By Frank Wicks
On March 11, a magnitude 8.9 earthquake struck on the ocean floor 230 miles north of Tokyo. Thousands of Japanese people are dead or missing. The earthquake created a 30-foot tsunami wave that came ashore where six nuclear reactors are located. These reactors are designed to split uranium atoms via a chain reaction to produce heat and steam to drive turbines to generate electricity for several million people. The uranium chain reaction was automatically shut down. However, the smaller atoms produced by fission continued to decay and produce heat that must be removed by circulating cooling water.
Unfortunately, emergency pump power was lost because transmission lines and diesel generators were damaged. Temperatures of the uranium fuel rose in the reactor and in the discharge storage pools. High temperature damaged the thin zirconium cladding that contained the fuel. Some fuel has also melted. Zirconium reacted with the water. Hydrogen was released and exploded. Four of the reactor buildings have been destroyed. Highly radioactive atomic isotopes are being released to the soil, air and water.
People have been evacuated from the surrounding areas. Radiation has entered the food chain. Sale of some milk and vegetables is being banned. Workers are being subjected to unhealthy levels of radiation. They are heroically trying to limit environmental impact. In desperation, water from helicopters and fire-hoses have been used along with salt water from the ocean.
The ultimate magnitude of the accident remains uncertain. It is now much more severe than the United States accident at Three Mile Island in 1979, but not nearly as destructive as the 1986 Chernobyl accident in the Soviet Union. It is too early to know how this accident will ultimately impact the acceptability of nuclear power in the United States and for future generations.