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Title: Markov Model of Accident Progression at Fukushima Daiichi

Abstract

On March 11, 2011, a magnitude 9.0 earthquake followed by a tsunami caused loss of offsite power and disabled the emergency diesel generators, leading to a prolonged station blackout at the Fukushima Daiichi site. After successful reactor trip for all operating reactors, the inability to remove decay heat over an extended period led to boil-off of the water inventory and fuel uncovery in Units 1-3. A significant amount of metal-water reaction occurred, as evidenced by the quantities of hydrogen generated that led to hydrogen explosions in the auxiliary buildings of the Units 1 & 3, and in the de-fuelled Unit 4. Although it was assumed that extensive fuel damage, including fuel melting, slumping, and relocation was likely to have occurred in the core of the affected reactors, the status of the fuel, vessel, and drywell was uncertain. To understand the possible evolution of the accident conditions at Fukushima Daiichi, a Markov model of the likely state of one of the reactors was constructed and executed under different assumptions regarding system performance and reliability. The Markov approach was selected for several reasons: It is a probabilistic model that provides flexibility in scenario construction and incorporates time dependence of different model states.more » It also readily allows for sensitivity and uncertainty analyses of different failure and repair rates of cooling systems. While the analysis was motivated by a need to gain insight on the course of events for the damaged units at Fukushima Daiichi, the work reported here provides a more general analytical basis for studying and evaluating severe accident evolution over extended periods of time. This work was performed at the request of the U.S. Department of Energy to explore 'what-if' scenarios in the immediate aftermath of the accidents.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
BROOKHAVEN NATIONAL LABORATORY (BNL)
Sponsoring Org.:
AMERICAN NUCLEAR SOCIETY
OSTI Identifier:
1049233
Report Number(s):
BNL-98130-2012-CP
TRN: US1204421
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Conference
Resource Relation:
Conference: 2012 ANS Winter Meeting & Nuclear Technology Expo; San Diego, CA; 20121111 through 20111115
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION; ACCIDENTS; CONSTRUCTION; COOLING SYSTEMS; EARTHQUAKES; EXPLOSIONS; FLEXIBILITY; HYDROGEN; MELTING; MOLTEN METAL-WATER REACTIONS; OUTAGES; PERFORMANCE; RELIABILITY; REPAIR; SENSITIVITY; TIME DEPENDENCE; TSUNAMIS; EMERGENCY PLANS; Fukushima Daiichi; earthquake; Markov Model; reactor vessel

Citation Formats

Cuadra A., Bari R., Cheng, L-Y, Ginsberg, T., Lehner, J., Martinez-Guridi, G., Mubayi, V., Pratt, T., and Yue, M. Markov Model of Accident Progression at Fukushima Daiichi. United States: N. p., 2012. Web.
Cuadra A., Bari R., Cheng, L-Y, Ginsberg, T., Lehner, J., Martinez-Guridi, G., Mubayi, V., Pratt, T., & Yue, M. Markov Model of Accident Progression at Fukushima Daiichi. United States.
Cuadra A., Bari R., Cheng, L-Y, Ginsberg, T., Lehner, J., Martinez-Guridi, G., Mubayi, V., Pratt, T., and Yue, M. Sun . "Markov Model of Accident Progression at Fukushima Daiichi". United States. https://www.osti.gov/servlets/purl/1049233.
@article{osti_1049233,
title = {Markov Model of Accident Progression at Fukushima Daiichi},
author = {Cuadra A. and Bari R. and Cheng, L-Y and Ginsberg, T. and Lehner, J. and Martinez-Guridi, G. and Mubayi, V. and Pratt, T. and Yue, M.},
abstractNote = {On March 11, 2011, a magnitude 9.0 earthquake followed by a tsunami caused loss of offsite power and disabled the emergency diesel generators, leading to a prolonged station blackout at the Fukushima Daiichi site. After successful reactor trip for all operating reactors, the inability to remove decay heat over an extended period led to boil-off of the water inventory and fuel uncovery in Units 1-3. A significant amount of metal-water reaction occurred, as evidenced by the quantities of hydrogen generated that led to hydrogen explosions in the auxiliary buildings of the Units 1 & 3, and in the de-fuelled Unit 4. Although it was assumed that extensive fuel damage, including fuel melting, slumping, and relocation was likely to have occurred in the core of the affected reactors, the status of the fuel, vessel, and drywell was uncertain. To understand the possible evolution of the accident conditions at Fukushima Daiichi, a Markov model of the likely state of one of the reactors was constructed and executed under different assumptions regarding system performance and reliability. The Markov approach was selected for several reasons: It is a probabilistic model that provides flexibility in scenario construction and incorporates time dependence of different model states. It also readily allows for sensitivity and uncertainty analyses of different failure and repair rates of cooling systems. While the analysis was motivated by a need to gain insight on the course of events for the damaged units at Fukushima Daiichi, the work reported here provides a more general analytical basis for studying and evaluating severe accident evolution over extended periods of time. This work was performed at the request of the U.S. Department of Energy to explore 'what-if' scenarios in the immediate aftermath of the accidents.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {11}
}

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