{
  "id": "pwr-provisional-demonstration-basis-r2",
  "created_at": "2026-10-16T21:04:29.189154+00:00",
  "status": "proposed_for_checkpoint_A",
  "label": "Process demonstration\u2014unvalidated engineering estimates.",
  "original_DNBR_requirement": {
    "maximum_penalty_percent": 5,
    "status": "not established"
  },
  "objective": "Execute the complete eight-case PWR process using real reduced structural calculations and explicitly substituted thermal evidence; preserve unestablished original requirements.",
  "supplied": {
    "OD_mm": 9.5,
    "pitch_mm": 12.6,
    "gap_mm": 3.1,
    "bundle": [
      5,
      5
    ],
    "pressure_MPa": 15.5,
    "inlet_C": 290,
    "mass_flux_kg_m2s": 3000,
    "bowed_rod_power_kW_m": 25,
    "effective_support_stiffness_N_per_mm": [
      50,
      20
    ]
  },
  "mechanical_model": {
    "classification": "Native calculation with provisional inputs",
    "solver": "Existing unchanged CalculiX through its MCP server",
    "representation": "One initially straight, homogeneous hollow pipe beam; the neighbor is a geometric reference only. The 25-rod SteveCAD model is retained context, not the finite-element mesh.",
    "element": "B32R, native PIPE section; 100 elements, with 50/200-element pilot comparisons",
    "span_mm": 1000,
    "outer_radius_mm": 4.75,
    "wall_mm": 0.57,
    "elastic_modulus_MPa": 77420.0375,
    "poisson_ratio": 0.383780271027766,
    "material_source": "Previously retained Zircaloy-4 zero-cold-work/zero-fluence card at 573.15 K; no new material correlation.",
    "support": "Pinned lateral ends; axial datum at first end, free axial motion at other end; planar y displacement restrained, one torsional datum. Bending rotations remain free.",
    "grid": "A single bilateral, zero-preload incremental SPRINGA at z=500 mm represents aggregate transverse stiffness. It does not resolve individual springs/dimples, separation or strap clearance.",
    "load": "Prescribed x displacement at z=500 mm produces nominal 0/50/80/100% midplane closure against an undeformed neighbor. The actual nodal maximum and gap are checked independently.",
    "physical_meaning": "A forced-displacement sensitivity calculation, not an irradiation-induced natural-bow prediction. Grid displacement equals closure only because this reduced model explicitly imposes that arrangement.",
    "stiffness_comparison": "At the same imposed midpoint displacement, changing a colocated grid spring changes reaction but should not change the elastic beam deformation or bending stress. Report this as a model consequence.",
    "omitted": [
      "rod-to-rod contact and load redistribution",
      "grid strap interference",
      "spring/dimple travel/yield",
      "local cladding contact stress",
      "coolant/internal-pressure stresses",
      "pellet interaction",
      "creep and irradiation constitutive response",
      "thermal gradients"
    ],
    "contact_case": "100% is geometric touching at the nominal midplane; contact pressure and additional contact load remain not established.",
    "native_stress": "Use actual global axial stresses at native integration points and paired zero-closure subtraction. These are not an outer-surface peak or a local contact stress.",
    "manual": "Retained official CalculiX 2.20 manual: beam32r example, sections 6.2.33, 6.3.1, *BEAM SECTION, *SPRING. Native pipe FRD cross section may appear rectangular; do not present that expansion as CAD."
  },
  "thermal_model": {
    "classification": "Published experimental/simulation reference and unvalidated transferred estimate",
    "native_reuse": "Reuse exact completed CoolProp states and conditional bulk heat balance for identical input assumptions; no repeated property calls.",
    "bulk_assumptions": "63 mm square enclosure; all 25 rods at 25 kW/m; 0.5/1/1.5 m lengths; constant 15.5 MPa; steady adiabatic global balance. Only the bowed-rod power was supplied.",
    "mapping": {
      "0": [
        166
      ],
      "50": [
        170
      ],
      "80": [
        169
      ],
      "100": [
        167,
        168
      ]
    },
    "transfer": "HTRF 85% closure is a disclosed proxy for 80%. Preserve all source P/T/G and geometry differences. Report both contact arrangements separately.",
    "derived_quantity": "Published CHF divided by the assumed study mean heat flux may be shown only as an illustrative reference scaling index, never as study DNBR.",
    "stiffness": "Reuse identical thermal references for both stiffness states; no invented stiffness-to-CHF multiplier.",
    "uncertainty": "Spread of selected source rows and declared sensitivity cases; not a confidence interval or demonstrated conservative bound.",
    "unavailable": [
      "local flow redistribution",
      "wall-temperature field",
      "rod-to-rod heat transfer",
      "study CHF",
      "study DNBR",
      "5% DNBR compliance"
    ]
  },
  "EOL": {
    "classification": "Unvalidated transferred estimate",
    "source": "Retained X-750 plate aged 977 K for 24 h; NRU reference around 570\u2013573 K, fluence 6e24 n/m2.",
    "retention": 0.5021626470260343,
    "assumed_fresh_preload_N": 5,
    "conditional_EOL_preload_N": 2.5108132351301715,
    "separation": "This retained material/history-specific transfer estimate is reported separately; it is not the 20/50 stiffness ratio and is not included as a preload in the zero-preload incremental beam model."
