Effect of Nuclear Reactor Accidents on Modern Nuclear Power Plant Design Eric P. Loewen, Ph.D. Past President American Nuclear Society
April 22, 2013 United States Naval Academy Who? Esquire Magazine, 2009 Why? ANS and professional societies
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What? Our Journey Together Today Stationary Low Power Reactor One (SL-1)
Incidents: Three Mile Island
Chernobyl
Fukushima Fission Energy: Fast and Slow Neutrons Neutron Speeds
6 Challenging Times
Station Land Reactor-One January 3, 1961 SL-1 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 Site SL-1 Reactor Building Section Top of Reactor Afterwards SL-1 Reactor Perspective SL-1 Take-Aways
Design such that one control rod withdrawal will not bring reactor critical Operators are required to monitor the reactor plant New materials have been developed
SL-1 Take-Aways (Cont.)
Cold shut down conditions can lead to higher control rod worth Prompt criticality can disperse fuel at high temperatures in the coolant and cause steam explosions
Movie Break
SNL Metal/Water Experiments
This movie has been donated to the City College of New York. Binding Energy the New Fire
Three Mile Island March 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 plant Institute of Nuclear Power Operation (INPO) started Plant simulator use increased TMI Lessons Learned (Cont.)
Conduct of plant operations formalized Degreed person required in control room Safety systems worked; no one was harmed
U.S. nuclear power operations improved! Controlling binding energy
Chernobyl April 26, 1986
Chernobyl Nuclear Power Plants
Population of Chernobyl was 49,000 Each unit is rated at about 3,200 MWth (four units) Direct-cycle, boiling- water, pressure-tube reactors. Steam is produced within the assembly
Fission Energy: Fast and Slow Neutrons Chernobyl Plant Characteristics
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
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
Chernobyl Lessons Learned
Worst design, operation and accident: 55 killed Challenges from earth
The Sendai Earthquake March 11, 2011 The Event
• The Fukushima nuclear facilities were damaged in a magnitude 9 earthquake on March 11 (2.46pm JST), centered offshore of Sendai region (Tokyo 250km SW). – Plant design base was for magnitude 8.2 earthquake. The magnitude ~9 quake was greater in size. • Serious secondary effects followed including a significantly large tsunami (> factor of 3), significant aftershocks and fires at/from many industrial facilities. • Over 16,000 dead, 4,000 missing, 80,000 homeless limited resources - over 1000sq.km. land excluded
33 Accident Initiation
34 Six BWR units at the Fukushima Nuclear Station: – Unit 1: 439 MWe BWR, 1971 (unit was in operation prior to event) – Unit 2: 760 MWe BWR, 1974 (unit was in operation prior to event) – Unit 3: 760 MWe BWR, 1976 (unit was in operation prior to event) – Unit 4: 760 MWe BWR, 1978 (unit was in outage prior to event) – Unit 5: 760 MWe BWR, 1978 (unit was in outage prior to event) – Unit 6: 1067 MWe BWR, 1979 (unit was in outage prior to event)
Unit 1
35 Fukushima Accident Initiation
36 Overview of Boiling Water Reactor • Typical BWR/3 and BWR/4 Reactor Design • Similarities to BWR/4 Plants in Midwestern US
37 Major Design Parameters for Fukushima Dai-ichi Units 1-4
Unit 1 Unit 2 Unit 3 Unit 4 Commercial operation 1971 1974 1976 1978 Reactor design BWR-3 BWR-4 BWR-4 BWR-4 Rated power (MWe) 460 784 784 784 Thermal power (MWt) 1,380 2,381 2,381 2,381 Isolation cooling system IC RCIC RCIC RCIC
ECCS configuration HPCI (1) HPCI (1) HPCI (1) HPCI (1) ADS ADS ADS ADS CS (4) CS (2) CS (2) CS (2) LPCI (2) LPCI (2) LPCI (2) Primary containment vessel Mark-I Mark-I Mark-I Mark-I
Operation status at the In service In service In service Outage earthquake occurred ↓ ↓ ↓ Shutdown Shutdown Shutdown ECCS: Emergency core cooling system, HPCI: High pressure core injection system, ADS: Automatic depressurization system, CS: Core spray system, LPCI: Low pressure core injection system, IC: Isolation condenser, RCIC: Reactor core isolation cooling system AccidentTimeline Sequence of Major Summary Fukushima Earthquake at 14:46: LOSP Tsunami at 15:41: SBO Damage Sequences IC operating Unit 1 level loss
SC Saturated core damage Sea water injection Containment vent H2 Explosion RCS Repressurizes RCS Depressurized
Unit 3
Level RCIC operating HPCI operating l oss SC Saturated RPV Depressurization Sea water injection Sea water injection ? Core damage ? Containment vents H2 Explosion
Unit 2
RCIC - CST RCIC from suppression pool Level loss SC Saturated RPV Depressurization Sea water injection Fuel damage Containment vent Noise from torus room
Unit 4 (SFP) Explosion in Unit 4
Friday 11 Saturday 12 Sunday 13 Monday 14 Tuesday 15 Wednesday 16
Information39 within this illustration was developed from the INPO 11-005 Special Report and the Report of Japanese Government to IAEA Ministerial Conference on Nuclear Safety – Accident at TEPCO’s Fukushima Nuclear Power Stations – Transmitted by Permanent Mission of Japan to IAEA, June 7, 2011 Loss of four generation units No loss of human life The earth is a dangerous place to live Other Energy Accidents 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.
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