Condition Assessment: Rotating Equipment, Hot-Section Creep, and Foundation Permafrost

Summary: All three subjects screen at Critical or Very High risk and warrant immediate attention. The monitored bearing shows advanced wear with vibration RMS up 3.99× and a 63.93 °C temperature rise, consistent with imminent failure. The hot-section alloy (Alloy 617 at 875 °C / 65 MPa) is predicted to rupture in roughly 419 hours (well under 1 year) under sustained load, based on a screening-level Larson-Miller fit. The foundation site sits in continuous permafrost with a Very High degradation risk score (0.95) and a thin, sensitive active layer. None of these are final engineering determinations — each is a data-driven screening result that must be confirmed by direct inspection, fitness-for-service analysis, or geotechnical investigation before decisions are made.

1. Rotating Equipment — Bearing Vibration

Status: Critical

• Asset: Rolling-element bearing (run-to-failure test dataset), two accelerometer channels sampled at 25,600 Hz.
• Vibration RMS (channel 2) rose from a baseline of 0.64 to a final 1.49 — a 3.99× increase.
• Bearing temperature climbed 63.93 °C, from 35.27 °C baseline to 99.19 °C at the final snapshot.
• Final-snapshot kurtosis was 3.04, with kurtosis peaking as high as ~6.4 mid-run — a pattern consistent with advanced wear or inadequate lubrication.
• Likely issue: Advanced wear / inadequate lubrication, with significant bearing-temperature rise confirming the vibration signal.
• Recommended action (per source diagnostic): Remove from service or inspect immediately; confirm with spectrum/envelope analysis and check lubrication/temperature.

*Provenance note:* Results are derived from real run-to-failure test data (Mendeley Data, doi:10.17632/5hcdd3tdvb, CC-BY-4.0), using stored time-domain features (RMS, kurtosis, temperature) from 12 snapshots across the test run — not raw waveforms. This is a demo/public dataset used for illustrative diagnostics, not necessarily your specific asset; treat the numeric thresholds as indicative of the diagnostic method rather than a direct reading of your equipment unless this dataset corresponds to your actual bearing.

2. Hot-Section Creep — Alloy 617

Status: Critical (<1 year)

• Conditions assessed: 875 °C at 65 MPa.
• Predicted rupture life: ~419 hours (~0 years).
• Larson-Miller parameter: 25,974 (C = 20), from a master curve fit to 306 real creep-rupture tests (R² = 0.975).
• Nearest experimental records (871 °C, 62–69 MPa) show measured rupture lives ranging from 545 to 1,930 hours, illustrating substantial heat-to-heat and product-form scatter around the mean-curve prediction.

*Provenance note:* Based on the draft ASME/INL technical basis for Alloy 617 (INL/EXT-15-36305 Rev. 2, DOE/INL public domain data); NIMS-sourced rows were excluded due to licensing. This is a mean-curve screening estimate only — actual rupture life for a specific heat/product form can differ significantly from the curve, as shown by the nearest-record scatter above. A heat-specific fitness-for-service assessment is required before any run/repair/replace decision.

3. Foundation Permafrost — Site (70.29°N, -148.5°W)

Status: Very High risk (score 0.95, confidence 0.79)

• Zone: Continuous permafrost.
• Mean annual air temperature: −9.7 °C (CHELSA v2.1, 1981–2010 normals).
• Mean annual ground temperature: −5.9 °C at top of permafrost (Obu 2019); −4.3 °C at 0.5 m, −5.0 °C at 1 m, −5.9 °C at 2 m depth (GIPL, bias-corrected +2.1 °C to borehole data).
• Active layer thickness: 0.54 m — a thin active layer, meaning near-surface freeze/thaw activity is close to the foundation zone.
• Talik thickness: 0 m (no unfrozen zone detected beneath permafrost at this location).
• Regional warming rate: 0.65 °C/decade from the 2010 climate baseline — relevant to long-term foundation planning.

*Provenance note:* This is a fused-model estimate (Pastick et al. 2015, USGS public domain; Obu et al. 2019, CC-BY-3.0; GIPL/SNAP UAF RCP4.5 2021 baseline, CC-BY 4.0; CHELSA v2.1, CC0) at 0.05° resolution. GIPL outputs are model projections without historical hindcast. Confidence (0.79) reflects source agreement and distance from the 2010 baseline, not certainty of ground conditions at the exact site.

Recommended Next Steps

1. Bearing: Remove from service or schedule immediate inspection; run spectrum/envelope analysis and verify lubrication and temperature trends before any further operation.
2. Alloy 617 component: Do not treat the ~419-hour estimate as a hard deadline in either direction — commission a heat-specific creep/fitness-for-service assessment, and consider derating stress/temperature or scheduling replacement given the Critical classification.
3. Foundation site: Commission a geotechnical/permafrost field investigation (borehole thermistors, active-layer monitoring) before any construction or foundation design decision, given the Very High risk score and thin active layer.
4. Treat all three results as prioritization inputs for engineering follow-up, not as substitutes for certified inspection or analysis.

Screening-level assessment computed from the stated data sources. Field investigation and certified fitness-for-service assessment are required before any engineering decision.