EOP-FRHS-2 — Response to Steam Generator Overpressure
Purpose
Provides operator actions to respond to steam generator overpressure conditions. This is a Critical Safety Function Restoration Procedure (CSFRP) for Heat Sink — Orange path.
Entry Conditions
- Entered from EOP-CFST-1 when Heat Sink CSF status tree indicates an overpressure condition on one or more steam generators
Key Actions
- Verify affected SG isolation
- Check affected SG level
- Assess affected SG steam release
- Attempt to depressurize affected SG using available means (MS10 relief valves, BF&O bypass, etc.)
- If depressurization unsuccessful, transition to EOP-FRHS-3
Exam — 2023 Q85
This question was security-redacted. It tested SRO knowledge of actions during a SG overpressure event in conjunction with security procedures (K/A W/E13 G2.4.28). Reference: 2-EOP-FRHS-2 (R41).
Exam — 2022 Q26
AFW should remain isolated to affected SG(s) until a steam release path is established. AFW is a high pressure system which may cause further overpressure in a SG with no steam release path.
Exam — 2018 Q72
Step 5 — permitted steam release paths include 13 AFW Pump (turbine-driven AFW). If MS18 (MS Warmup) and MS10 (Atmospheric Relief Valves) cannot be opened, the 13 AFW Pump is a valid release path because the affected SG is a source of steam for the turbine-driven pump. Step 9 — if unable to release steam from the affected SG, maintain RCS T-HOTs less than 540 °F using the UNAFFECTED SGs. Trap: establishing cool AFW flow to the affected SG does NOT reduce SG pressure — it adds inventory. The 13 AFW Pump works as a release path because it consumes steam from the affected SG.
Connections
- Related systems: Steam Generator & Blowdown, AFW, Main Steam
- Related exam questions: 2018 Q72, 2022 Q26, 2023 Q85
- Related exam: 2018 NRC Written Exam, 2022 NRC Written Exam, 2023 NRC Written Exam