Inputs Needed
- 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
Outputs
- Understanding of risk scenarios that account for higher levels of risk
Overview
In this action, review the risk scenarios calculated based on the data collected in previous actions about energy and water systems that support critical loads. Most users will take no direct action, but rather review information generated automatically by the TRN to better understand how risk is calculated.
In-Depth
Risk in the TRN is calculated based on risk scenarios. Each risk scenario is defined by a unique combination of a critical load and a hazard that could cause an interruption to the energy or water supply to that load. In this action, you will review the unweighted and weighted risk results for each risk scenario generated automatically for your TRN framework based on previous inputs.
Specifically, these calculations are based on the hazard frequencies and outage durations collected in Risk Assessment Action 2, as well as critical load information collected in Baseline Development and Risk Assessment. 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 automatically estimates the probability that the redundant system could fail. This probability represents the vulnerability of the system and is used in the risk assessment. This key risk component, along with hazard frequency and consequence (characterized as outage duration) are brought together in the calculation of unweighted risk. Weighted risk is calculated by multiplying unweighted risk by the relevant criticality weighting factors.