Q89 — SW CFCU Isolation / Water Hammer
022A2.04 (3.2)
Given:
• Unit 2 is in MODE 4.
• Personnel performing work in Containment notify the Control Room of a large Service Water Cooler leak on 22 CFCU.
• The crew has entered S2.OP-AB.SW-0001, Loss of Service Water Header Pressure.
In accordance with S2.OP-AB.SW-0001, complete the following statements concerning isolating a service water leak on a CFCU:
(1) The CRS will direct stopping 22 CFCU and isolating the SW leak by closing the ____(1)___.
(2) The basis for this action is to ___(2)___.
• Unit 2 is in MODE 4.
• Personnel performing work in Containment notify the Control Room of a large Service Water Cooler leak on 22 CFCU.
• The crew has entered S2.OP-AB.SW-0001, Loss of Service Water Header Pressure.
In accordance with S2.OP-AB.SW-0001, complete the following statements concerning isolating a service water leak on a CFCU:
(1) The CRS will direct stopping 22 CFCU and isolating the SW leak by closing the ____(1)___.
(2) The basis for this action is to ___(2)___.
A. (1) SW58 (Inlet Water Valve) first and then the SW72 (Outlet Water Valve).
(2) allow closing the SW54 (CFCU SW Inlet) and SW76 (CFCU SW Outlet) in the field with a lower differential pressure across the valves.
(2) allow closing the SW54 (CFCU SW Inlet) and SW76 (CFCU SW Outlet) in the field with a lower differential pressure across the valves.
B. (1) SW72 (Outlet Water Valve) first and then the SW58 (Inlet Water Valve).
(2) allow closing the SW54 (CFCU SW Inlet) and SW76 (CFCU SW Outlet) in the field with a lower differential pressure across the valves.
(2) allow closing the SW54 (CFCU SW Inlet) and SW76 (CFCU SW Outlet) in the field with a lower differential pressure across the valves.
C. (1) SW58 (Inlet Water Valve) first and then the SW72 (Outlet Water Valve).
(2) minimize the possibility of water hammer following restoration.
(2) minimize the possibility of water hammer following restoration.
D. (1) SW72 (Outlet Water Valve) first and then the SW58 (Inlet Water Valve).
(2) minimize the possibility of water hammer following restoration.
(2) minimize the possibility of water hammer following restoration.
▶ Show Answer & Explanation
✓ D. Correct. S2.OP-AB.SW-0001(Q), Loss of Service Water Header Pressure, Attachment 5 directs the closure order of SW72 (Outlet) first to minimize water hammer potential.
✗ A. Incorrect. Plausible because the candidate may believe that the inlet valve would be closed first to allow the CFCU to drain. The candidate may also believe this action will result in a lower differential across the manual valves located in the field on 78' elevation.
✗ B. Incorrect. The first part is correct. The second part is plausible because the candidate may also believe this action will result in a lower differential across the manual valves located in the field on 78' elevation.
✗ C. Incorrect. Plausible because the candidate may believe that the inlet valve would be closed first to allow the CFCU to drain. The second part is correct.
Ref: S2.OP-AB.SW-0001(Q), Loss of Service Water Header Pressure and Bases | LO: N/A | Source: New | Cognitive: Comprehension
Connections
- Related systems: Service Water, CFCUs
- Related procedures: AB.SW-0001 — Loss of SW Header Pressure
- Related exam: 2020 NRC Written Exam