Factors Considered in Material Selection

1

• Factors Considered in Material Selection
• (Nuclear Reactors)
• Physical Properties
• Density
• Melting Point
• Coefficient of Linear Expansion
• Thermal Conductivity
• Mechanical Properties
• Yield Strength
• Tensile Strength
• Elongation at Fracture (Ductility)
• Creep Strength
• Fatigue Life
• Creep-Fatigue Interaction
• Impact Strength and Fracture Toughness
• Neutronic Characteristics

2

• Factors Considered in Material Selection
• (Nuclear Reactors)
• Ability to Withstand Stress, Environment and
  Temperature Over Life Time
• Previous Experience Under Similar Conditions, if
  any
• Availability
• Affordability
• Ease of Fabrication
• Susceptibility to Chemical Attack and Corrosion
• Guidelines for Design in Codes
• Potential for Activation Under Neutron
  Bombardment

3

• Steels Commonly Used in
• Nuclear Plants
• Carbon Steels ( C 0.10 to 0.20 )
• (Pressure Vessels of PWR, BWR, Pipings of BWR
  -Primary Pressure Boundary Piping)
• A501, A508, A533, SA333
• Low Alloy (Bainitic) Steels
• (Turbine Rotors, Discs)
• 1Cr-1Mo-0.25V
• 2.25Cr-1Mo (Grade 22)
• Ni-Cr-MoV (A469, Class 8)
• Ni-Cr-MoV (A470, Class 8)
• Ni-Cr-MoV (A471, Class 8)
• Ferritic(Martensitic) Stainless Steel
• (turbine blades, end fittings in PHWR)
• AISI 403 (S40300)
• AISI 410 (S41000)

4

• Steels Commonly Used in
• Nuclear Plants
• Austenitic Stainless Steels
• (Good Strength Ductility Resistance to
  Corrosion at High Temperatures)
• AISI 304
• AISI 316
• AISI 304 L (Low Carbon, lt0.03 )
• AISI 316 L (Low Carbon, lt0.03 )
• AISI 304 LN (Low Carbon Nitrogen)
• AISI 316 LN (Low Carbon Nitrogen)
• AISI 321 (Ti stabilised)
• AISI 347 (Nb stabilised)
• AISI 308 (Welding electrodes)
• Primary Coolant Pipeings of BWR 304 SS
• 304 SS Susceptible for IGSCC
• If IGSCC is to be Avoided 304 L, 316 L, 347
  Inconel 600 can be used

5

• Superalloys Commonly Used in
• Nuclear Plants
• Superalloys
• Inconel Alloys (Ni-Cr Series)
• Inconel 600
• Inconel 625
• Inconel 690
• Inconel 800
• Nimonic PE16
• Inconel 718
• Inconel 617
• Alloy 800H

To Avoid SCC in Steam-Water System BWR, PWR,
PHWR
FBRs (Tie Rods,Cladding Core Cover Plate
HTGR (Heat Exchanger Tubes)
6

• Materials Commonly Used in
• Nuclear Plants
• Steam Generator Tubing
• LWR Inconel 600
• PWR Inconel 600
• PHWR Inconel 800
• HTGR Alloy 800 H - Creep Resistance
• PFBR Mod. 9Cr-1Mo -Creep, SCC
• FBTR 2 1/4Cr-1Mo - Low Temp. lt427 oC
• Steam Condenser
• Admiralty Brass - Fresh water
• Aluminum - Bronze
• Aluminum - Brass (SB 261)
• Cupro - Nickel (SB111, 251)

SCC Resistance
Sea Water Cooled Condensers (Higher Corrosion
Resistance)
Higher Life upto 40 yrs
7
ASTM Standards for Mechanical Properties
Evaluation
8

• FUEL STRUCTURAL MATERIALS
• Selection Criteria
• Low neutron absorption cross section
• Low cost
• Adequate tensile strength
• Adequate creep strength
• Adequate ductility after irradiation
• Corrosion resistance
• Materials

9

• CONTROL MATERIALS
• Selection Criteria
• Neutron absorption cross section
• Adequate mechanical strength
• Corrosion resistance
• Chemical and dimensional stability
• (under prevailing temperature and
  irradiation)
• Relatively low mass to allow rapid movement
• Fabricability
• Availability and reasonable cost
• Materials
• Boron, Cadmium, Gadolinium, Hafnium, Europium

10

• MODERATOR MATERIALS
• To slow down and moderate fast neutrons from
  fission
• Materials with light nuclei are most effective

Moderating ratio macroscopic scattering cross
section / absorption cross section

• REFLECTOR MATERIAL
• To cut down the neutron leakage losses from core
• Desired properties same as moderators

Water Heavy Water Beryllium Graphite
Thermal Reflectors
11

• SHIELDING MATERIAL
• To protect personnel and equipment from the
  damaging effects of radiation
• Good moderating capability
• Reasonable absorption cross section
• Cost and space availability
• Neutron, a,b and g shielding
• Both light and heavy nuclei are preferred
• WATER
• PARAFFIN
• POLYETHYLENE
• Pb, Fe, W
• Boral (B4C in Al matrix)
• Concrete

12
Major Power Reactors and their Ceramic Components
a pellets b sphere-pac c coated particles
13

• SCHEME OF PRESENTATION
• Fundamental Aspects of Mechanical Testing and
  Various Mechanical Properties
• ASTM Standards for Various Mechanical Tests
• Factors Considered in Materials Selection
  (Nuclear Reactors)
• Types of Materials in Nuclear Reactors
• Cladding Materials in Thermal Reactors (Zirconium
  Alloys)
• Cladding Materials in FBRs
• Different NDT Techniques Principles
• Application of NDT Techniques in Nuclear Industry
• Different Types of Corrosion
• Corrosion Protection Methods
• Corrosion in Nuclear Plants