Q16 — Main Steam Warmup MSIV Opening
039 MRSS-K5.01 (2.9)
Given:
- The crew is performing S2.OP-SO.MS-0001 (Main, Reheat, Turbine Bypass Steam Warmup) and is preparing to open 21-24MS167 (Main Steam Isolation Valves)
In accordance with S2.OP-SO.MS-0001, which ONE of the following completes the statements below?
The reason that 21-24MS7 (Main Steam Loop Drain Valves) are opened before 21-24MS167 is to _(1)_.
The crew will open 21-24MS167 when there is less than a MAXIMUM of _(2)_ psid across each valve.
- The crew is performing S2.OP-SO.MS-0001 (Main, Reheat, Turbine Bypass Steam Warmup) and is preparing to open 21-24MS167 (Main Steam Isolation Valves)
In accordance with S2.OP-SO.MS-0001, which ONE of the following completes the statements below?
The reason that 21-24MS7 (Main Steam Loop Drain Valves) are opened before 21-24MS167 is to _(1)_.
The crew will open 21-24MS167 when there is less than a MAXIMUM of _(2)_ psid across each valve.
A. (1) prevent pressurized steam from forcing residual water in the piping to cause water hammer on downstream components (2) 15
B. (1) prevent pressurized steam from forcing residual water in the piping to cause water hammer on downstream components (2) 50
C. (1) remove any collected corrosion products or impurities to ensure Main Turbine blading is not impinged (2) 15
D. (1) remove any collected corrosion products or impurities to ensure Main Turbine blading is not impinged (2) 50
▶ Show Answer & Explanation
✓ B. Correct. For Part 1, the reason that 21-24MS7 (Main Steam Loop Drain Valves) are opened before 21-24MS167 is to prevent pressurized steam from forcing residual water in the piping to cause water hammer on downstream components. For Part 2, The crew will open 21-24MS167 when there is less than a maximum of 50 psid across each valve.
✗ A. Part 1 is correct. For Part 2, there are multiple steps in S2.OP-SO.MS-0001 that require actions to be performed when MS Header pressure is ~15 psig. The candidate could incorrectly conclude that 21-24MS167 will be opened when there is less than a maximum of 15 psid across each valve.
✗ C. For Part 1, preventing damage to the Turbine is a general concern and the candidate could incorrectly conclude that 21-24MS7 are opened to remove corrosion products or impurities to ensure Main Turbine blading is not impinged. For Part 2, there are multiple steps in S2.OP-SO.MS-0001 that require actions when MS Header pressure is ~15 psig. The candidate could incorrectly conclude 15 psid is the maximum delta-P for opening MS167s.
✗ D. For Part 1, preventing damage to the Turbine is a general concern and the candidate could incorrectly conclude that 21-24MS7 are opened to remove corrosion products or impurities. Part 2 is correct.
Ref: S2.OP-SO.MS-0001 | LO: NOS05MSTEAM-11 — Given industry operating experience, review the OE and outline a course of action to prevent recurrence | Source: Modified Bank (ILOT 0901) | Cognitive: Lower (Memory)
Connections
- Related systems: Main Steam
- Related procedures: S2.OP-SO.MS-0001 — Main Steam Warmup
- Related exam: 2018 NRC Written Exam