PPS: Plant Protection System Flashcards Preview

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Flashcards in PPS: Plant Protection System Deck (80):
1

What is the PPS setpoint for the VOPT? What happens when this setpoint is reached?

110% Max
9.7% > steady state power (Band Function)
10.6%/min rate of change

Actuation: Reactor Trip

2

What is the PPS setpoint for the High Log Power?What happens when this setpoint is reached?

> .01% power
- used while shutdown

Actuation: Reactor Trip

3

What is the PPS setpoint for the High Local Power Density (LPD) Trip? What happens when this setpoint is reached?

> 21 kw/ft

Actuation: Reactor Trip

4

What is the PPS setpoint for the Low DNBR Trip? What happens when this setpoint is reached?

< 1.34

Actuation: Reactor Trip

5

What is the PPS setpoint for the High Pressurizer Pressure Trip? What happens when this setpoint is reached?

> 2383 psia

Actuation: Reactor Trip

6

What is the PPS setpoint for the Low Pressurizer Pressure Trip? What happens when this setpoint is reached?

< 1837 psia (variable)

Actuation: Reactor Trip, SIAS, CIAS

7

What is the PPS setpoint for the Low SG Pressure Trip? What happens when this setpoint is reached?

< 960 psia (variable)

Actuation: Reactor Trip, MSIS

SG lockout at > 185 psid

8

What is the PPS setpoint for the Low SGWL Trip? Any other actuations with setpoints?

< 44.3 % - Reactor Trip
< 25.8 % - AFAS
< 20.3 % - DAFAS

9

What is the PPS setpoint for the High SGWL Trip?

> 91%

Actuation: Reactor Trip, MSIS

10

What is the PPS setpoint for the High Containment Pressure Trip? What happens when this setpoint is reached?

> 3 psig

Actuation: Reactor Trip, MSIS, CIAS, SIAS

11

What is the PPS setpoint for the High-High Containment Pressure Trip? What happens when this setpoint is reached?

> 8.5 psig

Actuation: CSAS

12

What is the PPS setpoint for the Low Reactor Coolant Flow Trip? What happens when this setpoint is reached?

Variable

Actuation: Reactor Trip

13

What is the PPS setpoint for the Low Refueling Water Tank Level? What happens when this setpoint is reached?

< 9.4%

Actuation: RAS

14

What is the basis for the VOPT?

Protects the reactor core during positive reactivity addition excursion (Uncontrolled CEA Withdrawal, CEA Ejection)

15

What is the basis for the High Log Power Trip?

Protects the integrity of the fuel cladding and helps protect the Reactor Coolant Pressure Boundary in the event of an unplanned criticality from a shutdown condition.

16

What is the basis for the High Pressurizer Pressure Trip?

Protects against the possibility of exceeding the RCS pressure safety limit during these postulated events:
- Loss of Vacuum
- CEA Withdrawal from Low Power Conditions
- CVCS Malfunction
- Main Feedwater Line Break

17

What is the basis for the Low Pressurizer Pressure Trip?

This is designed to trip the reactor to assist the ESF System in the event of a LOCA.

18

What is the basis for the High Containment Pressure Trip?

Prevents exceeding the containment design pressure during design basis LOCA or MSLB.

19

What is the basis for the Low Steam Generator Pressure Trip?

Provides protection against an excessive rate of heat extraction from the SGs and resulting rapid, uncontrolled cooldown of the RCS. This trip is needed to trip the reactor in the event of a MSLB or MFLB.

20

What is the basis for the Low Steam Generator Level Trip?

Ensures that the reactor is tripped to ensure the design pressure of the RCS is not exceeded during these events:
- Inadvertent opening of an ADV
- Loss of Vacuum
- Loss of Feed
- MFLB
- Single RCP Rotor Seizure

21

What is the basis for the High Steam Generator Level Trip?

Provided to protect the turbine from moisture carryover in case of a steam generator overfill event.

22

What is the basis for the Low Reactor Coolant Flow Trip?

Provides protection against a RCP Sheared Shaft Event

23

What is the basis for the High Local Power Density Trip?

Provides protection against fuel centerline melting due to the occurrence of excessive LDP peaks during the following events (things that add positive reactivity):
- Decrease in Feedwater Temperature
- Increase in Feedwater Flow
- Increase in SD (not MSLR) with no Turbine Trip
- Uncontrolled CEA withdrawal at low power
- Uncontrolled CEA withdrawal at power
- CEA misoperation (excluding a dropped 4 finger CEA)

24

What is the basis for the Low DNBR Trip?

Provides protection against core damage due to the occurrence of locally saturated conditions in the hot channel during [events that add positive reactivity] and is the primary reactor trip.

25

What PPS trips come from NI inputs?

VOPT
Hi Log Power
DNBR
LPD

26

What components make up PPS?

