125vdc Flashcards
Where is the U2 125vdc battery?
TB 549 (above MCR)
Where is the U3 125vdc Battery?
Upper level battery room above U3TB 538.
Where is the U2 125vdc alt battery
SBO building
What powers the 2(3) 125vdc battery Charger?
MCC 29-2(39-2)
What Powers the 2(3)A 125vdc Charger?
MCC 28-2(38-2)
What powers the U2 125vdc alt battery charger?
MCC 65-1
What timeframe load is the 125vdc designed to handle?
Start and handle normal DC and all SSD DC loads on one unit AND
Operations to limit consequences of design basis event on other unit for 4 hours
What is the purpose of 125vdc dist. system?
Provides reliable DC power to operate equipment such as solenoid valves, logic systems (PCIS & ECCS), and circuit breaker power for 4kV and 480V buses.
What is the normal mode of operation for the 125vdc battery chargers?
Float
What provides Div I 125vdc normally?
The Unit 125vdc battery charger
What supplies the Div II 125vdc loads?
Opposite Unit 125vdc battery system.
During normal operations, what normally provides the power source for 125vdc loads?
Unit 125vdc battery chargers.
Why is the Unit 2 125vdc alt battery larger than the U3 battery?
Sized larger because of the larger losses from longer cable runs to go from SBO to Power block.
What is the U3 125vdc alt battery charger power source (normally)?
MCC 35-2
What is the purpose of the battery chargers?
The battery chargers provide the normal 125vdc power, and keep batteries fully charged in float pmode.
What supplies the main 125vdc power to the Unit Div. I RB Loads?
RB Distribution Panel
What supplies normal power to 125vdc Reserve Bus 2(3)?
Main Bus 3A (Main Bus 2A-1)
What is a Level 2 Ground?
Requires Immediate immediate ground checking and IR
125vdc : <125kOhm (to ground) (>70v w/no buttons or >90 v w/either button)
250vdc : >183.6v with no buttons or > 215.5v w/either buttons
What is a Level 3 Ground?
14days to find and notify distribution operator:
125vdc: <20kOhm (>115v w/no buttons or >120 v with either button)
250vdc: >229.4 v w/no buttons or >244.1v w/either button
(A+B = C : Positive button + negative button = no button)
How are battery voltages displayed in MCR?
6 position switch on 902-8 panel
* THERE IS AN AMMETER ON BATTERY DISCHARGE THAT COULD CAUSE 902(3)-8 F-9 “250V-125V 24/48V BATT DISCHARGE HI” alarm*
What loads are lost upon loss of U2 125vdc Reactor Building Distribution Panel Loss?
Control Power for 23-1 & 28
RB Vent Dampers Close
2/3 EDG control power transfer to U2 RB Bus
IsoCondenser Isolates
What happens with loss of Main Bus 2A-1?
U2 RB Bus lost
Lose control power to 23 and 36
RFP and Cond. Pps auto start disabled.
All RFP trip relays disabled (continue to run)
HPCI logic alternate disabled
CS & LPCI Div I logic lost
ADS Div I logic lost
All ADS valve solenoids transfer to alternat feed lost
ISCO logic lost - causes ISCO isolation
MCR indication of inboard MSIVs lost
Loss of U3 Reserve Bus 3B-1 and all loads
What happens if the feed to Bus 2A-1 loads lost?
Breaker Control for Bus 21 and 25 lost various panels (Gen backup relay, EHC, Voltage Reulation exciter, annunciator panel 902-34, H2 and Stator Water Cooling Panel)
What happens with loss of 2B-1 Bus?
Loss of Control to Bus 24, 24-1, and 29 U2 EDG control Power lost ATWS 70B Inverter supply lost Div II LPCI and CS logic ADS Div II logic HPCI logic normal feed MCR indication for outboard MSIV
