Nuclear Legacy: Chernobyl Turns 25

The worst nuclear disaster the world has ever known, began with a trial run of an experimental cooling protocol on April 26, 1986. A power surge occurred in reactor #4 at the Chernobyl Nuclear Power Plant, near the town of Pripyat in the Ukraine (then part of the USSR.) An emergency shut down was attempted, but the situation was already out of control. Another power surge - stronger than the first - ruptured the containment vessel through a series of explosions that launched radioactive fuel and core materials into the atmosphere. When the reactor's graphite moderator was exposed to open air, it ignited in a fire that sent a plume of smoke, ripe with radioactive material into the atmosphere.

Map of Chernobyl's radioactive fallout

The plume drifted over parts of the former Soviet Union and Europe releasing into the open more radioactive material than the atomic bomb dropped of Hiroshima during World War II. The most effected regions include Belarus, Ukraine and what is now Russia - though radioactive material was detected at elevated levels throughout Europe.

The disaster killed 31 people who either worked at the reactor or were part of the emergency response crew, but the number of people who have been killed as a result of subsequent radiation exposure vary from the World Health Organization's estimated 4,000 to the Greenpeace estimate of 200,000 or more.

The Soviet Union tried hard to downplay the April 26th fire and explosion back in 1986, but two days later on April 28th workers at the Forsmark Nuclear Power Plant in Sweden 680 miles from Chernobyl detected radioactive particles on their clothes. Sweden's search for the source of the radioactivity (after it was determined that there was no problem at their plant) led to the conclusion that a serious incident had occurred in the western part of the Soviet Union. Chernobyl become the center of world wide attention.

On the 25th anniversary of the Chernobyl disaster, society is still dealing with the legacy of fear, misinformation, and health effects left by the destroyed power plant. Chernobyl was ranked as a level 7 disaster on the International Nuclear Event Scale (INES,) which is the highest possible ranking. The world is still reeling from March's Fukushima nuclear disaster in Japan, the only other INES level 7 disaster in history. But Fuskushima is not Chernobyl. Fukushima has not caused the level of death and destruction as Chernobyl - and the plants were of completely different designs.

The nuclear reactors at Chernobyl were made based on a now defunct Soviet design, which had known cooling problems. The plant's workers were testing a new cooling protocol because it was known that in the event of a power outage the system in place (back up generators, etc.) would not have been able to cool the reactors quickly enough. There has been much speculation about who is to blame for the Chernobyl incident - if it was the reactor design or if it was human error.

Chernobyl as it is today

The first reports out of Chernobyl blamed the workers - reporting that they didn't have adequate training and experience, that they were operating the plant with key safety systems (like the Emergency Core Cooling System) turned off, and that they knowingly ignored regulations. However, over time the role of these accusations has been downplayed, while flaws in the design of the control rods (part of the cooling system) and the reactors ability to deal with the build up of steam has been blamed for the bulk of the incident.

The initial clean up of Chernobyl was done by "liquidators" who moved the majority of debris into the damaged reactor, which was covered in sand, lead and boric acid dropped from helicopters. A concrete enclosure was built around the damaged reactor - a task that exposed the construction workers to significant amounts of radiation.

In February I did a post on What We Don't Know about Chernobyl - namely that the site of the damaged reactor has been without a proper containment vessel all these years. The concrete sarcophagus originally erected around the destroyed reactor is still in place, and there are cracks in it. The money was never raised to build a more permanent enclosure.

The Fukushima disaster has brought Chernobyl back into the headlines, and today on its 25th anniversary we have to stop and ask ourselves how our understanding of nuclear power has been influenced and shaped by that April day back in 1986. In the wake of a nuclear disaster many people question whether the science is really safe, but I think the question we should really be asking is whether the science, in human hands, is really safe. It isn't an issue of nuclear power - it is an issue of what happens when people try to harness nuclear power.

Japan: All Nuclear Disasters Are Not Created Equal

Sadly, the headlines are once again swamped with stories of the latest natural disaster to wreak havoc on the Pacific Rim. On March 11, 2011 an earthquake (8.9 on the richter scale) and subsequent tsunami (a wave created by the shifting bedrock in the ocean following an earthquake) shocked Japan leaving thousands dead, and many more missing.

Nuclear energy is a widely used source of power in Japan. As a result of the earthquake and tsunami, damage to the nuclear power plants has resulted in several explosions and the release of radioactive material. While the media is fixated on the threat posed by the imperiled nuclear power plants, there is a significant amount of misinformation, information without context, information in the wrong context, and complex information that is just not explained adequately in the media's coverage.

The following list will hopefully clear up some of the confusing information I've seen in the popular coverage of Japan's nuclear situation.
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Diagram of the type of reactor at Fukushima
Source: Nuclear Energy Institute

1. The design of nuclear reactors vary: The nuclear reactors in trouble in Japan are the Mark 1 design by General Electric. This design has been controversial since the 1970's when it was discovered that the cooling, ventilation, and containment systems (the areas causing trouble in the Japanese plants) could be problematic in the event of a meltdown, explosion, or other event. The New York Times' article Reactor Design in Japan Has Long Been Questioned states that the most common type of nuclear reactor is a pressurized water reactor where the system is encased in steel and cement and that, "the type of containment vessel and pressure suppression system used in the failing reactors at Japan's Fukushima Daiichi plant - and in 23 American reactors at 16 plants - is physically less robust, and it has long been thought to be more susceptible to failure in an emergency than competing designs." The New York Times' article goes on to explain that many American plants manufactured in General Electric's Mark 1 design have been modified to fix the problems in the original plans. Americans should not be panicking that the nuclear reactors in the United States have the same problems as the ones in Japan. Each nuclear power plant needs to be evaluated in its own right for safety.

