westinghouse proprietary class 2 © 2011 westinghouse ...fsrug.org/presentations 2011/westinghouse -...

© 2011 Westinghouse Electric Company LLC. All Rights Reserved.Westinghouse Proprietary Class 2

Westinghouse Nuclear Automation

Digital Feed Water Upgrades

Westinghouse Nuclear Automation

Digital Feed Water UpgradesExperience, Validation

& d& Lessons Learned

P fil F d iPanfilo FedericoProduct Manager, Distributed Controls and

Information SystemsInformation Systems(412) 374-6448 Office(412) 523-9959 Cell

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Westinghouse Control SystemsWestinghouse Control Systems● Westinghouse uses Ovation® Distributed Control

System as highly reliable platform for non-safety t l f ti i PWR BWR & VVERcontrol functions in PWRs, BWRs & VVERs

– Eliminate plant trips– Reduce or eliminate critical path time– Eliminate single-point vulnerability– Eliminate hardware calibration time– Provide advanced diagnostics down to point level

U t d d d t l l i & h d– Use standard and proven control logic & hardware configurations

– Reduce operator burden and challengesCommon interface across control systems– Common interface across control systems applications and platform

– Advanced platform that supports the latest technologies and common designs with AP1000

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Ovation ® Well Suited For NuclearOvation Well Suited For Nuclear• Designed for the power industry with Nuclear attributes

I t t Pl t O t Si l ti S l ti• Integrates Plant Operator Simulation Solution• Integrates System Security ModelSystem functions defined by roles & responsibilitiesy y pUser actions defined down to point level

• Alarm System Eight alarm levels (four high & four low) Eight alarm levels (four high & four low) Alarm cutout Modal alarming based on plant conditions

• Controller Application Software is in a Drawing Sheet format using SAMA symbols

• Scalable & Integrated Cyber security solution

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• Scalable & Integrated Cyber security solution


Ovation® ApplicationsAnd Experience

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Ovation® Applications in Nuclear

Control Applications (Analog/Pneumatic/Digital)

Ovation® Applications in Nuclear

pp ( g g ) NSSS Controls – Advanced Feedwater Control, Pressurizer

Level & Pressure, Chemical Volume Control Systems, Rx Temperature, Steam Dump, Rod Control Demand, Reactor Water Level, Reactor Recirculation, Reactor Pressure

BOP Controls Moisture Separator Re heater Heater drains BOP Controls – Moisture Separator Re-heater, Heater drains, Drain tanks, Waste Processing, Sampling Systems, etc.

Main Turbine and Feed Pump control & protection systems p p yincluding electro hydraulics

Vibration Monitoring System (CSI-6500 or Bently Nevada)

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Ovation® Applications in Nuclear (cont)

Control Applications (Analog/Pneumatic/Digital cont)


Control Applications (Analog/Pneumatic/Digital cont) Rod Control Logic Comtrol Rod Position Indication SystemRod Position Indication System Bus technologies (Profibus and Foundation Fieldbus) Wireless Technologies – monitoring applicationsFlux Mapping Systems and Traverse Incore Generator Monitoring and Protection Automatic Voltage Regulator – Alterrex, WTA

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Ovation® Applications in Nuclear (cont)Information System Applications

S f t P t Di l S t (SPDS)


Safety Parameter Display Systems (SPDS) Smart Alarm systems (Westinghouse Product) Plant Computer systems including Nuclear Application Programs Plant Computer systems including Nuclear Application Programs

Plant Simulators Stimulated Solutions – hardware based Simulated Solutions – manually coded application software Emulated Solutions – automatically generated software running

on virtual machines

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Westinghouse Ovation® ProjectsWestinghouse Ovation Projects U.S. Plants● AP1000™- Vogtle 3&4, VC Summer 2&3 g ,

(In Process MCR, SIM, all non-safety including FWCS )● Duke Energy – Catawba 1&2 (NSSS/FWCS, SIM)● Duke Energy – McGuire 1&2 (NSSS/ FWCS, FPCS, MTS,SIM)● Exelon – Byron 1&2; Braidwood 1&2 (TCPS TGTMS MSR MTS SIM)● Exelon Byron 1&2; Braidwood 1&2 (TCPS, TGTMS, MSR, MTS, SIM)● Exelon – Clinton (RWLCS, SIM) in process● FP&L – St. Lucie (TCPS, SIM)● Hope Creek (SPDS, SIM)

