Q76 (SRO) — LOCA-2 Charging Pump Reduction
008 PZR Vapor Space Accident-AA2.23 (4.3)
Given:
REFERENCE PROVIDED
• 2PR3 (PZR SAFETY VALVE) is fully open and will NOT reseat
• The crew is performing 2-EOP-LOCA-2 (POST LOCA COOLDOWN AND DEPRESSURIZATION) Step 22, "Charging Pump Reduction"
• 21 and 22 Charging Pumps are running
• 21 and 22 SI Pumps are running
• 21 and 22 RHR Pumps are stopped but available
• Containment Pressure is 2.5 psig
• ONLY 23 RCP is running
• RCS Subcooling is 50 °F
• PZR Level is 30%
• RCS T-HOTs are reading as follows:
Which ONE of the following completes the statement below?
The crew's NEXT Action(s) will be to ___
REFERENCE PROVIDED
• 2PR3 (PZR SAFETY VALVE) is fully open and will NOT reseat
• The crew is performing 2-EOP-LOCA-2 (POST LOCA COOLDOWN AND DEPRESSURIZATION) Step 22, "Charging Pump Reduction"
• 21 and 22 Charging Pumps are running
• 21 and 22 SI Pumps are running
• 21 and 22 RHR Pumps are stopped but available
• Containment Pressure is 2.5 psig
• ONLY 23 RCP is running
• RCS Subcooling is 50 °F
• PZR Level is 30%
• RCS T-HOTs are reading as follows:
| 21 T-HOT | 22 T-HOT | 23 T-HOT | 24 T-HOT |
|---|---|---|---|
| 375 °F | 370 °F | 364 °F | 368 °F |
Which ONE of the following completes the statement below?
The crew's NEXT Action(s) will be to ___
A. GO TO 2-EOP-LOCA-2 POST STEP 34
B. STOP 21 or 22 CHARGING Pump ONLY PER 2-EOP-LOCA-2 Step 22.4
C. RETURN TO 2-EOP-LOCA-2 POST STEP 14
D. RUN AT LEAST ONE RHR PUMP IN SI MODE THEN STOP 21 or 22 CHARGING Pump PER 2-EOP-LOCA-2 Steps 22.2 and 22.4
▶ Show Answer & Explanation
✓ B. Correct. Containment Conditions are NORMAL since Containment Pressure is less than 4.0 psig. IAW 2-EOP-LOCA-2 POST Step 22 Table C, Required Subcooling with 2 SI Pumps Running, 1 RCP Running and NORMAL Containment Conditions is 38 °F. Actual subcooling is 50 °F. Since the subcooling requirement is met, PZR level must be greater than 25% for NORMAL Containment Conditions. Actual PZR Level is 30%. Since the RCS subcooling and PZR Level requirements are BOTH met, the crew's next action (IAW 2-EOP-LOCA-2 POST Step 22) is to stop 21 or 22 Charging Pump.
✗ A. GOING TO 2-EOP-LOCA-2 POST STEP 34 is an option for 2-EOP-LOCA-2 (POST LOCA COOLDOWN AND DEPRESSURIZATION) Step 22, "Charging Pump Reduction". This would require the candidate to incorrectly perform Step 22.1 (Is RCS Subcooling Greater Than Required By Table C) and then correctly perform 22.2 (Are At Least Two T-Hots less than 365 °F).
✗ C. RETURNING TO 2-EOP-LOCA-2 POST STEP 14 is an option for 2-EOP-LOCA-2 (POST LOCA COOLDOWN AND DEPRESSURIZATION) Step 22, "Charging Pump Reduction". This would require the candidate to correctly perform Step 22.1 (Is RCS Subcooling Greater Than Required By Table C) and then to incorrectly perform Step 22.4 (Is PZR Level Greater Than 25% (33% Adverse)).
✗ D. RUNNING AT LEAST ONE RHR PUMP IN SI MODE THEN STOP 21 or 22 CHARGING Pump is an option for 2-EOP-LOCA-2 (POST LOCA COOLDOWN AND DEPRESSURIZATION) Step 22, "Charging Pump Reduction". This would require the candidate to incorrectly perform Step 22.1 (Is RCS Subcooling Greater Than Required By Table C) and then incorrectly perform 22.2 (Are At Least Two T-Hots less than 365 °F).
Ref: 2-EOP-LOCA-2 POST Step 22 | LO: NOS05LOCA02-03 | Source: New | Cognitive: Higher
Connections
- Related systems: ECCS, CVCS, Pressurizer & PRT, RCS
- Related EOPs: EOP-LOCA-2 — Post LOCA Cooldown and Depressurization
- Related exam: 2019 NRC Written Exam