EPRI MRP Research on Irradiation Effects on PWR Internals Materials NRC-ANL Meeting

EPRI MRP Research on
Irradiation Effects on
PWR Internals Materials
NRC-ANL Meeting
September 25-26, 2007
H. T. Tang
EPRI
MRP Internals Program Development Time Line Summary
1999 - 2000
1999 - 2003
Owners
Groups
© 2007 Electric Power Research Institute, Inc. All rights reserved.
1999 - 2007
EPRI
2006 - 2008
2005 - 2007
Utility,
EPRI,
NEI
EPRI,
Utilities
2
2009
Cracked Baffle/Former Bolts
Crack
N° 1
© 2007 Electric Power Research Institute, Inc. All rights reserved.
3
MRP PWR Internals Testing Projects –
Objectives
•
Characterize irradiated PWR internals materials properties
– Mechanical Property
– IASCC Susceptibility
– IASCC Initiation/Growth
– Fracture Toughness
– Microstructure/Void swelling
– Thermal Aging/Irradiation Embrittlement Synergism (CASS)
– Stress Relaxation/Creep
•
Develop irradiated materials screening criteria, material
constitutive equation and damage threshold – for
functionality/safety analysis and I&E Guidelines Development
© 2007 Electric Power Research Institute, Inc. All rights reserved.
4
IASCC Initiation –
Functional Parameters
• Radiation
• Stress
• Time
• Temperature
• Environment
• Materials
© 2007 Electric Power Research Institute, Inc. All rights reserved.
5
Dpa Distribution Example
Former Elevation 4
Location
A
B
C
D
© 2007 Electric Power Research Institute, Inc. All rights reserved.
N eutron Fluence (E >
1.0 MeV)
[n/cm 2]
1.69e+22
9.37e+22
1.34e+22
6.70e+22
Atom D isplacements
[dpa]
24.7
136
19.7
97.3
6
Reactor Spectrum Profiles
© 2007 Electric Power Research Institute, Inc. All rights reserved.
7
MRP PWR Internals Testing Projects
•
•
•
•
•
•
International IASCC Project
GONDOLE Void Swelling Experiment
Halden Crack Growth Project
BORIS 7 Irradiated Materials Testing – Completed
Decommissioned PWR Materials Testing – Completed
JOBB Program – Completed
© 2007 Electric Power Research Institute, Inc. All rights reserved.
8
Program Materials
Program
Alloy
Component
US Baffle-Former
bolts
CW316 SS
Baffleformer bolts
Baffleformer bolts
347SA SS
CW304 SS
International
IASCC Adv. Com.
Decommissioned
304 SS
JOBB/MRP
PWR
CW316 SS
Lock bars &
washers
BMI thimble
PWR
CW 316 SS
Bar
BOR60
304SA SS
Baffle
PWR
304SA SS
Former
PWR
304SA SS
Barrel
PWR
304SA SS
Baffleformer bolts
PWR bolting
PWR
Baffleformer bolts
Core barrel
weld
PWR bolting
BOR60
CW316 SS-W
304SA SS- FTI
308 SS WeldFTI
347SA SS-W
© 2007 Electric Power Research Institute, Inc. All rights reserved.
Irradiation
Source
PWR
PWR
BOR60
BOR60
BOR60
Irradiation
environment
Water
8-15 dpa
Water
2-21 dpa
Water
20 dpa
Water
01-65 dpa
Sodium
0, 20, 40 dpa
Water
0-23 dpa
Water
0-18 dpa
Water
0-0.07 dpa
Water
0-23 dpa
Sodium
0, 20 dpa
Sodium
0, 20 dpa
Sodium
0, 20 dpa
Sodium
0, 20 dpa
9
Hot Cell Testing
Program
Alloy
Component
Tensile
Fracture
Toughness
SSRT
US B-F bolts
CW316 SS
x
x
x
x
x
x
CW304 SS
CW316 SS
Baffleformer bolts
Baffleformer bolts
Lock bars
BMI thimble
x
x
x
x
x
x
CW 316 SS
304SA SS
Bar
Baffle
x
x
x
x
x
x
304SA SS
304SA SS
304SA SS
Former
Barrel
Baffleformer bolts
Baffleformer bolts
Baffleformer bolts
Core barrel
weld
Baffleformer bolts
x
x
x
347SA SS
International
IASCC Adv. Com.
