If an operator is expected to be in the reactor area constantly, what would the conditional modifier for personnel presence be?

When evaluating the conditional modifier for personnel presence in a situation where an operator is expected to be constantly present in the reactor area, a value of 1 is appropriate. This indicates that the presence of the operator does not reduce the likelihood of an event occurring because they are always there to manage operations and respond to potential issues.

In Layer of Protection Analysis (LOPA), a conditional modifier of 1 signifies that the personnel's presence does not contribute to a reduction in risk, as they are fully available to intervene or address incidents in real-time. This contrasts with lower values, such as 0.5, 0.1, or 0.25, which would suggest varying degrees of absence or reduced effectiveness of personnel presence in risk management, thus implying a significant reduction in the operator's ability to react to potential incidents. Since the scenario clearly states the operator's constant presence, a modifier of 1 best represents the uninterrupted risk mitigation that personnel provide in such a setting.