JPM Sim-g — RCS Cooldown Using MS10s
Sim | RO/SRO | 039 A4.07 (2.8/2.9)
Location: Simulator
Time-Critical: No
Alternate Path: No
Estimated Time: 5 minutes
Initial Conditions:
- The Unit 2 Reactor was manually tripped and Safety Injection was actuated due to a verified Steam Generator Tube Rupture on 24 Steam Generator.
- All required actions in EOP-TRIP-1 are complete.
- The crew is currently implementing EOP-SGTR-1, Steam Generator Tube Rupture, and all steps up to Step 9 are complete.
- Steam Dump Permissive light on 2RP4 is NOT illuminated due to an instrumentation failure. Steam Dumps are NOT available.
Initiating Cue:
- You are the Plant Operator.
- The CRS DIRECTS you to PERFORM an RCS Cooldown starting at Step 10 of 2-EOP-SGTR-1.
Time-Critical: No
Alternate Path: No
Estimated Time: 5 minutes
Initial Conditions:
- The Unit 2 Reactor was manually tripped and Safety Injection was actuated due to a verified Steam Generator Tube Rupture on 24 Steam Generator.
- All required actions in EOP-TRIP-1 are complete.
- The crew is currently implementing EOP-SGTR-1, Steam Generator Tube Rupture, and all steps up to Step 9 are complete.
- Steam Dump Permissive light on 2RP4 is NOT illuminated due to an instrumentation failure. Steam Dumps are NOT available.
Initiating Cue:
- You are the Plant Operator.
- The CRS DIRECTS you to PERFORM an RCS Cooldown starting at Step 10 of 2-EOP-SGTR-1.
Task Standard:
Correctly implements the steps of EOP-SGTR-1 to cooldown the RCS using MS10s to the required temperature of 503°F.
Correctly implements the steps of EOP-SGTR-1 to cooldown the RCS using MS10s to the required temperature of 503°F.
▶ Show Critical Steps & Key Actions
| Step | Critical Element | Standard |
|---|---|---|
| 10 * | Determine required RCS temperature using Table B | Uses Table B; determines required RCS temperature based on current ruptured 24 SG pressure (approx. 1045 psi) is 503°F. |
| 10.1 | Is intact SG available for cooldown? | Yes — 3 intact SGs are available for cooldown. |
| 10.2 | Are condenser steam dumps available? | NO — Steam Dumps are NOT available (permissive light on 2RP4 is NOT illuminated). |
| 10.2 * | Dump steam at maximum rate using intact SG MS10s | LOWERs setpoint on all intact SGs (21, 22, 23) until each MS10 is fully open. |
| 10.5 | Is hottest CET less than RCS cooldown temp? | No — waits for CET to reach target temperature (approx. 6-8 minutes). |
| 10.6 * | Stop cooldown — adjust each intact SG MS10 setpoint to match current SG pressure | Adjusts each intact SG MS10 setpoint to match current SG pressure, stopping steam release. |
Key Decision Point:
This JPM tests the RCS cooldown pathway during an SGTR when condenser steam dumps are unavailable. The applicant must: (1) use Table B to determine the target RCS temperature based on ruptured SG pressure (1045 psi corresponds to 503°F target); (2) recognize that steam dumps are NOT available due to the instrumentation failure (permissive light not illuminated on 2RP4) and select the MS10 atmospheric relief valves as the cooldown method; (3) lower setpoints on the three intact SGs (21, 22, 23 — NOT ruptured 24 SG) to fully open the MS10s for maximum-rate cooldown; (4) stop the cooldown by matching MS10 setpoints to current SG pressures when hottest CET reaches 503°F. Key SGTR concept: cooldown to a target temperature allows subsequent RCS depressurization to equalize pressure across the ruptured tube.
This JPM tests the RCS cooldown pathway during an SGTR when condenser steam dumps are unavailable. The applicant must: (1) use Table B to determine the target RCS temperature based on ruptured SG pressure (1045 psi corresponds to 503°F target); (2) recognize that steam dumps are NOT available due to the instrumentation failure (permissive light not illuminated on 2RP4) and select the MS10 atmospheric relief valves as the cooldown method; (3) lower setpoints on the three intact SGs (21, 22, 23 — NOT ruptured 24 SG) to fully open the MS10s for maximum-rate cooldown; (4) stop the cooldown by matching MS10 setpoints to current SG pressures when hottest CET reaches 503°F. Key SGTR concept: cooldown to a target temperature allows subsequent RCS depressurization to equalize pressure across the ruptured tube.
Ref: 2-EOP-SGTR-1 (R32) | Task: N1150190501 | K/A: 039 A4.07 — Ability to manually operate and/or monitor in the control room: Steam dump valves | Source: New | View JPM PDF
Connections
- Related systems: Main Steam, Steam Generator & Blowdown
- Related EOPs: EOP-SGTR-1 — Steam Generator Tube Rupture
- Related exam: 2020 NRC Operating Exam