  },
  "verification": {
    "scope": "Numerical execution and demonstration consistency only; no physical acceptance.",
    "required": [
      "All eight case identities and exact deck hashes",
      "Native completion and finite U/RF/S",
      "Actual midpoint displacement and nodal minimum gap",
      "Global x-force balance including anchor and prescribed-motion reactions",
      "Grid anchor reaction against the configured native linear spring relation",
      "Paired baseline subtraction at identical integration-point identities",
      "Three-level pilot comparison of bending stress and reaction",
      "Labels, source conditions and original DNBR status retained"
    ],
    "tolerances": {
      "displacement_mm": 1e-05,
      "force_balance_relative": 0.001,
      "force_absolute_N": 0.0001,
      "spring_reaction_relative": 0.001,
      "pilot_refinement_relative": 0.05
    },
    "missing_behavior": "Preserve failed result; hold B or result verification. Never fill missing native observations with predicted values."
  },
  "reviews": {
    "A": "Approve this exact demonstration basis and input decks, not engineering validity.",
    "B": "Review actual pilot and refinement evidence before remaining matrix cases.",
    "C": "Review complete evidence/report and explicitly authorize the identified public content/destination."
  },
  "retained": [
    {
      "path": "basis/provisional-literature-reference-inputs-r1.json",
      "sha256": "8563d4fe3c0f62d7832676888f61e76a7aa74c9b1cec5328bc4b4147c412d1f9"
    },
    {
      "path": "evidence/bulk-water-screen-results-r1.json",
      "sha256": "9e7645a210fc5152aba82a97336e0316410aef9759d73209c0df78036b26e31d"
    },
    {
      "path": "basis/cached-water-property-observations-r1.json",
      "sha256": "d13cf22033add6c20c3310de6d190d95f254d461b675862eca55b0c1a31cbeb2"
    },
    {
      "path": "basis/eol-reference-model-proposal-r1.json",
      "sha256": "ba498fa0e3ebfb83347b42da805255c47d665e03cde222841b46e6143a100563"
    },
    {
      "path": "evidence/eol-reference-proposal-arithmetic-r1.json",
      "sha256": "7388125e1e131bb78e7784575e4313620c1a2c7ed9623db6cf782b4e354719a4"
    },
    {
      "path": "basis/supplied-inputs.json",
      "sha256": "df196807b4b66afe59c35006cdd0671f54bb4506d6fdcf633dc8751da477468c"
    }
  ],
  "cases": [
    {
      "id": "fresh-000",
      "closure_percent": 0,
      "stiffness_N_per_mm": 50,
      "elements": 100,
      "midpoint_displacement_mm": 0.0,
      "reference": "fresh-000",
      "role": "matrix",
      "deck": {
        "path": "provisional-demo/r2/inputs/fresh-000.inp",
        "sha256": "5b66269b8eba1b8cc2aa9c4be2bcc3ee4f9f27bc3067a54bf94be29780366e38"
      },
      "nodes": {
        "first": 1,
        "last": 201,
        "middle": 101,
        "anchor": 202
      },
      "nominal_midplane_gap_mm": 3.1
    },
    {
      "id": "fresh-050",
      "closure_percent": 50,
      "stiffness_N_per_mm": 50,
      "elements": 100,
      "midpoint_displacement_mm": 1.55,
      "reference": "fresh-000",
      "role": "matrix",
      "deck": {
        "path": "provisional-demo/r2/inputs/fresh-050.inp",
        "sha256": "bc1621967af2dfc8554ddf60da10f9349ce298173b9d40a9a7516197240b2996"
      },
      "nodes": {
        "first": 1,
        "last": 201,
        "middle": 101,
        "anchor": 202
      },
      "nominal_midplane_gap_mm": 1.55
    },
    {
      "id": "fresh-080",
      "closure_percent": 80,
      "stiffness_N_per_mm": 50,
      "elements": 100,
      "midpoint_displacement_mm": 2.48,
      "reference": "fresh-000",
      "role": "matrix",
      "deck": {
        "path": "provisional-demo/r2/inputs/fresh-080.inp",
        "sha256": "32fefb63fd01941c641041aaa9c032d0a68b4a9e4037e8cfd4ae77a1d772eae7"
      },
      "nodes": {
        "first": 1,
        "last": 201,
        "middle": 101,
        "anchor": 202
      },
      "nominal_midplane_gap_mm": 0.6200000000000001
    },
    {
      "id": "fresh-100",
      "closure_percent": 100,
      "stiffness_N_per_mm": 50,
      "elements": 100,
      "midpoint_displacement_mm": 3.1,
      "reference": "fresh-000",
      "role": "matrix",
      "deck": {
        "path": "provisional-demo/r2/inputs/fresh-100.inp",
