United States Nuclear Regulatory Commission - Protecting People and the Environment

CCF Parameter Estimates

Quantitative results of the common-cause failure (CCF) data collection effort are presented for the current data set.

Equipment failures that contribute to CCF events are identified during searches of Licensee Event Reports (LER), Nuclear Plant Reliability Data System (NPRDS) failure reports, and Equipment Performance and Information Exchange (EPIX) failure reports.

The quantitative results are presented as both alpha factors and multiple Greek letter parameter estimations. The alpha factor distributions are also presented.

Current Results:

Historical Results:

Page Last Reviewed/Updated Tuesday, December 8, 2020