Q92 — Loss of Condenser Vacuum Turbine Trip
055 Condenser Air Removal-G2.4.11 (4.2)
Given:
• The crew is performing S2.OP-AB.COND-0001 (LOSS OF CONDENSER VACUUM) due to a malfunction of the Condenser Air Removal system
• With Condenser Backpressure degrading, Unit 2 Turbine Load is being lowered in an attempt maintain condenser backpressure within the Allowable Operating Region of S2.OP-AB.COND-0001 Attachment 4, Condenser Absolute Pressure Limits
At time 19:00
• Condenser Backpressure has just exceeded the limit of S2.OP-AB.COND-0001 Attachment 4
• Unit 2 is at 45% Reactor Power
At 19:00 and in accordance with S2.OP-AB.COND-0001, which ONE of the following completes the statement below?
The crew will TRIP the _(1)_.
After the Reactor/Turbine is tripped, the crew will _(2)_.
• The crew is performing S2.OP-AB.COND-0001 (LOSS OF CONDENSER VACUUM) due to a malfunction of the Condenser Air Removal system
• With Condenser Backpressure degrading, Unit 2 Turbine Load is being lowered in an attempt maintain condenser backpressure within the Allowable Operating Region of S2.OP-AB.COND-0001 Attachment 4, Condenser Absolute Pressure Limits
At time 19:00
• Condenser Backpressure has just exceeded the limit of S2.OP-AB.COND-0001 Attachment 4
• Unit 2 is at 45% Reactor Power
At 19:00 and in accordance with S2.OP-AB.COND-0001, which ONE of the following completes the statement below?
The crew will TRIP the _(1)_.
After the Reactor/Turbine is tripped, the crew will _(2)_.
A. (1) Reactor (2) NOT perform S2.OP-AB.COND-0001 concurrently with 2-EOP-TRIP-1, Reactor Trip Or Safety Injection
B. (1) Reactor (2) perform S2.OP-AB.COND-0001 concurrently with 2-EOP-TRIP-1, Reactor Trip Or Safety Injection
C. (1) Turbine (2) NOT perform S2.OP-AB.COND-0001 concurrently with S2.OP-AB.TRB-0001, Turbine Trip Below P-9
D. (1) Turbine (2) perform S2.OP-AB.COND-0001 concurrently with S2.OP-AB.TRB-0001, Turbine Trip Below P-9
▶ Show Answer & Explanation
✓ D. Correct. For Part 1 and at 19:00, Reactor Power is 45% which is less than P-9. IAW S2.OP-AB.COND-0001 (LOSS OF CONDENSER VACUUM) CAS, the crew will trip the turbine when Condenser Backpressure exceeds the limit of S2.OP-AB.COND-0001 Attachment 4. For Part 2 and IAW S2.OP-AB.COND-0001 CAS, after the Turbine is tripped, the crew will perform S2.OP-AB.COND-0001 concurrently with S2.OP-AB.TRB-0001, Turbine Trip Below P-9.
✗ A. Incorrect but plausible. For Part 1, if Reactor Power had been above P-9, tripping the Reactor would have been correct IAW S2.OP-AB.COND-0001 CAS. For Part 2, transitioning to EOP-TRIP-1 and not continuing with S2.OP-AB.COND-0001 is correct if the reactor had been required to be tripped.
✗ B. Incorrect but plausible. For Part 1, if Reactor Power had been above P-9, tripping the Reactor would have been correct IAW S2.OP-AB.COND-0001 CAS. For Part 2, the candidate could have incorrectly concluded that performing EOP-TRIP-1 and S2.OP-AB.COND-0001 concurrently was required.
✗ C. Incorrect but plausible. Part 1 is correct. For Part 2, the candidate could incorrectly conclude that performing S2.OP-AB.COND-0001 concurrently with S2.OP-AB.TRB-0001, Turbine Trip Below P-9 was not required.
Ref: S2.OP-AB.COND-0001 | LO: NOS05ABCOND-05 (LOSS OF CONDENSER VACUUM) | Source: New | Cognitive: Higher
Connections
- Related procedures: AB.COND-0001 — Loss of Condenser Vacuum, AB.TRB-0001 — Main Turbine Abnormality
- Related systems: Condenser Air Removal, Main Turbine
- Related EOPs: EOP-TRIP-1 — Reactor Trip or Safety Injection
- Related exam: 2019 NRC Written Exam