About RADS

In October 1994, the U. S. Nuclear Regulatory Commission (NRC) initiated rulemaking to require licensees to report reliability and availability data for the most risk-significant systems and equipment. Following the publication of the rule, the nuclear power industry proposed a voluntary alternative to the rule. The industry proposed to voluntarily provide data from its Safety System Performance Indicator (SSPI) System and the Equipment Performance and Information Exchange (EPIX) system, the replacement for NPRDS. These data would be used to meet NRC’s need for reliability data for Probabilistic Risk Assessment (PRA) and risk-informed applications.

As a result, the NRC has directed the staff to accept the voluntary alternative. The NRC will develop a data system that will contain the voluntary data and other data available to the NRC. This NRC Reliability and Availability Data System, denoted the RADS here, will provide NRC staff and industry a source of unit-specific and generic component-level data on reliability (demand failure probability, standby-stress failure rate, and rate of failure to operate) and train or component level data on availability (planned unavailability and unplanned unavailability). The RADS will be used by NRC staff:

· To provide improved estimates for identifying risk-significant generic issues and their priority.

· To develop risk-related performance indicators that would improve the process for selecting units for more focused attention

· To provide reliability parameters for NRC Simplified Plant Analysis Risk (SPAR) models

· To focus NRC inspections on the most risk significant systems

· To review requests for unit-specific licensing actions.

· In monitoring maintenance rule implementation

· In reliability analyses of selected risk-significant systems and components

· In identifying candidate common cause failure events

· In identifying times of concurrent train unplanned unavailability.

In addition, the RADS may be used by industry in submitting applications for unit-specific licensing actions.