B33 - Recirc Flashcards
(43 cards)
What are signs of a seal #1 failure?
2 pressure high
staging flow high
Seal temp drop
What are signs of a seal #2 failure?
2 seal pressure low
Low staging flow
What are the signs of pressure breakdown orifice plugging?
2 seal pressure low (could reach 0)
Low staging flow
Both seal temps high
What are the signs of #1 and #2 seal failure?
Seal pressure low in both seal cavities
staging flow low
What are signs of staging flow orifice plugging?
2 seal pressure approaching seal #1 pressure
staging flow low
both seal temps rise
What setpoints send both HPUs to Maintenance?
< 1650 psig discharge pressure
> 150 deg F oil hot
< 60 gallons oil empty
1.23 psig drywell pressure
FCV control signal abnormal
HPU shutdown pushbutton
What alarm comes in when both loops are in maintenance?
FCV A/B motion inhibit
What signals transfer HPU to STBY loop?
< 1650 psig discharge pressure
> 145 deg F oil warm
<70 gallons tank low
Overcurrent/undervoltage
What are the breaker interlocks?
CB2 and CB5 can’t be closed at the same time
To close CB2 A or B, CB5 A AND B must be open, CB1 must be closed
opening CB1 opens CB2
CB5 must be open to close CB3 or CB4
opening CB3 or CB4 opens CB5
Suction or discharge < 90% open, trips open CB2 and CB5
What is the logic for a fast start?
> 3 mlbm/hr feedwater flow
start opens CB1 and CB2 and starts a 40 second timer
After 3 seconds CB5 closes
95% speed, 40 second timer resets
What is the slow start logic?
< 3 mlbm/hr feedwater flow
CB5 and CB1 close/ 40 second timer starts
@95% speed, CB5 opens
@25% speed, CB2 closes/ 40 second timer resets
What’s the sequence for manually downshifting a recirc pump to slow speed?
Press both downshift buttons simultaneously
CB5 A/B opens
CB1 A/B closes to start LFMGs
@ 25% speed, CB2 A/B close
If 40 second timer times out before 25% CB1 and CB5 trip
Trip XFER INC annunciator comes in
(no interlocks, but SOI directs FCV to min before downshift)
What are the start permissives?
Suction/discharge > 90% open
CB5 racked in
FCV at min ED (approx 22%)
FCV manual
Stop-Lock not depressed
Incomplete sequence reset
Thermal interlocks met
What pressures should be seen on Recirc Seals?
Seal #1, 1050 psig
Seal #2, 525 psig
What provides purge to recirc seal and how much?
CRD provides 1.5 - 2gpm purge pressure to seal
what are the setpoints for Recirc pump thermal shock setpoints?
50 F diff temp loop to loop
50 F diff temp loop to dome
100 F diff temp Dome to drain
What do the Recirc pump thermal shock setpoints interlock prevent?
(50,50,100)
Prevents pump start or upshift
What is min ED for the recirc FCV
22-24%
How fast do FCV move in fast detent and slow detent?
Fast = 1.6%
Slow = .16%
What are the electrical and hydraulic limits?
Electrical: open 11%, closed 11%
Mechanical: open 30%, closed 60%
How many pumps do you upshift at a time?
1
How many pumps do you downshift at a time?
2
How much flow do recirc pumps provide?
44,600 gpm or 16.9 mlbm/hr (driving flow)
What is rated core flow?
112.5 mlbm/hr