RPS
ESFAS
SPS
DAFAS

27

What two major PPS trips are input directly from CPCs?

Low DNBR
High LPD

28

What PPS trips are receive their inputs from NI's?

VOPT
Low DNBR
High Log Power
High LPD

29

What happens to the PPS if a single power supply to a Logic Matrix is lost?

2 RTCBs Open

30

What happens to the PPS if a single power supply to a Logic Matrix is lost with a trip in on the opposite channel?

2 RTCBs open
- even though one of the logic matrix power supplies is gone, the contacts for the individual trips that lost power remain closed, creating a path for the remaining power supply to provide power its associated relays, keeping those relays energized which keeps its RTCBs closed.

31

What happens to the RTCBs if a single PN bus is lost?

2 RTCBs open

32

What happens to the PPS if a single PN bus is lost with a trip in on an opposite channel?

All 4 RTCBs open
- since the whole PN bus is gone, detectors that provide inputs into the logic matrix will fail, resulting in open contacts on the effected channel. This opens 2 of the RTCBs. The channel that has the trip in will have an open contact for that trip. With no path around due to the PN bus lost, the other 2 RTCBs will open.

33

What operational bypasses are there associated with the PPS?

DNBR/LPD
High Log Power
Low Pressurizer Pressure

34

What does the DNBR/LPD operational bypass do and when do we use it? Are there any limitations on when it can be implemented?

- Defeats the Low DNBR and High LPD trips from the Core Protection Calculator (CPC)
- Used during a normal reactor startup: rod configurations during this time would cause DNBR/LPD trips
- Power must be less than 10(-4)% power to use this. Should power increase above this value, these trips will automatically be enabled.

35

What does the Low Pressurizer Pressure operational bypass do and when do we use it? Are there any limitations on when it can be implemented?

- Defeats the Low Pressurizer Pressure trips
- Allows reactor system heatup and cooldown.
- Can only be implemented when RCS Pressure < 400 psia. Should pressure increase > 500 psia, this trip will be automatically enabled.

36

What does the High Log Power operational bypass do and when do we use it? Are there any limitations on when it can be implemented?

- Defeats the High Log Power trip
- Allows the reactor to be brought into the Power Range during a startup
- Can only be implemented when power is > 10(-4)% and is normally bypassed while at power. Should power decrease below this value, this trip will automatically be enabled.

37

What does depressing the Low Pressurizer Pressure Reset pushbutton do?

It lowers the trip setpoint to 400 psia below and the pre-trip setpoint 200 psia below current RCS pressure.

38

What does depressing the Low Steam Generator Pressure Reset pushbutton do?

It lowers the trip setpoint to 200 psia below and the pre-trip setpoint 100 psia below current SG pressure.

39

Where are the Low Pressurizer Pressure and Low SG Pressure Reset pushbuttons located?

B05
BCP
RSP

40

What do the phase current lights located on B05 and C and D PPS Cabinets indicate?

Current flow to CEDMs

41

What is the control power for the RTCBs?

PK

42

How many trip channel bypasses can be input on the same parameter at a time.

1

43

C channel has a trip in and was bypassed. If A channel is then bypassed for the same parameter what would happen?

A would stay in bypass and C would come out and trip.
A-B-C-D is the hierarchy for which channel will REMAIN IN BYPASS if two are attempted at the same time.

44

What is the Power Trip Test Interlock (PTTI)?

PTTI will initiate a DNBR/LPD trip in the event of NI switch misalignments or voltage problems. There is no pre-trip for this.

45

Describe the CPC Test Interlock associated with the RPS.

The Low DNBR and High LPD channel trips are interlocked such that both must be in bypass to test the associated CPC channel.

46

What will happen if you take the Linear Calibration switch on the Ex-Core Safety Channel NI drawer to other than the OPERATE position?

You will get an associated channel VOPT
(this also trips the PTTI and gives you DNBR and LPD trips as well)

47

What will happen if you take the Logarithmic Calibration switch on the NI drawer to other than the OPERATE position?

You will get an associated channel High Log Power Trip

48

What is the purpose of the Matrix Testing Interlock associated with RPS?

Allows the testing of only one logic matrix at a time.

49

What is unique about the P and T lights on the ROMs on B05?

They will not automatically go out. After the condition clears, these must be manually reset.

50

What happens when you press and then release the TEST pushbutton on a ROM on B05?

Pressing it will perform a lamp test on all the P, T, and BYPASS lights.
Releasing it will extinguish the BYPASS lamps only.

51

What happens when you press and then release the RESET pushbutton on a ROM on B05?

Pressing it will extinguish the P and T lamps if the test condition or alarm condition has cleared.

52

How do the Initiation Relay Status Monitors on each ROM on B05 behave?

They are on while at power and if an ESFAS signal is

53

What indications are available on the PPS Status Panels?

