SFP cooling

Question 1

What is the primary function for maintaining 23 feet of water over the top of fuel assemblies in the SFP?

Answer 1

to remove 99% of all iodine activity that could be released from a ruptured irradiated fuel assembly

Question 2

What are the design features of the SFP/ SFP cooling that prevent draining the SFP?

Answer 2

• the cooling suction is located 4’ below normal water level
• return line ends 8 ‘ above f.a. and has a siphon break hole at 136’ 3” to prevent draining if get reverse flow

Question 3

Describe controls of SFP pumps?

include trips

What is the SFP leak detection system monitoring?

Answer 3

LVP - if power lost pump must be restarted

(SFP pump 2 trips on on Phase A)

Any leaks in the SFP liner, valves periodically opened to quantify leakage

Question 4

1. What could happen if SFP temp > 120 deg and process water through demin?
2. What could happen when transfer tube is open and a pressure differntial exists between CNMT and FHB?
3. What way will water flow if there is a leak in the SFP Hx?
4. Why do we minimize time running both SFP pumps in paralel?

Answer 4

1. damage resin
2. manometer effect P_cnmt > P_FHB, L_sfp go up, L_{rx cavity} go down
3. into SFP, P_ccw > P_sfpc
4. pump 2 will deadhead (weaker)