Core Damage Frequency
CDF
Core damage frequency (CDF) is the expected number of core damage events per reactor-year, typically targeted below 10^-5.
Derived from PRA Level 1, CDF sums initiating event frequencies times failure probabilities. US fleet average ~5x10^-5/year pre-Fukushima, reduced via upgrades. Risk-informed apps adjust surveillance based on CDF.
Why it matters now
Low CDF enables 2025-2026 SMR financing for PPAs, with NRC emphasizing <10^-5 for advanced designs amid HALEU bottlenecks.