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)

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

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)

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

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)

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

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)

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

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

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

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

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

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