As workers struggle to cool reactors and spent fuel ponds to avoid a massive release of radiation at the Fukushima Daiichi nuclear power plant, people are expressing renewed fear for nuclear power. The U.S. hasn't built new nuclear reactors since the 1979 accident at Pennsylvania's Three Mile Island. Now, there might be a further delay in the expansion of nuclear power. However, we shouldn't let fear get in the way of rationally discussing atomic energy.
When considering Japan's nuclear crisis, we have to put it in perspective. Japan was hit by the fifth largest earthquake recorded since 1900 and then suffered a tsunami. Overall, the nuclear reactors performed somewhat admirably. The automatic shutdown worked, while the containment vessels stayed mostly intact through several hydrogen explosions. The backup generators managed to withstand the 8.9 earthquake, but failed after the tsunami. Hence, there was a lack of power for the cooling systems, which led to heating at the reactor cores from secondary decay products.
Nevertheless, only short-lived radioactive isotopes have been released outside of the plant's vicinity. By March 21st, engineers have restored electricity to three of the six reactors and planned to test water pumps. If the situation continues to improve, the nuclear plant would have survived the disaster reasonably well.
With that said, further investigations will probably reveal much room for improvement. For example, engineers already know that the design of Mark 1 reactors at the Fukushima Daiichi plant is prone to failure in emergencies. The U.S. has 23 Mark 1 reactors, which is concerning. Improvements have been made to the original design, such as the addition of vents to release pressure during overheating. However, we don't know what improvements were made at the Fukushima Daiichi plant or if they were effective. It might be safer for us to build new nuclear reactors from updated designs that are more robust, rather than fix-up reactors built on faulty designs from the 1960s.
As we wait for more information from Japan, we can only hope that engineers will stabilize the nuclear reactors soon and that the radiation spread will be minimal. In the meantime, President Obama has asked the Nuclear Regulatory Commission to thoroughly review the safety of U.S. nuclear plants and determine their ability to withstand natural disasters.