Ten years ago today, the world watched in horror as the largest nuclear disaster in history unfolded at the Chernobyl Nuclear Station in the Ukraine.

University of Arizona staff of the Nuclear Reactor Lab in the Engineering building pay little attention to past nuclear disasters, said Tim White, a graduate student in nuclear engineering and treasurer of the American Nuclear Society's Student Branch at the UA.

"Chernobyl didn't really affect my perceptions of nuclear power. Chernobyl and our plants are different," White said.

John Williams, a professor of aerospace and mechanical engineering and director of the nuclear reactor laboratory at the UA, said the reactor at the UA is used as a teaching tool and is almost harmless because of the fuel used.

The fuel has a negative feedback characteristic to limit any possibility of an accidental release of energy beyond its capacity, Williams said.

There has been a reactor in the engineering building since 1958 and the present reactor has been there since 1972, Williams said.

The reactor generates at most 300,000 watts of energy, enough to power three kitchen ovens, said Wayne Lohmeier, electronic technician at the reactor.

Chernobyl generated much more energy. Each of the four reactors was capable of producing one billion watts of electric power.

The Soviet government originally tried to cover-up the Chernobyl disaster, but within two days, Swedish monitoring stations reported abnormally high levels of radioactivity in the atmosphere, exposing the accident.

Chernobyl was operating four nuclear reactors on April 26, 1986 when a poorly-executed experiment created an explosion in reactor No. 4.

The explosion created a fireball which blew the heavy steel and concrete lid off the reactor, releasing large amounts of radiation into the atmosphere.

The reactor was encased in a tomb composed of two feet of steel and six feet of concrete.

"Anyone who understands nuclear reactors understands that Chernobyl was the worst thing that can happen in a reactor," Williams said.

The Chernobyl explosion released more radioactivity into the Earth's atmosphere than the nuclear bomb dropped on Hiroshima, contaminating the air as far west from the Ukraine as France and Italy.

Chernobyl is 65 miles north of Kiev, capitol city of the Ukraine with 2.6 million residents.

According to the Encyclopedia Brittanica, the initial death toll was 32 people.

In the years since the disaster, however, there have been numerous cases of radiation sickness and deaths from cancer. Livestock have been born deformed and millions of acres of farmland have been contaminated.

Williams said that scientists may never accurately know how many humans were affected by the Chernobyl disaster.

But Tuesday, a fire spread through five villages surrounding Chernobyl, stirring up the contaminants resting in the soil.

Experts are now concerned that additional radiation has entered the atmosphere and will result in more sickness around the nuclear plant.

When asked if the Chernobyl disaster had had a profound affect on society's perception of nuclear power, Harry Doane, nuclear reactor supervisor at the UA, said, "It's American and human logic to say 'It didn't happen in my backyard, I don't care.'"

Sue Terrigino, manager of strategic communications for Palo Verde Nuclear Generating Station, said that communication with the public is imperative for the future of nuclear power.

Palo Verde is 55 miles from downtown Phoenix and generates power for residents of Arizona, California, New Mexico and Texas.

"There were a lot of lessons learned from Chernobyl, and most of those had to do with control room communication," Terrigino said.

"However, we know intuitively that disasters like Chernobyl can't happen here that way," Terrigino said.

Terrigino said that the Chernobyl reactor was designed much differently than American reactors, thus the same type of accident is impossible.

Palo Verde Nuclear Generating Station operates three reactors, which together generate just under 3.8 billion watts, enough power for about 4 million people.

The Chernobyl Nuclear Station still operates two of its reactors. Reactor No. 4 has been enclosed in a steel and concrete sarcophagus which has been deemed structurally unsound by experts because it is deteriorating.

In the United States, there are strict regulations regarding nuclear energy.

"There's a lot more scrutiny," Terrigino said.

She said the employees at Palo Verde have, on average, been working at the plant for eight years and are well qualified and trained.

Williams said, "It's unfortunate that the environmental benefits of nuclear power are not being recognized to a greater extent."

White said, "There are hazards with nuclear power, but there are also some with coal - nuclear power is more regulated than other methods. It's not the only answer, but it's a part of the solution."