{
  "spore": "profile",
  "id": "zirconium-alloys",
  "spore_version": "0.2",
  "family": "refractory-metals",
  "name": "Zirconium alloys (Zircaloy, ZIRLO, Zr-2.5Nb, Zr-Al)",
  "abbreviation": "Zr alloys",
  "role": "corrosion-resistant structural alloys for nuclear fuel cladding, reactor pressure tubes and chemical-process equipment",
  "category": "metals",
  "type": "refractory-metals",
  "summary": "Zirconium alloys add small amounts of tin, iron, chromium, nickel or niobium to zirconium. The grades that matter most are Zircaloy-2 and Zircaloy-4 (fuel cladding in water reactors), Zr-2.5Nb (pressure tubes in CANDU reactors), and ZIRLO (Westinghouse cladding). In the ATI reactor-grade sheet, Zircaloy-4 has a density of 6.55 g/cc, a melting point of 1850 degC and a thermal conductivity of 21.5 W/m-K, and its annealed 2 mm strip has a room-temperature tensile strength of 541 MPa in the longitudinal direction. The corrosion table prints 0.36 mm/a for Zircaloy-4 in 70 % hydrochloric acid at 160 degC. A research alloy, ZrAl14Ti3, reaches 888 MPa offset yield strength at room temperature in one open-access paper, but no commercial Zr-Al grade was found.\n",
  "best_for": "Nuclear fuel cladding and reactor pressure tubes, where low thermal neutron absorption (0.22 barns for Zircaloy-4) and corrosion resistance in water and steam both matter (ATI reactor-grade sheet)",
  "weakest_at": "Hydride embrittlement: hydrogen from water oxidation forms hydrides that blister and crack the cladding (Wikipedia), and hot hydrochloric acid still attacks Zircaloy-4 at 0.36 mm/a",
  "identity": {
    "formula": "Zr-based alloys. Nominal Zircaloy-4 is Zr-1.5Sn-0.2Fe-0.1Cr (wt %). Zircaloy-2: Zr with Sn 1.20 to 1.70, Fe 0.07 to 0.20, Cr 0.05 to 0.15, Ni 0.03 to 0.08 wt %. Zircaloy-4: Zr with Sn 1.20 to 1.70, Fe 0.18 to 0.24, Cr 0.07 to 0.13 wt %. Zr-2.5Nb: Zr with Nb 2.40 to 2.80 wt %. ZIRLO: Zr with Nb about 1 and Sn 0.7 to 1 wt % (Wikipedia alloy table; iron level not given there). Zr-Al: research alloys ZrAl14Ti3 and ZrAl14Ti9 (at. %), not a commercial composition.",
    "designations": [
      {
        "system": "UNS",
        "code": "R60802",
        "source": "ati-reactor-grade",
        "where": "Composition table, UNS Grade column, Zircaloy-2"
      },
      {
        "system": "UNS",
        "code": "R60804",
        "source": "ati-reactor-grade",
        "where": "Composition table, UNS Grade column, Zircaloy-4"
      },
      {
        "system": "UNS",
        "code": "R60904",
        "source": "ati-reactor-grade",
        "where": "Composition table, UNS Grade column, Zr-2.5Nb"
      },
      {
        "system": "Trade name",
        "code": "Zircaloy-2",
        "source": "ati-reactor-grade",
        "where": "Zirconium alloys text, Zircaloy-2 paragraph"
      },
      {
        "system": "Trade name",
        "code": "Zircaloy-4",
        "source": "ati-reactor-grade",
        "where": "Zirconium alloys text, Zircaloy-4 paragraph"
      },
      {
        "system": "Trade name",
        "code": "ZIRLO",
        "source": "wikipedia-zr-alloys",
        "where": "Alloy table, ZIRLO row (Westinghouse; name stands for zirconium low oxidation)"
      }
    ],
    "source": "ati-reactor-grade",
    "where": "Composition (weight percent) table, columns Zircaloy-2, Zircaloy-4 and Zr-2.5Nb; ZIRLO from the Wikipedia alloy table; Zr-Al from the PMC paper title and abstract"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "corrosion"
    ],
    "applications": [
      "structures",
      "thermal-control"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, Zircaloy-4",
      "value": 6.55,
      "bound": "exact",
      "unit": "g/cc",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temperature": "not stated",
        "unit_in_source": "6.55 g/cc (0.237 lbs/cu.-in.)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, Properties of Zircaloy-4 table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Density",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, Zircaloy-4",
      "value": 1850,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "unit_in_source": "1850 °C (3,362 °F)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Melting Point",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, Zircaloy-4",
      "value": 21.5,
      "bound": "exact",
      "unit": "W/m-K",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temperature": "not stated",
        "unit_in_source": "21.5 Watts/m-K (149 BTU-in/hr-ft2-F)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Thermal Conductivity",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Heat capacity, Zircaloy-4",
      "value": 0.285,
      "bound": "exact",
      "unit": "J/g-°C",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temperature": "not stated",
        "unit_in_source": "0.285 J/g-°C (0.07 BTU/lb-°C)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet; the table calls it heat capacity",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Heat Capacity",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, Zircaloy-4 at 25 degC",
      "value": 6,
      "bound": "exact",
      "unit": "µm/(m·°C)",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temperature": "25 °C",
        "unit_in_source": "6 µm/m °C (3.3 µin/in-°F)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Coefficient of Thermal Expansion at 25 C",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity, Zircaloy-4",
      "value": 99.3,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temperature": "not stated",
        "unit_in_source": "99.3 Gpa (14,402 ksi)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Modulus of Elasticity",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "Shear modulus, Zircaloy-4",
      "value": 36.2,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temperature": "not stated",
        "unit_in_source": "36.2 Gpa (5,249 ksi)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Shear Modulus",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Poisson's ratio, Zircaloy-4",
      "value": 0.37,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temperature": "not stated"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Poisson's Ratio",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, Zircaloy-4 longitudinal, room temperature",
