Q19 — Dropped Rod / NIS Indication
APE 3 AA2.03 (3.6)
Given:
• Unit 1 is at 45% Power.
• Control Rod Bank D is at 155 steps.
Rod Control is in AUTO.
Subsequently at time 0930:
• OHA E-48, ROD BOTTOM, is LIT.
• The crew suspects a dropped rod in control rod Bank D near the outer periphery of the core.
Which ONE of the following completes both statements?
1. The Power Range NIS Channel NEAREST the dropped rod will indicate _(1)_ as compared to the other Power Range Channels.
2. At time 1305, repairs are made and permission to recover the drop rod is authorized. Rod withdrawal restrictions _(2)_ apply.
• Unit 1 is at 45% Power.
• Control Rod Bank D is at 155 steps.
Rod Control is in AUTO.
Subsequently at time 0930:
• OHA E-48, ROD BOTTOM, is LIT.
• The crew suspects a dropped rod in control rod Bank D near the outer periphery of the core.
Which ONE of the following completes both statements?
1. The Power Range NIS Channel NEAREST the dropped rod will indicate _(1)_ as compared to the other Power Range Channels.
2. At time 1305, repairs are made and permission to recover the drop rod is authorized. Rod withdrawal restrictions _(2)_ apply.
A. _(1)_ higher
_(2)_ will NOT
_(2)_ will NOT
B. _(1)_ higher
_(2)_ will
_(2)_ will
C. _(1)_ lower
_(2)_ will NOT
_(2)_ will NOT
D. _(1)_ lower
_(2)_ will
_(2)_ will
▶ Show Answer & Explanation
✓ C. Correct. The Power Range Channel near the dropped rod will indicate lower as compared to the other PR channels. Since less than 4 hours has elapsed since the first indication of a dropped rod, then step 3.36 applies and no withdrawal rate, power level or ramp rate restrictions apply.
✗ A. Incorrect. First part is incorrect. The PR channel near the dropped rod will indicate lower. The operator may believe that the PR channel would indicate higher. Second part is correct.
✗ B. Incorrect. First part is incorrect. Second part is correct. Plausible because the operator may believe that insufficient time has elapsed since the indication of a dropped rod and that withdrawal rate restrictions are applicable.
✗ D. Incorrect. First part is correct. Second part is incorrect. Plausible because the operator may believe that insufficient time has elapsed since the indication of a dropped rod and that withdrawal rate restrictions are applicable.
Ref: NOS05ABROD2, S1.OP-AB.ROD-0002 (R11) | LO: NOS05ABROD2, Obj 4.a.1 — For the following analyzed transients/accidents: Dropped Rod, Determine the expected alarms and indications | Source: New | Cognitive: Comprehension/Analysis
Connections
- Related systems: RPS/SSPS
- Related procedures: AB.ROD-0002 — Dropped Rod
- Related exam: 2022 NRC Written Exam