2018 Q51 — RCP Vibration / LCO 3.4.1.2

✓ B. Correct. For Part 1, IAW S2.OP-AB.RCP-0001 CAS, when motor flange vibration greater than 5 mils, the crew will perform S2.OP-AB.RCP-0001 Attachment 2 and stop 22 RCP. For Part 2, LCO 3.4.1.2 only requires two of the reactor coolant loops to be OPERABLE (if the rod control system is de-energized). Consequently, at 07:00:00, RTB B is open and BOTH RTB Bypass Breakers are not racked in, so LCO 3.4.1.2 is met.

✗ A. Incorrect but plausible. Part 1 is correct. For Part 2, LCO 3.4.1.2 requires all loops to be OPERABLE if rod control is energized. Consequently, based on the question stem conditions, the candidate could incorrectly conclude that all four of the reactor coolant loops are required to be OPERABLE. This would then cause the candidate to further incorrectly deduce that LCO 3.4.1.2 is not met.

✗ C. Incorrect but plausible. For Part 1, S2.OP-AB.RCP-0001 CAS requires the RCP to be secured when shaft vibration is greater than 20 mils or motor flange vibration is greater than 5 mils. Consequently, the candidate could incorrectly conclude that the 22 RCP is stopped when the motor flange vibration exceeded a minimum of 20 mils. For Part 2, LCO 3.4.1.2 requires all loops to be OPERABLE if rod control is energized. Consequently, based on the question stem conditions, the candidate could incorrectly conclude that all four of the reactor coolant loops are required to be OPERABLE. This would then cause the candidate to further incorrectly deduce that LCO 3.4.1.2 is not met.

✗ D. Incorrect but plausible. For Part 1, S2.OP-AB.RCP-0001 CAS requires the RCP to be secured when shaft vibration is greater than 20 mils or motor flange vibration is greater than 5 mils. Consequently, the candidate could incorrectly conclude that the 22 RCP is stopped when the motor flange vibration exceeded a minimum of 20 mils. Part 2 is correct.

Ref: S2.OP-AB.RCP-0001, LCO 3.4.1.2 | LO: NOS05ABRCP0-06 | Source: New | Cognitive: Higher