P-Signals & C-Signals

Question 1

P-4

→What is it?
→Setpoint
→Coincidence

Answer 1

→reactor trip (Protection Grade signal)
→Setpoint: reactor trip breakers open
→Coincidence: train associated trip breaker AND bypass breaker open or not connected

Question 2

P-4

What does it do?

Answer 2

→Arms Steam Dump system to allow steam dump operation in the T-avg mode from Plant Trip Controller
→Activates Main Turbine trip
→Blocks auto re-actuation of SI after manually resetting SI*
→Will generate a FWI signal IF T-avg is below low T-avg setpoint of 564 deg F*
→Seals in FWI signal due to SI or HI-HI S/G level (P-14)*
(P-4 signals processed by SSPS)

Question 3

P-6

→What is it?
→Setpoint
→Coincidence

Answer 3

→source range reactor trip block permissive
→Setpoint: >10^-10 amps
→Coincidence: 1/2 IR

Question 4

P-6

What does it do?

Answer 4

→Allows manual block of SR Hi Flux trip (2/2 block switches)
→Block switches also de-energize SR Hi Volts
→When <5x10-11 amps on 2/2 channels then: SR Hi volts re-energized, SR trip and Flux Doubling protection re-instated (aforementioned occurs automatically)

Question 5

P-7

→What is it?
→Setpoint
→Coincidence

Answer 5

→at power permissive
→Setpoint: none
→Coincidence: P-10 or P-13 met
(2/4 Excore NI >10% or 1/2 Turb Impulse Press >10%)

Question 6

P-7

What does it do?

Answer 6

Following Rx trips re-instated with P-7 met:
→PZR Lo Pressure
→PZR Hi Level
→RCP Undervoltage
→RCP Underfrequency
→Low Flow in 2 RCS Loops
Above trips are blocked when P-7 no longer met.

Question 7

P-8

→What is it?
→Setpoint
→Coincidence

Answer 7

→3 loop flow permissive
→Setpoint: >48%
→Coincidence: 2/4 PR channels

“8 and 3 look almost alike”

Question 8

P-8

What does it do?

Answer 8

→Allows for Rx trip when low flow condition is sensed on 2/3 channels on 1 RCS loop.
→Automatically blocked with 3/4 NIS channels < 48%.

Question 9

P-9

→What is it?
→Setpoint
→Coincidence

Answer 9

→turbine trip permissive
→Setpoint: >50%
→Coincidence: 2/4 PR channels

Question 10

P-9

What does it do?

Answer 10

→When met, generates Rx Trip if Turbine Trip occurs
→Automatically blocked when <50% on 3/4 PR channels.

Question 11

P-10

→What is it?
→Setpoint
→Coincidence

Answer 11

→nuclear at power permissive
→Setpoint: >10%
→Coincidence: 2/4 PR channels

Question 12

P-10

What does it do?

Answer 12

When met it performs the following:
→Feeds P-7
→Automatically 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 Shutdown annunciator and CNTMT Evacuation alarm defeated

When 3/4 PR channels <10% the following are automatically re-instated:
→IR Trip
→C-1
→PR Trip (Low setpoint)
→Removes permissive to P-7

Question 13

P-11

→What is it?
→Setpoint
→Coincidence

Answer 13

→PZR SI block permissive
→Setpoint: <1960 psig
→Coincidence: 2/3 protection channels

Question 14

P-11

What does it do?

Answer 14

When met allows manual blocking of:
→Low PZR Pressure SI
→Low Steam line Pressure SI
(once blocked the Negative Steam Line Pressure High Rate is armed)

Once PZR Pressure is >1960 psig on 2/3 channels, then:
→Low PZR Pressure SI armed
→Low Steam line Pressure armed
→Negative Steam Line Pressure High Rate is blocked and sends an OPEN signal to SI Accumulator isolation valves

Question 15

P-12

→What is it?
→Setpoint
→Coincidence

Answer 15

→Lo-Lo T-avg permissive
→Setpoint: 553 deg F
→Coincidence: 2/4 channels

Question 16

P-12

What does it do?

Answer 16

→When met automatically closes all steam dump valves
→The 3 cooldown steam dump valves may be opened by using bypass switch.

Question 17

P-13

→What is it?
→Setpoint
→Coincidence

Answer 17

→turbine at power permissive
→Setpoint: turbine power > 10% (PT-505/506)
→Coincidence: 1/2 turbine impulse pressure channels

Question 18

P-13

What does it do?

Answer 18

→Feeds P-7 permissive.
→Automatically removes signal to P-7 when no longer met

Question 19

P-14

→What is it?
→Setpoint
→Coincidence

Answer 19

→S/G Hi-Hi Level (Protection)
→Setpoint: U1 84%, U2 81.5%
→Coincidence: 2/3 detectors on any 1 S/G

Question 20

P-14

What does it do?

