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NUREG Investigation Report No. NUREG-LER-2022-001 2022 Operational Operational
Susquehanna 1 号机 主蒸汽隔离阀阀座磨损泄漏
Susquehanna Steam Electric Station, Unit 1 (NRC LER 50-387/2022-001-01)
Related equipment → Control valve (control_valve)
0Fatalities
0Injuries
FailureMechanism code ELP
⌗Failure Mode · ISO 14224 Mapping
Damage mechanism (recorded in KB)
FailureELP
ISO functional code (as recorded)
ISO 14224:2016 functional failure code
ELP · External leakage - process
ISO ELP — External leakage - process.
1What Happened

主蒸汽隔离阀(MSIV)阀座密封面磨损+沉积物导致内漏，被判不可运行（违反技术规格书）

2Root Cause

阀座密封面磨损与材料沉积物致内漏；未能识别阀门劣化趋势

3Reliability Lessons (from investigation root cause)
  • The 'Root Cause' above is the core lesson of this accident; not split further.
4Associated Failure Mechanisms (Keywords)
主蒸汽隔离阀 隔离阀 阀座 磨损 泄漏 内漏 阀门
About the Failure-Mode Code (click to expand)

The recorded code ELP is an ISO 14224:2016 functional failure code (describes what the equipment failed to do). The damage mechanism (how it failed) is shown in the Mapping block above. The two are distinct dimensions in ISO 14224.

5Evidence Source (transparent)
Authority：U.S. Nuclear Regulatory Commission (NRC) — Licensee Event Report (LER)
Official Report：www.nrc.gov ↗
Data Verification：verified_url_nrc_pdf_2026-07-24
↗Related Failure Modes · Traceability
阀门内漏/卡涩 FPH-C5-FM1Valve Body Corrosion / Erosion fmValve-seat Surface Damage -> Internal Leak fm_2Valve-plug Erosion fm_3Valve Stem Sticking / Bending fm_4Packing Wear -> External Leak fm_5Diaphragm Rupture fm_6Spring Fatigue / Fracture fm_7I/P Converter Failure i_pFeedback Link Loosening fm_8Coil Burnout fm_9Valve Plug Sticking -> Failure to Actuate fm_10Contact Corrosion / Poor Contact fm_11Filter-element Blockage -> Insufficient Supply fm_12Pressure-Relief Valve Set-point Drift fm_13阀座工艺介质泄漏 seat_leakage_process回座失效（持续泄漏） failure_to_reseat内漏增大·排量下降 internal_leakage_capacity内置安全阀泄漏/起跳 builtin_relief_valve_leak
Report No. NUREG-LER-2022-001 · Data from NUREG (US NRC) public investigation conclusions, compiled by Reliability AI, for reliability demonstration purposes only. This case is derived from public incident investigation reports for learning purposes only. AIM does not endorse or guarantee its accuracy.