nuclear reactor physics at three mile island and chernobyl eric p

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.