CHERNOBYL DISASTER BY NUR RAHMAH HAYATI

On April 26, 1986, the world’s worst nuclear power plant accident occurs at the Chernobyl nuclear power station in the Soviet Union. Thirty-two people died and dozens more suffered radiation burns in the opening days of the crisis. That moment marked the worst nuclear disaster the world has ever encountered, releasing catastrophic amounts of radioactive material into the environment, which quickly spread over Ukraine, Belarus and as far away as Western Europe.

 WHAT

The explosion of the reactor at Chernobyl's nuclear power plant was so all-encompassing and unprecedented in scope, that the devastation and consequences. The explosion released into the atmosphere 126 different radioisotopes with half-lives that will last for years. Radiation intensity at Chernobyl was 100 times the radiation caused by the atomic bomb dropped on Hiroshima. The explosion left damage in its wake, instantly taking lives and sealing the fate of generations to come.

WHERE

The Chernobyl station was built in the late 1970s on the banks of the Pripyat River, Chernobyl had four reactors, each capable of producing 1,000 megawatts of electric power. It was located at the settlement of Pripyat, about 65 miles north of Kiev in the Ukraine.

On the evening of April 25, 1986, a group of engineers began an electrical-engineering experiment on the Number 4 reactor. The engineers, who had little information of reactor physics, wanted to see if the reactor’s turbine could run emergency water pumps on inertial power.

Today, Chernobyl’s thirty-kilometre circumference was label as “dead zone.” It is one of several closed areas in Ukraine and Belarus that are estimated too jeopardise to inhabit--though some people continue to live there. Today, thousands of people still live in Russia, Belarus, and Ukraine, the region affected by the radiation generated from Chernobyl and the area once known as the Jewish Pale of Settlement.

 WHEN

APRIL 25, 1986

1:05   pm: Power Plant decreasing, signifying the start of the reactor shutdown.
2:00   pm: Emergency Core Cooling System is disconnected and power is reduced to 30 MW.
11:10 pm: Power reduction resumed.

APRIL 26, 1986

Operating Reactivity Margin (ORM) decreases to below 30 rods. No station manager’s approval for operation with less than 30 rods.

1:00  am: Increased power to 200 MW by removing rods.
1:07  am: 2 additional recirculation pumps started—all 8 are running. All but six rods are removed.
1:19 am: Increased feed water flow to steam drums. Required immediate shutdown— warning ignored and test initiated.
1:22:30 am: Feed water flow to steam drums decreased to very low value - 30 seconds later reactor inlet temperature begins to rise.
1:23:04 am: Turbine valves closed.
1:23:40 am: Emergency Scram initiated by button AZ-5
1:23:43 am: Power increasing rapidly due to positive void coefficient.
1:23:48 am: Explosion occurs, followed by a second explosion seconds later.

 AFTERMATH

Up to 60 sq. mi. of Soviet farmland is likely to remain severely polluted for decades, unless steps are taken to eliminate the tainted topsoil. Reason: caesium 137 and strontium 90, two radioactive particles spewed by the blaze, decay very slowly. It could take years for the ground to be free of them. Together with the shorter-lived iodine 131, the substances promise to pose short- and long-term problems for people, crops and animals.

Based on Belarus national cancer statistics, Greenpeace expected that up to 270,000 cancers and 93,000 fatal cancer cases have been caused by Chernobyl. The report also estimated that 60,000 people have additionally died in Russia because of the Chernobyl accident, and estimates of the total death toll for the Ukraine and Belarus could reach another 140,000. The Greenpeace report said the rate of cancer in Belarus had jumped 40 percent between 1990 and 2000, with children not yet born at the time of the disaster showing an 88.5-fold increase in thyroid cancers.—Greenpeace 2006.