Q37 — CW Malfunction Reactor Trip
075 CWS-A2.01 (4.2)
Given:
• Unit 2 is at 25% Reactor Power and rising as part of plant startup
At time 15:00
• The Circulating Water Intake Structure becomes damaged resulting in four of the Circulators becoming out of service
At time 15:01
• The crew enters S2.OP-AB.CW-0001 (CIRCULATING WATER SYSTEM MALFUNCTION)
Which ONE of the following completes the statement below?
In accordance with S2.OP-AB.CW-0001, the crew is REQUIRED to ___
• Unit 2 is at 25% Reactor Power and rising as part of plant startup
At time 15:00
• The Circulating Water Intake Structure becomes damaged resulting in four of the Circulators becoming out of service
At time 15:01
• The crew enters S2.OP-AB.CW-0001 (CIRCULATING WATER SYSTEM MALFUNCTION)
Which ONE of the following completes the statement below?
In accordance with S2.OP-AB.CW-0001, the crew is REQUIRED to ___
A. INITIATE a Rapid Load Reduction until condenser vacuum stabilizes within operational limits
B. COMMENCE an IMMEDIATE controlled plant shutdown
C. TRIP the Turbine
D. TRIP the Reactor
▶ Show Answer & Explanation
✓ D. Correct. IAW S2.OP-AB.CW-0001 CAS, with 4 or more circulators out of service AND Reactor Power greater than or equal to P-10 (10%), then the crew is required to TRIP the Reactor.
✗ A. Incorrect but plausible. When 4 of the 6 circulators become nonfunctional, condenser backpressure will degrade. S2.OP-AB.CW-0001 CAS contains guidance to perform a Rapid Power Reduction to stabilize condenser backpressure. Consequently, the candidate could incorrectly conclude that given the current plant conditions, a rapid load reduction is required.
✗ B. Incorrect but plausible. S2.OP-AB.CW-0001 Attachment 7 contains guidance to perform an immediate controlled turbine shutdown. Consequently, the candidate could incorrectly conclude that given the current plant conditions, a controlled plant shutdown is required.
✗ C. Incorrect but plausible. S2.OP-AB.CW-0001 CAS contains guidance to trip the turbine if condenser backpressure is outside the allowable operating region and Reactor Power is less than P-9 (49%). Consequently, the candidate could incorrectly conclude that given the current plant conditions, a Turbine trip is required.
Ref: S2.OP-AB.CW-0001 | LO: NOS05ABCW01-11 (CIRCULATING WATER SYSTEM MALFUNCTION), Obj 5 — Given a set of initial plant conditions: A. Determine the appropriate abnormal procedure B. Describe the plant response to actions taken C. Describe the final plant condition | Source: New | Cognitive: Comprehension/Analysis
Connections
- Related systems: Circ Water
- Related procedures: AB.CW-0001 — Circulating Water Malfunction
- Related exam: 2019 NRC Written Exam