Q82 — PZR Level Control Malfunction Charging
028 PZR Level Control Malfunction - A2.03 (4.2)
Given:
• Unit 2 is at 100% Reactor Power
• 21 Charging Pump is in service
• 21 and 22 Group Backup PZR Heaters are in AUTOMATIC
• The RO notices the following parameters at 09:00 and 09:40:
Which ONE of the following completes the statements below?
At 09:40, 21 and 22 Group Backup PZR heaters are _(1)_.
The crew will reduce charging flow in accordance with _(2)_.
• Unit 2 is at 100% Reactor Power
• 21 Charging Pump is in service
• 21 and 22 Group Backup PZR Heaters are in AUTOMATIC
• The RO notices the following parameters at 09:00 and 09:40:
| Parameter | 09:00 | 09:40 |
|---|---|---|
| Charging Master Flow Controller Flow Demand | 36% | 75% |
| Charging Flow | 88 GPM | 99 GPM |
| PZR Level | 59.0% | 64.3% |
| PZR Pressure | 2235 psig | 2236 psig |
| 21-24 RCP Seal Injection Flow | 7.9 GPM | 8.9 GPM |
At 09:40, 21 and 22 Group Backup PZR heaters are _(1)_.
The crew will reduce charging flow in accordance with _(2)_.
A. (1) ON (2) S2.OP-SO.CVC-0001 (CHARGING, LETDOWN AND SEAL INJECTION)
B. (1) ON (2) S2.OP-AB.CVC-0001 (LOSS OF CHARGING)
C. (1) OFF (2) S2.OP-SO.CVC-0001 (CHARGING, LETDOWN AND SEAL INJECTION)
D. (1) OFF (2) S2.OP-AB.CVC-0001 (LOSS OF CHARGING)
▶ Show Answer & Explanation
✓ A. Correct. For Part 1 and based on plant parameters at 09:40, 21 and 22 Group PZR Backup Heaters are ON (Actual PZR level is 5% or more greater than Program PZR level (64.3 - 59.0 = +5.3%)). For Part 2, with charging flow demand, charging flow and PZR level ALL rising, this is an indication of a failure of Charging Master Flow Controller. Additionally, at 09:40 the only control room alarms present in the control (associated with the failed Charging Master Flow Controller) are OHA E-20 (PZR HTR ON LVL HI) and Control Console Bezel 3-18 PZR LEVEL HI Alarm. In accordance with S2.OP-AR.ZZ-00005 OHA E-20 ARP, the crew will REDUCE charging IAW S2.OP-SO.CVC-0001 (CHARGING, LETDOWN AND SEAL INJECTION). Control Console Bezel 3-18 PZR LEVEL Alarm Response Procedure refers the crew to OHA E-20 ARP.
✗ B. Incorrect but plausible. Part 1 is correct. For Part 2, S2.OP-AB.CVC-0001 (LOSS OF CHARGING) would correctly address a failure of Charging Master Flow Controller in which charging flow is REDUCED. Consequently, the candidate could incorrectly conclude that the crew will reduce charging flow in accordance with S2.OP-AB.CVC-0001 (LOSS OF CHARGING).
✗ C. Incorrect but plausible. For Part 1, actual PZR Pressure is normal at 09:40. Consequently, the candidate could incorrectly conclude that the Backup heaters are OFF. Part 2 is correct.
✗ D. Incorrect but plausible. For Part 1, actual PZR Pressure is normal at 09:40. Consequently, the candidate could incorrectly conclude that the Backup heaters are OFF. For Part 2, S2.OP-AB.CVC-0001 (LOSS OF CHARGING) would correctly address a failure of Charging Master Flow Controller in which charging flow is REDUCED. Consequently, the candidate could incorrectly conclude that the crew will reduce charging flow in accordance with S2.OP-AB.CVC-0001 (LOSS OF CHARGING).
Ref: S2.OP-AR.ZZ-00005, S2.OP-AB.CVC-0001 (LOSS OF CHARGING) | LO: NOS05ABCVC1-04 — Given a set of initial plant conditions, determine the appropriate abnormal procedure | Source: New | Cognitive: Higher
Connections
- Related systems: CVCS, Pressurizer Level & Press Control
- Related procedures: S2.OP-SO.CVC-0001 — CVCS Normal Operations, S2.OP-AR.ZZ-0005 — Overhead Annunciators Window E
- Related abnormals: AB.CVC-0001 — Loss of Charging
- Related exam: 2019 NRC Written Exam