O-13 - Castle Bravo (1954) yielded 15 Mt against a predicted 4-8 Mt because the model neglected lithium-7 reactions
Used by the paper as its flagship historical example of model (as opposed to theory or calculation) failure: the underlying theory of the relevant nuclear reactions was understood, but the model of which reactions mattered was too narrow. Fallout affected the Marshall Islands and killed a Japanese fisherman.
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Why this is evidence
A carefully checked, high-stakes, hard-physics safety-relevant calculation failed not through bad theory or arithmetic but through a too-narrow model of which processes mattered — the failure mode internal rigor cannot catch. H-11 predicts such historical failures exist even in the most scrutinized nuclear-weapons-grade work; under H-46’s picture of robust expert safety argumentation, a headline model failure of this kind in exactly this genre of calculation is more surprising.