Decommissioned
304 SS
MRP - Bor-60
Irradiation
CW316 SS-W
304SA SS- FTI
308 SS WeldFTI
347SA SS-W
© 2007 Electric Power Research Institute, Inc. All rights reserved.
x
x
x
Crack
Crack
initiation growth
rate
x
x
x
x
x
x
x
x
x
x
x
x
x
Microstructure
/swelling
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
10
PWR Internals Testing Projects
•
•
•
•
•
•
International IASCC Project
GONDOLE Void Swelling Experiment
Halden Crack Growth Project
BORIS 7 Irradiated Materials Testing
Decommissioned PWR Materials Testing
JOBB Program
© 2007 Electric Power Research Institute, Inc. All rights reserved.
11
International IASCC Advisory Committee
Project – International Cofunding
•
Goals
– To quantify mechanical and corrosion properties of highly PWR
spectrum irradiated PWR internals materials
• Tensile
• Crack initiation (IASCC)
• Microstructure
– To provide database and crack initiation model for PWR internals
long-term operation functionality analysis
•
Status
– Phases 1, 2 and 3 completed; Phase 4 being proposed
•
Project Materials
– Thimble tubes from PWRs
– Samples from decommissioned Zorita – Phase 4 Program
© 2007 Electric Power Research Institute, Inc. All rights reserved.
12
Thimbles Tested in Phase 3
80
76
Ringhals
Beaver Valley
Robinson
dpa
60
51
40
31
20
0
0
Thimble Tip
25
Top of Active Fuel
(5.2")
© 2007 Electric Power Research Institute, Inc. All rights reserved.
50
75
100
Distance from Thimble Tip, inches
125
150
Bottom of Active Fuel
(149.2")
13
Beaver Valley Thimble Sections
BV-1B
1 to 38 dpa
BV-2B
51 to 51 dpa
BV-3B
1 to 38 dpa
© 2007 Electric Power Research Institute, Inc. All rights reserved.
14
dpa Ranges for Individual Thimble
Sections
Plant
Beaver Valley
Unit 1
H. B. Robinson
Unit 2
Ringhals
Unit 2
Section Length
Thimble
Section ID
inches
cm
BV-1B
17.40
44.2
BV-2B
14.50
BV-3B
dpa Change over
Section Length
dpa
Range
per inch
per cm
1 to 38
2.1
0.8
36.8
51 to 51
0
0
17.00
43.2
1 to 38
2.2
0.9
HBR-9B
5.98
15.2
17 to 22
0.8
0.3
HBR-10A
17.01
43.2
26 to 30
0.2
0.09
RG-1
9.45
24.0
9 to 50
4.3
1.7
RG-2
9.50
24.1
76 to 76
0
0
RG-3
4.25
10.8
52 to 61
2.1
0.8
RG-4
5.65
14.4
29 to 52
4.1
1.6
© 2007 Electric Power Research Institute, Inc. All rights reserved.
15
O-Ring Stress State
© 2007 Electric Power Research Institute, Inc. All rights reserved.
16
Crack Initiation Model based on Phases 2
and 3 Results
120%
Chooz A
Failures
Non-Failures
Barsback
Bugey 2
% of Irradiated Yield Strength
100%
80%
Failures
stress threshold
60%
Non-Failures
40%
Functionality
Analysis
Curve
20%
0%
0
10
20
30
40
50
60
70
80
dpa
© 2007 Electric Power Research Institute, Inc. All rights reserved.
17
Phase 4 Proposed Program
•
Test highly irradiated PWR internals harvested from Zorita, a
decommissioned Spanish PWR
– Maximum fluence ~ 58 dpa
– 304SS, 316SS, 347SS, Inconel-X750, Inconel-600, CF8 Cast
Austenitic
• Mechanical properties
• IASCC Crack Initiation/Growth
• Fracture toughness
• Void Swelling
•
Provide needed highly PWR irradiated materials data
Program is planned for 2008 to 2010 pending materials samples
harvesting, scope definition and international cofunding
© 2007 Electric Power Research Institute, Inc. All rights reserved.
18
Zorita Plant
• PWR – decommissioned
• 160 MWe 1 Loop
• Initial criticality: 06·1968
Commercial start: 02·1969
• 38 years of operation (26
EFPY)
• Highest fluence regions ~
58 dpa
José Cabrera (Zorita) Nuclear Power Plant
Photograph courtesy of Foro Nuclear
© 2007 Electric Power Research Institute, Inc. All rights reserved.