P i t B h (PCS SIM)● Point Beach (PCS, SIM)● SCE – San Onofre 2&3 (TCS, FWCS, FPCPS, CVCS, SIM)● South Texas 1&2 (PCS, AS, SIM)● South Texas 3&4 ABWR (In Process; MCR, All BOP )( )● Surry 1&2 (PCS, SIM)● SNC – Farley 1&2 (In Process, TCPS, MSR, SIM) ● SNC – Vogtle 1&2 (FWCS, SIM) delivered – not installed● Wolf Creek - (In Process TCPS FPCPS BOP MTS SIM)

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● Wolf Creek - (In Process, TCPS, FPCPS, BOP, MTS, SIM)


Westinghouse Ovation® ProjectsWestinghouse Ovation Projects Foreign Plants ● AP1000™** – China 4 Units (In process; Haiyang 1&2 Sanmen 1&2 MCR● AP1000 – China 4 Units (In process; Haiyang 1&2, Sanmen 1&2, MCR,

all non-safety, including FWCS, SIM)● Almaraz 1&2 – Spain (TCS,NSSS/FWCS, FP, BOP, MTS, SIM) PCS in Process● Angra – Brazil (AVR) FWCS in process● Asco1&2 – Spain (LEFM) PCS, NSSS/FWCS & TCPS in process:● Kozloduy 5&6 – Bulgaria (NSSS/FWCS, BOP, TCPS, PCS, SIM)● Koeberg 1&2 – South Africa (PCS, SIM)● Krsko Slovenia (TCPS SIM)● Krsko – Slovenia (TCPS, SIM)● Leningrad 3&4 RBMK; PCS● Ringhals 2 – Sweden (MCR, all non-safety including FWCS, SIM)● Qinshan 3&4 – China (TCS)Q s a 3& C a ( CS)● Shin Kori 1&2 – Korea (MCR, NSSS/FWCS, BOP, SIM)● Shin Kori 3&4** – Korea (MCR, all non-safety including FWCS, SIM)● Shin Wolsong 1&2** – Korea (MCR, all non-safety including FWCS, SIM)

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● South Ukraine Unit 3&4 – Ukraine (PCS, SIM)


Westinghouse Ovation® ProjectsWestinghouse Ovation Projects Foreign Plants (cont)● Vandellos 2 – Spain (PCS, TCPS, MSR, TGTMS, MTS, SWS, SIM) p ( , , , , , , )

FPCPS & NSSS/FWCS in process ● Yonggwang 1&2 – Korea (TCPS, MSR, MTS, SIM)● Zaporozhe VVER1000 – Russia Multi-Unit SPDS

Legend: • **- New Plant• AS - Annuciators System• ATS – Automatic Turbine Startup

• MTS – Maintenance Training System• MSR – Moisture Separator Controls• NSSS - Nuclear Steam Supply System

PCS Plant Comp ter S stem• AVR – Automatic Voltage Regulator• BOP – Balance of Plant• CVCS – Chemical Volume Control

System• FPCS Feedpump Control System

• PCS – Plant Computer System• RWLCS – Reactor Water Level Control

System• SIM – Plant Simulator• SPDS – Safety Parameter Display System• FPCS – Feedpump Control System

• FPCPS – Feedpump Control and Protection System

• FWCS – Feedwater Control System• Leading Edge Flow Meter - LEFM

SPDS Safety Parameter Display System• SWS – Service Water System• TCS – Turbine Control System• TCPS – Turbine Control Protection System• TGTMS – Turbine Generator Temperature

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g g• MCR - Main Control Room Monitoring System


Westinghouse WDPF ProjectsWestinghouse WDPF Projects ● Ginna – (FWCS, SIM)

A 1&2 S i (TCS NSSS/FWCS FP MTS SIM)● Asco1&2 – Spain (TCS,NSSS/FWCS, FP, MTS, SIM)● Prarie Island 1&2 – (FWCS, SIM, MTS)● Ringhals 3&4 Sweden (MCR NSSS/FWCS MTS SIM)● Ringhals 3&4 – Sweden (MCR, NSSS/FWCS, MTS, SIM)● Salem 1&2 – (FWCS, PCS, SIM, MTS)● Sizewell B – England (MCR, all non-safety including FWCS, g ( , y g ,

