Q95 — CCW Abnormality / RCP BRG CLG WTR FLO LO
G2.1.7 (4.7)
Given:
• Unit 2 is in MODE 3
• Reactor Trip Breakers are CLOSED
• ALL control rods are fully inserted into the core
• The crew is performing S2.OP-AB.CC-0001 (Component Cooling Abnormality)
At time 10:00
• 21 RCP BRG CLG WTR FLO LO alarm actuates
In accordance with S2.OP-AB.CC-0001, which ONE of the following completes the statements below?
If the 21 RCP BRG CLG WTR FLO LO alarm is still valid, _(1)_ is the EARLIEST time that the crew is required to perform S2.OP-AB.CC-0001 Attachment 2 (Stopping Reactor Coolant Pumps).
While performing S2.OP-AB.CC-0001 Attachment 2, the crew _(2)_ required to manually TRIP the Reactor.
• Unit 2 is in MODE 3
• Reactor Trip Breakers are CLOSED
• ALL control rods are fully inserted into the core
• The crew is performing S2.OP-AB.CC-0001 (Component Cooling Abnormality)
At time 10:00
• 21 RCP BRG CLG WTR FLO LO alarm actuates
In accordance with S2.OP-AB.CC-0001, which ONE of the following completes the statements below?
If the 21 RCP BRG CLG WTR FLO LO alarm is still valid, _(1)_ is the EARLIEST time that the crew is required to perform S2.OP-AB.CC-0001 Attachment 2 (Stopping Reactor Coolant Pumps).
While performing S2.OP-AB.CC-0001 Attachment 2, the crew _(2)_ required to manually TRIP the Reactor.
A. (1) 10:02 (2) is
B. (1) 10:02 (2) is NOT
C. (1) 10:05 (2) is
D. (1) 10:05 (2) is NOT
▶ Show Answer & Explanation
✓ C. Correct. For Part 1, IAW S2.OP-AB.CC-0001 (Selected CAS Items), if five minutes have elapsed since RCP BRG CLG WTR FLO LO alarm actuated, the crew will perform Attachment 2, Stopping Reactor Coolant Pumps. Since the 21 RCP BRG CLG WTR FLO LO alarm actuated at 10:00:00, 10:05:00 is the earliest time that the crew is required to perform S2.OP-AB.CC-0001 Attachment 2. For Part 2, IAW S2.OP-AB.CC-0001 Attachment 2, if the Reactor Trip Breakers are CLOSED, the crew will perform a manual Reactor TRIP prior to stopping the affected RCPs.
✗ A. Incorrect but plausible. For Part 1, S2.OP-AB.CC-0001 (Selected CAS Items) has an action which requires RCPs to be secured within 2 minutes to prevent RCP damage (RCP Seal Injection Flow AND RCP Thermal Barrier Component Cooling flow are lost concurrently). Consequently, the candidate could incorrectly conclude that if the 21 RCP BRG CLG WTR FLO LO alarm is still active, 10:02:00 is the earliest time that the crew is required to perform S2.OP-AB.CC-0001 Attachment 2 (Stopping Reactor Coolant Pumps). Part 2 is correct.
✗ B. Incorrect but plausible. For Part 1, S2.OP-AB.CC-0001 (Selected CAS Items) has an action which requires RCPs to be secured within 2 minutes to prevent RCP damage (RCP Seal Injection Flow AND RCP Thermal Barrier Component Cooling flow are lost concurrently). Consequently, the candidate could incorrectly conclude that if the 21 RCP BRG CLG WTR FLO LO alarm is still active, 10:02:00 is the earliest time that the crew is required to perform S2.OP-AB.CC-0001 Attachment 2 (Stopping Reactor Coolant Pumps). For Part 2, since the plant is in MODE 3 with ALL of the control rods already inserted fully into the core, the candidate could incorrectly conclude that a manual reactor trip is not required which allows the crew to secure the affected RCP faster.
✗ D. Incorrect but plausible. Part 1 is correct. For Part 2, since the plant is in MODE 3 with ALL of the control rods already inserted fully into the core, the candidate could incorrectly conclude that a manual reactor trip is not required which allows the crew to secure the affected RCP faster.
Ref: S2.OP-AB.CC-0001 | LO: NOS05ABCC01-09 Obj 4 | Source: Bank | Cognitive: Higher | SRO Only: Analyze plant parameters and determine when to implement attachments/appendices
Connections
- Related systems: CCW, RCPs
- Related procedures: AB.CC-0001 — Loss of Component Cooling Water
- Related exam: 2018 NRC Written Exam