Key findings

  • Designers, operators and regulators of nuclear power plants believe they need plan only for events that are statistically probable - thus neglecting events that can endanger the public and the environment

  • Assumptions and calculations of risk are valid only if accident scenarios play out according to predictions. Those assumptions and calculations are sometimes flawed.

  • Reactor owners and safety officials argue the old "one-size-fits-all" rulebook approach is expensive and inefficient; allowing utilities latitude to estimate risks and respond accordingly saves money and eases regulatory burdens.

  • Risk-based safety programs lose effectiveness without aggressive regulatory oversight, safety experts say.