SIM)● Temelin 1&2– Korea (MCR, all non-safety including FWCS,

SIM)SIM)

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Non-Safety Functional Design, o Sa ety u ct o a es g ,Plant Modeling Process

& Validation Testingg

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Westinghouse Control SystemsWestinghouse Control Systems● All control systems undergo a rigorous design - validation

process p● Extensive validation testing is performed in hierarchical levels

where each level builds upon the previous● At the heart of this process is the Software In Loop (SWIL)

Validation testing which utilizes a plant specific engineeringValidation testing which utilizes a plant-specific engineering model to close the process loop– The Pressurized Water Reactors (PWR’s) SWIL plant models

have been developed and refined with over 25 years of p yexperience with successful results

– These models have been validated against multiple plants with various types of steam generatorsTh SWIL lid ti t ti th t fi ld t i d– The SWIL validation testing ensures that no field tuning and system modifications are needed during plant startup & evolution to full power.

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Control System Design ProcessControl System Design Process● Design Input Data Collection (Baseline Data)● Design● Design

– Functional Diagrams/Functional Requirements– Database, Control Logic Sheet & Graphics

● Modeling & AnalysisC S ( CS )– Advanced Control Simulation Language Model (ACSL)

(plant specific model configured for given application)– Setpoints List

● Control System Software TestingControl System Software Testing– Software-in-Loop (SWIL) Test , Results & Report– Phased Factory Acceptance Tests (FAT)

● SimulatorSt t● Startup– Site Acceptance Test Procedure/Guidelines– Power Ascension Test (PAT) Guideline– PAT On-site startup support

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PAT On site startup support


Design Input Data Collection Key SourcesKey Sources● System Information

– Characteristics of I&C Systems being • Organizational Interfaces:

- Project Managerreplaced

– Design basis (existing & upgraded)

● Process Information

Project Manager- Project Engineers- Design/Integration Engineers- Startup Engineers● Process Information

– Characteristics of Field Devices– Sensors & Control Devices

(Pumps, Valves, etc)

Startup Engineers- System Engineers (Plant

Systems, Subject Matter Experts)

– Characteristics of Process/Components– SG/Vessel, Piping, other

NSSS/BOP components

p )- Component Engineers

(SG/Vessel, Valves, Pumps)- I&C Engineersp

– Characteristics of Operation & Plant Performance– Statepoints, procedures, historical

data (plant computer)

- Operations

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data (plant computer)


ACSL Model Configuration OverviewACSL Model Configuration Overview● Design/operational data collected from plant, reviewed for

accuracy, completeness, consistency (i.e. no discrepancies)y, p , y ( p )● Configuration data loaded into ACSL based plant model● The plant-specific ACSL plant model is tied into ACSL based

control system models transient cases are evaluatedcontrol system models transient cases are evaluated● Adjustments are made until subject matter expert (SME) is

confident that the plant model and control system models are di tlresponding correctly

● SME peer check is also performed to ensure suitability for use● Once model review & response checks are complete, setpoint p p , p

sensitivity tests are performed● ACSL based control system model is disconnected and Ovation

control system is switched in; transients cases are re-performed

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control system is switched in; transients cases are re performed and evaluated


Setpoint DeterminationSetpoint Determination● Dynamic transient analysis using high-fidelity ACSL model of

process running faster than real timep g– Steam Generators or Reactor Vessel– Steam Dump or Steam Bypass – Reactor Pressure Regulation

Feed System– Feed System– Steam System– NSSS (core)

● Evaluation response over the full range of operation and operational transient conditions– Normal Operation– Contingency Operations

● Provides high confidence set of initial tunings● Provides a basis for validation of design

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o des a bas s o a da o o des g


Feed Water Control Design Overview - Example

●S/G Model Description Example– Nodes of S/G Model

Feed Water Control Design Overview Example

Nodes of S/G Model– Primary side tubes– Secondary side tube bundle area (inside of wrapper)– Riser section (from bundle exit through primary separators)Riser section (from bundle exit through primary separators)– Upper downcomer (generally downcomer area from start of

transition cone to top of primary separators)– Lower downcomer (straight cylindrical portion of downcomer

belo transition cone)below transition cone)– Steam dome (region above top of risers or primary separators)

