Fukushima Daiichi is Not Chernobyl – But Both are Disasters
Fukushima and Chernobyl Differences
It is unfair to compare the size of disasters because lives are affected and destroyed. Nonetheless, the situation at Fukushima Daiichi, although very serious, should not be equated at the same level as Chernobyl.* There is much reason for serious concern, but not for panic, particularly on the West Coast of the USA.
The international press has been quick to report the radiation levels in Fukushima Daiichi as many tens or hundreds of times the level of natural background radiation we are normally exposed to. Normal background radiation is about 0.2 rems per year. Although technically true, the radiation levels the average human can tolerate before showing the first signs of Acute Radiation Syndrome (ARS) are about 500 the normal background dose or about 100 rems. At that rate, symptoms can be “mild” (headache, pain, nausea, diarrhea) and rarely result in immediate death. The risk of developing cancer grows statistically but still remains below 1 percent. A dose of 300 rems is often lethal and will have have high incidence of disease in survivors. At 600 rems is a guaranteed painful death.
Exposure is cumulative, so one exposure of 120 rems in five minutes with nothing the rest of the year is the same as a constant monthly exposure of 10 rems. Although technically the same accumulated dose, the body that is exposed to lower but constant levels of radiation may have lower risk of ARS and cancer. Like wise, exposure to two large doses of 60 rems per year is likely less risky than a single dose of 120 rems. The more time and lower intensity between exposures, the more human body cells are able to recover. It also makes a difference if the dose is distributed evenly across the entire body or in a certain part. Exposure to 120 rems in one finger may increase the risk of affecting the limb in question, but will likely not have a chance of giving the patient generalized ARS.
The average levels reported* within Fukushima Daiichi are still below 25 rems per YEAR. This is 25 times above the maximum suggested annual dose, but still very much within safe exposure levels suggested by many governments and the nuclear industry*. Astronauts and lab technicians are often exposed to similar levels. Although not as high, frequent fliers, pilots, and anybody who has had an MRI are likely 100 percent to 500 percent above the usual recommended annual dose. As a point of comparison, some workers and firefighters in Chernobyl were exposed to 300-600 rems in a matter of HOURS, and died as a consequence of that. An estimated 50,000 – 100,000 people around Chernobyl are thought to have been exposed to an annual dose between 25 – 150 rems in a matter of days or weeks, resulting in less than 250 “official” (I note the lack of credibility in Soviet statistics) cases of ARS.
The press reports MAXIMUM rates in Fukushima Daiichi to be within the range of “Lethal”. Again, this is technically true but needs to be put into the context of how widespread and how constant this dose was.* The highest readings came from directly above the compromised reactors. The equivalent of about 325 rems up to 800+ rems per year was briefly recorded, but this reading was not found to sustain itself for more than an a few minutes. This nonetheless leaves the issue of where such radiation hotspots will settle or dissipate into the earth and ocean and enter the food chain. The average recording at the edge of the plant’s perimeter is equivalent to about 25-50 rems per year, but it is unclear if this is taken on the ground (near humans) or in the atmosphere.
The most important things to consider when differentiating the conditions at Fukushima Daiichi as compared to those at Chernobyl, are the integrity of the isolation layers and capacity of the emergency cooling systems to operate. Chernobyl was caused by serious design flaws coupled with gross human error. Reactor #4 literally lost its roof, and the emergency systems were instantly fried and lost for ever. In contrast the structure at Fukushima Daiichi bravely withstood a class 9.0 earthquake, a tsunami with 7m waves, fires, and hydrogen induced explosions. Cracks appeared in the structure and exposed radioactive material to the atmosphere, but this was less than in Chernobyl (I am NOT saying this is minimal). Critically, the emergency cooling pumps, flooded by the tsunami are already partially restored and doing their job.
The two tables compare the individual risk scenarios and help illustrate the thresholds of radiation exposure. For balanced reading of the situation in Fukushima Daiichi, I recommend the World Nuclear News site.
RISK OF FUKUSHIMA DAIICHI vs. CHERNOBYL
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UNDERSTANDING RADIATION EXPOSURE
FUKUSHIMA DAIICHI vs. CHERNOBYL
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See Pripyat 25 Years Later
Full Disclosure: I am not an expert in radiation or nuclear power plants. I am writing this and sharing it because of the various queries I’ve received as a photographer that has worked in both the Ukraine and in Japan, and reported on the issue of radiation. Since January 2011 I’ve spent considerable time in Chernobyl and Pripyat preparing photographic reportage and artistic work in anticipation of the 25 years since the Chernobyl meltdown. This exposed me to literature about radiation; put me in touch with experts in radiation, and granted me the chance to meet scores of workers and survivors from the Chernobyl incident. In late 2008 I developed reportage work in Nagasaki and Gunkanjima and was also exposed to the issues of radiation and nuclear disaster.
*Update: There are many discrepancies in the official data initially reported by the Japanese authorities. The government has also retroactively changed its “safe” exposure levels to higher thresholds. This is very worrisome. I will not go into all the details, as there is much in the media that can be found on the subject. As of January 2012 I am in Fukushima and will post information I find relevant.