      "value": 541,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temper": "annealed 2 mm thick strip",
        "orientation": "longitudinal",
        "temperature": "room temperature",
        "unit_in_source": "541 MPa (78.4 ksi)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, mechanical properties table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Mechanical properties of Zircaloy-4 annealed 2 mm thick strip table, row Ultimate Tensile Strength, Longitudinal, Room Temp",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, Zircaloy-4 transverse, room temperature",
      "value": 515,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temper": "annealed 2 mm thick strip",
        "orientation": "transverse",
        "temperature": "room temperature",
        "unit_in_source": "515 MPa (74.6 ksi)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, mechanical properties table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Mechanical properties of Zircaloy-4 annealed 2 mm thick strip table, row Ultimate Tensile Strength, Transverse, Room Temp",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, Zircaloy-4 longitudinal, 288 degC",
      "value": 271,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temper": "annealed 2 mm thick strip",
        "orientation": "longitudinal",
        "temperature": "288 °C",
        "unit_in_source": "271 MPa (39.3 ksi)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, mechanical properties table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Mechanical properties of Zircaloy-4 annealed 2 mm thick strip table, row Ultimate Tensile Strength, Longitudinal, 288 C column",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, Zircaloy-4 transverse, 288 degC",
      "value": 241,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temper": "annealed 2 mm thick strip",
        "orientation": "transverse",
        "temperature": "288 °C",
        "unit_in_source": "241 MPa (34.9 ksi)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, mechanical properties table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Mechanical properties of Zircaloy-4 annealed 2 mm thick strip table, row Ultimate Tensile Strength, Transverse, 288 C column",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, Zircaloy-4 transverse, room temperature",
      "value": 468,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temper": "annealed 2 mm thick strip",
        "orientation": "transverse",
        "temperature": "room temperature",
        "unit_in_source": "468 MPa (67.8 ksi)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, mechanical properties table; the longitudinal yield in the same table (80 MPa) is not used, see gaps",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Mechanical properties of Zircaloy-4 annealed 2 mm thick strip table, row Yield Strength, Transverse, Room Temp",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, Zircaloy-4 transverse, 288 degC",
      "value": 170,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temper": "annealed 2 mm thick strip",
        "orientation": "transverse",
        "temperature": "288 °C",
        "unit_in_source": "170 MPa (25.6 ksi)"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, mechanical properties table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Mechanical properties of Zircaloy-4 annealed 2 mm thick strip table, row Yield Strength, Transverse, 288 C column",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, Zircaloy-4 longitudinal, room temperature",
      "value": 28,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temper": "annealed 2 mm thick strip",
        "orientation": "longitudinal",
        "temperature": "room temperature"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, mechanical properties table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Mechanical properties of Zircaloy-4 annealed 2 mm thick strip table, row Elongation, Longitudinal, Room Temp",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, Zircaloy-4 transverse, room temperature",
      "value": 29,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "temper": "annealed 2 mm thick strip",
        "orientation": "transverse",
        "temperature": "room temperature"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, mechanical properties table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Mechanical properties of Zircaloy-4 annealed 2 mm thick strip table, row Elongation, Transverse, Room Temp",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_neutron_cross_section",
      "label": "Thermal neutron cross section, Zircaloy-4",
      "value": 0.22,
      "bound": "exact",
      "unit": "barns",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "neutron": "thermal",
        "unit_in_source": "0.22 barns"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, thermal neutron cross sections table; the name is not in spores/property-canon.yaml, see gaps",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Thermal neutron cross sections (barns) table, row Zircaloy-4",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_neutron_cross_section",
      "label": "Thermal neutron cross section, zirconium",
      "value": 0.18,
      "bound": "exact",
      "unit": "barns",
      "scope": "material",
      "conditions": {
        "form": "zirconium element",
        "neutron": "thermal",
        "unit_in_source": "0.18 barns"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet, thermal neutron cross sections table",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Thermal neutron cross sections (barns) table, row Zirconium",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "alpha_beta_transition_temperature",
      "label": "Alpha to alpha plus beta transformation, Zircaloy-4",
      "value": 810,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "note": "beta phase starts to form on heating"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet; non-canonical name, see gaps",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Alpha to Alpha + Beta Phase Transformation; text on crystal structure",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "alpha_beta_transition_temperature",
