format_version: "0.1"
id: fbd_reactor_2oo3
name: "Two-out-of-three overpressure trip (FBD)"
domain: chemical_batch
language: FBD
source:
  origin: authored
  reference: "Voted trip logic, authored for FBD language coverage"
  license: CC-BY-4.0
properties_file: props.yaml
safety_intent: "Any two of three pressure switches agreeing high must trip the reactor, but a single stuck-high switch must not trip it alone."
validation_status: candidate
variants:
  - file: clean.xml
    expected_verdict: true
    ground_truth:
      method: expert
  - file: bomb.xml
    expected_verdict: false
    violated_properties: [P1]
    ground_truth:
      method: fault-injection
      base_variant: clean.xml
      seeded_defect: "The (ps1 AND ps3) leg was dropped from the vote, so the outer switches cannot trip on their own."
      witness: "ps1=1, ps2=0, ps3=1 leaves trip=0 with two switches high."
metrics:
  pous: 1
  blocks: 4
  variables: 4
features: [blocks, voting, fan_in]
difficulty: medium
tags: [safety, voting, language-coverage]