Chapter 2.3, Problem 1CSR

Unstable Atoms Unleashed

Scientists believe that the isotopes Of uranium were forged in the explosion of a star and became incorporated Mo Earth as our solar system formed, today the radioactive form of this rare element is mined and concentrated to help satisfy humanity unquenchable desire for energy.

The chain reaction that generates heat in nuclear power plants begins when neutrons are released from radioactive uranium. These bombard other uranium Moms and cause them to split, in a self-sustaining chain reaction. When the tsunami struck the Fukushima plant, neutron-absorbing rods were immediately low-red around the fuel, halting the Cham reaction. But the breakdown of uranium generates additional radioactive isotopes, and these continued to spontaneously decay and generate heat This caused the disastrous breach that released these isotopes into the environment One isotope of particular concern is radioactive iodine.

Iodine enters the body in food and water. It becomes concern trated in the thyroid gland, which uses iodine to synthesize thyroid hormone. Unfortunately, the thyroid gland does not distinguish between radioactive and non-radioactive iodine-Children exposed to radioactive iodine are at increased risk for thyroid cancer, which may occur decades after exposure. To help protect them, Japanese authorities distributed iodine tablets to children near the tailed reactor this non-radioactive iodine satiates the thyroid, which then does not take up the radioactive form. Only time will reveal the full health effects of the fallout from Fukushima

CONSIDER THIS The Fukushima disaster led to a reassessment of safety precautions m nuclear power plants and a worldwide dialogue about the dangers of nuclear power, which also generates waste that remains radioactive for thousands of years. How can societies evaluate and compare the safety of nuclear power versus the safety of burning fossil fuels, from which humanity currently gets most of its energy? How can one compare the possibility of events that might cause a nuclear disaster—such as a magnitude 9 earthquake or the accidental escape of radioactive waste—with the certainty of continued carbon dioxide emissions and global climate change resulting from fossil fuel use? To what extent should societies invest m renewable energy, including wind and solar power?