What is the Real Radiation Danger?

I am no nuclear power expert, to be sure. There are nuclear engineers to seek for expertise on the specific about nuclear reactors and possible complications from a meltdown. The best site I have seen that briefly explains the worst case scenario as for as the reactor and possible meltdown is the M.I.T. education site, which is linked here.

I am, however, a physician; a radiologist in fact. As a radiologist, we go through intensive training regarding the uses and risks of radiation. So, I would call myself a relative expert on the dangers of radiation in general. And I can tell you, my colleagues and I in the radiology community have been largely disgusted by the information pouring through the media and government outlets regarding fears from exposure to radiation.

This is not to minimize the catastrophe going on in Japan. On the contrary, there are real risks to a meltdown and core rupture. But most of those risks are to the immediate populace, and even that risk is overstated.

How so?

The best case study regarding an incident such as this is, of course, the Chernobyl accident of April 26, 1986. Until this Japanese event, Chernobyl was by far the largest nuclear disaster in world history, and considered a level 7 event on the International Nuclear Event scale (with 7 being the worst disaster). In Chernobyl, the power burst led to numerous explosion and rupture of the reactor vessel core. An explosion of the graphite moderator components than sent a large plume of radioactive material directly into the air, which then dispersed through out the environment.

The radiation spread through out the Soviet states, most specifically in what is now Belarus, and even reached parts of western Europe.

But here is where the specifics get tricky.

The radiation at the reactor core at Chernobyl was immense, reaching 300 Sieverts (the metric measurement for radiation); no humans were exposed to this level, but this would cause near term death. In the control room itself, workers experienced 0.03-0.05 Sv immediately after the explosion. Around the site itself, and in nearby localities, radiation ranged from 0.005-0.01 Sv.

Most of the immediate radiation with high risks were secondary to short lived isotopes such as ¹³¹I. An isotope with a 'short life' or short half-life means that it decays quickly into less harmful or nonharmful isotopes, and thus does not continue to cause a long term threat.

So although exposure to this type of radiation was very harmful, those that evacuated likely were exposed to only small amounts of this most highly dangerous pollutant. Small amounts did carry into Europe. But because of their short half-lives, the isotopes had minimal deleterious health effects.

So what was the long term effect? Now, 25 years later, we can answer the question definitively... and the answer is that the effect was limited.

In 2006, the United Nations Scientific Committee of the Effects of Atomic Radiation (UNSCEAR), a group of eight UN agencies, including the International Atomic Energy Agency and the World Health Organization evaluated multiple studies on the effect of Chernobyl. 237 people suffered from immediate acute radiation sickness. 37 of these people ultimately died. However, the death toll over that the last two decades from causes directly related to Chernobyl were approximately fifty...50. These deaths were almost all from workers that were on site immediately during and in the days after the explosion. And that takes into account that there were over 1000 workers on site during that period of time. Thus, only about 5% of the workers that heroically tried to stop the disaster even died. Tragic, absolutely. But still, the effect was much less than feared.

Nine of the deaths occurred from children in the nearby town who eventually contracted thyroid cancer, out of 4,000 cases reported. These cases likely were related to the accident. Thyroid cancer is highly treatable, however, and thus the death rate is very low. Even in local areas, there was no significant evidence of increased congenital malformations or fertility problems.

The report main conclusions are the following [bolded added for effect]:

Among the residents of Belaruss 09, the Russian Federation and Ukraine there had been, up to 2002, about 4,000 cases of thyroid cancer reported in children and adolescents who were exposed at the time of the accident, and more cases are to be expected during the next decades. Notwithstanding problems associated with screening, many of those cancers were most likely caused by radiation exposures shortly after the accident. Apart from this increase, there is no evidence of a major public health impact attributable to radiation exposure 20 years after the accident.There is no scientific evidence of increases in overall cancer incidence or mortality rates or in rates of non-malignant disorders that could be related to radiation exposure. The risk of leukaemia in the general population, one of the main concerns owing to its short latency time, does not appear to be elevated. Although those most highly exposed individuals are at an increased risk of radiation-associated effects, the great majority of the population is not likely to experience serious health consequences as a result of radiation from the Chernobyl accident. Many other health problems have been noted in the populations that are not related to radiation exposure.^[76]

By and large, we have not found profound negative health impacts to the rest of the population in surrounding areas, nor have we found widespread contamination that would continue to pose a substantial threat to human health...

In Japan, the radiation levels are much lower. On March 18, the media reported that elevated radiation readings were obtained 18 miles northwest of the Fukushima plant; 0.0017 SV, to be exact. To put that into context, that is equivalent to about 2 years worth of normal background radiation. In the Chernobyl accident, that same dosage was achieved approximately 500 miles away.

And to further the point: no one documented that received those kind of doses in Chernobyl ever had any direct medical problems, even after weeks and months of exposure at that level.

One last point, mostly scientific in nature. Much of the historical risks attributed to radiation have been obtained by studies of the nuclear fallout at Hiroshima and Nagasaki. The entire concept that there is no minimal threshold of radiation that is safe emanates from those studies. However, with large scale studies of people exposed to radiation from the Chernobyl accident, both in the immediate vicinity and distant exposure, these concepts are now highly disputed in the scientific community. The biological reasoning for these old theories is highly suspect. If the old theory was correct, we should have seen thousands of incidents of cancer and deaths; this has not borne out.

So, after careful analysis, what really strikes someone as the biggest danger from these large scale nuclear disasters? Fear. In the aftermath of Chernobyl, women through out Europe rushed to their doctors, fearing congenital abnormalities. It is estimated that 100 women in Italy alone went ahead with abortions because of their fears...or twice as many as the number who actually died over two decades from direct exposure.

There are serious risks to the radiation being emitted from the Japanese nuclear plant. Most of those risks are to those in the immediate vicinity, especially those within a 5 mile radius. And even in that region, the biggest risk is thyroid cancer. If you live in the immediate vicinity, say 50 miles or closer to the site, taking postassium iodide pills could help. Otherwise, it is a complete and utter waste.

If there is a large scale explosion and core breech, that distance will magnify, but unlikely to be greater than 100 miles. Even the fears of significant health risks to residents in Tokyo are overblown. Thus, people in the Western Hemisphere should take a slow, deep breath, and wait to see what happens. As of right now, there is nothing to fear from the Japanese disaster.