B33 - Recirc Flashcards
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
What is flow rate of steam and feed flow?
18.9 mlbm/hr
What RPM are recirc pumps running in fast/slow speed?
Fast = 1800 rpm
slow = 450 rpm
What are the cavitation interlocks for recirc pumps?
<7.4 delta T between reactor sat temp and recirc for 15 seconds
11.4” reactor water level
< 3 mlbm/hr for 15 seconds feedwater flow
what is the result of a cavitation signal?
Downshift
What are the power supplies for recirc pumps?
A - 11HD
B - 12HE
What are the power supplies for LFMG?
A - 13AD
B - 14AE
What are the power supplies for LFMG voltage regulators?
A - 13B21
B - 12B11
What are the ATWS/ARI setpoints?
-41.6”
> 1126 psig Rx pressure
Arm and depress both pushbuttons
What are the pump supplies for ATWS/ARI-RPT with what channels they power and what breakers do they trip?
E channel 1 trips breakers 2 and 5 (1,2,5)
K channel 2 trips breakers 1 and 4 (2,1,4)
How long does it seal for and how is it reset?
32 seconds (reset with pushbuttons)
How does the recirc pump respond to this trip?
Trip off
What are the EOC-RPT setpoints?
TSV < 675 psig bypassed < 26% Rx power
TCV < 970 psig bypassed < 26% Rx power
What are the power supplies to each division of EOC-RPT and what breakers do they trip?
Div 1 11DA channel 1 trips breaker CB3 A/B
Div 2 11DB channel 2 trips breaker CB4 A/B
How do recirc pumps respond to this?
downshift
What is the loop match criteria?
< 70% flow rate within 10% 4460 gpm
> 70% flow rate within 5% 2230 gpm
When a FCV runback occurs, what does flow rate reduce to?
55%
What are the signs of a loss of purge flow?
Slight rise in seal temp (no alarms)
What are signs of loss of CCW?
Rise in seal temps
What are the signs of loss off both CCW and purge flow?
Rapid temp rise on both seals
high temp alarms on both seals