19
Prospective Phase 4 Cofunding Members
• Japan
– Kyushu Electric Power Co.
– Shikoku Electric Power Co.
– Hokkaido Electric Power Co.
• Europe
– NOK
– TRACTEBEL Engineering
– VATTENFALL/RINGHALS AB
• US
– EPRI
– NRC (Materials Samples Harvesting and Shipping)
© 2007 Electric Power Research Institute, Inc. All rights reserved.
20
MRP PWR Internals Testing Projects
•
•
•
•
•
•
International IASCC Project
GONDOLE Void Swelling Experiment
Halden Crack Growth Project
BORIS 7 Irradiated Materials Testing
Decommissioned PWR Materials Testing
JOBB Program
© 2007 Electric Power Research Institute, Inc. All rights reserved.
21
GONDOLE Experiment in Osiris Reactor
(CEA Saclay) for Swelling Assessment
• Goals
– To quantify void swelling of PWR spectrum irradiated PWR
internals materials
– To provide database and void swelling model for PWR
internals long-term operation functionality analysis
• Approach
– Irradiate PWR internals materials in mixed spectrum Osiris
reactor
• Project Materials
– Virgin PWR internals materials
– Pre-irradiated materials
• Status
– Ongoing (2004-2011)
© 2007 Electric Power Research Institute, Inc. All rights reserved.
22
Background
SA304SS > SA316SS > CW316SS
SA
304SS
% Swelling
SA
316SS
CW
316SS
Irradiation Dose, dpa
304SA at 1.4E-8 dpa/s
0.020
300C
0.018
320C
340C
0.016
360C
380C
0.014
Volumetric Swelling
• Limited PWR data show very small
swelling (low dose CW316, SA304
and SA347)
• Fast reactor data, many from nonPWR type of materials, show
significant void swelling under high
dose and temperature conditions
• 304 appears to swell more that 316
• Swelling is coupled with state of creep
and stress relaxation
• Need PWR spectrum high dose and
high temperature swelling data to
develop PWR applicable void swelling
models
Typical Swelling Response for Stainless
Steels at Breeder Reactor Temperatures
400C
0.012
0.010
0.008
0.006
0.004
0.002
0.000
0
2
4
6
8
10
Time (years)
© 2007 Electric Power Research Institute, Inc. All rights reserved.
23
12
14
16
18
20
GONDOLE Scope
• Collect available virgin and irradiated materials
• Prepare material samples
– TEM
– Density
– Temperature variation
• Irradiate samples in the Osiris test reactor (mixed
spectrum)
• Evaluate results
• Develop void swelling model
© 2007 Electric Power Research Institute, Inc. All rights reserved.
24
GONDOLE Experiment Conditions
‰ Temperature
360°C - 400°C
‰ Damage dose per year
3.5 dpa + measurements
4.5 dpa without unloading
‰ max dose: 15 dpa
© 2007 Electric Power Research Institute, Inc. All rights reserved.
‰ Unirradiated materials
SA / CW 304 and 316
Weld Materials, ….
‰ Materials already
irradiated with mixed
spectrum
25
GONDOLE Experiment Swelling
Specimens
‰ Density
Irradiated and unirradiated
• Weight ≈ 0.5 g
thickness ≈ 1.5 mm
or
• Swelling measurements
‰ Discs φ 3 mm
Irradiated and unirradiated
• Microstructure
• Small Punch Test + Micro-hardness
• Swelling
‰ Specimens with thermal gradient (flux gradient)
Unirradiated
1 or 2
SA 304 or CW 316
‰ Temperature
360°C - 400°C
‰ Damage dose per year
3.5 dpa + measurements
4.5 dpa without unloading
"Representative" of the
baffle plate or bolt
‰ max dose: 15 dpa
© 2007 Electric Power Research Institute, Inc. All rights reserved.
26
PWR Internals Testing Projects
•
•
•
•
•
•
•
Overview
International IASCC Project
GONDOLE Void Swelling Experiment
Halden Crack Growth Project
BOR 60 Irradiated Materials Testing
Decommissioned PWR Materials Testing
JOBB Program
© 2007 Electric Power Research Institute, Inc. All rights reserved.
