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TRANSCRIPT
1
Preparing for the Nuclear Renaissance: An Overview of Seismic Research and
Regulations at the US NRC
UC Davis Dr. Annie Kammerer, P.E.
January 2008
2
History • Atomic Energy Commission (1954) • Energy Reorganization Act of 1974
– Department of Energy • Nuclear weapons, promotion of nuclear power, care of low-
level radioactive waste, and other energy-related work – Nuclear Regulatory Commission
• Regulation of the civilian uses of nuclear materials including power production, medical and other uses
• Nuclear Non-Proliferation Act of 1978 • Limits the spread of nuclear weapons. Established criteria
governing U.S. nuclear exports licensed by the NRC and strengthened international safeguards system
3
History • 1950s to 1970s US built plants • 1979 Three Mile Island Accident • 1986 Chernobyl Nuclear Disaster • 435 nuclear plants in 30 countries
generating 16% of total power (104 in US) • New financial incentives in US energy
policy
4
Organization Congressional
Oversight
Existing and New Reactor
Licensing
Yucca Mountain
Nuclear Facility Research
Presidential Appointees
5
Regulations
• Code of Federal Regulations • Regulatory Guidance
– Guidance on how regulations are interpreted by NRC staff
– Not required but closely followed by industry (de facto regulations)
• Standard Review Plan – Checklist that regulators use during reviews
• NUREG and NUREG/CR – Reports that provide technical basis
6
New Regulatory Guide 1.208 • “A Performance-Based Approach to Define the
Site-Specific Earthquake Ground Motion” • Safe Shutdown Earthquake Ground Motion (SSE)
– 10,000 year probabilistic motion with design factors – Targets frequency of onset of inelastic behavior
• Operating-Basis Earthquake Ground Motion (OBE) – Half of SSE loading – plant must be closed and inspected
• Soil-Structure-Interaction Guidance under development
7
Certified Plant Design • Standardization of plant designs • Use of certified design spectrum • Site-specific spectrum compared with
certified design spectrum • Floor spectra from SSI used for design of
contents
8
For each spectral frequency
+ + =
9
For each spectral frequency
+ + = Chapter 2 Earth Science & Natural Hazards
Chapter 3 Earthquake Engineering
Cha
pter
4 In
tern
atio
nal A
ctiv
ities
Cha
pter
5 R
egul
ator
y G
uide
s
10
For each spectral frequency
+ + = 2.3
2.4
2.6 2.7
3.1 3.2
2.8 2.10
2.2 2.5
2.9
3.33.43.5
3.6 3.7 3.8 3.11 3.13 3.9
3.10 3.12
Integrated Planning for Multidisciplinary work
11
For each spectral frequency
+ + = 2.3
2.4
2.6 2.7
3.1 3.2
2.8 2.10
2.2 2.5
2.9
3.33.43.5
3.6 3.7 3.8 3.11 3.13 3.9
3.10 3.12
Active (07)
Upcoming (08)
Monitoring (09+)
Awaiting NGA (09+)
Long term (09+)
Long-Term Planning of current and future projects
12
Workshops and “Next Generation” approaches
• NRC initiated early seismic hazard work • Seismic research moving from the development of
individual tools and methods – Different databases, gray literature, proprietary reports,
proprietary software • The now mature field is moving to integration through
workshops, working groups and “next generation” approaches – Common databases & inputs, community consensus,
documentation of thought processes, outliers & uncertainties better understood
13
• Consistent, complete, and agreed upon data sets and information
• All key experts in the research area involved • “Next Generation” implies fundamental
redevelopment of technical tools or approaches
• Both best estimates & estimates of uncertainties
Workshops and “Next Generation” approaches
14
Key Ideas
Wave Passage Effects Scattering Effects
coherency = cross correlation of the phase angles of the Fourier spectra of two motions
Fourier amplitude doesn’t matter
Incoherency Research
15
Scattering
• Function of distance and frequency
• Function of material hardness?
• Only one hard
rock site (w/ multiple events)
16
Pinyon Flat Seismograph Array in Plan View
arrows show seismograph locations
17
Example of Set of Array Data
Anomalous records were removed (See the funny red one?)
18
Updated ITF Model from 12/06 “Common Understanding”
Frequency (Hz)
Coh
eren
cy
Phase angles of Fourier spectra stay coherent
Phase angles of Fourier spectra
are random
19
Structure Stick Model with Outriggers and Offset Mass Centers
• Based on Westinghouse AP1000 Plants
• Outriggers and offset masses explore rocking and torsion
• Sticks linked above foundation
Z
Y
CIS
SCVASB
150'
150'l
l lX
4011 5
NodeNumber Location401 Base of Steel Containment Vessel406 Low on Steel Containment Vessel417 Top of Steel Containment Vessel417out Steel Containment Vessel Outrigger1 Foundation of Auxiliary Shield Building80 Low on Auxiliary Shield Building80mc Low on Auxiliary Shield Building Mass Center120 Top of Auxiliary Building120out Top of Auxiliary Building Outrigger120mc Top of Auxiliary Building Mass Center310 Top of Shield Building310out Shield Building Outrigger5 Base of Containment Internal Structure535 Low on Containment Internal Structure535mc Low on Containment Internal Structure Mass Center538 Top of Containment Internal Structure538out Top of Containment Internal Structure Outrigger538mc Top of Containment Internal Structure Mass Center
l
l
l
l
l
401
406
417 l
80
310 l
417out
120mc
120out
310out
65'
1
l120
-20'
-10'
l5
l75'-10'
-10'
535
538out
535mc
538mc
80mc
-20'
-10'
538
-10'-10'
75'
l
l
l
l
l
l
l
l
SCV
ASB
CIS75'
20
Implementation in SSI
Cross correlation of every foundation node point using
incoherency matrix based on ITF
(includes non-diagonal
elements)
21
Free-Field vs. SSI and Incoherency
Response Spectra, Foundation, x-Direction
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0.1 1 10 100
Frequency (Hz)
Spec
tral
Acc
eler
atio
n (g
)
SSI, Incoherent FIM, x-direction
Fixed Base, x-direction
ITF & SSI
Horizontal Motion
22
Impact of Incoherency in SSI
Response Spectra, Foundation, x-Direction
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0.1 1 10 100
Frequency (Hz)
Spec
tral A
ccel
erat
ion
(g)
SSI, Coherent, x-direction
SSI, Incoherent, x-direction
SSI, Incoherent FIM, x-direction
Fixed Base, x-direction
Horizontal Motion
23
Vertical Translation & Rocking Transfer Functions
Rock Site, 150x150 fdn, Vertical & Rocking
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 10 20 30 40 50 60 70 80Frequency
Inco
here
ncy
Tran
sfer
Fun
ctio
n
CLASSI Vertical Translation CLASSI Translation due to RockingSASSI Vertical Translation SASSI Translation due to Rocking
KEY POINT:
Incoherency increases rocking and rotation in SSI
Is not accounting for incoherency really
conservative?