      "label": "Alpha plus beta to beta transformation, Zircaloy-4",
      "value": 980,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "Zircaloy-4 (UNS R60804)",
        "note": "transformation to full beta phase"
      },
      "method": "Value printed in the ATI reactor-grade zirconium data sheet; non-canonical name, see gaps",
      "status": "ground",
      "source": "ati-reactor-grade",
      "where": "Properties of Zircaloy-4 table, row Alpha + Beta to Beta Phase Transformation",
      "source_detail": {
        "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
        "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
        "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
        "year": 2015,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Offset yield strength, ZrAl14Ti3 (research alloy)",
      "value": 888,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "alloy": "ZrAl14Ti3 (at. %), hot-rolled and quenched",
        "temperature": "room temperature",
        "measure": "offset yield, as printed in the abstract",
        "scatter": "plus or minus 12 MPa"
      },
      "method": "Value printed in the abstract of the open-access PMC paper; research alloy, not a commercial grade",
      "status": "ground",
      "source": "pmc-zral",
      "where": "Abstract, sentence beginning Mechanical property evaluation showed",
      "source_detail": {
        "title": "Microstructure and Mechanical Properties of Hot-Rolled ZrAl14Ti3 and ZrAl14Ti9 Alloys (open access, PMC12525182)",
        "id": "PMID 41095285, PMCID PMC12525182",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12525182/",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, ZrAl14Ti3 (research alloy)",
      "value": 1056,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "alloy": "ZrAl14Ti3 (at. %), hot-rolled and quenched",
        "temperature": "room temperature",
        "scatter": "plus or minus 19 MPa"
      },
      "method": "Value printed in the abstract of the open-access PMC paper",
      "status": "ground",
      "source": "pmc-zral",
      "where": "Abstract, sentence beginning Mechanical property evaluation showed",
      "source_detail": {
        "title": "Microstructure and Mechanical Properties of Hot-Rolled ZrAl14Ti3 and ZrAl14Ti9 Alloys (open access, PMC12525182)",
        "id": "PMID 41095285, PMCID PMC12525182",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12525182/",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Fracture elongation, ZrAl14Ti3 (research alloy)",
      "value": 23,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "alloy": "ZrAl14Ti3 (at. %), hot-rolled and quenched",
        "temperature": "room temperature",
        "scatter": "plus or minus 1 %"
      },
      "method": "Value printed in the abstract of the open-access PMC paper",
      "status": "ground",
      "source": "pmc-zral",
      "where": "Abstract, sentence beginning Mechanical property evaluation showed",
      "source_detail": {
        "title": "Microstructure and Mechanical Properties of Hot-Rolled ZrAl14Ti3 and ZrAl14Ti9 Alloys (open access, PMC12525182)",
        "id": "PMID 41095285, PMCID PMC12525182",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12525182/",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Offset yield strength, ZrAl14Ti9 (research alloy)",
      "value": 998,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "alloy": "ZrAl14Ti9 (at. %), hot-rolled and quenched",
        "temperature": "room temperature",
        "measure": "offset yield",
        "scatter": "plus or minus 6 MPa"
      },
      "method": "Value printed in the abstract of the open-access PMC paper",
      "status": "ground",
      "note": "The paper says this is 110 MPa above ZrAl14Ti3 at the same condition.",
      "source": "pmc-zral",
      "where": "Abstract, sentence beginning The ZrAl14Ti9 alloy displayed",
      "source_detail": {
        "title": "Microstructure and Mechanical Properties of Hot-Rolled ZrAl14Ti3 and ZrAl14Ti9 Alloys (open access, PMC12525182)",
        "id": "PMID 41095285, PMCID PMC12525182",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12525182/",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, ZrAl14Ti9 (research alloy)",
      "value": 1069,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "alloy": "ZrAl14Ti9 (at. %), hot-rolled and quenched",
        "temperature": "room temperature",
        "scatter": "plus or minus 7 MPa"
      },
      "method": "Value printed in the main text of the open-access PMC paper, comparison paragraph with ZrAl14Ti3",
      "status": "ground",
      "source": "pmc-zral",
      "where": "Main text, paragraph beginning Compared with ZrAl14Ti3 (results and discussion)",
      "source_detail": {
        "title": "Microstructure and Mechanical Properties of Hot-Rolled ZrAl14Ti3 and ZrAl14Ti9 Alloys (open access, PMC12525182)",
        "id": "PMID 41095285, PMCID PMC12525182",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12525182/",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Fracture elongation, ZrAl14Ti9 (research alloy)",
      "value": 23,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "alloy": "ZrAl14Ti9 (at. %), hot-rolled and quenched",
        "temperature": "room temperature",
        "scatter": "plus or minus 2 %"
      },
      "method": "Value printed in the abstract of the open-access PMC paper",
      "status": "ground",
      "source": "pmc-zral",
      "where": "Abstract, sentence beginning The ZrAl14Ti9 alloy displayed",
      "source_detail": {
        "title": "Microstructure and Mechanical Properties of Hot-Rolled ZrAl14Ti3 and ZrAl14Ti9 Alloys (open access, PMC12525182)",
        "id": "PMID 41095285, PMCID PMC12525182",
        "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12525182/",
        "kind": "paper",
        "license": "CC BY 4.0"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Hydrochloric acid, 70 %, 160 °C (Zircaloy-4)",
      "headline": "Hot concentrated hydrochloric acid attacks Zircaloy-4 at a measurable rate.",
      "effect": "The corrosion table prints 0.36 mm/a (14 mpy) for Zircaloy-4 in 70 % HCl at 160 °C.",
