NUMAC Leak Detection - 1.0

Question 1

Which systems are monitored by NUMAC and what causes isolations?

Answer 1

Nuclear Measurement Analysis and Control
1. MSIV Closure – 160F Main Steam Tunnel Temp
2. RHR (hi temp alarms only), RWCU (temps & diff flow), RCIC (temps & diff temps), and HPCI (temps & diff temps) isolations described in individual notes.

Question 2

What are the power supplies for the NUMACs?

Answer 2

1. 10C620 (HPCI) – 1AJ481 (Lower Relay Room)
2. 10C621 (RCIC)– 1BJ481 (Lower Relay Room)
3. 10C640 (RCIC)– 1DJ481 (Lower Relay Room)
4. 10C641 (HPCI)– 1CJ481 (Lower Relay Room)
5. 10C609 – ‘A’ RPS bus (Back of MCR)
6. 10C611 – ‘B’ RPS bus (Back of MCR)

Question 3

Where are the NUMACs located?

Answer 3

1. HPCI/RCIC/RHR in LRR
2. MSIV/RWCU in back of MCR.

Question 4

What happens when a flow element erodes?

Answer 4

If a flow element erodes, it will actuate at a higher gpm.