27
Halden Crack Growth Test in PWR
Environment
• Obtain in-pile, long term, crack
growth data under PWR
operating conditions (active flux
environment)
• Test specimens from preirradiated materials harvested
from PWR and BWR (LWR
irradiated)
• Cofunded by BWRVIP and FRP
• Year to year commitment
pending testing scope and
cofunding from BWRVIP and
FRP
© 2007 Electric Power Research Institute, Inc. All rights reserved.
Outlet thermocouples
Fe/Fe 3 O4 electrode
Test Setup
2 Pt electrodes
Displacement Gauge
Irradiated insert: 304 SS
Fluence: ~9.0 x 10
21
n/cm
2
Booster rod
Irradiated insert: 347 SS
Fluence: ~1.5 x 10
21
n/cm
2
Irradiated insert: 347 SS
Fluence: ~1.5 x 10
21
n/cm
2
GT
ND
Irradiated insert: 316 NG
Fluence: ~0.9 x 10
21
n/cm
2
Pt electrode
Inlet thermocouples
28
Materials Samples
© 2007 Electric Power Research Institute, Inc. All rights reserved.
29
Crack Growth vs. Yield Strength
© 2007 Electric Power Research Institute, Inc. All rights reserved.
30
PWR Internals Testing Projects
•
•
•
•
•
•
•
Overview
International IASCC Project
GONDOLE Void Swelling Experiment
Halden Crack Growth Project
BOR 60 Irradiated Materials Testing
Decommissioned PWR Materials Testing
JOBB Program
© 2007 Electric Power Research Institute, Inc. All rights reserved.
31
BOR-60 Irradiated Materials Testing
•
Goals
– To quantify mechanical and corrosion properties of fast reactor
spectrum irradiated PWR internals materials (accelerated irradiation
testing)
• Tensile
• Fracture Toughness
• Crack initiation
• Microstructure
– To provide database and predictive equations for PWR internals longterm operation functionality analysis
•
Approach
– Irradiate representative PWR Internals materials samples in BOR-60
•
Project Materials
–
–
–
–
SA 304L Baffle plates, Formers, Core barrel
CW 316, 347 Baffle bolts
308 Welds, 304 HAZ
CASS
© 2007 Electric Power Research Institute, Inc. All rights reserved.
32
JOBB Materials in BOR 60 - Boris 6 & 7
Materials
Specimen
type
5 dpa
308 TIG/MIG
weld and 304
HAZ
(CE)
304 SA and CW
(CE)
Tensile
O-ring
CT
3mm disc
Tensile
O-ring
CT
3mm disc
Tensile
O-ring
CT
3mm disc
Tensile
O-ring
CT
3mm disc
12
2
1
16
6
1
0
8
0
0
0
0
19
5
6
24
316 two heats
(W, EDF)
Cast austenitic –
as-received &
two levels of
thermal aging*
(W)
10 dpa 20 dpa 40 dpa
9
2
2
16
12
2
1
16
12
3
0
16
13
3
6
24
15
4
2
16
14
3
2
16
7
3
0
16
0
0
0
0
*400 oC for 100 and 1000 hours
© 2007 Electric Power Research Institute, Inc. All rights reserved.
33
4
0
0
16
5
2
2
16
5
1
0
16
0
0
0
0
Fracture Toughness Testing
• CT specimens
– B: 5mm, W: 20mm
– 304 SS & 308 SS
– irradiated in BOR-60 fast reactor to
6-48 dpa
• 8 specimens precracked at RT
– 7 tested @ 320 °C
– 1 tested @ RT
© 2007 Electric Power Research Institute, Inc. All rights reserved.
34
BOR-60 Fracture Toughness Testing
Summary
• 8 Specimens Tested
– 304 SA: 6, 26, 26 and 48 dpa
– 304 CW: 26 and 47 dpa
– 308 Weld: 26 and 45 dpa
• Results
– 304 SA & 304 CW: toughness remaining high at high fluence when
tested at 320°C
– 304 SA: low toughness at high fluence when tested at RT
– 308 Weld: low toughness at high fluence when tested at 320°C
– Results are bound by lower bound curve defined for evaluation
assessment
• Low Temperature Intergranular Fracture
– Observed in room temperature toughness test
– Observed in all 304 SS precracks
© 2007 Electric Power Research Institute, Inc. All rights reserved.
35
BOR-60 Crack Initiation Tests (O-rings)
Specimen
Number
Material
/Code
Fluence
(dpa)
Test
Temp.