      "rating": "moderate",
      "conditions": {
        "medium": "hydrochloric acid, 70 %",
        "temperature": "160 °C",
        "unit_in_source": "mm/a (MPY)",
        "rating_basis": "Space Mushroom rating from the printed rate: none for nil, low below 0.1 mm/a, moderate from 0.1 mm/a"
      },
      "source": "ati-reactor-grade",
      "where": "Corrosion rate data for Zircaloy-4 table, row HCl 70 %, 160 °C"
    },
    {
      "environment": "Ferric chloride, 1 %, 135 °C (Zircaloy-4)",
      "headline": "A small amount of ferric chloride corrodes Zircaloy-4 at 0.18 mm/a.",
      "effect": "The table prints 0.18 mm/a (7 mpy) for Zircaloy-4 in 1 % FeCl3 at 135 °C.",
      "rating": "moderate",
      "conditions": {
        "medium": "ferric chloride, 1 %",
        "temperature": "135 °C",
        "unit_in_source": "mm/a (MPY)",
        "rating_basis": "as for the first entry"
      },
      "source": "ati-reactor-grade",
      "where": "Corrosion rate data for Zircaloy-4 table, row FeCl3 1 %, 135 °C"
    },
    {
      "environment": "Sulfuric acid, 70 %, 150 °C (Zircaloy-4)",
      "headline": "Zircaloy-4 stays under 0.13 mm/a in hot sulfuric acid.",
      "effect": "The table prints under 0.13 mm/a (under 5 mpy).",
      "rating": "low",
      "conditions": {
        "medium": "sulfuric acid, 70 %",
        "temperature": "150 °C",
        "unit_in_source": "mm/a (MPY)"
      },
      "source": "ati-reactor-grade",
      "where": "Corrosion rate data for Zircaloy-4 table, row H2SO4 70 %, 150 °C"
    },
    {
      "environment": "Nitric acid, 70 %, 120 °C (Zircaloy-4)",
      "headline": "Zircaloy-4 barely corrodes in hot 70 % nitric acid.",
      "effect": "The table prints 0.05 mm/a (2 mpy).",
      "rating": "low",
      "conditions": {
        "medium": "nitric acid, 70 %",
        "temperature": "120 °C",
        "unit_in_source": "mm/a (MPY)"
      },
      "source": "ati-reactor-grade",
      "where": "Corrosion rate data for Zircaloy-4 table, row HNO3 70 %, 120 °C"
    },
    {
      "environment": "Copper chloride, 0.1 %, 144 °C (Zircaloy-4)",
      "headline": "Dilute copper chloride gives a low rate.",
      "effect": "The table prints 0.03 mm/a (1 mpy).",
      "rating": "low",
      "conditions": {
        "medium": "CuCl2, 0.1 %",
        "temperature": "144 °C",
        "unit_in_source": "mm/a (MPY)"
      },
      "source": "ati-reactor-grade",
      "where": "Corrosion rate data for Zircaloy-4 table, row CuCl2 0.1 %, 144 °C"
    },
    {
      "environment": "Sodium chloride, 25 %, 250 °C (Zircaloy-4)",
      "headline": "Hot brine does not attack Zircaloy-4 measurably.",
      "effect": "The table prints nil.",
      "rating": "none",
      "conditions": {
        "medium": "NaCl, 25 %",
        "temperature": "250 °C",
        "unit_in_source": "nil"
      },
      "source": "ati-reactor-grade",
      "where": "Corrosion rate data for Zircaloy-4 table, row NaCl 25 %, 250 °C"
    },
    {
      "environment": "Nitric, sulfuric or hydrochloric acid with ferric, cupric or nitrate ions, above the boiling point",
      "headline": "ATI says rates stay under 0.13 mm/a for these acid-and-impurity mixtures.",
      "effect": "The sheet says these solutions generally give corrosion rates of less than 0.13 mm/a (5 mpy) even at temperatures well above the boiling point. This is a general statement for the zirconium alloys, not a single printed test.",
      "rating": "low",
      "conditions": {
        "basis": "general statement in the zirconium alloy properties text",
        "unit_in_source": "mm/a (mpy)"
      },
      "source": "ati-reactor-grade",
      "where": "Zirconium alloy properties text, first paragraph under ZIRCONIUM ALLOY PROPERTIES"
    },
    {
      "environment": "Air or water (oxide film)",
      "headline": "Zircaloy-2 and Zircaloy-4 oxidise at the same rate in air or water, and their protection comes from the oxide film.",
      "effect": "Wikipedia says oxidation occurs at the same rate in air or in water, that a sub-micrometre zirconium dioxide film forms quickly, and that Zircaloys 2 and 4 behave very similarly. No rate in mm or mg per area is printed in the page.",
      "rating": "unknown",
      "conditions": {
        "basis": "Wikipedia summary; no measured rate read in this run"
      },
      "source": "wikipedia-zr-alloys",
      "where": "Oxidation of zirconium alloy section"
    }
  ],
  "risks": {
    "hazards": [],
    "failure_risks": [
      {
        "mode": "Delayed hydride cracking of Zircaloy cladding",
        "trigger": "Hydrogen uptake, and stress raisers such as notches and cracks, during reactor cycles or spent-fuel storage of high-burnup fuel rods",
        "consequence": "Hydride precipitation embrittles Zircaloy, and delayed hydride cracking threatens the safety and structural integrity of fuel cladding. The paper gives no rate.",
        "severity": "high",
        "source": "arxiv-zircaloy4",
        "where": "Introduction, paragraph 1"
      },
      {
        "mode": "Hydrogen embrittlement of cladding",
        "trigger": "Hydrogen released when zirconium oxidises in water diffuses into the alloy and forms hydrides",
        "consequence": "Hydrides are less dense and weaker than the alloy, and their formation results in blistering and cracking of the cladding.",
        "severity": "high",
        "source": "wikipedia-zr-alloys",
        "where": "Introduction, paragraph 1"
      },
      {
        "mode": "Acid attack in hot hydrochloric acid",
        "trigger": "70 % HCl at 160 °C, as in the Zircaloy-4 corrosion table",
        "consequence": "The printed corrosion rate is 0.36 mm/a (14 mpy), so the alloy thins steadily in this service.",
        "severity": "moderate",
        "source": "ati-reactor-grade",
        "where": "Corrosion rate data for Zircaloy-4 table, row HCl 70 %, 160 °C"
      },
      {
        "mode": "Directional strength of cold-rolled strip",
        "trigger": "Cold rolling produces a strong texture in Zircaloy strip, and the crystal basal poles sit about 35 degrees to the transverse plane",
