Q21 — Containment Spray Logic / Channel Removed from Service
W E14 EA1.08 (4.0)
Given:
• Unit 2 at 100%
• Containment Pressure Channel III out of service (properly removed)
• Then trip + SI due to LOCA
• Containment pressures: Ch I 15.2, Ch II 14.7, Ch III 0.0, Ch IV 14.5 psig
Are CS/Phase B setpoints met, and what opens the CS2 valves?
• Unit 2 at 100%
• Containment Pressure Channel III out of service (properly removed)
• Then trip + SI due to LOCA
• Containment pressures: Ch I 15.2, Ch II 14.7, Ch III 0.0, Ch IV 14.5 psig
Are CS/Phase B setpoints met, and what opens the CS2 valves?
A. CS/Phase B NOT met, CS2s open on CS signal
B. CS/Phase B NOT met, CS2s open on Phase B signal
C. CS/Phase B ARE met, CS2s open on Phase B signal
D. CS/Phase B ARE met, CS2s open on CS signal
▶ Show Answer & Explanation
✓ A. Correct. With Ch III removed from service (bypassed), logic goes from 2/4 to 2/3. Only Channel I is above 15 psig. 1/3 does not meet 2/3 coincidence — CS and Phase B NOT actuated. CS pump discharge valves (CS2s) open on CS actuation signal only, not Phase B.
✗ B. Phase B and CS actuate at the same pressure, but CS2s open on CS signal specifically, not Phase B signal.
✗ C. Only 1/3 channels above 15 psig, 2/3 coincidence not met. CS and Phase B are NOT actuated.
✗ D. Only 1/3 channels above 15 psig, 2/3 coincidence not met. CS and Phase B are NOT actuated.
Ref: 2-EOP-TRIP-1 (R42), NOS05CSPRAY-07 | LO: NOS05CSPRAY-07, Obj 15.a | Source: New | Cognitive: Comprehension/Analysis
Connections
- Related systems: Containment Spray, RPS/SSPS
- Related procedures: EOP-TRIP-1 — Reactor Trip or Safety Injection
- Related exam: 2023 NRC Written Exam