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
Low Neutron Capture Cross Section (Core)
High Neutron Capture Cross Section (Control Rod)

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
Toxicity and Health Impact

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)
Sandvick Sweden HT9
Sandvick Sweden HT7
French R8
French EM12
Japanese HCM9M
(Creep Strength, Oxidation and Corrosion Resistance)

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, <0.03 %)
AISI 316 L (Low Carbon, <0.03 %)
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
Stainless Steels are extensively used in FBRs

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. <427 oC
Steam Condenser
Admiralty Brass - Fresh water
Aluminum - Bronze
Aluminum - Brass (SB 261)
Cupro - Nickel (SB111, 251)
Titanium
Type 304 SS
SCC Resistance
Sea Water Cooled Condensers (Higher Corrosion Resistance)
Higher Life upto 40 yrs

7. ASTM Standards for Mechanical Properties Evaluation
Type of Test
Standard
Tensile
ASTM E8M (1994)
ASTM E21 (1992)
Creep rupture and stress rupture
ASTM E139 (2000)
Hardness
ASTM E10 (1984)
ASTM E18 (1984)
ASTM E92 (1984)
High cycle fatigue
ASTM E466 (1999)
Low cycle fatigue
ASTM E606 (1999)
Impact
ASTM E23 (1999)
Fracture Toughness (plane strain)
ASTM E399 (1989)
Fracture toughness (JIC)
ASTM E813 (1989)

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:
Reactor
Cladding
BWR
Zircaloy-2 / Zircaloy-4
PWR
Stainless Steel 304
Zircaloy-4
PHWR
Zircaloy-2
Zr-2.5%Nb Alloy
LMFBR
Type 316SS (20% CW)
Alloy D9 (20% CW)
(Modified 9Cr-1Mo)
HTGR
Graphite

9. PWR (Clad in CW 304 SS/Inconel 627)
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
B4C
BWR (Clad in 304 SS)
80% Ag-15%In+5%Cd
PWR (Clad in CW 304 SS/Inconel 627)
LMFBR

10. 2100 (0.2% light water as impurity)
MODERATOR MATERIALS
To slow down and moderate fast neutrons from fission
Materials with light nuclei are most effective
Materials
Moderating ratio
Light water 70
Heavy water
2100 (0.2% light water as impurity)
12000 (100% heavy water)
Metallic Beryllium
150
Graphite
170
Beryllium oxide
180
{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 (U-Pu)C,a,b (U-Pu)Na, (U-Pu)O2b
Ceramic Components
Reactor Type
Coolant
Fuel
Control Rod
Primary
Alternates
BWR
H2O
UO2a
UO2a, (U-Pu)O2a,b
B4C, UO2-Gd2O3
PWR
UO2a (U-Pu)O2a,b
(U-Th)O2a,b
Al2O3-B4C
UO2-Gd2O3
HWR
D2O
(U-Pu)O2a
B4C
AGR
CO2 -
HTGR He
UC2c
(ThO2)
(UO2)
(U-Pu)O2c, (U-ThO2)c
Gd2O3-Al2O3, Eu2O3
GCFR
(U-Pu)C,a,c (U-Pu)Na,c
Eu2O3
LMFBR Na
(U-Pu)C,a,b (U-Pu)Na, (U-Pu)O2b
LWBR
(U-Th)O2a
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