City College of New York
NUCLEAR REACTOR PHYSICS AT
THREE MILE ISLAND AND CHERNOBYLEric P. Loewen, Ph.D.
VP/President-Elect American Nuclear Society
February 17, 2011
About ANS
Professional organization of engineers and scientists devoted to the applications of nuclear science and technology11,500 members come from diverse technical backgroundsDedicated to improving the lives of the world community within government, academia, research laboratories and private industry
AMEX August 15, 2007
Esquire Magazine, 2009
Times Square, 2010
The American Nuclear Society
Challenging Times
Incidents:
Stationary Low Power Reactor One (SL-1)
Three Mile Island
Chernobyl
Fission Energy: Fast and Slow Neutrons
Challenging Times
Station Land Reactor-OneJanuary 3, 1961
Movie Break
AEC SL-1 Movie
This movie has been donated to the City College of New York.
SL-1 Site
SL-1 Reactor Building Section
Top of Reactor Afterwards
SL-1 Reactor Perspective
United States Army experimental nuclear power reactor 3 MWt (200 kWe) January 3, 1961 underwent a steam explosion and meltdown Removal of single control rod caused reactor to go prompt critical Power jumped to 20 GW in 4 minutes
SL-1
Design such that one control rod withdrawal will not bring reactor critical Operators are required to monitor the reactor plantNew materials have been developed
SL-1 Take-Aways
Cold shut down conditions can lead to higher control rod worthPrompt criticality can disperse fuel at high temperatures in the coolant and cause steam explosions
SL-1 Take-Aways (Cont.)
Movie Break
SNLMetal/WaterExperiments
This movie has been donated to the City College of New York.
Challenging Times
Three Mile IslandMarch 27, 1979
Fission Energy: Fast and Slow Neutrons
Pressurized Water Reactor
Simplified PWR Showing Three Mile Island Release Paths
TMI Lessons Learned
Industry is only as strong as the weakest plantInstitute of Nuclear Power Operation (INPO) started Plant simulator use increased
TMI Lessons Learned (Cont.)
Conduct of plant operations formalizedDegreed person required in control roomSafety systems worked; no one was harmed
Challenging Times
ChernobylApril 26, 1986
Fission Energy: Fast and Slow Neutrons
Chernobyl Nuclear Power Plants
Population of Chernobyl was 49,000Each unit is rated at about 3,200 MWth (four units)Direct-cycle, boiling-water, pressure-tube reactors. Steam is produced within the assembly
The reactor fuel rods (~1,700) are each contained in individual zircaloy pressure tubes embedded in a matrix of graphite blocks
Each pressure tube contains 18 zircaloy-clad UO2
fuel pins, enriched to 1.8% U-235
Reactor is 40 feet in diameter and 26 feet high
On-line refueling at a rate of about one assembly/day
Chernobyl Plant Characteristics
USSR RBMK – 1000
Final Scenario
1:23:02 Test begins at reactor power of 200 MWth.
1:23:04 Power in the reactor increases (500 MWth) due to void buildup and pressure increases; eight reactor coolant pumps still operating.
1:23:31 Operator manually initiates reactor scram, but it is too late, since 15-20 seconds are required for control rod insertion.
Seconds Later
1:23:40 Reactor is now on a high power, short period ramp, and reactor power reaches 110% normal (estimate).
1:23:43 Doppler feedback curtails first burst.
At the End
1:23:44 Second rector excursion to four times normal (estimate). (Fuel in channels, void complete, flow blocked.)
1:23:45 Pressure falls and reactor coolant pump flow returns to core; two audible/visible explosions observed.
Aftermath
Reactor shield block destroyed and all 1,700 pressure tubes severed
The audible explosions caused by a succession of events in sequence: Transient overpower reactor excursion Loss of flow Fuel-coolant interaction Hydrogen production Hydrogen combustion
Aftermath, continued
Fuel hydrodynamic dispersal occurred, and eventual melting and slumping of remainder of fuel took hours The graphite fire followed all of these rapid events and contributed to the long-term radioactivity release
Chernobyl Lessons Learned
Movie Break
SPERT EXPERIMENTS
This movie has been donated to the City College of New York.
Other Energy
Accidents
Other Energy Accidents: Oil
An explosion and fire ruptured a pipeline between an oil tanker and a PetroChina facility in China’s Dalian port in the Liaoning province, releasing an estimated 315,000 to 365,000 barrels of oil into the Yellow Sea. Photo courtesy of Imaginechina/Zumapress.com
Other Energy Accidents: Gas
A natural gas pipeline exploded, setting off a blaze that destroyed a San Bruno, California neighborhood, killing eight people and wrecking 37 homes. Photo courtesy of Dan Honda/Zuma Press
Other Energy Accidents: Coal
Twenty-nine miners died after an explosion at the Pike River coal mine in New Zealand on November 19. Photo: Xinhua/Zumapress.com
Other Energy Accidents: Wind
Windmill on fire in Palm Springs, California. Photo courtesy of Metacafe.com.
Other Energy Accidents: Oil
Off shore oil rig explosion off the Louisiana coast takes 11 lives. Photo courtesy of UPI.
Other Energy Accidents: Hydro
Sayano–Shushenskaya hydroelectric power station accident in Russia take 76 lives. Photo courtesy of the Daily Mail.
What Now?
Join ANS!
Thank You!
For more information contact the ANS Public Outreach department at 800-323-3044 or visit
ww.ans.org.
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