It’s been almost 12 years since the Chernobyl nuclear catastrophe shook the world. The disaster happened not only due to some design error of the nuclear reactor but also to human mistakes.Victor G. Baryakhtar, professor of physics and mathematics at National Technical University of Ukraine, talked to about 40 people about the accident and its consequences Thursday at Smith Laboratories.On April 26, 1986, an experiment to improve the safety of a nuclear reactor turned out to be the world’s worst nuclear accident because of human errors, Baryakhtar said.Part of the safety test involved reducing the heat energy level to nearly a fourth of what it was. But the thermal power suddenly dropped to nearly zero. To compensate, the operator removed the control rods, the nuclear reactor went critical and the meltdown occurred, according to Baryakhtar.Up to now, the disaster has affected more than 2.4 million people in Ukraine, Belorussia and Russia. The continuous after effects of the disaster are unknown.Baryakhtar was appointed chairman of the Soviet Scientific Committee right after the accident. Since then, he has investigated the cause and effects of the Chernobyl disaster.Nearby rivers used by many Ukrainian people were contaminated by radioactive materials. All kinds of foods, including vegetables and milk, were polluted.Influences on the human body from exposure to the radioactive dusts and intake of contaminated substance showed in the blood system, the nervous system and the stomach, Baryakhtar said.”But the psychological impact on the people who relocated from the highly contaminated area is much greater,” he said.They have no homeland and an uncertain future, and they are concerned about who will pay for their health, Baryakhtar said.Baryakhtar said every country with nuclear power plants should develop a safety system in case of an accident. The United States should definitely have such programs because the U.S. has the largest number of nuclear plants in the world.Baryakhtar said he fears that deterioration of the concrete encasing the nuclear reactor which caused the Chernobyl disaster is reaching a very dangerous point. If the concrete collapses, radioactive dust could spread all over Europe.To repair this situation, international support is needed, Baryakhtar said.Baryakhtar ended his speech with the quote by President Vaclav Havel of Czech Republic on his visit to Chernobyl: “The superpower needs both super responsibility and nobility of the soul.”Maarten Rutgers, an assistant professor of physics, said he had never heard all the specific reasons about why Chernobyl occurred. “I did not know that it was because of the human error,” he said.