Q79 — AB.RCP-0001 Seal Cooling Loss and Natural Circulation
015/017 RCP Malfunctions-AA2.10 (3.7)
Given:
• Unit 2 is in MODE 3 with ALL Reactor Trip Breakers CLOSED
• 21 CV Pump is running
At time 18:00:00
• 2CC131 (RCP THERM BAR CC CONT VALVE) goes closed
• 21 CV Pump trips and 22 and 23 CV Pumps can NOT be started
• The crew enters S2.OP-AB.RCP-0001 (Reactor Coolant Pump Abnormality)
At time 18:20:00
• While performing S2.OP-AB.RCP-0001 Attachment 2 (Stopping Reactor Coolant Pumps) the crew observes the following temperatures:
21 RCP: 222 °F 22 RCP: 227 °F 23 RCP: 220 °F 24 RCP: 223 °F
(RCP Seal Inlet Temperatures)
In accordance with S2.OP-AB.RCP-0001 Attachment 2, which ONE of the following completes the statements below?
The crew _(1)_ REQUIRED to close 21-24CV104s (SEAL LEAKOFF) within 3-5 minutes after stopping 21-24 RCPs.
At 18:20:00, the crew will cool the RCP seals by performing _(2)_.
• Unit 2 is in MODE 3 with ALL Reactor Trip Breakers CLOSED
• 21 CV Pump is running
At time 18:00:00
• 2CC131 (RCP THERM BAR CC CONT VALVE) goes closed
• 21 CV Pump trips and 22 and 23 CV Pumps can NOT be started
• The crew enters S2.OP-AB.RCP-0001 (Reactor Coolant Pump Abnormality)
At time 18:20:00
• While performing S2.OP-AB.RCP-0001 Attachment 2 (Stopping Reactor Coolant Pumps) the crew observes the following temperatures:
21 RCP: 222 °F 22 RCP: 227 °F 23 RCP: 220 °F 24 RCP: 223 °F
(RCP Seal Inlet Temperatures)
In accordance with S2.OP-AB.RCP-0001 Attachment 2, which ONE of the following completes the statements below?
The crew _(1)_ REQUIRED to close 21-24CV104s (SEAL LEAKOFF) within 3-5 minutes after stopping 21-24 RCPs.
At 18:20:00, the crew will cool the RCP seals by performing _(2)_.
A. _(1)_ is NOT _(2)_ S2.OP-AB.RC-0004 (Natural Circulation)
B. _(1)_ is NOT _(2)_ S2.OP-AB.RCP-0001 Attachment 4 (Re-establishing RCP Seal Cooling)
C. _(1)_ IS _(2)_ S2.OP-AB.RCP-0001 Attachment 4 (Re-establishing RCP Seal Cooling)
D. _(1)_ is _(2)_ S2.OP-AB.RC-0004 (Natural Circulation)
▶ Show Answer & Explanation
✓ A. Correct. For Part 1 and based on the question stem, RCP Seal Injection Flow AND RCP Thermal Barrier Component Cooling flows are lost concurrently. Since Seal Leakoff is < 6 gpm, then IAW S2.OP-AB.RCP-0001 Attachment 2, the crew is not REQUIRED to close 21-24CV104s (SEAL LEAKOFF) within 3-5 minutes after stopping 21-24 RCPs (Step 1.4). For Part 2, IAW S2.OP-AB.RCP-0001 Attachment 2 Step 5.0, since ALL RCP Seal Inlet Temperatures are NOT less than 225 °F, the crew will cool the RCP seals by performing S2.OP-AB.RC-0004 (Natural Circulation).
✗ B. Part 1 is correct. For Part 2, if ALL RCP Seal Inlet Temperatures were less than 225 °F, the crew will cool the RCP seals by performing S2.OP-AB.RCP-0001 Attachment 4. Consequently, the candidate could incorrectly conclude that at 18:20:00, performing S2.OP-AB.RCP-0001 Attachment 4 is required.
✗ C. For Part 1, since RCP Seal Injection Flow AND RCP Thermal Barrier Component Cooling flows are lost concurrently, the candidate could incorrectly conclude that the crew is REQUIRED to close 21-24CV104s (SEAL LEAKOFF) within 3-5 minutes after stopping 21-24 RCPs. For Part 2, if ALL RCP Seal Inlet Temperatures were less than 225 °F, the crew will cool the RCP seals by performing S2.OP-AB.RCP-0001 Attachment 4. Consequently, the candidate could incorrectly conclude that at 18:20:00, performing S2.OP-AB.RCP-0001 Attachment 4 is required.
✗ D. For Part 1, the candidate could incorrectly conclude that the crew is REQUIRED to close 21-24CV104s (SEAL LEAKOFF) within 3-5 minutes after stopping 21-24 RCPs. Part 2 is correct.
Ref: S2.OP-AB.RCP-0001 (Reactor Coolant Pump Abnormality) | LO: NOS05ABRCP0-06 (REACTOR COOLANT PUMP ABNORMALITY) | Source: Modified Bank | Cognitive: Higher
Connections
- Related systems: RCPs, CCW, CVCS
- Related procedures: AB.RCP-0001 — RCP Abnormality, AB.RC-0004 — Natural Circulation
- Related exam: 2018 NRC Written Exam