S2.OP-IO.ZZ-0006 — Hot Standby to Cold Shutdown
DRAFT — Reconstructed from exam materials
Purpose
Provides the procedure for transitioning Unit 2 from Hot Standby (Mode 3) to Cold Shutdown (Mode 5), including cooldown, depressurization, and equipment realignment steps.
Key Actions / Information
Exam — 2020 Q39
During cooldown per IOP-6, the Low PZR Pressure SI and High Steam Flow SI signals are blocked (P-11 enables SI block at < 1915 psig). However, the Containment High Pressure SI signal at 4 psig (2/3 channels) is NOT blocked and remains active. If a rapid depressurization of all SGs occurs inside containment, the Containment High Pressure SI will actuate even though Low PZR Pressure SI is blocked.
Exam — 2022 Q32
Per IOP-6, when reducing RCS temperature below 350°F, the letdown line is realigned from the normal high-pressure letdown path to the low-pressure letdown path via CV18 (Low Pressure Letdown Control Valve).
Connections
- Related systems: RPS/SSPS, Containment, RCS
- Related exam questions: 2020 Q39, 2022 Q32
- Related exam: 2020 NRC Written Exam, 2022 NRC Written Exam