(°C)
Targeted
Test
Stress
YS at
330C
(MPa)
Applied
Test
Stress
(MPa)
45
340
Y.S.
970
976
J5-41
316CW
J1-44
308/J1
25.7
340
Y.S.
800
806
J7-44
304SA/J7
48.1
340
Y.S.
800
803
J2-43
HAZ
25
340
Y.S.
800
807
© 2007 Electric Power Research Institute, Inc. All rights reserved.
36
PWR Internals Testing Projects
•
•
•
•
•
International IASCC Project
GONDOLE Void Swelling Experiment
Halden Crack Growth Project
BOR 60 Irradiated Materials Testing
Decommissioned PWR Materials Testing –
Completed
• JOBB Program
© 2007 Electric Power Research Institute, Inc. All rights reserved.
37
Baffle/Former Plate Sample Locations –
SA304
Top of the upper baffle
Upper Baffle
3
2
Lower region of the
upper baffle
1 4
Core former location
© 2007 Electric Power Research Institute, Inc. All rights reserved.
38
Core Barrel Sample Location
44”
324°
© 2007 Electric Power Research Institute, Inc. All rights reserved.
39
Material Sample Dimensions
Component
Barrel
Baffle 1
Baffle 2
Baffle 3
Baffle 4
Former
© 2007 Electric Power Research Institute, Inc. All rights reserved.
Length
in (cm)
Thickness
in (cm)
Width
in (cm)
7.4
1.714
6.97
(-18.8)
(-4.354)
(-17.7)
7.59
(-19.28)
7.71
(-19.58)
7.68
(-19.51)
7.93
(-20.14)
5
(-12.7)
0.499
(-1.276)
0.501
(-1.273)
0.501
(-1.273)
0.502
(-1.275)
1.022
(-2.596)
1.36
(-3.45)
1.39
(-3.53)
1.48
(-3.76)
1.43
(-3.63)
5
(-12.7)
40
Specimen Cutting
½T-CT
© 2007 Electric Power Research Institute, Inc. All rights reserved.
41
Radiation Analysis
• 3D discrete ordinates transport code (TORT ORNL)
• BUGLE-96 cross-section library (47 neutron
and 20 gamma ray energy groups)
• Three statepoints: BOL, MOL, and EOL.
© 2007 Electric Power Research Institute, Inc. All rights reserved.
42
Radiation Analysis
Baffle Plate Results - Midplane
Macroscopic Sample Data from Decomissioned PWR Core Midplane XYZ TORT
Fast (E > 1.0 MeV) Neutron Fluence and Stainless Steel 304 dpa
Baffle Plate - Right
Core Side Surface
Point
Phi
dpa
1
1.5E+22
21.4
2
8.2E+21
11.9
3
1.5E+22
21.4
4
8.2E+21
11.9
Middle of Plate
Point
Phi
1
1.3E+22
2
6.9E+21
3
1.3E+22
4
6.9E+21
dpa
19.2
10.1
19.2
10.1
Back Side Surface
Point
Phi
dpa
1
1.2E+22
17.3
2
5.7E+21
8.4
3
1.2E+22
17.3
4
5.7E+21
8.4
Looking at Sample from Core Side of Sample
© 2007 Electric Power Research Institute, Inc. All rights reserved.
Pnt 3
Pnt 4
Pnt 1
Pnt 2
43
Radiation Analysis
Former Plate Results - Midplane
Macroscopic Sample Data from Decomissioned PWR Core Midplane XYZ TORT
Fast (E > 1.0 MeV) Neutron Fluence and Stainless Steel 304 dpa
Former Plate 3 - Inner Corner Sample
Bottom Surface
Point
Phi
1
1.2E+22
2
3.5E+21
3
4.2E+21
4
7.5E+21
dpa
18.1
5.3
6.3
11.1
Middle of Plate
Point
Phi
1
1.2E+22
2
3.6E+21
3
4.4E+21
4
7.7E+21
dpa
18.4
5.5
6.4
11.4
Top Surface
Point
Phi
1
1.2E+22
2
3.5E+21
3
4.2E+21
4
7.5E+21
Looking Down at Sample from Above
Pnt 3
Pnt 4
Pnt 2
Pnt 1
© 2007 Electric Power Research Institute, Inc. All rights reserved.
