Q24 — FRCC-1 RCP Start Criteria
EPE 74 EA1.06 (3.6)
Given:
- Unit 2 experienced a small break LOCA.
- The crew is implementing 2-EOP-FRCC-1, Response to Inadequate Core Cooling, and is currently attempting to restore core cooling.
- RCS pressure is 1600 psig.
- NO Charging Pumps can be started.
- ALL RCPs have been stopped.
- SG depressurization was NOT effective in restoring core cooling.
- CETs are 1205 °F and rising slowly.
- 21 SG NR level is 10% and all other SG NR levels are 6%.
- Containment pressure is 3.5 psig.
- The crew is performing step 18, RCP START FOR TEMPORARY CORE COOLING.
Which ONE of the following describes how the crew will operate the RCP(s) in accordance with 2-EOP-FRCC-1?
- Unit 2 experienced a small break LOCA.
- The crew is implementing 2-EOP-FRCC-1, Response to Inadequate Core Cooling, and is currently attempting to restore core cooling.
- RCS pressure is 1600 psig.
- NO Charging Pumps can be started.
- ALL RCPs have been stopped.
- SG depressurization was NOT effective in restoring core cooling.
- CETs are 1205 °F and rising slowly.
- 21 SG NR level is 10% and all other SG NR levels are 6%.
- Containment pressure is 3.5 psig.
- The crew is performing step 18, RCP START FOR TEMPORARY CORE COOLING.
Which ONE of the following describes how the crew will operate the RCP(s) in accordance with 2-EOP-FRCC-1?
A. Start ALL RCPs.
B. Start 21 RCP ONLY.
C. Do NOT start any RCPs and open one PZR PORV ONLY.
D. Do NOT start any RCPs and open BOTH PZR PORVs.
▶ Show Answer & Explanation
✓ B. Correct. IAW 2-EOP-FRCC-1 step 18, if CETs are greater than 1200 °F and at least one SG NR level is greater than 9% (15% adverse), then the crew will start one RCP at a time for each idle loop with a SG NR level greater than 9%. After the RCP is started the crew will loop around step 18 until CETs are less than 1200 °F. Based on the condition in the stem, the crew should only start 21 RCP since 21 SG is the only SG with NR level greater than 9% and the containment pressure is Normal or < 4 psig. If no SG NR levels are greater than 9%, then the crew will reset Phase A, open both CA330s and then open both PZR PORVs and Rx Head Vents to reduce RCS pressure.
✗ A. Incorrect. Plausible because the operator may believe there is adequate NR levels in all SGs that meets the requirement to start and sacrifice all RCPs. However, SG NR levels do not support starting all RCPs. Starting an RCP with insufficient level in the SG can lead to creep failure of the SG tubes.
✗ C. Incorrect. Plausible because the operator may believe that only one PORV is required to adequately reduce RCS pressure similar to actions performed in other EOPs. For example, in EOP-SGTR, the procedure directs the crew to open only one PZR PORV to reduce RCS pressure.
✗ D. Incorrect. Plausible if the operator believes that the RCP start criteria for an adequate SG NR level is not met. See Answer B for further explanation.
Ref: 2-EOP-FRCC-1 (R40) | LO: NOS05FRCC00-06, Objective 5 | Source: New | Cognitive: Comprehension/Analysis
Connections
- Related systems: ECCS, RCS
- Related EOPs: EOP-FRCC-1 — Response to Inadequate Core Cooling
- Related exam: 2022 NRC Written Exam