Q44 — Feedwater Isolation on SG Hi-Hi Level
059 K4.19 (3.2)
Given:
• Unit 2 is at 100% Reactor Power.
Subsequently, the following occurs:
• A malfunction with 21BF19 causes the SG level to rise uncontrollably.
• The reactor automatically trips.
Which ONE of the following describes the expected plant response?
• Unit 2 is at 100% Reactor Power.
Subsequently, the following occurs:
• A malfunction with 21BF19 causes the SG level to rise uncontrollably.
• The reactor automatically trips.
Which ONE of the following describes the expected plant response?
A. BOTH SGFPs trip and the BF13s, BF19s, and BF40s close.
B. BOTH SGFPs trip and ONLY the BF19s and BF40s close.
C. ONLY the BF19s and BF40s close.
D. ONLY the BF13s, BF19s and BF40s close.
▶ Show Answer & Explanation
✓ A. Correct. SG HI-HI Level Rx Trip (P-14, 2/3 NR levels on 1 SG > 67%) will actuate Feedwater Isolation that will trip the Main Turbine and both SGFPs, and then close all the BF13s, BF19s, and BF40s.
✗ B. Incorrect. Plausible because the applicant may confuse the valves that close on a Feedwater Interlock which are the BF19s and BF40s only.
✗ C. Incorrect. The BF19s and BF40s will ONLY close when there is a Feedwater Interlock signal (P-4 and Tavg < 554 °F). In this case, a P-14 signal was generated from a SG level HI-HI resulting in a FW Isolation signal.
✗ D. Incorrect. Plausible because the applicant may confuse the actions of a Feedwater Isolation with Feedwater Interlock and that the Main Turbine and SGFPs will not trip on a Feedwater Isolation.
Ref: NOS05CNFDW-19 | LO: NOS05CNFDW-19, Obj 4.S — Describe how the following components impact the Condensate and Feedwater System during normal and abnormal conditions: Main Feedwater Containment Isolation Valves | Source: Bank — Salem | Cognitive: Fundamental/Memory
Connections
- Related systems: Feed & Condensate
- Related exam: 2022 NRC Written Exam