Q67 — Independent Verification / Throttled Valve Position
T3 G2.2.14 (3.9)
Given:
- A valve lineup is being performed on a system that requires Independent Verification
- The valve lineup contains a valve that is required to be throttled open two turns
- Permission has been granted to move the valve as required to verify its position
What are the actions necessary to verify the position of this throttled open valve?
- A valve lineup is being performed on a system that requires Independent Verification
- The valve lineup contains a valve that is required to be throttled open two turns
- Permission has been granted to move the valve as required to verify its position
What are the actions necessary to verify the position of this throttled open valve?
A. One operator will go out ALONE and fully close the valve, then reopen it two full turns. Then, the second operator will go out ALONE and verify the valve is properly positioned by visual observation of the valve stem.
B. One operator will go out ALONE and fully open the valve, then close the valve the same number turns. Then, the second operator will go out ALONE and verify the valve is properly positioned by visual observation of the valve stem.
C. One operator will go out ACCOMPANIED by a second operator. One of the operators will fully close the valve, then reopen it two full turns while the second operator observe the actions.
D. One operator will go out ACCOMPANIED by a second operator. One of the operators will fully open the valve, then close the valve the same number of turns while the second operator observe the actions
▶ Show Answer & Explanation
✓ C. Correct. Per OP-AA-108-101-1001 and OP-AA-1008-101-1002, when a throttled valve position requires verification, then the valve is fully closed, then reopened to the required number of turns. The independent verification is performed by a second operator by either; independently counting the number of turns, verification of process variable, or verification of valve position for valves with incremental indicators against the tagout footnote or procedure.
✗ A. Plausible because typical independent verification of valve positions is performed after the first operator performs the valve manipulation and the second operator goes out alone to independently verify its position.
✗ B. Plausible because typical independent verification of valve positions is performed after the first operator performs the valve manipulation and the second operator goes out alone to independently verify its position.
✗ D. Plausible because the operator may confuse the direction of how the throttled valve must be positioned prior to returning to its throttled position. Fully closed vs. fully open.
Ref: OP-AA-108-101-1001 (R2), OP-AA-101-1002 (R11) | LO: NOS05CONDOP-14, Objective 5. Describe requirements for the following Control Room or Field Activities in accordance with applicable Conduct of Operations Manual Administrative Procedures: Shift Relief and Turnover | Source: Bank - Millstone U2 NRC RO69 | Cognitive: Fundamental/Memory
Connections
- Related procedures: OP-AA-108-101-1001 — Equipment Lineup Verification, OP-AA-108-101-1002 — Independent/Concurrent Verification
- Related exam: 2023 NRC Written Exam