- Colored Initiation Status Relays that mimic the ones on B05.
- RTCB Positions
- C and D have the CEDMCS Phase Current lamps

54

There is a single green CPC/CWP lamp on each Bistable Control Panel. What is its normal condition and when would it change?

Normally on.
Goes out when a CWP has been generated by CPC on either DNBR or LPD on that channel.

55

What ESF resets are available at the Initiation Reset Panels?

All of them except AFAS.

56

What happens when you depress the RPS button on the Initiation Reset Panel for a condition that has cleared. Keylock is in UNLK.

It will close its associated RTCB.

57

What indication is provided to the operator on the front of the Relay Card Rack at the bottom of the PPS Cabinets?

A red ground light. Light goes out if theres a ground.

58

What PPS controls and indications are available at the RPS?

- Low PZR Pressure Bypass Switch with permissive indicator
- Low SG Pressure Reset Switch
- Low PZR Pressure Reset Switch
- Low PZR Pressure Pre-Trip indicator
- Low SG Pressure Pre-Trip indictor

59

How can you determine which RPS trip parameter was the first to make its 2/4 logic on the Reactor Trip First Out Alarm Panel?

It'll be the indication in fast flash

60

Can the Reactor Trip First Out Alarm Panel distinguish between a parameter that is in trip and a parameter that is in bypass?

- No
- A parameter in bypass will still send its logic signal to the Plant Computer that there's a "trip".

61

Describe how RPS will act to trip the reactor and how an ESFAS trip is different.

RPS - two channels of the same parameter trip which opens contacts on 6 matrix ladders. One of these ladders will have the same trip on both legs which will de-energize those 4 associated matrix relays. That in turn opens 1 contact on each initiation relay tripping all 4 RTCBs.
ESFAS - The same as RPS except theres another step. The initiation relays for these trips go on to open contacts in actuation circuits located in the Aux Relay Cabinets. A-C legs for valves; B-D legs for pumps. A combination of A-B or C-D is required to achieve an ESFAS actuation.

62

List the parameters that will initiate a SIAS.

1837 psia Pressurizer Pressure (Variable with Setpoint Reset)
3.0 psig Containment Pressure

63

List the parameters that will initiate a CIAS.

1837 psia Pressurizer Pressure (Variable with Setpoint Reset)
3.0 psig Containment Pressure

64

List the parameters that will initiate a CSAS.

8.5 psig Containment Pressure

65

List the parameters that will initiate a RAS.

RWT Level of 9.4%
- Never manually initiate this if you haven't reached the set point. A RAS is initiated under the assumption that theres a certain amount of water that has been sent to containment.

66

List the parameters that will initiate a MSIS.

Low SG Pressure of 960 psia (Variable with Setpoint Reset)
High SGWL of 91%
3.0 psig Containment Pressure
- you should never get a MSIS without a Reactor Trip

67

List the parameters that will initiate a AFAS.

Low SGWL of 25.8% WR
AND
not less than 185 psig below the opposite SG

68

How would you manually initiate an ESFAS signal?

Using all 4 actuation switches.

A/C alone or B/D alone will not give you an actuation.
A/B alone or C/D alone will give you an actuation.
AFAS requires all 4 every time

69

How long will an automatic ESFAS signal (except AFAS) remain in after the initiating condition clears?

Until the operator unlocks and manually resets it using the reset pushbutton on the PPS cabinets.

70

How would you manually initiate an ESFAS signal from the Aux Relay Cabinets?

By depressing both of the associated trip pushbuttons simultaneously.

71

How would you manually reset an ESFAS signal from the Aux Relay Cabinets?

By depressing one of the associated reset pushbuttons.

72

Why don't the AFAS manual initiation switches spring return to normal?

Because of the way the AFAS signal is wired. If they returned to normal, the valves would close until an actual AFAS setpoint was reached. This gives the operator the ability to initiate an AFAS before the 25.8% AFAS setpoint.

73

When does the SPS trip the Reactor?

2409 psia

74

When a single SPS channel reads > 2409 psia, what happens?

The associated channels RTCB opens. Therefore, not all combinations of two channels tripping will cause a trip.

75

What two things does the SPS do when a legitimate 2/4 logic is met?

Opens associated RTCBs (A-C, B-D will not trip the reactor)
Opens MG set output contactors (A-C, B-D will not open these contactors)

76

When does DAFAS initiate?

< 20.3% WR SGWL
SPS trip
No MSIS
No AFAS

77

What scenario is the DAFAS designed to address?

ATWS with a Loss of Feed and Failure of AFAS to actuate.

78

What doesn't DAFAS initiate if theres been a MSIS?

To prevent feeding a faulted Steam Generator.

79

When does a DAFAS reset occur?

MSIS
SGWL > 40.8% WR

80

How many keys are required to bypass DAFAS?

8