2. Comparisons to Chernobyl or Three Mile Island are difficult to make: Chernobyl, located in the Ukraine, was a nuclear disaster that occurred on April 25, 1986 due to a flawed reactor design and human error. The Chernobyl reactor was of a soviet design, and according to the World Nuclear Association, "the design of the reactor is unique and the accident is thus of little relevance to the rest of the nuclear industry outside of the Eastern bloc." Chernobyl was the only nuclear accident to cause human deaths due to direct exposure to radioactive material. Comparisons can be made to the situation in Japan about the extent of damage, but only once the situation is under control has been thoroughly assessed. Three Mile Island was an American accident in 1979 that occurred when a cooling malfunction caused part of the nuclear reactor's core to melt. There were no adverse health effects associated with any radiation released from the plant after the accident. The build up of hydrogen gas following the meltdown was a factor in the Three Mile Island accident, and is causing problems in Japan but again differences in exact reactor design and protocol make it difficult to compare the situations.

3. The International Nuclear and Radiological Event Scale is not definite: Even though the INES scale is intended to help publicly convey the threat created by a nuclear event, designation of a certain level on the scale is not a reason to panic. The INES scale runs from 1 (very little danger to the general public) to 7 (widespread health and environmental impacts). Right now everyone is rushing to label the situation in Japan, but so far it is classified as somewhere between level 4 and level 6. The numbers (or levels) are not hard and fast, but it is a clear indication that this is a major event and should be treated with all necessary precautions to ensure the safety of the Japanese people.

4. Radiation is not distributed evenly: When a nuclear power plant experiences an explosion or a meltdown that causes the release of radioactive particles or debris into the environment it can be very complicated to track what areas are going to be effected by radiation. According to members of the Union of Concerned Scientists precipitation like wind or rain can cause the radioactive material to be distributed sporadically. The areas closest to the effected plant will be the first concern for scientists and policy makers assessing the radioactive fallout, but other areas (even far from the immediate vicinity of the plant) need to be assessed for radioactivity.

Map of Japanese Nuclear Sites
Source: International Nuclear Safety Center

5. Not all Japanese nuclear plants are in danger: There are 54 nuclear reactors in Japan located at 18 different sites throughout the country. The reactors in the north of the country experienced the most damage, particularly the Fukushima Daiichi plant which is located closest to the area hit by the earthquake. There are six nuclear reactors at Fukushima Daiichi. Reactors 5 and 6 have had water pumped into them and are currently at a low risk of an incident. Reactor 1 experienced an explosion on Saturday March 12th that damaged 70% of the fuel rods in the reactor, but so far it is reported that the containment vessels are intact. Reactor 2 experienced an explosion on Tuesday March 15th that damaged the suppression pool - a part of the cooling system leaving the fuel rods exposed. This reactor is leaking radiation. Reactor 4 experienced an explosion on Wednesday March 16th that caused a fire in a pool of spent fuel that is exposed to the air. The spent fuel contains more radiation than the fuel rods inside the reactor, so leaving them exposed (as they are now) means that radiation is leaking out into the environment. Reactor 3 is currently the center of an intense effort to cool the fuel rods by pumping in sea water. This reactor is the only one at the Fukushima Daiichi plant that uses plutonium, and thus contains the most radiation. The Kyodo News has a breakdown of the damage to the plant by reactor that contains more information.
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Reuters has a great info graphic, that breaks down the earthquake, tsunami and the nuclear disaster. The BBC also has an interesting article about the way that nuclear situation in Japan will impact further nuclear development around the world. As more information comes out I'll try to update this post, but I hope that I've been able to provide some background on elements that I've seen in multiple articles about Japan's nuclear situation.

What We Don't Know

The site of the Chernobyl Nuclear Power Plant, where one of the world's worst environmental disasters took place in 1986 doesn't have a protective casing around it. Seriously? I wasn't even born when Chernobyl exploded, how is it possible that all this time it hasn't had a permanent casing around the radioactive wreckage?

Chernobyl in 2004. Source: Wikimedia Commons.

Radiation contaminated huge swatches of land across Europe in the late 80's due to Chernobyl, and no one ever found it important enough to spend the money to build a permanent casing around the damaged nuclear fuel rods. How is that possible?

Twenty five years after the Chernobyl explosion the money needed to put a protective casing around the damaged nuclear fuel rods hasn't been raised. The existing protective casing was intended to be only temporary, and won't be a permanent solution to the radiation problem. A permanent structure has been under construction, but money to build it is going to run out before it is completed.

Countries all over the world have pledged money to build the containment structure, with European countries leading with the most donations. I understand that we are currently in an economic crisis, but how have 25 years passed without enclosing the radioactive ruins becoming a priority? This should have been done long before the world experienced its recent economic downturn.

This story has me thinking about all the things we don't know. I never would have thought that there wasn't a permanent structure around Chernobyl. It wouldn't have even occurred to me to find out if there was one because its the sort of thing I would just assume had been taken care of. I can't help but wonder what other issues are just never publicized...scary things to think about.