Chernobyl25 years

Physics and Human Affairs, EMPACTS Project

NorthWest Arkansas Community CollegeMelody Thomas, Instructor

Science and Construction of Chernobyl

Steven Thomas and Zac Colvin

Nuclear Fission

Splitting of one atom into two

Nuclear-pertaining to the nucleus

Accelerated Neutron

Uranium

92nd ElementTwo natural

isotopes

Video on Nuclear Fission

http://www.youtube.com/watch?v=G1jtWR_tcX4

How a Nuclear Plant Works

Steam Generation.

Turbines produce electricity.

Chernobyl Construction

4 RBMK reactors completed between 1970 and 198322 square kilometer artificial lake115000-130000 people lived within a 30 km radius

RBMK-1000Graphite Moderated Reactor1970’s design with flaws

Positive Void Coefficient

Build up in steam bubbles (voids) lead to increase in temperature.

Power builds to 100 times normal capacity

Operating Reactivity Margin

Bare minimum safety regulations were met.

Positive Scram Effect.

Sourceshttp://science.howstuffworks.com/nuclear-p

ower1.htmhttp://www.youtube.com/watch?v=G1jtWR_

tcX4https://www.britannica.com/EBchecked/topi

c-art/421629/19492/Sequence-of-events-in-the-fission-of-a-uranium-nucleus

http://www.world-nuclear.org/info/chernobyl/inf07.html

http://nuclearinfo.net/Nuclearpower/TheScienceOfNuclearPower

ChernobylBefore 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

Events Leading up to the disaster of April 26,

1986

•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 Resumed23:10

April 26, 1986

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withdrawn• Emergency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.

Leading up to the Accident• 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

Things continuing to decline

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.

The Moment before and of the Explosion

• Power increasing rapidly due to positive void coefficient1:23:

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

The Moments after

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.

What Went Wrong 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.

What Went Wrong 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 operators withdrew a majority of the e reactor’s control rods, but even with the rods withdrawn, they were unable to increase the power level

What went wrongThis 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.

Explosion!

Contributing Factors

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.

Faulty Reactor DesignThe 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.

The Days Following:

•Pripyat evacuatedApril 27•Announced to the

world the reactor was damaged.

April 28

•Chernobyl evacuated.

May 2

Radiation Fallout

http://www.youtube.com/watch?v=9_Mj5IbXwW0&feature=youtu.be

Radiation PatternThe 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.

Radiation PatternsWithin 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.

References•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

References: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/reaction/readings/chernobyl.html

India Dujay, Katie Drake, and Mary Beth Teufel

Short Term Affects of Chernobyl

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.

Environmental Affects The mapping of radionuclides over 200,000

square kilometers of Europe, varied by rain and winds.

Health Concerns & Relocation

“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

disasterFour 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.

Disaster Reports Delayed

“ 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.”

What forced them to speak?

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.

Further Bureaucratic Silence

Mikail Gorbachev further exacerbated the matter by remaining silent for 18 days, choosing not to speak publicly until 3 weeks after the incident.

Political Fallout Across The Map

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 StatesThe Netherlands AustriaWest Germany

Silence is Lifted 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.

62 Nation International Cooperation

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.

References 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-wo

rst-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 ‘glasnost’ - 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. <http://www.msnbc.msn.com/id/12403612/ns/world_news-europe/>.

Greenwald., John. "5/12/86 DEADLY MELTDOWN." Breaking News, Analysis, Politics, Blogs, News Photos, Video, Tech Reviews - TIME.com. 1996. Web. 16 Apr. 2011. <http://www.time.com/time/daily/chernobyl/860512.cover.html>.

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. <http://www.time.com/time/daily/chernobyl/860602.polfallout.html>.

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. <http://www.time.com/time/daily/chernobyl/860630.sovpress.html>.

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. <http://www.time.com/time/daily/chernobyl/860908.convention.html>.

The Long Term Effects of Chernobyl

• 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

Worldwide effects

The Spread of

Radiation

Nordic Countries

Europe

The Rest of the World

Progress of the clean up

New Containment Structure

Pripyat—Ghost Town

The Exclusion Zone

Pripyat School—25 years later

Precautions with Nuclear Energy

Rod Standards Minimum

Emergency Cooling

Redundant Backups

Reactor #4—Site of the Fatal Mistake that Caused the Disaster.

Pro’s of Nuclear Energy

Little Pollution

Reliability

Safety

Con’s of Nuclear Energy

Waste disposal

Meltdowns

Health in Chernobyl

Teams of Doctors Help Out

No Government Support for Returnees

Better to Die at Home than in a Strange Place

This Week at ChernobylRichard 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.”

Acknowledgments

Melody Thomas, Physics and Human Affairs InstructorNWACC 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

Dr. Art Hobson