RVLIS stands for which system?

• A. Reactor Vessel Level Latching Indication System
• B. Reactor Vessel Levels Indicating System
• C. Reactor Vessel Level Indication System
• D. Reactor Vessel Level Indicating Subsystem

Answer: (B)

The name describes what the instrument does: it provides real-time indication of the reactor vessel water level across multiple thresholds. The plural “Levels” signals that the system covers several level points rather than a single value, and “Indicating System” shows it’s an integrated set of instruments that display those levels to operators. This is not about a latching function or a smaller subsystem; those ideas would imply different roles or scope. Therefore, the term Reactor Vessel Levels Indicating System best fits how this instrumentation is described and used in practice.