Q51 — CAV System Rad Monitor AP Mode
073 A2.02 (2.7)
Given:
• BOTH Units 1 and 2 are at 100% Power.
• Unit 2 RO reports OHA A-6, RMS HI RAD OR TRBL, is LIT
• The 2R1B-1, Control Room Intake Radiation Monitor Channel 1, is in ALARM.
• BOTH control rooms Control Area Ventilation (CAV) Systems are operating in NORMAL Mode.
Which ONE of the following completes both statements?
1. What is the expected response of the CAV systems?
2. Based on the above condition, how should the control room operators respond in accordance with S2.OP-AR.ZZ-0001, Overhead Annunciators - Window A?
Note: AP = ACCIDENT PRESSURIZE
• BOTH Units 1 and 2 are at 100% Power.
• Unit 2 RO reports OHA A-6, RMS HI RAD OR TRBL, is LIT
• The 2R1B-1, Control Room Intake Radiation Monitor Channel 1, is in ALARM.
• BOTH control rooms Control Area Ventilation (CAV) Systems are operating in NORMAL Mode.
Which ONE of the following completes both statements?
1. What is the expected response of the CAV systems?
2. Based on the above condition, how should the control room operators respond in accordance with S2.OP-AR.ZZ-0001, Overhead Annunciators - Window A?
Note: AP = ACCIDENT PRESSURIZE
A. 1) BOTH Units 1 and 2 CAV systems should be operating in AP Mode.
2) Manually initiate AP Mode from Unit 1.
2) Manually initiate AP Mode from Unit 1.
B. 1) BOTH Units 1 and 2 CAV systems should be operating in AP Mode.
2) Manually initiate AP Mode from Unit 2.
2) Manually initiate AP Mode from Unit 2.
C. 1) ONLY Unit 2 CAV system should be operating in AP Mode.
2) Manually initiate AP Mode from Unit 2.
2) Manually initiate AP Mode from Unit 2.
D. 1) ONLY Unit 2 CAV system should be operating in AP Mode.
2) Manually initiate AP Mode from Unit 1.
2) Manually initiate AP Mode from Unit 1.
▶ Show Answer & Explanation
✓ B. Correct. A tear in the detector foil will cause the detector to read or fail high. A detector failing high would result in the 2R1B-1 going into Alarm. This should result in the automatic actuation of the CAV systems in Accident Pressurize (AP) Mode on BOTH units. The unit that initiated the actuation signal will have its intake close and the opposite units intake dampers will open. Since the high radiation actuation signal came from Unit 2 and based on the stem that both CAV systems are still operating in Normal Mode, then the control room operators should manually initiate CAV to AP Mode from Unit 2 only. This will ensure that the intake dampers on Unit 2 are closed during an accident from Unit 2. Manually actuating AP Mode from Unit 2 will place both units CAV systems in the AP Mode.
✗ A. Incorrect. First part is correct. Second part is incorrect. Plausible if the operator believes that you need to actuate CAV in AP Mode from the opposite unit. Actuating CAV from Unit 1 is not the correct response to a high radiation signal from the Unit 2 intake duct. Actuating CAV from Unit 1 will open the Unit 2 intake dampers on the unit that potentially has the accident or radiological release.
✗ C. Incorrect. Plausible if the operator believes that on a 2R1B-1 high alarm that only the Unit 2 CAV will actuate in AP Mode only. Second part is correct.
✗ D. Incorrect. Plausible if the operator believes that on a 2R1B-1 high alarm that only the Unit 2 CAV will actuate in AP Mode and to actuate the Unit 1 CAV the operator will need to manually actuate from Unit 1.
Ref: S2.OP-SO.CAV-0001 (R43), S2.OP-AB.RAD-0001 (R30) | LO: NOS05RM000-20, Obj 15 — Given a Radiation Monitoring System failure, predict the effect of the Radiation Monitoring System failure on the following: Radioactive effluent releases | Source: New | Cognitive: Comprehension/Analysis
Connections
- Related systems: Radiation Monitoring
- Related procedures: S2.OP-AR.ZZ-0001 — Overhead Annunciators Window A
- Related exam: 2022 NRC Written Exam