The Baseline for plant configuration to mitigate the various design basis events is described by which item?

• A. A probabilistic risk index
• B. The In-Service Testing schedule
• C. Technical Specification's Limiting Condition for Operation (LCO)
• D. The Mitigating Systems Performance Index (MSPI)

Answer: (C)

Focus on the baseline that ensures safety during design-basis events: the Limiting Condition for Operation described in the Technical Specifications. LCOs set the minimum performance and operability requirements for safety-related systems and components. They specify which equipment must be operable and outline the actions and timeframes needed to restore operability if a surveillance or condition is not met. This creates the essential operating envelope that guarantees those mitigating capabilities are ready when a design-basis event occurs.

Other options don’t establish that baseline. A probabilistic risk index focuses on overall risk quantify rather than the required operability of specific systems. The In-Service Testing schedule tracks routine testing, not the mandatory operability criteria during operation. The Mitigating Systems Performance Index monitors how well mitigating systems perform in practice, but it’s a performance metric, not the baseline criteria that define when equipment must be available to handle design-basis events.