24
For each spectral frequency
+ + = 2.3
2.4
2.6 2.7
2.8 2.10
2.2 2.5
2.9
Active (07)
Upcoming (08)
Monitoring (09+)
Awaiting NGA (09+)
Long term (09+)
2.2 Mmax (‘07) Key Seismic Zone Updates (‘08) Sensitivity & uncertainty study to address
issues and prioritize research needs (‘08) 2.3 Next Generation Attenuation (NGA-East) (‘07) 2.4 Application of SSHAC Guidelines (‘07)
25
NGA-East Before NGA-West After
1997 Attenuation Relations, SS, M=7, Generic Rock
0.01
0.1
1
1 10 100 1000Distance (km)
Peak
Acc
eler
atio
n (g
)
Boore, Joyner, Fumal
Campbell
Abrahamson and Silva
Sadigh et al.
NGA 2006, SS, M=7, Vs=760
0.01
0.1
1
1 10 100 1000Distance (km)
Peak
Acc
eler
atio
n (g
)
Campbell and BozorginiaChiou and YoungsAbrahamson and SilvaBoore and Atkinson
• Went from ad hoc relationship development to unified approach
• Mutually agreed upon databases, technical bases & assumptions
• Epistemic uncertainties reduced and characterized
• Broad community consensus (removed points of contention)
26
NGA-East • Follows up on original NGA project • Previous lack of systematic, integrated evaluation of
existing models and new data • Approach
– Standard agreed upon assumptions – Standard and complete database – Development program first to scope project and bring in
multiple agencies – Cooperative agreement – USGS in-kind participation in development project
• Currently doing preliminary work – Technical Basis for assumptions – Development of earthquake record database
27
Mmax Workshop
• Mmax is largest magnitude for a source • Issue for area sources in CEUS for long
return periods • Limited technical basis due to lack of systematic,
integrated evaluation of existing models and new data • Follows “best practices” for seismic workshops
– Sensitivity study – Foundation document compiled & sent to participants before
workshop for review. Also downloadable at USGS. – All key researchers sponsored, but open to anyone
• Results incorporated into USGS database
28
Northeast (NESZ)
Charleston (CSZ)
Eastern Tennessee
(ETSZ)
New Madrid (NMSZ)
Key Seismic Zone Updates
29
SSHAC Guidelines
• “Recommendations for PSHA: Guidance on Uncertainty and Use of Experts” NUREG/CR-6372
• Senior Seismic Hazard Analysis Committee (SSHAC) sponsored by NRC, DOE & EPRI
• Need practical recommendations on how to apply and how to update
• General framework but limited practical details • Much has been learned in trying to apply SSHAC
– Yucca Mountain (two level 4s – seismic and volcano) – PEGASOS (level 4) – EPRI (level 3)
30
3.1 3.2
3.1 Random Vibration Theory 3.2 Site response methods
• Multiple methods accepted in NUREG 6728 – Theoretical framework but
few details – Only recently used – Implementation differs
between practitioners – Focus on better
understanding
• Multiple modeling tools currently in use – Non-linear, SHAKE, and RVT
methods – Comparison of methods – Developing public RVT
software with PEER Active Projects
31
Tsunami Hazard Research
• Collect existing data • Investigate seismic sources • Map past landslides • Examine past landslides in
geological context • Model past landslides • Map areas for potential future slides
32
Data Collection
33
Past Landslides
34
Past Landslides
35
Tsunami Model of Slide H
eigh
t (m
)
-20
-1
0
0
10
2
0
-200 -100 0 100 200
Distance (km)
36
Debris Thickness
37
Seismic Sources
Puerto Rico
38
Generation and Propagation Modeling
39
US Tsunami Mapping?
40
NRC/USGS Collaborative Program
• NGA East Program Development • Inter-plate Mmax workshops • East Tennessee Seismic Zone Studies • PSHA Epsilon values
41
Integrated PSHA & Site Response
Find effects of all possible earthquakes, weight each by the likelihood will actually
happen in a given year, combine the events
For each spectral frequency
42
Integrated PSHA & Site Response
Integration of Site
Response
For each spectral frequency
• What is the best method?
• When does it matter?
• How do we increase availability of software & knowledge?
43
NRC Research: CAV Filtering
0
1
2
0.1 1 10 100Frequency (Hz)
Spec
tral A
ccel
erat
ion
(g)
Mean Rock UHRS 1 E-6/yr
• Cumulative Absolute Velocity
• Better predictor of damage than peak acceleration
• Removes quakes too short to cause damage
44
Questions?