Q21 — PZR Reference Leg Leak
APE 28 AK1.01 (2.8)
Given:
- Unit 2 is operating at 100% Power.
- ALL systems are in AUTO.
- A leak develops on the reference leg on the controlling Pressurizer (PZR) Level Channel.
Which ONE of the following completes the statement concerning the effect on Pressurizer Level assuming no operator action?
Indicated PZR Level will be _(1)_ and actual PZR Level will _(2)_.
- Unit 2 is operating at 100% Power.
- ALL systems are in AUTO.
- A leak develops on the reference leg on the controlling Pressurizer (PZR) Level Channel.
Which ONE of the following completes the statement concerning the effect on Pressurizer Level assuming no operator action?
Indicated PZR Level will be _(1)_ and actual PZR Level will _(2)_.
A. _(1)_ higher; _(2)_ rise
B. _(1)_ higher; _(2)_ lower
C. _(1)_ lower; _(2)_ rise
D. _(1)_ lower; _(2)_ lower
▶ Show Answer & Explanation
✓ B. Correct. A leak on the reference leg will result in a lower differential pressure sensed across the level transmitter causing the indicated PZR level to indicate higher than the actual level. Due to the higher indicated PZR level on the controlling channel, the Master Flow Controller will lower charging flow resulting in the actual PZR level to lower.
✗ A. Incorrect. First part is correct. Actual PZR level will lower due to the higher indicated PZR level causing the Master Flow Controller to lower charging flow. Plausible because the operator may incorrectly determine the effect on the DP transmitter following a reference leg failure.
✗ C. Incorrect. First part is incorrect. Second part is incorrect. Plausible because the operator may incorrectly determine the effect on the DP transmitter following a reference leg failure.
✗ D. Incorrect. First part is incorrect. Second part is correct. Plausible because the operator may incorrectly determine the effect on the DP transmitter following a reference leg failure.
Ref: NOS05PZRL, GFES Fundamentals | LO: NOS05PZRPL-12, Objective 4b | Source: Bank – Salem 2015 NRC RO8 | Cognitive: Comprehension/Analysis
Connections
- Related systems: Pressurizer & PRT, CVCS
- Related exam: 2022 NRC Written Exam