JPM SRO-A1 — Determine Which ECCS Pumps Can Be Stopped
Admin | SRO | G2.1.7 (4.7)
Location: Classroom
Time-Critical: No
Alternate Path: No
Estimated Time: 5 minutes
Initial Conditions:
- At 0500 Salem 2 reactor was manually tripped and Safety Injection automatically actuated as a result of a small break LOCA.
- 21 RHR pump was C/T for maintenance and 22 RHR pump tripped while in 2-EOP-LOCA-1.
- The crew has transitioned to 2-EOP-LOCA-5 due to no recirculation capability.
- The crew is performing the major action steps (minimum SI flow for decay heat removal) of 2-EOP-LOCA-5.
- The following ECCS pumps are running:
- 21 SI pump with indicated flow of 420 gpm
- 22 Charging pump with indicated flow of 360 gpm
Initiating Cue:
- You are the Unit 2 CRS at Step 19.2 of 2-EOP-LOCA-5.
- DETERMINE the following:
1. At time 0550 hours, what is the minimum SI flow required from Figure A (attached)?
2. Which ECCS pumps can be stopped (if any) to reduce injection flow as close as possible to minimum flow from Figure A (assume that ECCS pump flows remain stable)?
Time-Critical: No
Alternate Path: No
Estimated Time: 5 minutes
Initial Conditions:
- At 0500 Salem 2 reactor was manually tripped and Safety Injection automatically actuated as a result of a small break LOCA.
- 21 RHR pump was C/T for maintenance and 22 RHR pump tripped while in 2-EOP-LOCA-1.
- The crew has transitioned to 2-EOP-LOCA-5 due to no recirculation capability.
- The crew is performing the major action steps (minimum SI flow for decay heat removal) of 2-EOP-LOCA-5.
- The following ECCS pumps are running:
- 21 SI pump with indicated flow of 420 gpm
- 22 Charging pump with indicated flow of 360 gpm
Initiating Cue:
- You are the Unit 2 CRS at Step 19.2 of 2-EOP-LOCA-5.
- DETERMINE the following:
1. At time 0550 hours, what is the minimum SI flow required from Figure A (attached)?
2. Which ECCS pumps can be stopped (if any) to reduce injection flow as close as possible to minimum flow from Figure A (assume that ECCS pump flows remain stable)?
Task Standard:
1. Min flow injection of 390 gpm (+/- 10 gpm).
2. Stops 22 Charging pump.
1. Min flow injection of 390 gpm (+/- 10 gpm).
2. Stops 22 Charging pump.
▶ Show Critical Steps & Key Actions
| Step | Critical Element | Standard |
|---|---|---|
| 1 * | Using Figure A, determine minimum SI flow at 50 minutes after trip | Time after trip = 0550 - 0500 = 50 minutes. From Figure A (Minimum ECCS Flow Versus Time After Trip), minimum SI flow is 390 gpm (+/- 10 gpm). |
| 2 * | Determine which ECCS pumps can be stopped | 21 SI pump (420 gpm) must remain in service — it alone exceeds the 390 gpm minimum. 22 Charging pump (360 gpm) can be stopped — it alone does NOT meet the 390 gpm minimum, and the 21 SI pump alone provides sufficient flow. |
Key Decision Point:
The applicant must first calculate time after trip (0550 - 0500 = 50 minutes), then read Figure A to determine 390 gpm minimum. The critical determination is which pump to keep and which to stop: 21 SI pump at 420 gpm exceeds the 390 gpm minimum alone, so it must stay running. 22 Charging pump at 360 gpm is below the minimum by itself and therefore can be stopped. Compare with the similar 2023 SRO-A1.a JPM where NEITHER pump could be stopped (160 gpm + 220 gpm = 380 gpm, but neither alone meets the 290 gpm minimum at 100 minutes).
The applicant must first calculate time after trip (0550 - 0500 = 50 minutes), then read Figure A to determine 390 gpm minimum. The critical determination is which pump to keep and which to stop: 21 SI pump at 420 gpm exceeds the 390 gpm minimum alone, so it must stay running. 22 Charging pump at 360 gpm is below the minimum by itself and therefore can be stopped. Compare with the similar 2023 SRO-A1.a JPM where NEITHER pump could be stopped (160 gpm + 220 gpm = 380 gpm, but neither alone meets the 290 gpm minimum at 100 minutes).
Ref: 2-EOP-LOCA-5 (Rev 31) | Task: 1150680502 | K/A: G2.1.7 — Ability to evaluate plant performance and make operational judgments based on operating characteristics, reactor behavior, and instrument interpretation | Source: New | View JPM PDF
Connections
- Related systems: ECCS, RHR
- Related EOPs: EOP-LOCA-5 — Loss of Emergency Coolant Recirculation, EOP-LOCA-1 — Loss of Reactor or Secondary Coolant
- Related exam: 2019 NRC Operating Exam