After the initial earthquake workers rushing from buildings saw pipes bursting Some pipes carried water to cool three nuclear reactors The power went out plunging the entire plant into darkness Without power pumps couldn’t circulate cool water through the reactor When temperatures climb high enough the fuel rods melt This is a nuclear meltdown During a meltdown the fuel may melt through the floor and dump radioactive material into the ground or water or release it into the air Even after the nuclear reactions stop automatically as they did at Fukushima Daiichi nuclear cores stay hot Fast Fact At Fukushima temperatures reached 4,800 degrees Fahrenheit 2,649 Celsius A powerful explosion ripped the roof off reactor Number 1 at the Fukushima Dai-ichi nuclear power plant The meltdown damaged four of the six reactors at the plant beyond repair 6
Fortunately the power plant’s backup power system came on after the earthquake Diesel-fuel-powered generators switched on to make electricity and keep the cooling pumps operating Unfortunately those backup generators were located in the plant’s basement When the tsunami waves struck they ruined the generators Diesel generators use diesel fuel a form of gasoline to create electricity Aside from these bus-sized generators nuclear power plants in the United States also have portable steam generators 7
The earthquake and tsunami killed almost 16,000 people and injured another 5,000 The nuclear meltdown of three reactors at the plant lasted for more than a week During that time the Japanese government ordered people living within 12 miles 19 kilometers of the plant to leave their homes as explosions at the plant spewed radioactive material into the sky More than 80,000 people left not returning home for months Some still have not been able to return The nuclear meltdown was not the only disaster Japan faced after the massive earthquake The tsunami washed away many towns and ports in a 216 square mile 560 square kilometer area It destroyed more than a million buildings 8
The former Soviet Union built nuclear-powered submarines like this one in the 1970s Today the United States Navy has 74 nuclear-powered submarines Today nuclear energy is all around us In the United States nuclear power plants generate 20 percent of the country’s electricity Nuclear power also is used to diagnose and treat cancer and power submarines and spacecraft How do we make sure nuclear power stays safe And how can we protect ourselves when meltdowns happen 9
