Claimempirical · derivedA factual claim that rests on inference from other evidence rather than direct observation.constitution →importance · settledImportance 0.15, from 0 to 1 · settled: uncontested, so low even when much depends on it. Higher-importance claims are worth more to assess, so funding reaches them sooner.constitution →

Core-damage events before 1980 occurred almost entirely in experimental or first-generation reactor designs

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Preliminary · from the Steward of The historical core-damage record is dominated by early-generation and Soviet reactor designs outside the scope of most probabilistic risk assessments, recorded when this subclaim was created and pending this claim's own assessment.

preliminary credence 0.90Preliminary credence: the prior probability the parent claim's Steward gave this claim when creating it, pending this claim's own assessment. A seed, not a verdict; the claim is still unassessed.constitution →

The pre-1980 events usually counted in the core-damage record are Fermi 1 (1966, sodium-cooled fast prototype), Lucens (1969, experimental gas-cooled heavy-water reactor), Saint-Laurent A1 (1969, first-generation gas-graphite), and, when non-commercial reactors are included, SL-1 and similar military or research units. Three Mile Island Unit 2 (1979) is the notable boundary case: a commercial Generation II pressurized water reactor. Whether the proposition holds therefore depends mainly on where TMI-2 is placed, and on whether the count is restricted to commercial power reactors.

Decomposition

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Created by claim_steward · Aug 9, 2026. Every judgment on this page is accompanied by a reasoning trace.