Earlier this week, Japan's nuclear safety ageny raised the level of last month's Fukushima Daiichi incident from a rating of five to a rating of seven according to the International Nuclear Event Scale (INES). In layman's terms, that means it has been raised from an ""Accident with wider consequences"" to a ""Major accident."" The amount of radiation released from the four nuclear reactors exceeded a minimum threshold, moving the incident in the level 7 range.
The only other 7 rating that has been issued was the Chernobyl nuclear incident in Ukraine in 1986. The radiation that has been emitted from Fukushima to date, however, is roughly one tenth of the radiation released from Chernobyl, according to International Atomic Energy Agency (IAEA) website. Moreover, the Chernobyl event crossed the threshold of radiation emissions immediately. A large amount of radioactive material was emitted into the air and quickly began to spread around Europe. At the Fukushima plant, the radiation was emitted more gradually, which made evacuation easier and limited the widespread radiation exposure to citizens significantly.
In addition, Chernobyl had a nuclear reactor that exploded, instantly killing two workers. At Fukushima, there were a few steam explosions in the buildings surrounding the six reactors at Fukushima, but none that were nearly as dangerous as the initial explosion at Chernobyl.
There have been no reported deaths specifically from radiation at Fukushima thus far. In the three months following the Chernobyl incident, by comparison, 28 of the firemen and emergency clean-up workers died because of radiation exposure. Estimates of civilians who developed radiation-related cancer were in the thousands from Chernobyl. It's difficult to predict exactly how many in Japan were exposed to high enough levels of radiation to develop cancer. However, because the emissions were more gradual, it's likely that this number will be much smaller.
There has been a lot of debate on how these events should affect our outlook on the safety of nuclear power plants in the United States. Clearly, no nuclear accident should improve the outlook on the safety of nuclear reactors.
In large part due to issues with the Fukushima cooling systems, there was damage to the reactors and power plant itself. More importantly, hazardous radioactive materials were released into the air and into the ocean.
On the other hand, it is certainly worth noting that it took a massive earthquake (the fifth largest since 1900) to cause these events. The earthquake, as well as huge tsunami waves, devastated buildings throughout Japan. Death and the missing total nearly 25,000 people. To date, there have been no civilian deaths at Fukushima.
The earthquake in Japan actually exceeded the design specifications for the Fukushima nuclear reactors. The reactors were designed to withstand an earthquake of magnitude 8 and a tsunami with waves as high as 5.7 meters (19 feet). However, the earthquake had a magnitude of 8.9, and the tsunami waves as high as 14 meters (46 feet).
Moreover, the design was a Generation II model called Boiling Water Reactors. Currently, there are several more modern Generation III designs that are in operation today, including some in Japan. These designs have more passive safety systems. These systems implement convective cooling and sprinkler systems automatically upon shutdown. Such systems would not need any operator intervention for a few days, whereas yet at Fukushima, intervention was necessary from operators within the first few hours.
Still, there are other past-generation nuclear reactor designs in operation today, and inevitably there will be more natural disasters in the future—eventually there may be even more devastating disasters than the one in Japan.
Most experts agree that Fukushima was much more controlled of an accident than Chernobyl, but it raises concerns for the future of nuclear power. The global nuclear community will need to re-examine the current designs of nuclear reactors and make appropriate adjustments in the future. Also, plant safety with regard to natural disasters will need to change, and only then will we have safer plants in the long run.
Joseph Zimny is a senior majoring in chemical engineering. Please send all feedback to opinion@dailycardinal.com.
