Q20 — Condenser Backpressure / Effect on Turbine
APE 51 AK1.02 (3.7)
Given:
• Unit 1 at 100%
• All circulators in service
• Condenser backpressure rising
What is the confirming indication and operational concern?
• Unit 1 at 100%
• All circulators in service
• Condenser backpressure rising
What is the confirming indication and operational concern?
A. Rising condenser diff temp, damage to LP turbine
B. Rising condenser diff temp, condensate pump cavitation
C. Lowering generator MWe, condensate pump cavitation
D. Lowering generator MWe, damage to LP turbine
▶ Show Answer & Explanation
✓ D. Correct. Rising backpressure makes LP turbines less efficient, resulting in lowering generator MWe output. Operational concern is overpressurization and damage to the main condenser/LP turbine.
✗ A. Condenser diff temp is not the best confirming indication — lowering MWe is the primary indicator of reduced LP turbine efficiency.
✗ B. Rising diff temp is the wrong indication. Concern is LP turbine damage, not condensate pump cavitation.
✗ C. Lowering MWe is the correct indication, but the concern is LP turbine damage not condensate pump cavitation.
Ref: NOS05MNTURB-14 | LO: NOS05MNTURB-14, Obj 13.c | Source: New | Cognitive: Fundamental/Memory
Connections
- Related systems: Main Turbine
- Related exam: 2023 NRC Written Exam