecological half-life.
  • Citation: “Long-Term Dynamics of Radionuclides Vertical Migration in Soils of the Chernobyl Nuclear Power Plant Exclusion Zone” by Yu.A. Ivanov, V.A. Kashparov, S.E. Levchuk, Yu.V. Khomutinin, M.D. Bondarkov, A.M. Maximenko, E.B. Farfan, G.T. Jannik, and J.C. Marra. AGU 2009 poster session.
D'coda Dcoda

There are at least 10 reasons to say 'no' to nuclear energy (India) [09Oct11] - 0 views

  • 1. Nuclear power involves radiation exposure at all stages of its fuel cycle: from uranium mining and fuel fabrication to reactor operation and maintenance; to spent-fuel handling, storage and re-processing. 2. Reactors leave a toxic trail of high-level radioactive wastes which remain hazardous for thousands of years.
  • 3. The half-life of plutonium-239 produced by fission is 24,000 years. We have neither any way of storing nuclear wastes safely for such long periods nor nuetralising or disposing of them. Should we burden posterity with such a legacy?
  • 4. Nuclear power is exorbitantly expensive if all the hidden costs are taken into account. That is why the private sector has not come forward to set up a nuclear power plant. 5. The industry claims nuclear power is safe but it is not. That is why it expends considerable effort in lobbying for laws to limit the operator’s or supplier’s liability for accidents to artificially low levels.
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  • 6. The industry acknowledges that nuclear power carries high risks of damage but wants governments, that is, the public, to subsidise and absorb them. 7. India has no independent authority that can evolve safety standards and regulate reactors for safety.
  • 8. India’s energy security could be achieved by a careful mix of conventional with biomass, solar-thermal and wind, as experts have pointed out. 9. After Fukushima, advanced countries had a rethink on nuclear power expansion plans and imposed a moratorium on new reactors. India, on the other hand, is planning a necklace of nuclear power plants along its coastline, unmindful of what it means to its fragile ecology and displacement of traditional fishermen.
  • 10. Last, but not the least, there are better and safer ways of boiling water to produce steam to turn turbines that generate electricity.
D'coda Dcoda

France Commits to Nuclear Future [07Jul11] - 0 views

  • As a long time proponent of nuclear power, last week France announced that it will invest $1.4 billion in its nuclear energy program, diverging from contentious deliberation from neighboring states on nuclear energy policy after the earthquake and tsunami in Japan that damaged the Fukushima Daiichi plant in March. The President of France, Nicholas Sarkozy, issued a strong commitment announcing the energy funding package by declaring there is “no alternative to nuclear energy today.” With the capital used to fund fourth generation nuclear power plant technology, focusing research development in nuclear safety, the announcement validates many decades of energy infrastructure and legacy expansion. France currently operates the second largest nuclear fleet in the world with 58 reactors, responsible for supplying more than 74 percent of domestic electricity demand supplied to the world’s fifth largest economy last year. At the end of last month, French uranium producer, Areva Group (EPA:AREVA), and Katko announced plans to increase production to 4,000 tonnes of uranium next year.  Katco is a joint venture for Areva, the world’s largest builder of nuclear power plants, and Kazatomprom the national operator for uranium prospecting, exploration and production for Kazakhstan.
  • German closure The pronouncement to maintain the nuclear prominence in France provides a strong counterweight to other countries in the region. Germany recently announced the phased shutdown of its 17 nuclear power stations by 2022.  Last week, Germany’s federal parliament voted overwhelmingly to close its remaining nine active plants according to a preset 11 year schedule. A Federal Network Agency, which oversees German energy markets, will decide by the end of September whether one of the eight nuclear plants already closed in recent months should be kept ready on a “cold reserve” basis, to facilitate the transition for national energy supply. The German commitment to an energy policy transition indicates that the national power mix towards renewable sources will have to double from its present range of 17 percent to an ambitious 35 percent. Subsidies for hydro electric and geothermal energy will increase; however, financial support for biomass, solar, and wind energy will be reduced. German Chancellor Angela Merkel has said she would prefer for utility suppliers not to make up any electrical shortfalls after 2022 by obtaining nuclear power from neighboring countries like France. Germany will require an expansive supergrid to effectively distribute electricity from the north to growing industrial urban centers like Munich, in the south. In order to execute this plan the new laws call for the addition of some 3,600 kilometers of high capacity power lines. Germany’s strategy will partially include the expansion of wind turbines on the North Sea, enabling some 25,000 megawatts’ worth of new offshore wind power which will have to be developed by 2030. Nuclear persistence in the United Kingdom Last month, the government in the United Kingdom maintained its strong commitment to nuclear energy, confirming a series of potential locations for new nuclear builds.  The national policy statements on energy said renewables, nuclear and fossil fuels with carbon capture and storage “all have a part to play in delivering the United Kingdom’s decarbonisation objectives,” and confirmed eight sites around the country as suitable for building new nuclear stations by 2025. The statements, which are to be debated in Parliament, include a commitment for an additional 33,000 megawatts of renewable energy capacity, while the government said more than $160 billion will be required to replace around 25 percent of the country’s generating capacity, due to close by 2020. The Scottish government has also softened its tough opposition to nuclear power, following recognition by the energy minister of a “rational case” to extend operations at Scotland’s two nuclear plants. Additional Eurozone participation In June, Italian voters rejected a government proposal to reintroduce nuclear power. The plan by Prime Minister Silvio Berlusconi to restart Italy’s nuclear energy program abandoned during the 1980s, was rejected by 94 percent of voters in the referendum. Another regional stakeholder, the Swiss government has decided not to replace the four nuclear power plants that supply about 40 percent of the country’s electricity. The last of Switzerland’s power nuclear plants is expected to end production by 2034, leaving time for the country to develop alternative power sources. Although the country is home to the oldest nuclear reactor presently in operation, the Swiss Energy Foundation has stated an objective to work for “an ecological, equitable and sustainable energy policy”. Its “2000 watt society” promotes energy solutions which employ renewable energy resources other than fossil fuels or nuclear power.
D'coda Dcoda

