Feb 16, 18 10:38 AM
Mednews announcements of latest treatments, medicines and discoveries
Feb 16, 18 10:30 AM
qtips used for cleaning your ears can cause damage to your eardrums.
Feb 15, 18 05:53 AM
blood-donation is to be encouraged to keep our health service functioning
Sept 21st 2016
CC BY 2.0 Eamonn Butler
The names Chernobyl and Fukushima connote nuclear disaster. But do you remember Three Mile Island? Have you ever heard of Beloyarsk, Jaslovske, or Pickering? These names appear among the 15 most expensive nuclear disasters.
1. Chernobyl, Ukraine (1986): $259 billion
2. Fukushima, Japan (2011): $166 billion
3. Tsuruga, Japan (1995): $15.5 billion
4. Three Mile Island, Pennsylvania, USA (1979): $11 billion
5. Beloyarsk, USSR (1977): $3.5 billion
6. Sellafield, UK (1969): $2.5 billion
7. Athens, Alabama, USA (1985): $2.1 billion
8. Jaslovske Bohunice, Czechoslovakia (1977): $2 billion
9. Sellafield, UK (1968): $1.9 billion
10. Sellafield, UK (1971): $1.3 billion
11. Plymouth, Massachusetts, USA (1986): $1.2 billion
12. Chapelcross, UK (1967): $1.1 billion
13. Chernobyl, Ukraine (1982): $1.1 billion
14. Pickering, Canada (1983): $1 billion
15. Sellafield, UK (1973): $1 billion
A new study of 216 nuclear energy accidents and incidents crunches twice as much data as the previously best review, predicting that
"The next nuclear accident may be much sooner or more severe than the public realizes."
The study points to two significant issues in the current assessment of nuclear safety. First, the International Atomic Energy Agency (IAEA) serves the dual masters of overseeing the industry and promoting nuclear energy. Second, the primary tool used to assess the risk of nuclear incidents suffers from blind spots.
The conflict of interest in the first issue is clear. The second issue may not be transparent to the layperson until they understand more fully how industry conducts the probabilistic safety assessments (PSAs) which are the source of the standard predictions of the risk of nuclear accidents. A PSA involves identifying every single possible thing that could go wrong, and assigning a probability that reflects the risk it will go wrong. Nuclear plants are then built with layers of interlocking safety mechanisms, that should reduce the probability to near zero that all of the failures necessary to result in a significant event could ever happen all at the same time.
It is a comprehensive and thorough method to help safety engineers reduce risks to levels that are acceptable relative to the benefits of the technology. It has certainly helped safety engineering make great strides in the effort towards 'zero accident' goals. However, the scientifically calculated risk probabilities from a PSA are only as good as the engineers' abilities to identify every single thing that could go wrong.
Every time some new thing goes wrong that wasn't thought of before, it is quickly integrated into the PSA and the assessment re-calculated and safety measures reinforced to again return the risks to the 'safe' levels. And industry keeps close track of everything that goes wrong, even when no accident occurs due to the layers of safety engineered in, which helps to fine-tune PSAs without the need for actual disasters. But every so often, a Chernobyl or Fukushima proves that our limitations outrun our technology for controlling the risks.
The new study, by researchers at the University of Sussex (England) and ETH Zurich (Switzerland), takes a different approach by submitting the data on events that have disrupted the nuclear industry to a statistical analysis. The report tracks the evolution of nuclear safety engineering that with the benefit of 20:20 hindsight in the wake of each nuclear disaster. It finds that nuclear accidents have substantially decreased in frequency, especially due to success of safety engineering in suppressing the "moderate-to-large" incidents.
But even with these optimistic trends, the report predicts that it is more likely than not that disasters at the extreme end of the IAEA scale will occur once or twice per century. Accidents on the scale of Three Mile Island have over a 50% probability of occurring every 10-20 years.
This may not spell the end of the nuclear industry though. One co-author of the study, Professor Didier Sornette, emphasizes that: "While our studies seem damning of the nuclear industry, other considerations and potential for improvement may actually make nuclear energy attractive in the future."
The team has made an open-source nuclear events database available online for further study of the issue. The papers are published in Energy Research and Social Science: Reassessing the safety of nuclear power and in the journal of Risk Analysis: Of Disasters and Dragon Kings: A Statistical Analysis of Nuclear Power Incidents and Accidents
For another perspective published on TreeHugger about nuclear power, see: The debate over nuclear power: An engineer looks at the issues
The more serious nuclear-accidents are nuclear power station explosions, accidents are rare but they are very serious. The accident at Chernobyl is pictured above, very well documented, caused many deaths and laid waste to thousands of square miles of contaminated land, including cities as pictured above and where ever there was fallout the land, the animals and the produce was unusable.
The above picture is of radiological contamination on an amusement park which was hastily abandoned due to the contamination caused by the Chernobyl accident, huge areas of the country was laid to waste with no possibility of human habitation for many hundreds of years, there are of course still wild animals living in the vicinity and these are monitored by the authorities to determine the effects of overexposure to radiation
There have been cases of accidental contamination where an x-ray machine has been taken out of service, scrapped and sent for recycling without first removing the radiation source, the recycled steel was then used to make very many everyday objects, a widespread investigation revealed radiation coming from such things as restaurant furniture and white goods, refrigerators and washing machines, fortunately in modern times the authorities are much more careful..
The other very serious accident was at a power station at Fukushima in Japan, this was caused by an earthquake just off the coast and resultant tsunami flooded the power generating facility and crippling the electrical supply to the cooling water pumps, this one also is well known and well documented and sadly the leaking contamination has yet to be contained.
These accidents have led to a general distrust of nuclear power stations and some countries have decided to phase them out altogether whereas in other parts of the world there are plans to build dozens more, of course the design is being improved constantly and the regulation of such facility is is much tighter now than it was previously, this applies to the construction and the operation of such facilities, Japan has 58 operating nuclear power stations and plans underway for a few more.
With the realisation that the demand for electricity is going to steadily increase, it is becoming more and more obvious that the only way we are going to survive an energy crisis is to build bigger and better nuclear power stations.
Fortunately with modern communication systems these dangerous situations can be monitored easily and warnings issued by local government, civil defense, police, local radio and television.