Before dawn on April 26, 1986, less than two miles south of what was then a city of 50,000, the Chernobyl Nuclear Power Plant's number four reactor exploded. Amy Daniels, Randi Walker, Erika Palos, Stormy Clary and Ashton Pepple
Plant power decreasing, signifying the start of the reactor shutdown 13:05 Emergency Core Cooling System disconnected, automated regulation system is shut off, power decreased to 30 mwt. 14:00 Power reduction Resumed 23:10
1:00 Increased power to 200mwt by withdrawing rods. 1:07 Two additional recirculation pumps- running. Decreased void All but 6 rods withdrawn Emergency Protection signals blocked by operators.
Increased feed water flow to stream drums Control room printout of core reactivity showed the excess reactivity required immediate shutdown- warning ignored and tests initiated. 1:19 Feed water flow to stream drums decreased to very low value. 30 seconds later reactor inlet temperature begins to rise. 1:22:30
1:23:04 Turbine feed valves closed Power went up 1:23:04 Test was over Operator saw rods moving on core map 1:23:40 Emergency scram initiated by button.
Power increasing rapidly due to positive void coefficient 1:23:43 Explosion occurs followed by a second explosion a few seconds later. This explosion blew the 1,000 ton steel and cement filled biologic shield off the top of the reactor, destroying the roof and exposing the hot core to the atmosphere 1:23:48
1:28 All firemen arrived on the scene 2:00 The largest fires on the roof of the reactor hall were brought under control by a group of Firefighters called in from Pripyat 5:00 Most of the fires were put out, but graphite fire had started, Causing the dispersion of radionuclides high in the atmosphere.
The immediate cause of the Chernobyl accident was a mismanaged electrical-engineering experiment. Engineers with no knowledge of reactor physics were interested to see if they could draw electricity from the turbine generator of the Number 4 reactor unit to run water pumps during an emergency when the turbine was no longer being driven by the reactor but was still spinning initially.
The experiment was delayed due to an electrical demand. The experimenters tried to make up for lost time by lowering the power level rapidly. That mistake caused a rapid buildup of neutron-absorbing fission by products in the reactor core, which poisoned the reaction. To compensate, the opera tors withdrew a majority of the e reactor’s control rods, but even with the rods withdrawn, they were unable to increase the power level
This made the system increasingly unstable and led to the loss of more control rods. They also bypassed most of the safety system which included the emergency core- cooling system. They disconnected the backup electrical system and the diesel generator.
This led to an explosion of reactor Number 4. The explosion was caused by a simple test of the emergency systems to be used in a power failure. Anyone who had any knowledge of nuclear technology would have known that the test program was inherently unsafe.
Control rods had a design flaw that now proved deadly: their tips were made of graphite. The graphite tip went in first, which rather than reduce the reaction, they increased it. The control rods displaced water from the rod channels as well, increasing reactivity further.
The reactor had no sort of containment structure which was a huge design flaw. If there would have been some sort of containment structure, like the ones in the United States, then most likely none of the radioactivity would have escaped, and there would have been no injuries or deaths.
Pripyat evacuated April 27 Announced to the world the reactor was damaged. April 28 Chernobyl evacuated. May 2
The radiation field held the strength for the 10 days that the Chernobyl fire continued, slowly falling off to near background levels by the end of three weeks.
Within a few weeks the radioactive effluents had both diffused and decay to undetectable levels. While the radiation field intensity eventually fell back to normal levels, exposure due to internally deposited radioactive effluents continued to provide a threat to the population.
Hyper Physics Chernobyl section, C.R. Navy, hosted by department of Physics and Astronomy of Georgia State University, 2005. D. Marples, “the Social Impact of the Chernobyl Disaster.” London, 1988, pp. 12-19 Glenn Alan Cheney, “Chernobyl: The Ongoing Story of the World’s Deadliest Nuclear Disaster, “Macmillan, 128pp. New York, 1993. A.P.Hill, “Dose Estimates from the Chernobyl Accident,” ANS Transactions, Winter 1987. R.A. Schlenker, “Internally Deposited Fallout from the Chernobyl Accident, “ANS Transactions, Winter 1987
Stone, Richard. "THE LONG SHADOW OF CHERNOBYL." National Geographic 209.4 (2006): 32. MasterFILE Premier. EBSCO. Web. 28 Feb. 2011. Images provided by Google. www.hc-sc.gc.ca/ewh-semt/occup- travail/radiation/dosim/res-centre/glossary-lexique- eng.php http://www.pbs.org/wgbh/pages/frontline/shows/reacti on/readings/chernobyl.html
While the long term effects of Chernobyl have been devastating to many, the immediate aftermath was completely shocking to those who were immediately affected by the nuclear disaster twenty five years ago.
The mapping of radionuclides over 200,000 square kilometers of Europe, varied by rain and winds.
