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Risk‐informed design of seismically isolated nuclear power plants
Andrew Whittaker, Ph.D., S.E.Professor
Director, MCEERChair, ASCE Nuclear Standards Committee
Department of Civil, Structural and Environmental Engineering
University at [email protected] 1
Seismic isolation: basis
USNRC Regulatory Information Conference, March 2017 2
Seismic isolation: bearings
USNRC Regulatory Information Conference, March 2017 3
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Seismic isolation: impediments
• Lack of new build nuclear construction
• Technology unfamiliar to nuclear A/E firms– 30 year US history for buildings and infrastructure
• No prior use in US nuclear facilities
– DOE complex or commercial nuclear fleet
• Benefits not quantified
– Now addressed: improved safety and ROM cost
• Lack of risk‐based regulatory guidance– Now addressed: ASCE/SEI Standard 4‐16, 3 NUREG/CRs, MCEER reports, journal
articles
• Lack of analysis tools
– Now addressed: LS‐DYNA, ABAQUS, OpenSees, all V+V’d
• Lack of appropriate SPRA tools– Now addressed: published techniques, ASCE/SEI 4‐16
4
5 10 15 20 25 30Frequency (Hz)
0
0.5
1
1.5
2
2.5
Me
dia
n f
loo
r sp
ect
ral a
cce
lera
tion
(g
)
Model 1
Model 2
Model 3
Model 4
5 10 15 20 25 30Frequency (Hz)
0
1
2
3
4
5
6
7
Me
dia
n f
loo
r sp
ect
ral a
cce
lera
tion
(g
)
201
216
Seismic isolation: risk reduction
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Seismic isolation: cost
0 0.1 0.2 0.3 0.4Ra
0
0.25
0.5
0.75
1
Pro
ba
bili
ty o
f u
na
cce
pta
ble
pe
rfo
rma
nce
Model 2
Model 3
Model 4
0.047
0.12
0.017
0.51
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Seismic isolation: cost
The INL is a U.S. Department of Energy National Laboratory operated by Battelle Energy Alliance
INL/EXT-16-40122
Characterizing the Benefits of Seismic Isolation for Nuclear Structures: A Framework for Risk-Based Decision Making
INL Seismic Research Group
November 2016
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Risk‐based guidance for isolation
• Performance statements• Isolators suffer no damage in the DBE
• Confirm by production testing all isolators
• Isolated facility impacts surrounding structure • 1% NEP for DBE shaking; 10% NEP for BDBE shaking
• Isolators sustain gravity and earthquake induced axial loads at 90%‐ile BDBE displacement
• Confirm by prototype testing
• Safety‐critical umbilical lines sustain 90%‐ile BDBE displacement with 90% confidence
• Confirm by testing and/or analysis
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4
Risk‐based guidance for isolation
USNRC Regulatory Information Conference, March 2017 10
Risk‐based guidance for isolation
• Isolation system and individual isolators– Capacity assumed fully correlated– Demand assumed fully correlated– Redundancy ignored– Lognormal distribution parameters– Variability small for high quality isolators
0 1 2 3 4 50
0.20.40.60.81
m
Pf
Withhardstop
0 1 2 3 4 50
0.2
0.4
0.6
0.81
m
Pf
Withouthardstop
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Risk‐based guidance for isolation
NA SU VO OR HA ID LA DC0
2
4
6
8
10
Site
Annual frequency (x10‐6)
90% confidence/110% EDB GMRS displacement
95% confidence/110% EDB GMRS displacement
99% confidence/110% EDB GMRS displacement
90% confidence/125% EDB GMRS displacement
90% confidence/50% of 110% EDB GMRS displacement for DC
NA SUVO ORHA ID LA DC0
0.2
0.4
0.6
0.8
1
Site
Annual frequency (x10‐6)Without hard stop With hard stop
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Seismic isolation: SMRs and ARs
NuScale, 2016
www.generationmpower.com
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Acknowledgments
• US Nuclear Regulatory Commission– Dr. Jose Pires
– Mr. Ramon Gascot Lozada
• US Department of Energy– Justin Coleman, INL
– Dr. Robert Budnitz, LBNL
• Ms. Chingching Yu, UB
• Professors Manish Kumar2, IITGN and IITB
• Professor Yin‐Nan Huang, NTU
• Dr. Michael Constantinou, UB
• Dr. Annie Kammerer
• Dr. James Johnson
• Dr. Robert Kennedy
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