- Redundant system data from Action 3 in the Baseline Development module for up to two energy or water redundant systems per critical load (referred to as a first and second redundant system)
- Critical load characterization from Action 2 in the Baseline Development module and Action 1 in the Risk Assessment module
- Input to risk screening tool
In this action, review the vulnerability of energy and water systems that support critical loads, which is calculated based on inputs from earlier actions. Vulnerability analysis in the TRN is specifically focused on the capability of onsite redundant energy and water systems to meet critical load requirements during a disruption, and the expected reliability of those systems. Condition of the primary energy and water supply infrastructure itself is considered to be implicit in the frequencies and outage durations selected in the hazard analysis.
A key input for the TRN risk assessment is the vulnerability of onsite redundant energy and water systems that support critical loads.
Based on data inputs from Baseline Development Actions 2 and 3 and Risk Assessment Actions 1 and 2, the TRN estimates the probability that the redundant system could fail. This probability represents the vulnerability of the system and is used in the risk assessment. If the estimated vulnerability seems unrealistic, use the professional judgement of relevant staff (e.g., energy and water managers) to assign a vulnerability probability category to the redundant systems. This is an estimate of the likelihood of failure based on the experience of these personnel.