Predicting accidents that are extremely unlikely to happen is now the business of American nuclear regulators. “The American people, and the regulators whose job it is to protect them from a catastrophic nuclear accident, are watching the unfolding events at a complex of crippled reactors in Japan with foreboding and an overriding question: Can it happen here? The answer—probably not—from the Nuclear Regulatory Commission is meant to reassure. … ‘We can never say that that could never happen here,’ said Anthony R. Pietrangelo, senior vice president and chief nuclear officer at the Nuclear Energy Institute.”