In pressurized water reactors, a leakage path from the primary to the secondary side is referred to as what?

• A. Secondary System Impurities
• B. PWR primary to secondary leakage
• C. Primary to feedwater leakage
• D. Steam generator leakage

Answer: (B)

In a pressurized water reactor, the boundary between the primary coolant loop and the secondary steam system is the steam generator tubes. A leakage path from primary to secondary is called primary-to-secondary leakage. This term specifically describes a transfer of coolant (and any radioactivity it carries) across that boundary, usually through steam generator tubes that have developed a leak. It’s a critical indicator of boundary integrity and radiological safety, because contaminants from the primary side can enter the secondary loop and reach the turbine and other parts of the plant.

Other terms either describe contaminants in the secondary system (not the transfer path), a leakage that doesn’t cross the primary–secondary boundary, or a leakage within the steam generator itself without stating the cross-boundary transfer. So the conventional and most precise way to name this path is primary-to-secondary leakage.