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Factors Considered in Material Selection (Nuclear Reactors) Physical Properties Density

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

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Factors Considered in Material Selection (Nuclear Reactors) Physical Properties Density

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  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

  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

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