.AR QSPDS ERFDADs RVLMS (Welch's Highlighted Notes)

Question 1

(QSPDS)

Function:

• ?

Inputs (direct inputs, except CIAS):

• ?

Answer 1

(QSPDS)

Function:

• Post-TMI requirement. Safety related instrumentation displayed for use in verification of adequate core cooling (ICC).
• Core exit thermocouples (CETs).
• Reactor vessel level from Reactor Vessel Level Monitoring System Heated Junction Thermocouples (HJTCs).
• Saturation margins calculated
• Outputs sent to ERFDADS and MCR indicators / recorders.

Inputs (direct inputs, except CIAS):

• PZR Level
• SG Level, Pressure, and ∆P (RCS flow)
• AFW flow
• CTMT Pressure, WR Sump Level, H2, Area Radiation
  
  • Not CTMT temperature
• Primary Coolant Area Radiation
• CST Level
• Reactor Log Power
• RCS wide range Pressure
• Reactor vessel level status
• Isolation Valve (CIAS) Status (SESS sends signal to QSPDS if ALL CIVs are closed for a CIAS)

Question 2

(QSPDS)

QSPDS PAM Indications (LCO 3.3.10 / Modes 1-3)

• ?

Answer 2

(QSPDS)

QSPDS PAM Indications (LCO 3.3.10 / Modes 1-3)

• RCS wide range Pressure (2 channels)
  
  • PT-190A and PT-190B
• Reactor vessel level (2 channels)
  
  • One channel has 8 sensors in a probe.
  • Channel is operable with ≥ 4 sensors (≥ 2 in upper head AND ≥ 2 in lower plenum)
• Subcooling Margin (2 channels)
  
  • One operable SCM Channel consists of one RCS Saturation Margin indicator AND one CET Saturation Margin indicator. Shall be from the same channel and the CET’s for that channel must also be operable.
  • Requires WR PZR PT (102A/B) for calculation
• CETs (2 channels per quadrant)
  
  • 2 channels per quadrant / 2 CETs per channel

Question 3

(QSPDS)

Power supplies (Class 120 Vac):

• Train A / B QSPDS displays: ?
• Train A / B Isolation Cabinets: ?

LCD Display Units:

• ?

Recorders (PAM):

• ?

Inadequate Core Cooling (ICC) Detection:

• ?

QSPDS TR A/B TRBL Alarm:

• ?

Answer 3

(QSPDS)

Power supplies (Class 120 Vac):

• Train A / B QSPDS displays: PNA-D25 / PNB-D26
• Train A / B Isolation Cabinets: PNC-D27 and PND-D28

LCD Display Units:

• Functioning if the square in the upper left corner is alternating between a solid square and an outline of a square.
• Select between various displays

Recorders (PAM):

• Records info coming from QSPDS
• RCS saturation margin: displays the more limiting of RCS or Upper Reactor Vessel Head saturation margin.
• CET / CET saturation margin recorder
• Rx Vessel Plenum and Head Level recorder

Inadequate Core Cooling (ICC) Detection:

• Margin to saturation (or subcooled margin)
• Reactor vessel water level (RVL)
• Reactor core exit temperature (CET)

QSPDS TR A/B TRBL Alarm:

• Power Supply or Software Failure
• CET High
• CET Saturation Lo
• Subcooled Margin Lo
• Rx Vessel Level Lo
• ICC (One or more of above inputs)

Question 4

(QSPDS)

CETs (Core Exit Thermocouples):

• how many detecors?
• temp range? °F
• Orange back light – ?
• Out of range…

Answer 4

(QSPDS)

CETs (Core Exit Thermocouples)

• 61 detectors on top of incore instrument strings
  
  • Enter through bottom of core
• 200-2300°F
• Orange back light – exceeded setpoint
• Out of range - ?????
  
  • Flagged by QSPDS and not used for further calculations unless accident conditions exist.
• LCO 3.3.10 requires 2 channels per quadrant / 2 CETs per channel

Question 5

(RVLMS) Reactor Vessel Level Monitoring System:

• Function/Purpose/Description…?
• Heater Controllers (located in cabinets SHA-C01 and SHB-C01)
  
  • ?

Answer 5

(RVLMS) Reactor Vessel Level Monitoring System:

• Indication of the size of bubble in the core (water level above the fuel to top of the head)
• Measures the “collapsed” liquid level above the Fuel Alignment Plate (FAP).
• Heated Junction Thermocouple (2 channels)
• Uses a combination of heated and unheated TCs.
• Enter core through “spare” CEDM nozzles in the reactor vessel head through the UGS.
• Level above the core is calculated from the strings of HJTCs.
  
  • Eight sensor levels per channel
  • Two TCs at each sensor level (One with a heater and one without)
• ∆T between the TCs determines if water exists at each level
  
  • Water - small ∆T (~90°F)
  • Void - ∆T > 200°F OR unheated TC ≥ 700°F
• • Four per channel located in the vessel head.
• Four per channel located in the plenum.
• Actual level is somewhere below the detector which was uncovered and above the next lower detector.
• When the next lower HJTC is uncovered, indicated level (LCD and recorder) will make a step change down.
• Plenum indication is INVALID with an RCP running.
• • Heater Controllers (located in cabinets SHA-C01 and SHB-C01)
    
    • Two heater controllers per channel. Automatically controls HJTC’s heater power to prevent overheating.
    • 1100°F or ∆T 500°F: power is reduced
    • 1400°F or ∆T 700°F: power is cutoff

Question 6

(RVLMS) Reactor Vessel Level Monitoring System:

Fuel Cladding Heatup Determination: ?

Subcooled Margin (SCM):

• ?