“This ground is permanently closed.” A week after the explosion in Chernobyl, the city council closed all playgrounds after detecting nuclear radiation levels.
Prypyat, which had 45,000 residents was totally evacuated in the first three days after the incident. Some buildings, including this orphanage and school are still waiting to be clean up.
Agriculture A calf with clef lip born shortly after the disaster Four of the 30 cattle that died in transport to Italy. The remainder were sent back to Poland after showing high levels of radiation.
Destruction of all fresh vegetables which arrived in Italy, Saturday, May 3, 1986 for fear of radioactive contamination. A row of boxes of fresh vegetables lies unsold at Milan's fruit and vegetables general market Saturday, May 03, 1986.
A cow inspecting a radioactive warning sign in Michelstadt, West Germany, May 5, 1986. People emptying milk from the cartons in Berlin, Saturday, May 11, 1986 to protest radioactive levels in milk and other food.
“ An accident has taken place at the Chernobyl power station, and one of the reactors was damaged. Measures are being taken to eliminate the consequences of the accident. Those affected by it are being given assistance. A government commission has been set up.”
Their initial reports of the incident were vague, and were only announced after officials in Sweden, 700 miles away, discovered sharp increases in radiation which appeared to be coming from the Soviet Union.
On the morning of the 28th, official at the Forsmark nuclear plant near Stockholm Sweden were alerted to alarmingly high levels of radiation at their facilities.
Mikail Gorbachev further exacerbated the matter by remaining silent for 18 days, choosing not to speak publicly until 3 weeks after the incident.
As the Soviet remains cloaked in secrecy and silence, the rest of the world prepared for attacks against the world of Nuclear power. The United States The Netherlands Austria West Germany
The first display of Glasnost, the Soviet campaign to forgo secrecy, came in the communist newspaper, Pravda, 10 days after the incident.
Chernobyl Glasnost opened the door for scrutiny of other social and domestic issues.
In September 1986, 600 delegates, including scientist and government officials from 62 nations, met at a conference sponsored by the International Atomic Energy Agency to discuss the incident at Chernobyl.
The conference was not just about Chernobyl, but about the future of Nuclear power throughout the world.
http://www.unscear.org/unscear/en/chernobyl.html http://www.world-nuclear.org/info/chernobyl/inf07.html http://photos.denverpost.com/mediacenter/2011/03/a-look-at-chernobyl-the-worlds-worst-nuclear-accident/#34 www.greenfacts.org/chernobyl http://library.thinkquest.org/3426/data/local-effects/agriculture.effects.html http://www.iaea.org/newscenter/focus/chernobyl/faqs.shtml "Chernobyl Cover-up a Catalyst for â€˜glasnostâ€™ - World News - Europe - Chernobyl Disaster: 20 Years Later - Msnbc.com." Msnbc.com - Breaking News, Science and Tech News, World News, US News, Local News- Msnbc.com. 24 Apr. 2006. Web. 16 Apr. 2011.. Greenwald., John. "5/12/86 DEADLY MELTDOWN." Breaking News, Analysis, Politics, Blogs, News Photos, Video, Tech Reviews - TIME.com. 1996. Web. 16 Apr. 2011.. Greenwald, John. "6/2/86 THE POLITICAL FALLOUT." Breaking News, Analysis, Politics, Blogs, News Photos, Video, Tech Reviews - TIME.com. 1996. Web. 16 Apr. 2011.. Moody, John. "6/30/86 GORBACHEV LOOSENS THE MEDIA'S REINS." Breaking News, Analysis, Politics, Blogs, News Photos, Video, Tech Reviews - TIME.com. Web. 16 Apr. 2011.. Serrill, Michael S. "9/8/86 ''WE ARE STILL NOT SATISFIED''" Breaking News, Analysis, Politics, Blogs, News Photos, Video, Tech Reviews - TIME.com. 1996. Web. 16 Apr. 2011..
Health in Chernobyl The Worldwide effects Progress of the clean up Precautions with nuclear energy The pro’s and con’s of nuclear energy Celeste Raphael, Matt Dahlgren and Drew Short
The Spread of Radiation Nordic Countries Europe The Rest of the World
Richard Balmforth Reuters 10:27 a.m. CDT, April 19, 2011 sns-rt-international-us-uktre73i10e-20110419 “KIEV (Reuters) - World powers, spurred by the nuclear crisis in Japan, on Tuesday pledged 550 million euros ($780 million) to help build a new containment shell at the site of the 1986 Chernobyl accident.”
Melody Thomas, Physics and Human Affairs Instructor NWACC Science and Mathematics/EMPACTS Dr. Art Hobson, Professor Emeritus, U of A Physics Dept. Author: “Physics, Concepts and Connections.” C. Dianne Phillips, NWACC EAST/EMPACTS Facilitator