Q70 — LOCA-2 T-COLD Cooldown Rate and BYPASS TAVG Pushbuttons
W/E03 LOCA Cooldown and Depressurization-EK2.1 (3.6)
Given:
• The crew is performing the RCS Cooldown To Cold Shutdown Steps of 2-EOP-LOCA-2 (Post LOCA Cooldown and Depressurization)
• Condenser Steam Dumps are available
Which ONE of the following completes the statements below?
In accordance with 2-EOP-LOCA-2, the crew will maintain T-COLD Cooldown Rate less than a MAXIMUM of _(1)_ °F / HR.
Depressing BEZEL Pushbutton(s) _(2)_ is/are the MINIMUM pushbutton manipulation(s) required to have the Condenser Steam Dumps function when TAVG is less than 543 °F.
• The crew is performing the RCS Cooldown To Cold Shutdown Steps of 2-EOP-LOCA-2 (Post LOCA Cooldown and Depressurization)
• Condenser Steam Dumps are available
TRAIN A
---
BYPASS
TAVG
---
BYPASS
TAVG
TRAIN B
---
BYPASS
TAVG
---
BYPASS
TAVG
In accordance with 2-EOP-LOCA-2, the crew will maintain T-COLD Cooldown Rate less than a MAXIMUM of _(1)_ °F / HR.
Depressing BEZEL Pushbutton(s) _(2)_ is/are the MINIMUM pushbutton manipulation(s) required to have the Condenser Steam Dumps function when TAVG is less than 543 °F.
| (1) | (2) |
A. 50 / A OR B
B. 50 / A AND B
C. 100 / A OR B
D. 100 / A AND B
▶ Show Answer & Explanation
✓ D. Correct. For Part 1, IAW 2-EOP-LOCA-2 Step 11, the crew will maintain T-COLD Cooldown Rate less than a maximum of 100 °F / HR. For Part 2, IAW 2-EOP-LOCA-2 Step 11, depressing BOTH "BYPASS TAVG" BEZEL Pushbuttons is the MINIMUM pushbutton manipulation(s) required to have the Condenser Steam Dumps function when TAVG is less than 543 °F.
✗ A. Incorrect but plausible. For Part 1, other procedures (S2.OP-IO.ZZ-0006 (HOT STANDBY TO COLD SHUTDOWN)) have an RCS Cooldown limit of 50 °F / HR. Consequently, the candidate could incorrectly conclude that 2-EOP-LOCA-2 also has an RCS Cooldown Rate limit of 50 °F / HR. For Part 2, if the Steam Dump Train A and Train B Blocking solenoids were in parallel, depressing BEZEL Pushbutton(s) A OR B would be the minimum pushbutton manipulation(s) to have the Condenser Steam Dumps function when TAVG is less than 543 °F. Additionally, for many safety systems, only 1 train is required to be OPERABLE for the safety system to perform its safety function. Consequently, the candidate could apply this logic to the steam dumps and incorrectly conclude that ONLY one Train of Steam Dumps need to be taken to "BYPASS TAVG" for Steam Dumps to function when TAVG is less than 543 °F.
✗ B. Incorrect but plausible. For Part 1, other procedures (S2.OP-IO.ZZ-0006 (HOT STANDBY TO COLD SHUTDOWN)) have an RCS Cooldown limit of 50 °F / HR. Consequently, the candidate could incorrectly conclude that 2-EOP-LOCA-2 also has an RCS Cooldown Rate limit of 50 °F / HR. Part 2 is correct.
✗ C. Incorrect but plausible. Part 1 is correct. For Part 2, if the Steam Dump Train A and Train B Blocking solenoids were in parallel, depressing BEZEL Pushbutton(s) A OR B would be the minimum pushbutton manipulation(s) to have the Condenser Steam Dumps function when TAVG is less than 543 °F. Additionally, for many safety systems, only 1 train is required to be OPERABLE for the safety system to perform its safety function. Consequently, the candidate could apply this logic to the steam dumps and incorrectly conclude that ONLY one Train of Steam Dumps need to be taken to "BYPASS TAVG" for Steam Dumps to function when TAVG is less than 543 °F.
Ref: 2-EOP-LOCA-2 (Post LOCA Cooldown and Depressurization) | LO: NOS05LOCA02-03 — Determine the indications that are monitored to ensure proper system/component operation for each step in the EOP for POST LOCA COOLDOWN AND DEPRESSURIZATION | Source: New | Cognitive: Higher
Connections
- Related systems: Steam Dumps, RCS
- Related EOPs: EOP-LOCA-2 — Post LOCA Cooldown and Depressurization
- Related exam: 2018 NRC Written Exam