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12 Cards in this Set
- Front
- Back
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1E AC Power Purpose |
Provide class 1E loads required for : Safe shutdown Maintain plant in a safe condition Mitigate consequence of accident |
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Incoming Feeder Voltage <w% for x seconds or bus decreases to y%
The z device will... |
w=92 x=20 y=70 z=27
27 device will trip and initiate: All motor circuit breakers trip LOP sequencing alarm is initiated Emergency start of EDG if both normal infeed voltages are <92%
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Alternate supply breaeker will close to supply power... Provided....
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Following a time delay of 0.7 sec. Time delay is to ensure motor breakers are open prior to closure of the alternate breaker
Provided: Auto close block is not selected Associated feeder is >92% No bus lockout signals Normal spply breaker is open |
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Motor feeders on 1E USS |
Have time delayed (.25 sec) UV relays which trip the motor feeder breakers from the bus |
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EDG start under |
LOP: Degraded voltage: both incoming feeders <92% with a 20 sec TD LOP: Both feeders are <92% and bus is <70%
LOCA: 1.68 psig OR -129 RPV level |
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If UV condition persists for >= 0.5 sec |
LOP sequencing circuit initiates PSIS to prevent auto starting of selected loads until LOP timers cycle. The time delays for starting CS and RHR pumps are part of the pump starting circuits and not controlled by the LOP timer |
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EDG will not load when... (4160) |
The flashing trip pushbutton acknowledge is on the 1E 4160 bus |
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4160 differential overcurrent initiates... |
86R: EDG regular lockout circuit Normal and alternate feeds trip open and auto closure is blocked USS transformer feeder breakers trip All motor circuit breakers are tripped |
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4160 bus overcurrent initiates: |
86T: EDG regular lockout circuit Normal and alternate feeds trip open and auto closure is blocked USS transformer feeder breakers trip All motor circuit breakers are tripped |
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With a bus over current and the supply breaker (norm or alt) does not trip... |
After 0.2 sec TD then it trips the 13.6 kV xfmr supply breakers. This will cause all of the 4160 busses supplied by the xfmr except the one tripped by the over current to transfer to the other xfmr Will also cause a fast transfer of the 502 and 503 loads over to their opposite xfmrs |
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LOCA is sensed from x logic... |
x= core spray
The EDGs are started the LOCA sequencer is initiated LOCA load shedding of selected non-1E loads occur PSIS will prevent starting of selected equipment until the LOCA sequencing circuit timers cycle |
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Incoming feeder interlocks |
AUTO CLOSE BLOCK must not be selected AND Associated bus must be >94% of normal |
