Switzerland nuclear free – for two days
Due to a combination of circumstances Switzerland was nuclear free in mid-August – without having any power problems.
Usually the five nuclear power reactors are taken out of service in summer for annual maintenance – one after the other. Because of material problems in the pressure vessel of Beznau I and an incident in Gösgen, Switzerland this summer suddenly found itself nuclear free for two days.
In March 2015 Beznau I was taken off the grid for a longer than usual maintenance. The operator Axpo wanted to change the cap of the pressure vessel and make some upgrades to the standby cooling system during the annual overhaul. Other nuclear power plants of the same type around the world have shown corrosion problems at their cap. Axpo wanted to prevent that – and improve the image of its world oldest nuclear power plant. Even though Beznau I at 46 years and Beznau II at 44 years have achieved their technical lifetime (they were conceived for 30 years originally), Axpo wanted to invest 700 million Swiss Francs and hope that the two power plants will be authorized to operate for up to 60 years.
Axpo's dream is not about to become reality. Because of the cracks found in the vessel of the Belgian nuclear power plant Doel 3 and Tihange 2, Axpo had to carry out an extra examination of the vessel. Beznau I should have been connected to the grid in June 2015, but the results of the examinations showed material defects in the reactor pressure vessel. The atomic authority asked for more examination and Beznau I will not be producing any power at least until spring 2016.
The other Swiss nuclear power plant still had work to do: at the beginning of August Leibstadt and Mühleberg began the annual overhaul. In summer power demand and prices are low, and the annual overhaul of Swiss nuclear power plants sometimes overlap. Beznau II was then shut down in mid-August to allow, as with Beznau I, a longer overhaul to change the cap and carry out the pressure vessel tests.
Finally, because Gösgen had a steam-leakage in the non-nuclear part of the power plant, five Swiss nuclear power plants were shut down at the same time for two days. And did we have a power problem? No!
Situation of the five Swiss nuclear power reactors as of August 2015:
|
Beznau I |
365 MW |
1969 |
46 years old |
Offline until 2016 |
|
Beznau II |
365 MW |
1971 |
44 years old |
Offline until Dec 2015 |
|
Mühleberg |
373 MW |
1972 |
43 years old |
Offline until end of Aug 2015 |
|
Gösgen |
970 MW |
1979 |
36 years old |
Operating after incident. |
|
Leibstadt |
1190 MW |
1984 |
31 years old |
Maintenance until early Sept. |
− Sabine von Stockar
Swiss Energy Foundation
Sabine.vonstockar@energiestiftung.ch
Global renewables surpass gas; climb to second place
The International Energy Agency's 'Electricity Information 2015' report states that renewable electricity generation has overtaken gas to become the second largest source of electricity worldwide, with renewables producing 22% of total electricity or 5,130 terawatt-hours (TWh) in 2013. That figure is more than double nuclear power's output of 2,359 TWh in 2013.
In 2013, 67.2% of world electricity production was from fossil fuel-powered plants (including 41.1% from coal). Renewables provided 22% (comprising hydro 16.6%, biofuels and waste 2.0%, with geothermal, solar, wind and other sources making up the remainder). Nuclear plants contributed 10.6%,
In 2013, global non-hydro renewable electricity, which rose to 1,256 TWh or 5.4% of global electricity production, surpassed oil-fired generation for the first time ever.
From 1973 to 2013, world gross electricity production increased from 6,144 TWh to 23,391 TWh, an average annual growth rate of 3.4%.
Sharp differences are evident between OECD and non-OECD countries:
IEA, 'Electricity Information 2015', www.iea.org/bookshop/666-Electricity_Information_2015
Free excerpt: www.iea.org/publications/freepublications/publication/Electricitytrends.pdf
Media release: www.iea.org/newsroomandevents/news/2015/august/renewable-electricity-gen...
Uranium contamination in US aquifers linked to nitrate
A common agricultural pollutant can free up naturally occurring uranium and create the potential for increased radioactivity in drinking water and some crops, according to new research by Jason Nolan and Karrie Weber from the Department of Earth and Atmospheric Sciences, University of Nebraska.
Groundwater data from two major US aquifers revealed naturally occurring groundwater uranium exceeding the US Environmental Protection Agency maximum contaminant level across 22,375 sq km where 1.9 million people live. Analysis revealed a moderately strong correlation between uranium and nitrate, a common groundwater contaminant. Nitrate is recognized to alter uranium solubility by oxidative dissolution of reduced minerals. The authors state "these results indicate that nitrate, a primary contaminant, should be considered as a factor leading to secondary groundwater U contamination in addition to the recognized role of alkalinity and calcium."
Their article concludes:
"Our data indicate that nitrate concentrations near the MCL [maximum contaminant level] are correlated to groundwater U contamination. Thus, nitrate-mediated U solubilization presents a threat to the quality of groundwater resources already under pressure because of population growth and global environmental change. This has the potential to negatively impact the health of millions of residents in the United States and around the world utilizing U-contaminated drinking water. Additionally, irrigation accounts for an estimated 43% of global groundwater use. Food crops irrigated with contaminated water have been demonstrated to accumulate U, thus leading to an additional route of U exposure through food crops. Given the ubiquitous nature of nitrate in aquifers and the strong correlation with U mobilization, increased testing of groundwater for U where nitrate is at or near the MCL should be conducted."
Jason Nolan and Karrie A. Weber, 2015, 'Natural Uranium Contamination in Major U.S. Aquifers Linked to Nitrate', Environmental Science and Technology Letters, 2, 215−220, http://pubs.acs.org/doi/pdf/10.1021/acs.estlett.5b00174
Nancy Gaarder, 18 Aug 2015, 'UNL researchers say common pollutant can lead to radioactivity in drinking water', www.omaha.com/news/nation/unl-researchers-say-common-pollutant-can-lead-...