DROPS Flashcards
What initiates AMSAC and what occurs? DSS?
AMSAC: > 45% power with < 15% FW flow initiates
Will trip the turbine and initiate EFW
DSS: @ 2430 psig
Trips turbine and regulating rods and Aux bus
15% flow = ~ 0.9E^6 lbm/hr
How does AMSAC/DSS logic work and what signals do they feed?
DROPS has 2 channels (1 & 2). Must have both channels energize for actuation.
DROPS channel 1 AMSAC initiates EFIC channel A trip and DROPS channel 2 AMSAC initiates EFIC channel D trip.
Turbine trip from AMSAC initiated by two relays wired in series to energize auto stop oil solenoid in turbine trip circuitry.
What are normal and backup power supplies for DROPS?
Normal: Y03
Backup: D cell batteries
What power signal feeds AMSAC?
Gamma Metrics linear power
When is AMSAC bypassed?
AMSAC automatically bypassed when power is below 45% and reinstated above 45%.
What RCS Pressure signal feeds DSS?
RCS wide range pressure
How does DSS trip the CRDs?
Contact opens in the circuit to regulating rods and aux bus to interrupt power to gate drives.
What would be the effect of A MFW flow (PDT-2628) element failed high?
Applicable AMSAC channel (CH 2) would not be able to actuate for A MFW since both channels have to meet the criteria.
What does the Test in Progress lamp mean if blinking? Solid?
Blinking indicates other DROPs channel has been placed in test or communication problem between channels.
If solid, it means applicable channel is in test.
What do the trip and trip confirmed lamps mean?
Trip lamps mean that DSS has attempted to trip CRD breakers, turbine or EFW.
Trip confirmed lamp indicates a trip confirm has been received from final actuation devices.
What causes a DSS/AMSAC Trouble alarm?
Any DSS or AMSAC trip confirm signal received OR DROPS battery voltage low
How does the DROPs reset function work?
The trip signal locks in after actuation requiring the channel to be reset. Trip function must be cleared prior to depressing reset. If condition not clear, the lights will flash indicating condition is still present.
