Chabot E45 Class Tour Slides
Ron Horn
Chief Consulting Engineer
Materials Technology
Key Topics
• Overview of Key BWR Components and their
metals and materials
• Which materials are used
• How are they made and checked
• What are the possible problems
• What different engineering disciplines are
needed to select, manufacture and fabricate
power plant components
• What key topics in E45 apply
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Ron Horn: Chabot College Feb. 13, 2012
•
Considerations for Selection
Strength at Temperature
General Corrosion Resistance
Cost
Stress Corrosion Resistance
Experience base/laboratory data in operating (BWR)
environments
Recognized standards used in Codes (ASTM, ASME, JIS, DIN)
Radiation resistance
Other mechanical and physical properties
• Weldability, Modulus, Coefficient of thermal expansion,
• Fatigue resistance, toughness
• Effects of irradiation
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Ron Horn: Chabot College Feb. 13, 2012
Overview of BWR
HEAD COOLING SPRAY NOZZLE
SPARE TOP HEAD NOZZLE
RPV TOP HEAD
DRYER HOLD DOWN BRACKET
RPV CLOSURE FLANGE
STUD, NUT AND WASHER
GUIDE ROD/BRACKET
RPV FLANGE AND
LEAK DETECTION NOZZLE
STEAM DRYER
MAIN STEAM NOZZLE
INSTRUMENTATION NOZZLE
INSTRUMENTATION NOZZLE
STEAM SEPARATOR
SHELL WELDS
INSTRUMENTATION NOZZLE
FEEDWATER SPARGER
CORE SPRAY
FEEDWATER NOZZLE
CORE SPRAY NOZZLE
CRD NOZZLE
RHR/LPCI NOZZLE
TOP GUIDE
RPV HORIZONTAL AND
VERTICAL SHELL WELDS
LPCI COUPLING
INSTALLATION WELDS
TOP GUIDE GRID
INSTRUMENTATION NOZZLE
SHROUD
SURVEILLANCE SPECIMEN
CONTROL ROD
CORE PLATE
JET PUMP ASSEMBLY
RECIRCULATION
INLET NOZZLE
RECIRCULATION OUTLET
NOZZLE
JET PUMP
INSTRUMENTATION
NOZZLE
CONTROL ROD GUIDE TUBE
AND FUEL SUPPORT CASTING
BOTTOM HEAD WELDS
SHROUD SUPPORT
ACCESS HOLE
INCORE HOUSING
SLC PIPE
RPV HOLD DOWN BOLT
INCORE HOUSING TO BOTTOM HEAD
DRAIN NOZZLE
CRD HOUSING
CRD HOUSING TO BOTTOM HEAD
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Ron Horn: Chabot College Feb. 13, 2012
Reactor Materials Usage
SS OVERLAY
RPV SHELL COURSE
LOW ALLOY STEEL
SA-533 GrB CL 1
RPV WALL
CLADDING - ER 308L/309L
INLAY - ALLOY 182
NOZZLE TO VESSEL WELD
SAW-LOW ALLOY WELD WIRE
BRACKET - 304 SS
NOZZLE TO VESSEL
WELD
WELD - ALLOY 182
INCONEL BUTTER
SAFE END TO NOZZLE
WELD
SA-508 CL 2
PAD
INCONEL BUTTER
SA-508 CL 1
SA 376 TYPE 304
Recirculation Inlet
Nozzle
RPV Attachment
Bracket
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Ron Horn: Chabot College Feb. 13, 2012
Metal Alloys Used in BWRs
•Stainless Steel (Type 304L):
•18 Cr-8 Ni and low Carbon
•Yield strength 30-40 ksi (lots of ductility)
– Solid solution strengthening
•Low alloy steel: cheaper
• Small amounts of Cr, Ni, Mn
• Yield strength ~ 50 ksi and UTS of 80 ksi)
– Requires heat treatment to achieve strength
• Weld Metals
– Compatible with the “wrought” material
– Similar composition
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Ron Horn: Chabot College Feb. 13, 2012
Alloy Strengthening
•Type 304 SS – yield strength 30-40 ksi
– Solid solution strengthening
•XM-19 – yield strength ~ 50 ksi
– Interstitial and solid solution
•Low alloy steel – yield strength ~ 50 ksi
– (Ultimate tensile strength ~80 ksi)
– Heat treatment
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Ron Horn: Chabot College Feb. 13, 2012
Processing-Composition-Properties
Why it isn’t enough to specify a material type
Three “levers” to pull to tailor
materials, but they don’t act
independently
Processing
Composition
Properties
Transformation Strengthening
Stress-strain Curve
Untempered
Martensite
400
350
Stress, ksi
300
Pearlite
250
200
150
100
50
0
0
Tempered
Martensite
10
20
30
40
50
Elongation, %
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Ron Horn: Chabot College Feb. 13, 2012
Steel Manufacturing Process
Hydrostatic test and Final NDE
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Ron Horn: Chabot College Feb. 13, 2012
Steel Forgings for Pressure Vessels
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Ron Horn: Chabot College Feb. 13, 2012
Examples: ABWR Steel Forgings
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Ron Horn: Chabot College Feb. 13, 2012
Welding Processes
F
W
H
S
(
P
v
W
I
L
Submerged Arc Welding
FineLineTM Welding
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Ron Horn: Chabot College Feb. 13, 2012
Possible Materials Degradation in BWRs
•Fatigue: due to stresses and strains from startup and
shutdown
• Also, flowing coolant or steam within reactor
system can lead to many loading cycles
• >1E11 cycles over the life of a plant (40-60 years)
• Stress corrosion cracking: material in contact with the
coolant
• Regions near welds are possible locations
•Many welds in a plant: the vessel and internal
structures are very large
•Aging and changes in the materials with operation
•Temperature is 288oC (550oF)
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Ron Horn: Chabot College Feb. 13, 2012
Example: Stress Corrosion Cracking
“Three Circles” represent required conditions for SCC
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Ron Horn: Chabot College Feb. 13, 2012
Stress Corrosion Cracking: Material Susceptibility
Sensitization in Stainless Steel
Cold Work in Stainless Steel
Pipe Weld
Susceptibility
Cr depletion in grain boundaries (C level >0.03%)
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Ron Horn: Chabot College Feb. 13, 2012
Examples: Material Degradation
Beltline Shroud Cracking
Ex. Cold Work Induced Cracking
Ex. Stress Corrosion Cracking
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Ron Horn: Chabot College Feb. 13, 2012
Different Engineering Skills
• Materials Engineer
• Designer (Mechanical Engineer)
• Welding Engineer
• Non-Destructive Testing Engineer
• Testing and Quality Engineer
• Materials Researcher
• Chemical Engineer
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Ron Horn: Chabot College Feb. 13, 2012
Related E45 Topics
Phase diagrams
• iron-carbon phase diagram
– iron-carbon alloy microstructure development; alloying
elements and phases
Solid phase transformations
• phase transformation kinetics: nucleation and growth
• multiphase transformation
• isothermal /continuous cooling phase transformation
diagrams
• Mechanical behavior of alloys – strength vs. microstructure
– Testing for YS and UTS, fracture mechanics
Applications and processing of metal alloys
• ferrous and nonferrous alloys, stainless steels
• forming and casting, post process heat treatment,
precipitation hardening
Ceramics: Applications and processing of ceramics
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Ron Horn: Chabot College Feb. 13, 2012
Questions?
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Ron Horn: Chabot College Feb. 13, 2012