Nuclear Energy Safe or Deadly?

Science World, Feb 7, 2000 by Sharon Guynup

A recent accident casts a grim shadow over nuclear energy.

You can't see it or smell it. You wouldn't know if it wafted through the window while your family ate dinner. But if radiation (radiating waves or particles emitted by some elements) were to accidentally spew from a local nuclear power plant--a plant that uses the radioactive element uranium to generate electricity--results could be dire.

"Immediately you might turn red and throw up," says Cindy Folkers at the Nuclear Information and Resource Center. Within a week, your hair and teeth might start to fall out--and your dog or cat could drop dead.

Exposure to radiation initiates changes in human cells that years later can lead to many types of cancer or cause organs to fail. It can also cause genetic mutations, changes in cells' hereditary information that can trigger birth defects for generations to come.

Yet many government leaders and nuclear industry officials around the world maintain that nuclear energy is necessary, efficient, and safe.

SAFETY FIRST?

The majority of America's energy still comes from burning coal, oil, and natural gas. Nuclear reactors, which split atoms of the radioactive elements uranium and plutonium to create nuclear energy, currently produce 20 percent of all electricity in the U.S. And stricter regulations have made plants safer than they were even 10 years ago, claims Victor Dricks, a spokesman at the U.S. Nuclear Regulatory Commission.

But what if something goes wrong, as it did last September 30 in Tokaimura, Japan? That morning, radioactive gas gushed into the air from a nuclear fuel factory 110 kilometers (70 miles) northeast of Tokyo. The Japanese Atomic Energy Research Institute recorded radiation readings immediately outside the plant at 20,000 times normal radiation levels! At least 55 people were exposed, mainly plant workers and firemen, two of whom may not survive radiation sickness.

Officials shut off all access to the city, ordered children to stay at school, and advised more than 300,000 city residents to remain indoors with windows tightly shut--and not to drink tap water. What went wrong?

CHAIN REACTION

Workers at the Tokaimura nuclear fuel factory mistakenly poured 16 kilograms (35 pounds) of uranium instead of the usual 2.4 kg (5.2 lbs) into a solution of nitric acid and water--the uranium solution is processed into fuel pellets that power nuclear reactors (see diagram, left).

The result was a sudden flash of blinding blue light--the ominous flash of radiation that occurs when uranium begins a chain reaction. When stray uranium neutrons (atomic particles with no electrical charge) strike other uranium molecules, the atoms split in an unchecked process called fission. This releases huge amounts of energy. (Controlled fission generates electricity in nuclear power plants.)

Twenty-one hours after the chain reaction began, rescue workers halted it by draining water from the mixing tank and smothering the uranium with boric acid, which absorbs maverick neutrons. The Tokaimura accident was the sixth major mishap at a Japanese nuclear facility since 1997.

Such accidents, as well as the ongoing use of nuclear energy itself, raise two serious concerns, says John Carew, a physicist at Brookhaven National Laboratories in Upton, N.Y.: safety and nuclear waste. Nuclear fission converts some uranium in fuel rods to plutonium, which remains radioactive for about 240,000 years. Spent fuel rods are stored in cooling ponds at nuclear plants. But ponds are filling up worldwide, and so far scientists haven't come up with safe permanent storage sites for nuclear waste.

If radioactive particles, or nuclides (NEW-clides) escape into the atmosphere from a nuclear power plant or factory, wind currents can blow particles over cities, countries, even around the world. Certain nuclides remain dangerous for hundreds or thousands of years, such as strontium (120 years) and cesium (300 years).

The amount of radiation released in Japan was too small to pose an international threat--unlike the 1986 explosion at the Chernobyl plant in Ukraine that irradiated over two million people in Ukraine, Russia, Belarus, and Eastern Europe (see sidebar, above).

So why use nuclear energy at all?

CAN IT HAPPEN HERE?

Fifty years ago, the U.S. government sought out new energy sources to replace diminishing supplies of fossil fuels: coal, oil, and natural gas. (Experts think the planet's coal reserves, for example, could vanish in 150 to 200 years.)

"We didn't have as many energy options--like solar and wind power--as we have today," says David Lochbaum, a nuclear safety engineer for the Union of Concerned Scientists.

Also, burning fossil fuels to create energy pollutes the atmosphere with carbon dioxide and toxic chemicals. Burning coal, for example, releases sulfur into the air, which returns to Earth as acid rain and harms plants and animals. Advocates of nuclear energy defend the process as non-polluting.

But in 1979, Pennsylvania's Three Mile Island (TMI) power plant proved that nuclear accidents can strike home: radioactive gases escaped when a reactor malfunctioned. Two decades later, a University of North Carolina study showed that residents near TMI had cancer rates 2 to 10 times higher than normal.