Answer 6

(RVLMS) Reactor Vessel Level Monitoring System:

Fuel Cladding Heatup Determination: Amount of superheat is relative to fuel length exposed and cladding temperature. Indirectly measured by calculating superheat (CETs and PZR pressure)

Subcooled Margin (SCM):

• Temperature compared to PZR Pressure (PT-102)
• Hottest Thot or Tcold RTDs (RCS Saturation Margin)
• Hottest of the upper three unheated HJTCs from RVLMS (Upper Head Saturation Margin)
• Representative CET statistically derived from all valid CET inputs (Representative CET Saturation Margin).
• (LCO 3.3.10 PAM) One operable SCM Monitor Channel consists of one RCS Saturation Margin indicator and one CET Saturation margin indicator. Shall be from the same channel and the CET’s for that channel must also be operable.

Question 7

(RVLMS) Reactor Vessel Level Monitoring System:

E-Plan/EOP:

• ?

Answer 7

(RVLMS) Reactor Vessel Level Monitoring System:

E-Plan/EOP:

• Potential loss of Fuel Clad Barrier (> 700°F CET or RVLMS < 21%): allows on-set of heat induced cladding damage. Subcooling lost in some areas of the core.
• Loss of Fuel Clad Barrier (> 1200°F): significant superheat and core uncovery are occurring.
• Potential loss of Fuel and RCS Barrier (< 24°F RCS SCM)
• ≥ 16% in the head: Level is above the top of hot legs.
• ≥ 21% plenum: Core covered indication

Question 8

(ERFDADS) Emergency Response Facilities Data Acquisition and Display System:

• Function?
• Design?
• Data Acquisition from:
  
  • ?
• Displays and operator consoles:
  
  • ?

Answer 8

(ERFDADS) Emergency Response Facilities Data Acquisition and Display System:

• Post-TMI NRC mandated system
• Designed to function at all times (normal ops and transients)- Data Acquisition, Displays, Calculation, and Archiving
• Data Acquisition from:
  
  • Plant Monitoring System
  • RMS
  • Met Tower
  • DFWCS
  • QSPDS
• Displays and operator consoles:
  
  • MCR
  • TSC
  • STSC

Question 9

(ERFDADS)

Power Supplies (NQN-D01):

• Primary: ?
• Backup: ?
• Alternate Backup: ?

TSC ERFDADS:

• ?

Answer 9

(ERFDADS)

Power Supplies (NQN-D01):

• Primary: NKN-M45 (UPS Inverter)
• Backup: NHN-M08 (via VR)
• Alternate Backup: NHN-M72 (Requires manual transfer)

TSC ERFDADS:

• Non-class 480Vac supply (UPS)
• 1 hour back-up battery
• TSC DG

Question 10

(ERFDADS)

SPDS Overview screen:

• ?

Data displays:

• ?

Answer 10

(ERFDADS

SPDS Overview screen:

• Class bus Voltages
• RCS and PZR Level
• RCS Temperature and pressure
• Containment Parameters
• SG Pressures and Levels
• Feedwater Flow
• ESFAS Actuations
• RCS Leak-rate
• Parameters (solid box – constant / ↑ or ↓ shows the trend)

Data displays:

• Green: Good value
• Magenta: Bad value (loss of data link, out of range)
• White: Suspect data (failed a data validity check)
• Cyan: Data manually inputted
• Orange: Exceeded rate of change setpoint
• Yellow (Level 2): Exceeded high or low setpoint
  
  • Level 2 alarm can be changed by operator
• Red (Level 1): Exceeded high-high or low-low setpoint
  
  • Level 1 alarm is pre-set and cannot be changed.

Question 11

(ERFDADS)

Silencing Alarms:

• ?

HPSI and LPSI curves:

• ?

Answer 11

(ERFDADS)

Silencing Alarms:

• Click SILENCE button on bottom of screen
• Reactor trip – alarms automatically silenced for 2 minutes (will start to alarm after 2 minutes)

HPSI and LPSI curves:

• Cold Leg flow vs Primary pressure
• Green area is acceptable flow.

Question 12

(ERFDADS)

RCS P/T - RCP NPSH Curve:

• Yellow - ?
• Red - ?

Plots RCS cooldown rates:

• ?

Radiation Monitors:

• Yellow – ?
• Red – ?

Answer 12

(ERFDADS)

RCS P/T - RCP NPSH Curve:

• Yellow - NPSH limit is exceeded
• Red - subcooling limit is exceeded

Plots RCS cooldown rates:

• 15 min average for RCS and REP CET

Radiation Monitors:

• Yellow – alert
• Red – high alarm

Question 13

(ERFDADS)

RCS Leakage:

• ?

Answer 13

(ERFDADS)

RCS Leakage:

• 30 min trend (four 7.5 min sections)
• Indicated leak rate lags behind changes in actual leak rate for at least 7.5 minutes
  
  • Indicated < Actual for at least 7.5 minutes
• ↔ slope indicates ↔ leakrate
• ↑ slope indicates ↑ leakrate
• Uses L_PZR, L_VCT, T_AVG, density
• 30 gpm leak will alarm at 8 gpm in < 3 minutes.
• ERFDADS alarm

Question 14

(ERFDADS)

Post Trip Archive Retrieval System (PTARS):

• ?

Emergency Response Data System (ERDS):

• ?

Answer 14

(ERFDADS)

Post Trip Archive Retrieval System (PTARS):

• ESFDADS and PTARS can both store 14 hours of data
• Reactor trip (saves 2 hours prior to trip, and 12 hours after)

Emergency Response Data System (ERDS):

• Data sent from our network to the NRC.
• Activated ≤1 hour after declaring Alert or higher.
• Activated by on-shift STA.