Q70 — Loss of Condenser Vacuum Trip Criteria
APE: 051 Loss of Condenser Vacuum-AA2.02 (3.9)
Given:
• Unit 2 is at 100% Reactor Power
At time 15:00
• The crew is reducing turbine load at 2 % / min in an attempt to stabilize condenser backpressure in accordance with S2.OP-AB.COND-0001 (LOSS OF CONDENSER VACUUM)
In accordance with S2.OP-AB.COND-0001, which ONE of the following completes the statement below?
___ is the MINIMUM load reduction rate at which a reactor trip is required.
• Unit 2 is at 100% Reactor Power
At time 15:00
• The crew is reducing turbine load at 2 % / min in an attempt to stabilize condenser backpressure in accordance with S2.OP-AB.COND-0001 (LOSS OF CONDENSER VACUUM)
In accordance with S2.OP-AB.COND-0001, which ONE of the following completes the statement below?
___ is the MINIMUM load reduction rate at which a reactor trip is required.
A. 15
B. 10
C. 7.5
D. 5
▶ Show Answer & Explanation
✓ D. Correct. IAW S2.OP-AB.COND-0001 CAS, if the turbine load reduction rate needs to increase to a MINIMUM of 5 % / min to stabilize condenser backpressure, then the crew is REQUIRED to TRIP the Reactor.
✗ A. Incorrect but plausible. Load reductions up to 15% / min are all within the capability of rod control and steam dumps. Consequently, all of the distractors are plausible.
✗ B. Incorrect but plausible. Load reductions up to 15% / min are all within the capability of rod control and steam dumps. Consequently, all of the distractors are plausible.
✗ C. Incorrect but plausible. Load reductions up to 15% / min are all within the capability of rod control and steam dumps. Consequently, all of the distractors are plausible.
Ref: S2.OP-AB.COND-0001 | LO: NOS05ABCOND-05 | Source: New | Cognitive: Lower
Connections
- Related systems: Condenser Air Removal, Main Turbine
- Related procedures: AB.COND-0001 — Loss of Condenser Vacuum
- Related exam: 2019 NRC Written Exam