– Separate mass/energy balances for exit properties– Momentum balance performed to calculate change in

various section flow rates

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Feed Water Control Design Overview - ExampleFeed Water Control Design Overview Example

●Proven Validation ApproachSWIL (S ft I L ) l d l lid ti t ti– SWIL (Software In Loop) closed loop validation testing with plant specific model ensures realistic plant operational response

– ACSL Models validated for various SG’s and now Reactor Vessels (BWR)

WestinghouseWestinghouse B&W Canada (5 Units) AREVA (5 Units) C b ti E i i (4 U it ) Combustion Engineering (4 Units)GE BWR 6 Reactor Vessel – Clinton and River Bend

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Feed Water Control Design Overview - ExampleFeed Water Control Design Overview Example

●Proven Control Application SWIL l d l l ti t ti id lid ti– SWIL closed-loop, real-time testing provides validation, allows integration test of graphics, alarms and controls with plant operators before system is manufacturedSetpoints verified for operational transients

(determined previously with ACSL control system models))

Dynamic set points (Gain, Integral & Derivative) for PID are carefully chosen For responsiveness to transientsFor responsiveness to transients For near steady state conditions Results in no tuning during plant startup

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Control Systems – PWR Model Overviewy

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Software In Loop (SWIL)Software In Loop (SWIL)● Upon completion of setpoint analyses, the ACSL plant-

specific control model is switched to Ovation virtual controllers for real-time, closed-loop validation testing

● Verifies delivered system contains the proper setpoints and control logic as presented in the functional requirement documents

● Test performed by Subject Matter Expert along with detailed checks of control logic tuning to verify that setpoints match the intended design

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Feed Water Application (SWIL)Feed Water Application (SWIL)● Validation of plant dynamic performance using transient test

i E lscenarios; Examples:– Ramp Load Increase from 1% Power to Turbine Synchronization Power Level at 1%/min– Turbine Synchronization and Initial Load Pickup

T bi T i With t R t T i ( t i t l l)– Turbine Trip Without Reactor Trip (at appropriate power level)– 100% Power ±10% Load Swing– 100% Power Ramp Load Decrease to 15% Power at 5%/min (bringing on various pumps at the

appropriate power)1 % 100% %/ ( ff– 15% Power Ramp Load Increase to 100% Power at 5%/min (taking off various pumps at the appropriate power level)

– Large Load Rejection (dependent upon plant design typically either 50 or 100% capability)– Loss of One Feedwater Pump– Level Setpoint Step at 5% Power– Level Setpoint Step at 100% Power– Level Setpoint Step at 50% Power with One Feedwater Pump Operating– Level Setpoint Step at 50% Power with Two Feedwater Pumps Operating.

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p p p p g


Feed Water Application Software (SWIL)Feed Water Application Software (SWIL)● Key Customer representatives participate in testing:

– Operations, systems engineering, training, etc.● Results of the testing (trend plots, Control Builder mark-ups,

and logbook entries) are collected into a test report and archived.

● Upon successful completion of this testing, the application software is ready for loading into simulator and FAT on target plant hardware.

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Westinghouse Test Plan OverviewWestinghouse Test Plan Overview● Covers validation test approach.● Each test phase builds upon previous testing in an● Each test phase builds upon previous testing in an

overlapping, structured approach in the order listed below:1. Initial Software Debug Tests2. Testing of Application Software (includes dynamic SWIL tests)3. Simulator Testing4. FAT 1: Target Hardware (power up, controller/network4. FAT 1: Target Hardware (power up, controller/network

redundancy failover & I/O checkout)5. FAT 2: Base System Hardware/software (network, OWS, EWS,

AVS Domain workstation and system security configurationsAVS, Domain workstation and system security configurations6. FAT 3: Including signal validation, graphics, hardware alarms

output redundancy and application hardware )7 Site Testing site acceptance tests and po er ascension test

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7. Site Testing – site acceptance tests and power ascension test


Feed Water (FW) Control SystemsFeed Water (FW) Control SystemsIn delivering digital FW control systems, W ti h liWestinghouse applies:• High Quality Application Software Development

