Tuesday, April 5, 2011

Chernobyl and Japan

The Chernobyl accident occurred in Ukraine during 1986. A faulty reactor design caused the destruction of the Chernobyl 4 reaction. 2 workers died on the night of the incident, and in the following months an additional 28 workers would die as well. Acute radiation symptom (ARS) was diagnosed in over a hundred people, with several dozen dying because of the radiation. Thyroid cancer was diagnosed in more children, due to an intake of radioactive iodine fallout.



The RBMK 1000 was designed by the Soviets sing slightly enriched (2% U-235) uranium dioxide fuel. Just before a regular shutdown, the reactor crew at Chernobyl began preparing for a test to see how long the turbines would spin after a loss of main electrical supply. This test was performed the previous year, but the power from the turbine stopped too rapidly, so new voltage regulator designs were going to be tested.




When the operator went to shut down the reactor, it was in an unstable condition. The control rods used a dramatic power surge when they were inserted into the reactor. The meeting of hot fuel and cool water led to an increase in pressure. Intense steam spread throughout the core causing an explosion that released nuclear fission into the atmosphere.



About 5 million people lived in areas contaminated by Chernobyl, with 45,000 people leaving the town of Pripyat. In the years to follow, 222,000 people moved into less contaminated areas. About 1,000 people returned unofficially to live in the contaminated zone.



By the year 2000, about 4,000 cases of thyroid cancer was diagnosed in children that had been exposed. Besides the thyroid cancer increase, there isn’t any evidence of any major public health impact from Chernobyl 14 years later.



During the early 1990’s, the US spend about $400 million on making the remaining reactors at Chernobyl safer. Close to 6,000 people worked at Chernobyl daily, until the last reactor was closed in 2000. Chernobyl 4 is now enclosed in a concrete shelter, with a new confinement structure currently being built.


Although there are similarities between Chernobyl and what has happened in Japan, the differences between them are clear. Chernobyl was a 3,000MW reactor while the reactors in Japan are only 500MW. In Chernobyl, an explosion occurred in a critical part of the reactor. The damage to the core in the reactor in Japan was minimal, for most of the reactors in Japan damage was only done to the protective layering.


I do not think we have to worry too much about Japan’s reactor. Technology has advance much further since the Chernobyl incident. I believe that scientist should work hard (once again) to revamp the design to current and future reactors.


Sources:

"Chernobyl Accident." World Nuclear. World Nuclear Association. Web. 1 Apr. 2011.

"Chernobyl: 25 Years After the Nuclear Disaster." Huffington Post. 2 Feb. 2011. Web. 1 Apr. 2011. .

Barry, Ellen. "Lessons Learned From Chernobyl For Japan." The New York Times. 19 Mar. 2011. Web. 1 Apr. 2011. .

Matthews, Owen. "Why Japan's Nuclear Meltdown Is No Chernobyl." Yahoo! News. 14 Mar. 2011. Web. 1 Apr. 2011. .


Pictures:

Sites Listed Above

http://www.oyetimes.com/images/stories/asia/Japan-FukushimaPlant.jpg