        "consequence": "ATI says the anisotropy gives significantly higher yield strength in the transverse direction, so the strength of a strip depends on its orientation. Designers must state the direction.",
        "severity": "moderate",
        "source": "ati-reactor-grade",
        "where": "Zirconium alloy text, crystal structure paragraph"
      }
    ],
    "side_effects": [
      {
        "text": "Reactor-grade zirconium limits hafnium to 0.010 % maximum. Hafnium has a thermal neutron cross section of 104 barns, against 0.18 barns for zirconium, so trace hafnium would absorb neutrons in the core.",
        "affects": "Neutron economy in reactor cores",
        "source": "ati-reactor-grade",
        "where": "Reactor grade paragraph; Thermal neutron cross sections table; Maximum impurities table"
      },
      {
        "text": "Zirconium reacting with water releases hydrogen gas, part of which diffuses into the alloy.",
        "affects": "Cladding structure through hydride formation",
        "source": "wikipedia-zr-alloys",
        "where": "Introduction, paragraph 1"
      }
    ],
    "handling": [
      {
        "text": "Specify the grade, since Zircaloy-2, Zircaloy-4 and Zr-2.5Nb differ in tin, iron, nickel and niobium content (ATI composition table).",
        "source": "ati-reactor-grade",
        "where": "Composition (weight percent) table"
      },
      {
        "text": "Keep hydrogen impurity at or below 0.0025 % in Zircaloy-2 and Zircaloy-4, and at or below 0.0010 % in Zr-2.5Nb (ATI maximum impurities table).",
        "source": "ati-reactor-grade",
        "where": "Maximum impurities table, row Hydrogen"
      },
      {
        "text": "The impurity limits are printed as maxima: Zircaloy-2 and Zircaloy-4 carbon 0.027 %, nitrogen 0.0080 %, silicon 0.0120 %; Zr-2.5Nb carbon 0.027 %, nitrogen 0.0065 % (ATI maximum impurities table).",
        "source": "ati-reactor-grade",
        "where": "Maximum impurities table, rows Carbon, Nitrogen, Silicon"
      }
    ],
    "mitigations": [
      {
        "text": "Corrosion resistance is improved by deliberately growing a thicker, black, lustrous zirconium oxide layer (Wikipedia).",
        "source": "wikipedia-zr-alloys",
        "where": "Oxidation of zirconium alloy section"
      },
      {
        "text": "Keep carbon below about 40 ppm and nitrogen below about 300 ppm, because larger amounts degrade corrosion resistance significantly (Wikipedia).",
        "source": "wikipedia-zr-alloys",
        "where": "Oxidation of zirconium alloy section"
      }
    ]
  },
  "uses": [
    {
      "application": "structures",
      "device": "Zircaloy-4 fuel cladding in pressurized water and CANDU reactors",
      "example": "ATI says Zircaloy-4 is typically used as fuel cladding in pressurized water reactors (PWR) and CANDU reactors, with the nominal composition Zr-1.5Sn-0.2Fe-0.1Cr.",
      "source": "ati-reactor-grade",
      "where": "Zirconium alloys text, Zircaloy-4 paragraph"
    },
    {
      "application": "structures",
      "device": "Zircaloy-2 fuel cladding in boiling water reactors and calandria tubing in CANDU reactors",
      "example": "ATI says Zircaloy-2 has been predominantly used as fuel cladding in boiling water reactors (BWR) and as calandria tubing in CANDU reactors.",
      "source": "ati-reactor-grade",
      "where": "Zirconium alloys text, Zircaloy-2 paragraph"
    },
    {
      "application": "structures",
      "device": "Zr-2.5Nb pressure tubes in CANDU reactors",
      "example": "ATI says Zr-2.5Nb has been used for pressure tubes in CANDU reactors, and that niobium increases its strength.",
      "source": "ati-reactor-grade",
      "where": "Zirconium alloys text, Zr-2.5Nb paragraph"
    },
    {
      "application": "structures",
      "device": "ZIRLO fuel cladding in boiling and pressurized water reactors (Westinghouse)",
      "example": "The Wikipedia alloy table lists ZIRLO with Sn 0.7 to 1 and Nb 1 wt %, for cladding in BWR and PWR reactors, made by Westinghouse.",
      "source": "wikipedia-zr-alloys",
      "where": "Alloy table, ZIRLO row"
    }
  ],
  "supply": [
    {
      "subject": "Zirconium mineral concentrates (zircon), 2025 mine production",
      "producers": [
        {
          "country": "Australia",
          "share_percent": 33.3,
          "year": 2025
        },
        {
          "country": "South Africa",
          "share_percent": 22.5,
          "year": 2025
        },
        {
          "country": "Mozambique",
          "share_percent": 13.3,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 8.3,
          "year": 2025
        },
        {
          "country": "United States",
          "share_percent": 8.3,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "Companies in Oregon and Utah recycled zirconium from new scrap generated during metal production and fabrication, and from old scrap. The USGS does not quantify this recycling.",
      "substitutes": [
        "USGS: niobium, stainless steel and tantalum provide some substitution in nuclear applications."
      ],
      "source": "usgs-mcs2026-zirconium",
      "where": "World Mine Production and Reserves table, zirconium mineral concentrates, 2025 column: Australia 400, South Africa 270, Mozambique 160, China 100, United States 100, world total 1,200 thousand t (rounded). Shares calculated by Space Mushroom as country value divided by the printed world total. Recycling and Substitutes sections."
    },
    {
      "subject": "Unwrought zirconium import sources, 2021 to 2024 window",
      "producers": [
        {
          "country": "China",
          "share_percent": 55,
          "year": 2024
        },
        {
          "country": "Germany",
          "share_percent": 15,
          "year": 2024
        },
        {
          "country": "Canada",
          "share_percent": 12,
          "year": 2024
        },
        {
          "country": "France",
          "share_percent": 7,
          "year": 2024
        }
      ],
      "critical_lists": [],
      "recycling": "Not quantified in the USGS summary.",
      "substitutes": [],
      "source": "usgs-mcs2026-zirconium",
      "where": "Import Sources (2021-24), Zirconium unwrought: China 55 %, Germany 15 %, Canada 12 %, France 7 %. The year given is the end of the window."
