P-Signals

P-Signals

1. P-4: Reactor Trip

   • Purpose: Protection Grade Signal
   • Setpoint: Reactor Trip Breakers Open
   • Coincidence: Train associated trip breaker and bypass breaker open or not connected.
   • Notes: Performs the following:
     • Activates Main Turbine Trip
     • Will generate FW Isolation signal if Tave below low Tave setpoint of 564 deg F (processed by SSPS)
     • Blocks auto re-actuation of SI after manually resetting SI (processed by SSPS)
     • Seals in FW Isolation signal due to SI or HI-HI S/G level (P-14) (processed by SSPS)
     • Arms Steam Dumps to allow operation in Tave mode from Plant Trip Controller

2. P-6: SR Rx Trip Block

   • Setpoint: > 10E-10 amps
   • Coincidence: 1/2 IR
   • Notes:
     • Allows manual block of SR Hi Flux Trip (2/2 block switches)
     • Block switches also de-energize SR Hi Volts
     • When <10E-10 amps on 2/2 channels then:
       • SR Hi Volts re-energized
       • SR trip and Flux doubling protection re-instated (occurs automatically)

3. P-7: At Power

   • Setpoint: None
   • Coincidence: P-10 or P-13 met
   • Notes: The following Rx Trips are re-instated with P-7 met (blocked when not met):
     • PZR Lo Pressure
     • PZR Hi Level
     • RCP Undervoltage
     • RCP Underfrequency
     • Low Flow in 2 RCS Loops

4. P-8: 3 Loop Flow

   • Setpoint: > 48%
   • Coincidence: 2/4 PR Channels
   • Notes: Allows Rx trip when low flow condition is sensed
     • On 2/3 channels for 1 RCS loop
     • Auto blocked when 2/4 channels < 48%

5. P-9: Turbine Trip

   • Setpoint: > 50%
   • Coincidence: 2/4 PR Channels
   • Notes: When met, generates RX Trip if Turbine Trip occurs
     • Auto blocked when < 50% on 3/4 PR channels

6. P-10: Nuclear At Power

   • Setpoint: > 10%
   • Coincidence: 2/4 PR Channels
   • Notes: When met, it performs the following:
     • Feeds P-7
     • Auto blocks SR Trip and de-energizes SR Hi Volts
     • Allows blocking of IR Trip and C-1
     • Allows blocking of PR Trip (Low setpoint)
     • SR Hi Flux at S/D annunciator and CTMT Evacuation alarm defeated
   • Notes: When 3/4 PR channels < 10% the following are auto re-instated:
     • IR Trip
     • C-1
     • PR Trip (Low setpoint)
     • Removes permissive to P-7

7. P-11: PZR SI Block

   • Setpoint: < 1960 psig
   • Coincidence: 2/3 PZR Pressure Channels
   • Notes: When met allows manual blocking of:
     • Low PZR Pressure SI
     • Low Steamline Pressure SI, once blocked the Neg Steam Line P Hi Rate is armed
   • Notes: Once PZR P > 1960 psig on 2/3 channels then:
     • Low PZR SI blocked, Open signal to SI Accum Isol Valves
     • Low Steamline P armed, Neg SL P Hi Rate blocked, Open signal to SI Accum Isol Valves

8. P-12: Lo-Lo Tave

   • Setpoint: 553 deg F
   • Coincidence: 2/4 Channels
   • Notes: When met:
     • Auto closes all steam dump valves
     • 3 Cooldown steam dump valves may be opened by bypass switch

9. P-13: Turbine At Power

   • Setpoint: Turbine PWR > 10% RTP
   • Coincidence: 1/2 Turbine Impulse P Channels
   • Notes: When met:
     • Feeds P-7
     • Auto removes signal to P-7 when no longer met

10. P-14: S/G Hi-Hi Level

    • Purpose: Protection
    • Setpoint: 84% (U1) / 81.5% (U2)
    • Coincidence: 2/3 detectors on any 1 S/G
    • Notes: When met performs the following:
      • Trips MFPs
      • Trips Main Turbine
      • Generates Main FW Isolation signal