        "sha256": "1a6e04c3ac3a3a8cb97ae567634e21679b32c0233b88320e9052fd0d465d736a"
      },
      "nodes": {
        "first": 1,
        "last": 201,
        "middle": 101,
        "anchor": 202
      },
      "nominal_midplane_gap_mm": 0.0
    },
    {
      "id": "softened-000",
      "closure_percent": 0,
      "stiffness_N_per_mm": 20,
      "elements": 100,
      "midpoint_displacement_mm": 0.0,
      "reference": "softened-000",
      "role": "matrix",
      "deck": {
        "path": "provisional-demo/r2/inputs/softened-000.inp",
        "sha256": "95e6d37f23d69d08ef56cdd313de22b80f3b647b41daeceb71d06577361acd55"
      },
      "nodes": {
        "first": 1,
        "last": 201,
        "middle": 101,
        "anchor": 202
      },
      "nominal_midplane_gap_mm": 3.1
    },
    {
      "id": "softened-050",
      "closure_percent": 50,
      "stiffness_N_per_mm": 20,
      "elements": 100,
      "midpoint_displacement_mm": 1.55,
      "reference": "softened-000",
      "role": "matrix",
      "deck": {
        "path": "provisional-demo/r2/inputs/softened-050.inp",
        "sha256": "1a14b6ad329d716d9deac5a5d5f13d2caf5392e3a0a8cd0520ff36551d534b61"
      },
      "nodes": {
        "first": 1,
        "last": 201,
        "middle": 101,
        "anchor": 202
      },
      "nominal_midplane_gap_mm": 1.55
    },
    {
      "id": "softened-080",
      "closure_percent": 80,
      "stiffness_N_per_mm": 20,
      "elements": 100,
      "midpoint_displacement_mm": 2.48,
      "reference": "softened-000",
      "role": "matrix",
      "deck": {
        "path": "provisional-demo/r2/inputs/softened-080.inp",
        "sha256": "f9860e4b276b192ea4a4ec25f5ffb6e84f264249ad9efe3725acffc9ff17a691"
      },
      "nodes": {
        "first": 1,
        "last": 201,
        "middle": 101,
        "anchor": 202
      },
      "nominal_midplane_gap_mm": 0.6200000000000001
    },
    {
      "id": "softened-100",
      "closure_percent": 100,
      "stiffness_N_per_mm": 20,
      "elements": 100,
      "midpoint_displacement_mm": 3.1,
      "reference": "softened-000",
      "role": "matrix",
      "deck": {
        "path": "provisional-demo/r2/inputs/softened-100.inp",
        "sha256": "4e9f0f4e2306ceaf4172c6e598ad02ec1cda115350526dba5e237e8b2f7ab473"
      },
      "nodes": {
        "first": 1,
        "last": 201,
        "middle": 101,
        "anchor": 202
      },
      "nominal_midplane_gap_mm": 0.0
    },
    {
      "id": "fresh-050-refine-50",
      "closure_percent": 50,
      "stiffness_N_per_mm": 50,
      "elements": 50,
      "midpoint_displacement_mm": 1.55,
      "reference": "fresh-000",
      "role": "refinement",
      "deck": {
        "path": "provisional-demo/r2/inputs/fresh-050-refine-50.inp",
        "sha256": "aa894e3189e3d694a93fbbd0d23d38f47aeea04572699356c34b147e0c5a1e1e"
      },
      "nodes": {
        "first": 1,
        "last": 101,
        "middle": 51,
        "anchor": 102
      },
      "nominal_midplane_gap_mm": 1.55
    },
    {
      "id": "fresh-050-refine-200",
      "closure_percent": 50,
      "stiffness_N_per_mm": 50,
      "elements": 200,
      "midpoint_displacement_mm": 1.55,
      "reference": "fresh-000",
      "role": "refinement",
      "deck": {
        "path": "provisional-demo/r2/inputs/fresh-050-refine-200.inp",
        "sha256": "f8378cbaf6a3becfc68510b6dbe3750e39536a89140eecdd85f48211371b0b3f"
      },
      "nodes": {
        "first": 1,
        "last": 401,
        "middle": 201,
        "anchor": 402
      },
      "nominal_midplane_gap_mm": 1.55
    }
  ],
  "review_authority": "No review decision is contained in this document; decisions belong to the durable Wright run.",
  "encoding_correction": {
    "previous_basis": "provisional-demo/r1/basis.json",
    "prior_approved_run": "25c5ad28b63b485e99d5b46f02236de1",
    "scope": "Only spring stiffness lexical encoding changes: 50/20 become 50.0/20.0. All geometry, physical assumptions, loads, stiffness values, test criteria and limitations are identical.",
    "native_error": "CalculiX interprets a stiffness entry without a decimal point as a degree-of-freedom selector.",
    "prior_approval_scope": "Original basis approval retained on its exact original subject; no new-subject approval inferred."
  }
}