44
dpa
18.2
5.3
6.3
11.1
Thermal Analysis
Typical Heat Generation Rate
© 2007 Electric Power Research Institute, Inc. All rights reserved.
45
Hot Cell Testing
Program
Alloy
Component
Tensile
Fracture
Toughness
SSRT
US B-F bolts
CW316 SS
x
x
x
x
x
x
CW304 SS
CW316 SS
Baffleformer bolts
Baffleformer bolts
Lock bars
BMI thimble
x
x
x
x
x
x
CW 316 SS
304SA SS
Bar
Baffle
x
x
x
x
x
x
304SA SS
304SA SS
304SA SS
Former
Barrel
Baffleformer bolts
Baffleformer bolts
Baffleformer bolts
Core barrel
weld
Baffleformer bolts
x
x
x
347SA SS
International
IASCC Adv. Com.
Decommissioned
304 SS
MRP - Bor-60
Irradiation
CW316 SS-W
304SA SS- FTI
308 SS WeldFTI
347SA SS-W
© 2007 Electric Power Research Institute, Inc. All rights reserved.
x
x
x
Crack
Crack
initiation growth
rate
x
x
x
x
x
x
x
x
x
x
x
x
x
Microstructure
/swelling
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
46
PWR Internals Testing Projects
•
•
•
•
•
International IASCC Project
GONDOLE Void Swelling Experiment
Halden Crack Growth Project
BOR 60 Irradiated Materials Testing
Decommissioned PWR Materials Testing –
Completed
• JOBB Program - Completed
© 2007 Electric Power Research Institute, Inc. All rights reserved.
47
JOBB Tensile Tests Results (up to 125 dpa)
at 330°C
1200
1200
1000
UTS (MPa)
YS (MPa)
1000
800
600
800
600
400
CW 316 (300-330°C)
400
CW 316 (300-330°C)
200
SA 304 (300-330°C)
200
SA 304 (300-330°C)
0
0
20
40
60
80
100
120
140
0
20
40
60
dose (dpa)
80
100
120
140
dose (dpa)
• Saturation of the hardening between 5 and 10 dpa; earlier for SA304 than for CW316
• Saturation hardening higher for 316CW (1000 MPa) than for 304SA (800 MPa)
• No significant change between 10 and 125 dpa (at 330°C)
© 2007 Electric Power Research Institute, Inc. All rights reserved.
48
JOBB Tensile Tests Results (up to 125 dpa)
at 330°C
40
Total Elongation (%)
Uniform Elongation (%)
2,5
2
CW 316 (300-330°C)
1,5
SA 304 (300-330°C)
1
0,5
30
CW 316 (300-330°C)
SA 304 (300-330°C)
20
10
0
0
0
20
40
60
80
100
120
140
0
20
40
60
80
100
dose (dpa)
dose (dpa)
• UE saturation level higher for CW316 than for SA304, TE similar (8-10%)
• No significant change between 10 and 125 dpa (at 330°C)
© 2007 Electric Power Research Institute, Inc. All rights reserved.
49
120
140
JOBB Tensile Property Summary
• Saturation of the tensile characteristics between 5 and 10 dpa;
higher for 316CW than for 304SA
• No significant change noticed between 10 and 125 dpa (at 330°C)
• Residual ductility at saturation is significant at ~10% total
elongation while uniform elongation is often <1%
• No heat to heat variations of tensile properties after irradiation for
CW 316 nor for SA 304
• 308 welds and CASS have roughly the same behaviour as SA 304
1 dpa ~ 7 x 1020 n/cm2 (E > 1.0 MeV)
© 2007 Electric Power Research Institute, Inc. All rights reserved.
50
JOBB Creep-Irradiation Results (up to
120 dpa)
Argon
Diameter 5,65 mm
55 mm
Diameter
mm
70 dpa
52 dpa
41 dpa
28 dpa
Unirradiated
6.5
Length
mm
Tube Length
6.0
0
© 2007 Electric Power Research Institute, Inc. All rights reserved.
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Summary
ƒ PWR internals material degradation mechanisms have
been extensively studied
ƒ Data obtained and to be obtained will support the
development of degradation models
ƒ The degradation models are technical bases for
ƒ component screening
ƒ functionality evaluation
ƒ inspection findings evaluation and disposition
ƒ flaw tolerance analysis
ƒ inspection and aging management guidelines development
© 2007 Electric Power Research Institute, Inc. All rights reserved.
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