Answer 20

→Trips Main Feed Pumps and Main Turbine
→Generates Main Feedwater Isolation signal

Question 21

C-1

→What is it?
→Setpoint
→Coincidence

Answer 21

→IR Rod Stop (prevent reaching IR & PR Hi flux trips)
→Setpoint: IR amps ≈ 20% PR
→Coincidence: 1/2 IR channels

Question 22

C-1

What does it do?

Answer 22

→Stops outward rod motion in auto AND manual.
→Can be manually blocked when P-10 is met (2/2 switches)
→Automatically unblocked when P-10 no longer met.

Question 23

C-2

→What is it?
→Setpoint
→Coincidence

Answer 23

→PR Rod Stop (prevent reaching PR hi flux trip)
→Setpoint: 103%
→Coincidence: 1/4 PR channels

Question 24

C-2

What does it do?

Answer 24

→Stops outward rod motion in auto AND manual.
→Can be bypassed at the NIS cabinets.

Question 25

C-3 →What is it? →Setpoint →Coincidence

Answer 25

→OTN16 Rod Stop & Turbine Runback →Setpoint: 3% < OTN16 Rx Trip setpoint (115 ± penalties) →Coincidence: 2/4 N-16 channels

Question 26

C-3 What does it do?

Answer 26

→Stops outward rod motion in auto AND manual. →Generates Turbine runback (runback works as follows, on for 1.5 sec @ 200%/min then off for 28.5 sec, cycle continues until C-3 clears).

Question 27

C-4 →What is it? →Setpoint →Coincidence

Answer 27

→OPN16 Rod Stop & Turbine Runback →Setpoint: 3% < OPN16 Rx Trip setpoint (>109%) →Coincidence: 2/4 N-16 channels

Question 28

C-4 What does it do?

Answer 28

→Stops outward rod motion in auto AND manual. →Generates Turbine runback (runback works as follows, on for 1.5 sec @ 200%/min then off for 28.5 sec, cycle continues until C-4 clears).

Question 29

C-5 →What is it? →Setpoint →Coincidence

Answer 29

→Low Power Interlock →Setpoint: ≤ 15% turbine power →Coincidence: 1/1 from PT-505 or 506

Question 30

C-5 What does it do?

Answer 30

→Based on which turbine 1st stage pressure transmitter is selected to input to rod control system. →Stops outward rod motion in auto w/ power <15%.

Question 31

C-7 →What is it? →Setpoint →Coincidence

Answer 31

→Loss of Load →Setpoint: 10% with time constant of 120 sec →Coincidence: based on turbine power load reduction

Question 32

C-7 What does it do?

Answer 32

→Allows dump valves to open in TAVG mode following load rejection. (Arms the Steam Dumps) →Setpoint is variable based on rate of load rejection i.e. 5%/min will actuate C-7 in 1 min, 10% step change will actuate C-7 immediately →Must be manually reset

Question 33

C-9 →What is it? →Setpoint →Coincidence

Answer 33

→Condenser Interlock →Setpoint: >12.3" Hg vacuum →Coincidence: Condenser vacuum plus 2/4 Circ Water Pump breakers closed "C-9, condenser's fine"

Question 34

C-9 What does it do?

Answer 34

→Allows steam dumps to open when C-9 is met

Question 35

C-11 →What is it? →Setpoint →Coincidence

Answer 35

→Control Bank D Rod Withdrawal Limit →Setpoint: 223 steps →Coincidence: N/A

Question 36

C-11 What does it do?

Answer 36

→Stops outward rod motion in auto only.

Question 37

C-16 →What is it? →Setpoint →Coincidence

Answer 37

→Stop Turbine Loading (prevent excessive T-avg droop) →Setpoint: 553° F auctioneered low T-avg OR auctioneered low T-avg < T-ref by 20° F →Coincidence: N/A

Question 38

C-16 What does it do?

Answer 38

→Stops turbine loading when met.

Question 39

C-20 →What is it? →Setpoint →Coincidence

Answer 39

→AMSAC →Setpoint: >40% turbine power, no TD →Coincidence: 2/2 from PT-505/506

Question 40

C-20 What does it do?

Answer 40

→Enables AMSAC actuation circuit →505 or 506 <40% Blocks AMSAC after 260 sec. TDDO, this actually turns on PCIP light

Question 41

Why is 5% deviation above or below PZR program level important?

Answer 41

→5% high - heaters turn on →5% low - actuates an alarm

Question 42

What controls the PZR spray valves when not in manual?

Answer 42

PZR master pressure controller (when in AUTO)

Question 43

What's the difference between mid-position light indication for the PORVs and for the safeties?

Answer 43

→PZR PORVs - both red and green lights →PZR Safeties - both lights are dark

Question 44

If PZR heaters and spray are both on, which one wins?

Answer 44

Spray will overcome heaters.

Question 45

Where does P-11 (PZR SI Block Permissive) input come from?

Answer 45

→PC1, 2, and 3 (NOT PC4) →coincidence is 2/3