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Sunday, March 20, 2011

Japan nuclear crisis: What does Alert Level 5 mean?

Note: This rather lengthy report intends to inform and educate on the Fukushima nuclear accident. It is by no means exhaustive. I tried my best to make it understandable to the public. Kindly refer to the links provided within the report for further details.
Readings at Monitoring Post outside the 20-kilometer zone of the Fukushima Dai-Ichi nuclear power plant on 17 March between 9:20 and 15:00 showed that the radiation to peak at reading point 32. According to the Japan's Education Ministry (MEXT), this is thought to be the result of a controlled containment venting and a simultaneous fire which carried radioactive particles inland. Click here to see the MEXT data.
Looking at the data, reading point 32 showed three spikes at 158, 167 and 170 microsieverts (mSv) per hour at 15:00, 13:10 and 14:00, respectively, 30 kilometers away from the plant.
The readings show lower doses of radioactive particles as one goes farther away from the plant.
As a result of such spikes in radiation measurements, the Japanese Nuclear and Industrial Safety Agency raised the alert level to 5 out of the possible 7 based on the International Nuclear and Radiological Event Scale (INES), according to the Massachusetts Institute of Technology (MIT) Department of Nuclear Science and Engineering Nuclear Information Hub.
What does INES Alert Level 5 mean?
INES Alert Level 5 means "Accident with Wider Consequence." It is analogous to the US Three Mile Island incident in 1979 that was due to a partial core meltdown causing severe damage to its reactor core. Click here to see the INES level scales.
At INES Alert Level 5, there is limited release of radioactive material that is likely to require the implementation of some planned countermeasures. At this level, several deaths result from radiation.
In addition, there is severe damage to the reactor core. There is release of large quantities of radioactive material within an installation with high probability of significant public exposure, which could arise from a major accident or fire.
INES Alert Level 6 means "Serious Accident." An example is the nuclear accident in Kyshtym, Russia in 1957 that released a significant amount of radioactive materials to the environment following an explosion of a high activity waste tank.
At INES Alert Level 6, there is a significant release of radioactive materials that likely requires implementation of planned countermeasures.
INES Alert Level 7—the highest level— means "Major Accident." Ukraine's Chernobyl disaster in 1986 falls under this level. It caused widespread health and environmental effects. There is external release of a significant fraction or reactor core inventory.

Considered as the worst nuclear plant disaster in history, the Ukraine of the former Soviet Union initially denied the accident at Chernobyl when Sweden detected high radiation levels near their plant on 28 April, which made the world distrust nuclear scientists. The plume had already reached vast areas over the western part of the former Soviet Union, and Eastern, Western and Northern Europe. As a direct result of the accident, 28 workers died from acute radiation syndrome including beta burns. Fifteen people died from thyroid malignancy. Several chromosomal defects were reported with deaths estimated to be between 4,000 and up to a million over the years.
At INES Alert Level 7, there is major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures.
According to the MIT, humans are exposed to radiation through various activities such as: cross country flights (0.02 – 0.05 mSv), chest X-ray (0.08 mSv per X-ray), sunlight/background (~3.6 mSv per year), abdominal CT scan (~8 mSv per CT).
There is no mention for using computers, mobile phones, television, and all the other gadgets we use daily.
The European Union puts an annual limit of radiation exposure to its airline crew at 20 mSv.
The US sets an annual limit of 50 mSv for its radiation workers.
At the lethal dose 4,000 mSv, there is half the chance of death.
What these numbers mean is that yesterday's peak of 170 mSv per hour, is above the 50 mSv per year that is allowed for radiation workers.
The authorities need to explain how this 170 will extrapolate to annual exposure to reassure the public. The Japanese authorities are monitoring the exposure levels constantly and the results of their readings are counter-checked by independent bodies, according to several reports.
What is reassuring based on the available information in Japan and other international bodies is that the radioactive particles are lower as they go away from the affected areas.
A report from Business Week said that people in the US are rushing to buy potassium iodide pills thinking that they will be protected from possible exposure following the Fukushima accident.
Radiation expert Jacqueline Williams of the University of Rochester Medical Center said, "Don't panic. This is close to an hysterical response."
She added that "there is no present danger or even a likelihood that radiation from the catastrophe in Japan—8,000 kilometers (5,000 miles) from the U.S.west coast—will have any effect on people in the United States."
It will be recalled that one month after it conducted its 24th subcritical nuclear test, Washington announced on 13 October—at the height of worldwide attention to the rescue of the 33 Chilean miners—that the first such test under the Obama administration was successfully carried out on 15 September in Nevada, said Japan Today.
The Telegraph said the White House received criticisms from Japanese officials even though the non-explosive nuclear experiments were not prohibited by the Comprehensive Nuclear Test Ban Treaty.
In 1995, a year before it signed the Comprehensive Test Ban Treaty, France underJacques Chirac’s administration conducted a series of nuclear tests over the Pacific Ocean. The decision received worldwide protests. France is one of the five nuclear-weapons states including China, Russia, the UK, and the US.
What do these mean?
We are currently living with radioactive particles as a result of our daily living and unwanted military tests, which is on top of what we get from nature and past nuclear accidents.
We do not know how much harmful biological health hazards was brought by such subcritical nuclear tests.
It is wise that we remain calm over the Fukushima accident.

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