Q87 — Loss of RHR in Mode 5 / RCS Inventory Loss
APE: 025 Loss of RHRS-AA2.02 (3.8)
Given:
• Unit 2 is in MODE 5
• 21 RHR Loop is in service
• PZR Level is 10% and stable
At time 17:00
• The crew enters S2.OP-AB.RHR-0001 (Loss Of RHR) due to a malfunction of 21 RH18 (RHR HX FLOW CONT VALVE)
At time 17:05 (5 minutes later)
• PZR level is 9% and lowering
• 2R11A (Containment Particulate Monitor) reading is rising
In accordance with S2.OP-AB.RHR-0001, which ONE of the following completes the statement below?
At 17:05, the crew will _(1)_.
• Unit 2 is in MODE 5
• 21 RHR Loop is in service
• PZR Level is 10% and stable
At time 17:00
• The crew enters S2.OP-AB.RHR-0001 (Loss Of RHR) due to a malfunction of 21 RH18 (RHR HX FLOW CONT VALVE)
At time 17:05 (5 minutes later)
• PZR level is 9% and lowering
• 2R11A (Containment Particulate Monitor) reading is rising
In accordance with S2.OP-AB.RHR-0001, which ONE of the following completes the statement below?
At 17:05, the crew will _(1)_.
A. IMMEDIATELY GO TO S2.OP-AB.LOCA-0001 (Shutdown LOCA)
B. perform S2.OP-AB.RHR-0001 Attachment 9 (Steam Generator Reflux Cooling)
C. IMMEDIATELY GO TO S2.OP-AB.RHR-0002 (Loss of RHR at Reduced Inventory)
D. START Safety Injection and Charging Pumps as required and CONTROL Pressurizer level between 5% and 50% while maintaining RHR System in service
▶ Show Answer & Explanation
✓ D. Correct. In accordance with S2.OP-AB.RHR-0001 CAS, "IF AT ANY TIME a loss of RCS inventory occurs, THEN PERFORM one of the following: IF in Mode 5 OR 6, THEN START Safety Injection and Charging Pumps as required AND CONTROL Pressurizer level between 5% and 50% while maintaining RHR System in service."
✗ A. Going to S2.OP-AB.LOCA-0001 (Shutdown LOCA) would have been correct if the unit was in MODE 4 when the RCS inventory was lost (IAW S2.OP-AB.RHR-0001 CAS).
✗ B. Performing S2.OP-AB.RHR-0001 Attachment 9 (Steam Generator Reflux Cooling) would have been correct if at any time a complete loss of all vital buses occurs, NOT as a result of a Beyond-Design-Basis-External-Event (IAW S2.OP-AB.RHR-0001 CAS).
✗ C. Going to S2.OP-AB.RHR-0002 (Loss of RHR at Reduced Inventory) would have been correct if RCS had been aligned for operation <101 ft. elevation (S2.OP-AB.RHR-0001 Steps 3.3 and 3.4).
Ref: S2.OP-AB.RHR-0001 (Loss Of RHR) | LO: NOS05ABRHR1-05 (LOSS OF RHR) — 4. Given a set of initial plant conditions: A. Determine the appropriate abnormal procedure, B. Describe the plant response to actions taken in the abnormal procedure, C. Describe the final plant condition that is established by the abnormal procedure. | Source: New | Cognitive: Higher
Connections
- Related systems: RHR
- Related procedures: AB.RHR-0001 — Loss of RHR, AB.LOCA-0001 — Shutdown LOCA, AB.RHR-0002 — Loss of RHR at Reduced Inventory
- Related exam: 2018 NRC Written Exam