    },
    {
      "subject": "Niobium (Zr-2.5Nb and ZIRLO alloying element), 2025 mine production",
      "producers": [
        {
          "country": "Brazil",
          "share_percent": 92.9,
          "year": 2025
        },
        {
          "country": "Canada",
          "share_percent": 5.4,
          "year": 2025
        },
        {
          "country": "Congo (Kinshasa)",
          "share_percent": 0.9,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: niobium recovery from scrap was negligible; the amount recycled was not available.",
      "substitutes": [
        "USGS: molybdenum, tantalum and titanium can be used as alloying elements in stainless and high-strength steels, and tantalum and tungsten in high-temperature superalloy applications; these substitutes carry a performance loss or higher cost."
      ],
      "source": "usgs-mcs2026-niobium",
      "where": "World Mine Production and Reserves table, mine production 2025e: Brazil 104,000, Canada 6,000, Congo (Kinshasa) 970 thousand t; world total 112,000 (rounded). Shares calculated by Space Mushroom. Recycling and Substitutes sections."
    },
    {
      "subject": "Tin (Zircaloy alloying element), 2025 mine production",
      "producers": [
        {
          "country": "China",
          "share_percent": 24.5,
          "year": 2025
        },
        {
          "country": "Indonesia",
          "share_percent": 21,
          "year": 2025
        },
        {
          "country": "Peru",
          "share_percent": 11.4,
          "year": 2025
        },
        {
          "country": "Brazil",
          "share_percent": 9.7,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: about 17,000 tons of tin from old and new scrap was estimated recycled in 2025, 22 % of apparent consumption.",
      "substitutes": [
        "USGS: aluminum alloys, alternative copper-base alloys and plastics can substitute for tin in some uses."
      ],
      "source": "usgs-mcs2026-tin",
      "where": "World Mine Production and Reserves table, mine production 2025e: China 71,000, Indonesia 61,000, Peru 33,000, Brazil 28,000 thousand t; world total 290,000 (rounded). Shares calculated by Space Mushroom. Recycling and Substitutes sections."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "ATI Zirconium Alloys technical data sheet: Reactor Grade Zirconium (Zircaloy-2, Zircaloy-4, Zr-2.5Nb), version 1, 2015",
      "type": "datasheet",
      "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
      "year": 2015
    },
    {
      "title": "Liu et al., Characterisation of microstructural creep, strain rate and temperature sensitivity and computational crystal plasticity in Zircaloy-4, arXiv:2109.05333",
      "type": "paper",
      "url": "https://arxiv.org/pdf/2109.05333",
      "year": 2021
    },
    {
      "title": "Zirconium alloys, Wikipedia (alloy composition table, oxidation, hydrides, applications; article titled Zircaloy)",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/Zircaloy",
      "year": 2026
    },
    {
      "title": "Zirconium, Wikipedia (Kroll process, standard atomic weight)",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/Zirconium",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Zirconium and Hafnium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zirconium-hafnium.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Niobium (Columbium)",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-niobium.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Tin",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.pdf",
      "year": 2026
    },
    {
      "title": "Open-access paper: Microstructure and Mechanical Properties of Hot-Rolled ZrAl14Ti3 and ZrAl14Ti9 Alloys (PMC12525182)",
      "type": "paper",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12525182/"
    }
  ],
  "gaps": [
    "No property values for Zircaloy-2, ZIRLO or Zr-2.5Nb were read in a page fetched in this run. The ATI sheet prints tensile and thermal values for Zircaloy-4 only. Open Zr-2.5Nb tensile papers (OSTI record, Springer article) returned no readable text here; search snippets are not used.",
    "ZIRLO iron content is not printed in any page read in this run. The Wikipedia alloy table gives only Sn and Nb for ZIRLO, so the nominal iron level is left out.",
    "Zircaloy-4 longitudinal yield strength at room temperature (80 MPa) in the ATI table sits oddly next to its 541 MPa tensile strength and looks anomalous, so it is not recorded. Only transverse and 288 degC yields are used.",
    "Zr-Al values come from two research alloys (ZrAl14Ti3 and ZrAl14Ti9, at. %, hot-rolled and quenched) in one paper. No commercial Zr-Al grade, and no property range across the Zr-Al composition, was found. Patent and supplier snippets were not used.",
    "Zr-Al and the commercial alloys have no hazard, SDS or GHS record read in this run, so risks.hazards is empty. The zirconium metal powder hazard is covered in the zirconium.yaml profile, not here.",
    "Non-canonical property names used: thermal_neutron_cross_section and alpha_beta_transition_temperature. Neither is in spores/property-canon.yaml.",
    "Hardness (89 Rb for Zircaloy-4), electrical resistivity, outgassing and radiation damage were printed or searched but not recorded as values for these alloys.",
    "Critical-mineral status of zirconium, tin and niobium is not stated in the USGS summaries read here, so critical_lists is empty.",
    "EN, DIN and JIS designations for these grades were not found in a page read in this run. Only UNS, ASTM-style trade names and the ZIRLO trade name are listed.",
    "No media is included for this profile.",
    "The year of the PMC paper is not printed on the page read in this run, so the source record gives no year."
