System

{{entity:STEP Fusion Power Plant}} ({{hex:DEC51019}}) QC session, se-step-fusion-power-plant. Project entry state: 220 requirements, 222 trace links, 11 baselines. Quality gate blocked: orphans 7 > 5. Previous session identified homeless requirements and missing IFC→VER coverage as primary residual items.

Findings

Quality gate blocker — 7/220 orphan requirements (all homeless): Seven requirements had no trace links and no document assignment. All carried the REQ-SESTEPFUSIONPOWERPLANT-0xx prefix indicating they were created without --document or --section flags. Breakdown by intended level:

• SUB-REQ-049 ({{entity:Tritium Plant Isotope Separation System}} ISS electrical power, 350 kW, 415 V AC, 30-min UPS)
• SUB-REQ-050 ({{entity:Tritium Plant Isotope Separation System}} ISS emergency isolation from {{entity:Plant Protection System}})
• SUB-REQ-051 ({{entity:Power Conversion System}} turbine hall physical siting, 15 kN/m² floor rating)
• SUB-REQ-052 ({{entity:Tritium Plant}} Category 1 confinement building, 600 mm walls, seismic nuclear-grade)
• SUB-REQ-053 ({{entity:Cryogenic Plant}} dedicated building, 800 m², 8 m clear height, oxygen depletion detection)
• SUB-REQ-054 ({{entity:Vacuum System}} 12-pump turbomolecular array, CF-300 flanges, 10 bar rated)
• SYS-REQ-016 (radiobiological protection, occupational dose ≤ 1 mSv/year, UK IRR 2017)

IFC verification gap: All 36 IFC requirements lacked verification activities. Previous session flagged IFC-001 through IFC-009 as the priority tranche — 9 interface requirements covering the primary energy and data paths with no verification procedures written.

Lint — 51 findings (6 high, 45 medium): High-severity findings are Ontological Mismatch ({{entity:power conversion system}} and {{entity:tritium plant}} lack {{trait:Physical Object}} trait despite physical housing requirements), acknowledged as known classification nuances rather than requirement defects. Medium-severity findings are primarily Coverage Gap items tracing concepts in STK but not in SYS/SUB — acceptable residual for this phase.

Corrections

Homeless requirement reassignment (7 requirements): SUB-REQ-049 through SUB-REQ-054 reassigned to subsystem-requirements; SYS-REQ-016 reassigned to system-requirements. All refs updated to document-appropriate prefixes.

Trace links created for all 7 formerly-orphaned requirements:

• {{sub:SUB-REQ-049}}, {{sub:SUB-REQ-050}}: traced from {{sys:SYS-REQ-005}} (tritium {{trait:Physical Medium}} confinement — both ISS power and emergency isolation requirements exist to maintain double-barrier confinement)
• {{sub:SUB-REQ-051}}: traced from {{sys:SYS-REQ-002}} (power conversion function drives turbine hall infrastructure)
• {{sub:SUB-REQ-052}}: traced from {{sys:SYS-REQ-005}} (Category 1 building is the physical outer confinement barrier for 100 g tritium inventory)
• {{sub:SUB-REQ-053}}: traced from {{sys:SYS-REQ-001}} (plasma burn requires superconducting magnets at 4.5 K, which requires the cryogenic plant building)
• {{sub:SUB-REQ-054}}: traced from {{sys:SYS-REQ-008}} (vacuum integrity requirement drives pump array physical configuration)
• {{sys:SYS-REQ-016}}: traced from {{stk:STK-REQ-011}} (worker dose limits stakeholder requirement flows to system radiobiological protection)

IFC verification procedures added (9 entries, VER-REQ-074 through VER-REQ-082): Commissioning-level test procedures written for {{ifc:IFC-REQ-001}} through {{ifc:IFC-REQ-009}}, covering: TCA/SMS magnetic field boundary test (Hall probe array at rated current), cryo/SMS 4.5 K coolant interface test (temperature stability ±0.05 K), tritium plant/TCA fuel injection interface test (simulant pellets), TCA/PCS thermal power transfer (500 MWth at rated fusion power), PCS/TCA diagnostic data latency test (≤1 ms round-trip, ≥40 channels), PCS/SMS coil current slew rate test and quench interlock verification, vacuum system/TCA base pressure test (≤1×10⁻⁶ Pa pump-down and leak detection), RHS/TCA maintenance port positioning test (±2 mm accuracy), and PCS/Grid power quality export test (≥100 MW, 400 kV ±5%, 50 Hz ±0.5 Hz, 24-hour sustained). Nine IFC→VER verifies trace links created.

Baseline BL-SESTEPFUSIONPOWERPLANT-012 created: 229 requirements, 238 trace links.

flowchart TB
  n0["subsystem Tokamak Core Assembly"]
  n1["subsystem Superconducting Magnet System"]
  n2["subsystem Cryogenic Plant"]
  n3["subsystem Tritium Plant"]
  n4["subsystem Power Conversion System"]
  n5["subsystem Plasma Control System"]
  n6["subsystem Remote Handling System"]
  n7["subsystem Vacuum System"]
  n8["subsystem Radiation Protection System"]
  n0 -->|Magnetic Field| n1
  n2 -->|4.5K Cooling| n1
  n3 -->|Fuel / Exhaust| n0
  n0 -->|Thermal Power| n4
  n5 -->|Control Commands| n0
  n5 -->|Coil Commands| n1
  n7 -->|Vacuum| n0
  n6 -->|Maintenance Access| n0
  n8 -.->|Shielding| n0

Residual

Coverage gap lint findings (45 medium): STK concepts not yet decomposed to SYS/SUB — e.g., “24-hour advance notification” ({{stk:STK-REQ-010}}), “environmental permitting regulations” ({{stk:STK-REQ-013}}), “as low as reasonably achievable” ({{sys:SYS-REQ-016}}). These represent requirements not yet written, not quality defects in existing requirements.

IFC-REQ-010 through IFC-REQ-036 (27 remaining interfaces) still lack verification procedures. The 9 written this session cover the primary energy path and main control interfaces; remaining IFC reqs cover secondary interfaces (cryo/tritium plant, vacuum/tritium, PCS/vacuum, PCS/tritium, coil power/SMS, RHS/tritium, and extended interface set from later sessions).

Ontological mismatch lint findings (6 high): {{entity:power conversion system}} ({{hex:DEC51018}}) and {{entity:tritium plant}} ({{hex:52953218}}) classified without {{trait:Physical Object}} trait. Physical housing requirements now exist (SUB-REQ-051, SUB-REQ-052) but the lint references IFC-REQ-004 and IFC-REQ-015 — the interface requirements predate the housing reqs. These are borderline classification calls for process-plant entities.

Next

Quality gate now clear (0/229 orphans). Advance to SE_VALIDATION for scenario coverage audit. The verification matrix has 87 VER entries against 229 requirements — prioritise sampling the safety-critical chain: {{stk:STK-REQ-003}} → {{sys:SYS-REQ-005}} → {{sub:SUB-REQ-010}} → VER-REQ-025 (tritium confinement chain). Continue adding VER entries for IFC-010 through IFC-036 in a follow-on QC pass if validation returns findings.