Q92 — Misaligned Rod Power Reduction
014 A2.04 (3.9)
Given:
• Unit 2 is at 100% Power.
• Rod Control Exercise Testing is in progress per S2.OP-ST.RCS-0001, Reactivity Control System Rod Control Assemblies.
• After withdrawing Control Bank C rods to the ARO position, the RO reports the following;
- Group Demand Counter for Control Bank C indicates 230 steps.
- ARPI indication on P-250 indicates one Control Bank C rod at 215 steps.
• The crew enters S2.OP-AB.ROD-0001, Immoveable/Misaligned Control Rods.
• Reactor Engineering confirms the misaligned rod.
Which ONE of the following describes the required action per S2.OP-AB.ROD-0001?
• Unit 2 is at 100% Power.
• Rod Control Exercise Testing is in progress per S2.OP-ST.RCS-0001, Reactivity Control System Rod Control Assemblies.
• After withdrawing Control Bank C rods to the ARO position, the RO reports the following;
- Group Demand Counter for Control Bank C indicates 230 steps.
- ARPI indication on P-250 indicates one Control Bank C rod at 215 steps.
• The crew enters S2.OP-AB.ROD-0001, Immoveable/Misaligned Control Rods.
• Reactor Engineering confirms the misaligned rod.
Which ONE of the following describes the required action per S2.OP-AB.ROD-0001?
A. Insert Control Bank C to 215 steps to realign the bank to the misaligned control rod.
B. Reduce power to less than 75% Rated Thermal Power.
C. Place the unit in HOT STANDBY within 6 hours.
D. Power operation at 100% may continue, provided shutdown margin is satisfied.
▶ Show Answer & Explanation
✓ B. Correct. IAW S2.OP-AB.ROD-0001 step 3.37, ONLY one rod indicates misalignment 12 or more steps if greater than 85% RTP, then step 3.41 refers to evaluate TS (including TS 3.1.3.1 movable control assemblies) and step 3.42 directs initiating power reduction to < 75% RTP to comply with TS 3.1.3.1 action c.3.d.
✗ A. Incorrect. This is not allowed per S2.OP-AB.ROD-0001. If the rod is to be recovered, then the rods are aligned to the current bank position. Credible distractor if the SRO believes that moving the bank to the misaligned rods is allowed by procedure, which actually the procedure aligns the misaligned rod to the bank.
✗ C. Incorrect. This action is for two misaligned rods. Credible distractor because it is a step in the procedure but for two or more misaligned control rods.
✗ D. Incorrect. This action is required by TS 3.1.3.1 action c.3, but it is not the only action required. The unit must be reduced to less than 75% RTP as well to comply with TS 3.1.3.1 action c.3.d.
Ref: S2.OP-AB.ROD-0001 (R11), TS 3.1.3.1 | LO: NOS05ABROD01-05, Obj 3 — Given a set of initial plant conditions: Describe the final plant condition that is established by the abnormal procedure | Source: Bank - Salem | Cognitive: Comprehension/Analysis
Connections
- Related systems: Control Rod Drive
- Related abnormals: AB.ROD-0001 — Immovable/Misaligned Control Rods
- Related procedures: S2.OP-ST.RCS-0001 — Rod Control Assemblies Surveillance
- Related tech specs: TS 3/4.1.3 — Movable Control Assemblies
- Related exam: 2022 NRC Written Exam