  ],
  "story": {
    "why": "Zircaloy-2 and Zircaloy-4 are the workhorse fuel cladding alloys of water reactors. Zircaloy-4 has the same tin content as Zircaloy-2 but more iron and no nickel, which the ATI sheet says reduces hydrogen uptake in certain reactor conditions. Zr-2.5Nb adds niobium for strength and is used for CANDU pressure tubes. ZIRLO, a Westinghouse alloy with about 1 wt % niobium and 0.7 to 1 wt % tin, is used for cladding in boiling and pressurized water reactors. The alloys keep the low thermal neutron cross section of zirconium (0.18 barns) and its corrosion resistance, with Zircaloy-4 at 0.22 barns.",
    "uses": [
      {
        "where": "Fuel cladding in pressurized water reactors",
        "line": "ATI says Zircaloy-4 is typically used as fuel cladding in pressurized water reactors and CANDU reactors. Wikipedia lists Zircaloy-4 as cladding and structural components in BWR, PWR and CANDU reactors."
      },
      {
        "where": "Cladding and calandria tubing in boiling water and CANDU reactors",
        "line": "ATI says Zircaloy-2 has been used mainly as fuel cladding in boiling water reactors and as calandria tubing in CANDU reactors."
      },
      {
        "where": "Pressure tubes in CANDU reactors",
        "line": "ATI says Zr-2.5Nb has been used for CANDU pressure tubes. Wikipedia adds that a Zr-2.5Nb alloy is formed into a knee or hip implant and then oxidised to give a hard ceramic bearing surface."
      },
      {
        "where": "ZIRLO cladding (Westinghouse)",
        "line": "The Wikipedia alloy table lists ZIRLO as Westinghouse cladding for BWR and PWR reactors, with 0.7 to 1 wt % Sn and 1 wt % Nb."
      }
    ],
    "can_do": [
      {
        "label": "Resist hot acid",
        "line": "Zircaloy-4 corrodes at 0.05 mm/a in 70 % nitric acid at 120 °C, and under 0.13 mm/a in 70 % sulfuric acid at 150 °C. Hydrochloric acid at 70 % and 160 °C is worse, at 0.36 mm/a.",
        "scope": "material",
        "value": "0.05 mm/a"
      },
      {
        "label": "Carry heat",
        "line": "Zircaloy-4 conducts heat at 21.5 W/m-K. ATI says zirconium alloys conduct heat better than stainless steel alloys.",
        "benchmark": "thermal_conductivity",
        "scope": "material",
        "value": "21.5 W/m-K"
      },
      {
        "label": "Weight",
        "line": "Zircaloy-4 has a density of 6.55 g/cc, and the ATI sheet gives its melting point as 1850 °C.",
        "benchmark": "density",
        "scope": "material",
        "value": "6.55 g/cc"
      },
      {
        "label": "Tensile strength",
        "line": "Annealed Zircaloy-4 strip has a room-temperature tensile strength of 541 MPa longitudinally and 515 MPa transversely. At 288 °C the longitudinal value falls to 271 MPa.",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material",
        "value": "541 MPa"
      },
      {
        "label": "Research alloy strength",
        "line": "In one open-access paper, the research alloy ZrAl14Ti3 reached an offset yield strength of 888 MPa, and ZrAl14Ti9 reached 998 MPa, with about 23 % fracture elongation for both. These are research alloys with no commercial grade.",
        "benchmark": "yield_strength",
        "scope": "material",
        "value": "888 MPa"
      }
    ],
    "compare": "Zircaloy-4 has a thermal neutron cross section of 0.22 barns, against 0.18 barns for pure zirconium, and a thermal conductivity of 21.5 W/m-K. Zr-Al is a different class: the research alloys reach about 888 to 1069 MPa at room temperature, far above the 541 MPa annealed Zircaloy-4 strip, but no corrosion or thermal data were found for them. Read the rows as grades of one family, not as a ranking that covers every alloy.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Thermal conductivity",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      },
      {
        "label": "Tensile strength",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material"
      }
    ],
    "handling": [
      "Specify the grade (Zircaloy-2, Zircaloy-4, Zr-2.5Nb or ZIRLO), because tin, iron, nickel and niobium levels differ.",
      "Keep hydrogen impurity low: 0.0025 % maximum in Zircaloy-2 and -4, 0.0010 % in Zr-2.5Nb.",
      "Keep carbon and nitrogen low, since large amounts degrade corrosion resistance (Wikipedia)."
    ],
    "good_for": [
      "Fuel cladding in water reactors: Zircaloy-4 is typically used in pressurized water and CANDU reactors (ATI).",
      "Low neutron absorption: 0.22 barns for Zircaloy-4, against 0.18 barns for zirconium (ATI).",
      "Corrosion in mild acid: under 0.13 mm/a for hot sulfuric acid and 0.05 mm/a for 70 % nitric acid at 120 °C (ATI)."
    ],
    "watch_out": [
      "Hot hydrochloric acid attacks Zircaloy-4 at 0.36 mm/a, and hydrogen from water forms hydrides that embrittle the cladding.",
      "Hafnium contamination adds neutron absorption: 104 barns for hafnium against 0.22 barns for Zircaloy-4.",
      "Strength of Zircaloy strip depends on direction, so the grain orientation must be stated."
