Q81 — EOP-FRHS-1 Heat Sink Established
W E05 EA2.2 (3.7)
Given:
• Unit 2 reactor tripped.
• During performance of 2-EOP-TRIP-2, Reactor Trip Response, the crew transitions to 2-EOP-FRHS-1, Loss of Secondary Heat Sink, due to Loss of ALL AFW flow.
Subsequently;
• 21 SGFP is running providing feed flow to 22 SG.
• All SG Narrow Range levels are offscale low.
• 22 SG Wide Range level is slowly rising.
Which ONE of the following completes both statements?
1. In accordance with 2-EOP-FRHS-1, operator actions to establish a heat sink _(1)_ complete.
2. Transition back to 2-EOP-TRIP-2 _(2)_ allowed.
• Unit 2 reactor tripped.
• During performance of 2-EOP-TRIP-2, Reactor Trip Response, the crew transitions to 2-EOP-FRHS-1, Loss of Secondary Heat Sink, due to Loss of ALL AFW flow.
Subsequently;
• 21 SGFP is running providing feed flow to 22 SG.
• All SG Narrow Range levels are offscale low.
• 22 SG Wide Range level is slowly rising.
Which ONE of the following completes both statements?
1. In accordance with 2-EOP-FRHS-1, operator actions to establish a heat sink _(1)_ complete.
2. Transition back to 2-EOP-TRIP-2 _(2)_ allowed.
A. 1) are
2) is
2) is
B. 1) are
2) is NOT
2) is NOT
C. 1) are NOT
2) is
2) is
D. 1) are NOT
2) is NOT
2) is NOT
▶ Show Answer & Explanation
✓ A. Correct. IAW 2-EOP-FRHS-1, Step 6, if NR level in at least one SG is greater than 9% (15% adverse), then return to procedure in effect; OR, if feed flow is verified to at least one SG by either CETs lowering or WR level rising in one SG, then maintain flow to restore NR to greater than 9% and return to procedure in effect. Per the stem, 22 SG WR level is rising slowly so heat sink has been established in one SG and the CRS can return to EOP-TRIP-2.
✗ B. Incorrect. First part is correct. Second part is incorrect. Plausible because the SRO may incorrectly interpret Step 6.1 (Maintain flow to restore NR level to greater than 9% [15% adverse]) and believe that although heat sink has been established, FRHS-1 requires the SG NR level to be greater than 9% to exit the procedure.
✗ C. Incorrect. First part is incorrect. Heat sink has been established. Second part is correct. Plausible because SRO may believe that the heat sink requirements are not met due to insufficient SG levels in one SG, but can exit the procedure because adequate feedflow has been established.
✗ D. Incorrect. First part is incorrect. Heat sink has been established. Plausible because SRO may believe that the heat sink requirements are not met due to insufficient SG levels. Second part is incorrect. Return to TRIP-2 is allowed based on one SG WR level is rising. Plausible because if the operator believes heat sink is not established, then you cannot exit the procedure per FRHS-1.
Ref: 2-EOP-FRHS-1 (R40) | LO: NOS05FRHS00-04, Objective 9 | Source: Bank – Commanche Peak 2016 NRC SRO81 | Cognitive: Comprehension/Analysis
Connections
- Related systems: AFW, Steam Generator & Blowdown, Feed & Condensate
- Related EOPs: EOP-FRHS-1 — Response to Loss of Secondary Heat Sink, EOP-TRIP-2 — Reactor Trip Response
- Related exam: 2022 NRC Written Exam