Even France to prioritize renewable over nuclear energy [11Jul11] - 0 views

  • French ecology minister, Nathalie Kosciusko-Morizet, has announced plans for France to step up its investments in renewable energy, throwing into doubt future nuclear power expansion in the country. France gets 80% of its electricity from its 58 reactors. "Our objective is to rebalance the energy mix in favour of renewables,” Kosciusko-Morizet told the Financial Times.  Regarding the future of nuclear, she told the FT: "We are investing in [nuclear] safety, not in growth objectives as we are doing in renewables." France is launching a bid for five new offshore wind farms
Dan R.D.

Is India exporting radiation to the world? [18Oct11] - 0 views

  • India has become a reprocessing hub for waste from around the world. But the regulation is lax, leading to concerns radioactive material may be in the products exported back to the world.
  • a scrap metal dealer had been admitted to the hospital and was showing symptoms of radiation exposure.
  • Deepak Jain, a 27-year-old had been rushed to the hospital after a high fever hadn't subsided for seven days and the skin on his hand started peeling off.
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  • Jain was among the eight people who were affected by radiation poisoning. He, like the others, had been exposed to cobalt-60, which had leaked from an irradiation machine being dismantled in the area. Jain refused the Rs 200,000 (A$ 4,000) compensation offered to him by the government and is instead suing Delhi University, from whose labs the machine originated. The university had bought the gamma irradiation machine in 1970 but it had not been used since the mid-1980s.
  • In the last few decades, India has quickly become the world's dumping ground for all sorts of waste, including hazardous material like old electronic gadgets or 'e-waste'. A large force of both formal and informal workers is involved in the acquiring, processing, and managing of this waste, yet, experts say the necessary checks and balances are missing.
  • This radiation then shows up in the finished products made from recovered materials that are exported back to the world. In 2007, radioactive steel originating from India was found in Germany and later that year, French officials reported that buttons for elevators, which had been made from recycled steel from India were emitting radiation.
  • "Waste flows from rich to poor and that's the nature of that flow," says Sinha. "I find it slightly amusing to say that processing waste is perhaps an economic activity and it will add to your GDP. I get the sense from the government that they are quite comfortable about this waste coming in." He says they routinely turn a blind eye to many of the things that are happening in the industry, which could be potential threats not only for the people involved in dealing with this waste, but the ecology and the country as a whole.
  • What happens in India, however, will have global reverberations, warns Chaturvedi. "India is exporting all kinds of things, in addition to the people who're being exposed and getting on planes," she says. "I think the point is how India's own secrecy is making it pretty much a radioactive menace for the rest of the world."
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