    ],
    "verdict": "Zircaloy-4 and Zr-2.5Nb are the grades with the most published data for nuclear service, and the printed data support their use in water and steam. The research Zr-Al alloys are stronger at room temperature, but they have no commercial grade or corrosion data yet. Hydride cracking and hot hydrochloric acid are the main limits.",
    "recipe": {
      "line": "Zircaloys are zirconium with small additions of tin, iron, chromium and, for Zircaloy-2, nickel. Zircaloy-4 has the nominal composition Zr-1.5Sn-0.2Fe-0.1Cr (ATI; also arXiv). Zr-2.5Nb is zirconium with 2.4 to 2.8 wt % niobium. Most zirconium metal is made by reducing zirconium(IV) chloride with magnesium in the Kroll process (Wikipedia), and the alloy is then melted with its additions.",
      "parts": [
        {
          "name": "Zirconium",
          "symbol": "Zr",
          "role": "Base metal. Wikipedia says nuclear-grade zirconium alloys are more than 95 weight percent zirconium.",
          "share_percent": 95
        },
        {
          "name": "Tin",
          "symbol": "Sn",
          "role": "Main alloying element in Zircaloy-2, Zircaloy-4 and ZIRLO; adds strength and helps corrosion resistance (ATI composition table).",
          "share_percent": 1.2,
          "share_high": 1.7
        },
        {
          "name": "Iron",
          "symbol": "Fe",
          "role": "Zircaloy-4 addition; Zircaloy-2 has 0.07 to 0.20 wt % (ATI composition table).",
          "share_percent": 0.18,
          "share_high": 0.24
        },
        {
          "name": "Chromium",
          "symbol": "Cr",
          "role": "Zircaloy-4 addition; Zircaloy-2 has 0.05 to 0.15 wt % (ATI composition table).",
          "share_percent": 0.07,
          "share_high": 0.13
        },
        {
          "name": "Niobium",
          "symbol": "Nb",
          "role": "Zr-2.5Nb binary alloy addition for strength (ATI composition table). ZIRLO has about 1 wt % Nb (Wikipedia).",
          "share_percent": 2.4,
          "share_high": 2.8
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "No safety data sheet or hazard classification for these alloy grades was read in this run, so no personal hazard is stated here.",
        "points": [
          {
            "label": "Hydrogen",
            "line": "Zirconium reacting with water releases hydrogen gas, according to the Wikipedia alloy summary. This is a reactor and storage concern."
          }
        ],
        "level": 0,
        "verdict": "No hazard class found"
      },
      {
        "title": "If it fails",
        "lead": "These are failure routes in the sources. The cladding route is documented in a paper, the acid routes are printed table results.",
        "points": [
          {
            "label": "Hydride cracking",
            "line": "A Zircaloy-4 paper says hydride precipitation embrittles the alloy, and delayed hydride cracking threatens fuel cladding near notches and cracks. Wikipedia says hydrides blister and crack the cladding."
          },
          {
            "label": "Hot acid",
            "line": "The corrosion table prints 0.36 mm/a for Zircaloy-4 in 70 % hydrochloric acid at 160 °C, and 0.18 mm/a in 1 % ferric chloride at 135 °C."
          },
          {
            "label": "Strip direction",
            "line": "ATI says cold-rolled Zircaloy strip is much stronger in the transverse direction, so the orientation must be specified."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Grade",
            "line": "Specify the grade, since tin, iron, chromium, nickel and niobium levels differ between Zircaloy-2, Zircaloy-4 and Zr-2.5Nb."
          },
          {
            "label": "Impurities",
            "line": "Hydrogen is limited to 0.0025 % in Zircaloy-2 and Zircaloy-4, and to 0.0010 % in Zr-2.5Nb. Hafnium is limited to 0.010 %, because hafnium has a cross section of 104 barns."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 26,
    "unreachable": 2,
    "caveats": 3,
    "note": "Read by an AI assistant on 2026-10-26 from the ATI reactor-grade PDF, the arXiv PDF, the PMC paper, the Wikipedia alloy and zirconium pages, and the USGS niobium, tin and zirconium summaries. Unreachable in this run: the OSTI ZIRLO record and the Springer Zr-2.5Nb article (timeout and blocked page). Caveats: the Zircaloy-4 longitudinal yield (80 MPa) is not used; ZIRLO and Zr-2.5Nb carry no numeric properties; Zr-Al values are from research alloys."
  },
  "sources": {
    "ati-reactor-grade": {
      "title": "Zirconium Alloys: Reactor Grade Zirconium, ATI Technical Data Sheet, version 1",
      "id": "UNS R60802 (Zircaloy-2), R60804 (Zircaloy-4), R60904 (Zr-2.5Nb)",
      "url": "https://www.atimaterials.com/Products/Documents/datasheets/zirconium/alloy/Zr_nuke_waste_disposal_v1.pdf",
      "year": 2015,
      "kind": "datasheet",
      "license": "Manufacturer datasheet, typical data, not for specification (cited, not reproduced)"
    },
    "arxiv-zircaloy4": {
      "title": "Characterisation of microstructural creep, strain rate and temperature sensitivity and computational crystal plasticity in Zircaloy-4 (Liu et al.)",
      "id": "arXiv:2109.05333",
      "url": "https://arxiv.org/pdf/2109.05333",
      "year": 2021,
      "kind": "paper",
      "license": "arXiv preprint (cited, not reproduced)"
    },
    "wikipedia-zr-alloys": {
      "title": "Zirconium alloys (Wikipedia, article reached from the Zircaloy redirect)",
      "url": "https://en.wikipedia.org/wiki/Zircaloy",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "wikipedia-zirconium": {
      "title": "Zirconium (Wikipedia; element, Kroll process, standard atomic weight)",
      "url": "https://en.wikipedia.org/wiki/Zirconium",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "usgs-mcs2026-zirconium": {
      "title": "Mineral Commodity Summaries 2026: Zirconium and Hafnium (Shelby N. Johnston, U.S. Geological Survey)",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zirconium-hafnium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-niobium": {
      "title": "Mineral Commodity Summaries 2026: Niobium (Columbium)",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-niobium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-tin": {
      "title": "Mineral Commodity Summaries 2026: Tin",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "pmc-zral": {
      "title": "Microstructure and Mechanical Properties of Hot-Rolled ZrAl14Ti3 and ZrAl14Ti9 Alloys (open access, PMC12525182)",
      "id": "PMID 41095285, PMCID PMC12525182",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC12525182/",
      "kind": "paper",
      "license": "CC BY 4.0"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/zirconium-alloys/"
}