The Chernobyl Disaster

           Late at night on April 25, 1986, workers at the nuclear power plant began to run a test on Reactor 4.  This test would show them how long the turbines would run and create energy after a power loss.  This energy would be used to pump through cold water to cool down the core.  After around 45 seconds, a backup power source would kick in, but they needed the reactor to be able to produce enough energy to keep the water pumping for those 45 seconds. 1.  At 1:23 in the morning, the reactor slowly slowed down. However as the momentum slowed down, the liquid coolant (water), started becoming bubbles (steam voids). In the reactor, the water not only served as a coolant for the core, but also absorbed neutrons. Since the water started becoming bubbles, there were becoming less neutrons absorbed.  Since the water was absorbing less neutrons, the unused water turned into more steam, which led to an increase of power.  The increase of power with the limited amount of coolant led to a increased core temperature.  After the power increase and the increased temperature of the core, the on site workers panicked. It is said that the workers were very inexperienced and not well informed about emergency procedures.  During this panic, a button was pressed that caused an emergency shutdown (SCRAM), on the reactor.  The emergency shutdown lowered the control rods into the core, then inserted neutron-absorbing material to absorb the radioactive material.  However there was a problem with the design of these control rods.  The tip of the control rods was graphite. Before the control rods entered the core, it supposedly displaced some of the coolant, which led to an explosion.3. The combination of the power increase due to the bubbles, an increase of the core temperature, and a shortage of coolant caused the core to explode.

            The consequences of this explosion were very extreme.  After the explosion, a ongoing fire lasted for 10 days. This fire produced a smoke that contained large amounts of radioactive iodine and Cesium. The iodine only lasted for about 8 days after the fire, however the cesium is still able to be found in some foods and soil in Europe. One of the main consequences of the radioactive leak was thyroid cancer, which was main an effect of the iodine.2. Thyroid cancer would cause deforms to you children and some adults. The radioactive material mainly spread to areas in the Soviet Union, but some did reach farther distances.5. Only a couple of deaths actually occurred from the explosion, which were the on site workers.  On September 6, 2005 the World Health Organization said that 50 deaths occurred from the entire disaster including the ones from the direct explosion. 4,000 children were diagnosed with Thyroid Cancer, however it has been reported that only 9 deaths actually occurred from the Cancer.4.  Since the accident, approximately 600,000 people have been involved with the emergency, containment, clean-up, and recovery procedures. 5
       The Japanese and Chernobyl Nuclear Reactor problems had some similarities, but were also different. Both reactors had problems with cooling the core, which in the Chernobyl disaster, caused an explosion. However the Chernobyl reactors also had many other problems go wrong. The Japanese reactors also have other problems other than the cooling problems, but none as catastrophic as Chernobyl's. In my opinion, the biggest difference between these two disasters is how they happened, and how the were fixed. The Chernobyl disaster definitely could have been prevented with more experienced technicians. In the Japanese disaster, there was no way they could have preventing an earth quake from damaging the reactors.6 Since the Japanese disaster happened in a more modern era, they clean-up process is going a lot more smoothly even though there is not even close to as much radiation leakage as Chernobyl had. Overall I would say there is not anything to worry about. It does not seem as if there will be an even close amount of radiation leakage as there was at Chernobyl's, and so far the radioactive containment process has gone well. 6. 




Works Cited
1)"Chernobyl | Chernobyl Accident | Chernobyl Disaster." World Nuclear Association | Nuclear Power - a Sustainable Energy Resource. Web. 06 Apr. 2011. <http://www.world-nuclear.org/info/chernobyl/inf07.html>.
2)"Chernobyl Disaster." ICRIN Home. Web. 06 Apr. 2011. <http://chernobyl.info/>.
3) "Chernobyl." Chernobyl, A Nuclear Disaster. Web. 06 Apr. 2011. <http://library.thinkquest.org/3426/>.
4 "Chernobyl Disaster." Formal Reasoning Group. Web. 06 Apr. 2011. <http://www-formal.stanford.edu/jmc/progress/chernobyl.html>.
5. "Scientific Facts on the Chernobyl Nuclear Accident." GreenFacts - Facts on Health and the Environment. Web. 06 Apr. 2011. <http://www.greenfacts.org/en/chernobyl/index.htm>.
6. Wolchover, Natalie. "Earthquakes Put Japan's Nuclear Reactors on Red Alert - FoxNews.com." FoxNews.com - Breaking News | Latest News | Current News. Web. 06 Apr. 2011. <http://www.foxnews.com/scitech/2011/03/11/earthquakes-japans-nuclear-reactors-red-alert/>
7.  "You Can Stop Worrying About A Radiation Disaster In Japan -- Here's Why." Business Insider. Web. 06 Apr. 2011. <http://www.businessinsider.com/japan-reactors-pose-no-risk-2011-3>.

 This is a picture of the rising smoke containing the radioactive material.

 This is a picture of a child with a deformity from Thyroid Cancer

 This is a nuclear reactor.

Here is a picture of the damage from the explosion.

Photos and Videos


http://www.freedomforfission.org.uk/img/pwrreactor.gif
http://www.personal.psu.edu/lmt193/blogs/lauren_thomas_ukr_100/chernobyl%201.jpg
http://www.solcomhouse.com/images/111chexp.gif
http://scienceblogs.com/gregladen/images/chernobyl_hydroceph.jpg
http://www.youtube.com/watch?v=-NlP2-Sbl9w
http://www.youtube.com/watch?v=bSRC1_OZPIg