ProcessProcess– Software Requirements Document– Software Description Document

S ft Lif l Pl– Software Lifecycle Plan – Failure Modes and Affects Analysis (software and hardware)– Software Hazards Analysis

P i t t ith 10CFR50 A di B– Processes consistent with 10CFR50 Appendix Bwhere commercial grade application software can be applied in critical applications

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Feed Water (FW) Control SystemsFeed Water (FW) Control SystemsWestinghouse NA uses “defense in design” to ens re deli er of a high q alit prod ctensure delivery of a high quality product:• Plant Specific Models and validation testing with application in closed

loop demonstrates deterministic behavior of the application early in d idesign process

• Applications are partitioned on controllers such as not to cause failures that could add positive reactivity or effect plant design basis

• Reliance on the control network is limited controllers and associated• Reliance on the control network is limited – controllers and associated I/O can continue to function with loss of network

• I/O designed on controller loss to revert to known or benign state• For critical control component, a hard control station is provided toFor critical control component, a hard control station is provided to

operator manual control – another layer of redundancy• Redundancy of system components at all levels

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Reactor Water Level &eacto ate e e &Steam Generator Water Level

Control Upgradespg

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Existing Analog Feed Water ControlExisting Analog Feed Water Control●Historically, Steam Generator Water Level has

been difficult to control– Analog-based systems are limited– Per INPO data; second leading system for plant trip– Steam Generator (SG) shrink and swell phenomena– Steam & feedwater measurement unreliable at low power levelsSteam & feedwater measurement unreliable at low power levels– Manual control with multiple operators required to bring up unit– Prone to single points of failure Analog Inputs – no active redundancy

Manual operator action in detecting input failures Modulating Outputs single driver card

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Modulating Outputs – single driver card


Typical Advanced Digital Feed Water System (ADFCS) ConfigurationSystem (ADFCS) Configuration● 1,2, 3 or 4 Redundant Controllers:

HMI T O t W k t ti ith ft t l●HMI -Two Operator Workstations with soft controls– M/A Stations for FW Valve & FP Controls

●One Engineer’s/Data Base Server Workstation●One Engineer s/Data Base Server Workstation●Network Equipment – Fast Ethernet Switches ●Anti-virus Station●New Cabinets or retrofit of existing cabinets●SLIM M/A’s for Main, Bypass and Feed Pumps

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ADFCS Main Control RoomADFCS – Main Control Room ● Redundant operator stations & LCD

displays in MCR 59 0 PCTdisplays in MCR ● SLIM M/A’s for all modulating valves, &

feed pumpsAdd d l f d d

59.0 PCT

100

SP PV OUT

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Added layer of redundancy upon controller failure

Works seamlessly with soft control

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6060

80

● Remove signal selector switches● Remove select recorders – steam/feed

water, wide and narrow range level20

40

20

40

, g● Remove individual channel indicators &

replace with median● Select indicators can remain “live”

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0

A0

20

M L

Rejectto Local

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● Select indicators can remain liveSLIM M/A Station


Typical ADFCS ArchitectureTypical ADFCS ArchitectureSS/EWS/DB/OWS/

Domain/OPH Server Drop 200

Security (AV) Host

IP Switch

Printer

Note 2

CISCOSYSTEMS CISC OSYSTEMS

NETWORK SWITCHESPrimary Root Switch Back-up Root Switch

MAIN CONTROLROOM

COMPUTER ROOM

CISCOSYSTEMS

PrimaryFan-outSwitch

CISCOSYSTEMS

Back-upFan-outSwitch

NETWORK SWITCHES

OperatorStation

Drop 210

OperatorStation

Drop 211

(Note 1) (Note 1)

Drop 10/62

OCR 400Controller

OCR 400ControllerDrop 11/61

3 & 4

ExtendedI/O Cabinet

L d

59.0 PCT

100

80

20

40

60

0

A

SP PV OUT

0

20

40

60

80

100

M L

Rejectto Local

59.0 PCT

100

80

20

40

60

0

A

SP PV OUT

0

20

40

60

80

100

M L

Rejectto Local

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Loops 1 & 2 Loops 3 & 4Legend:

UTP Cable

Fiber Optic CableMedia ConverterOther T/P viaKVM Extenders


Feed Water Overview Graphic4 Loop Plant Feed Pump Soft M/A4 Loop Plant – Feed Pump Soft M/A

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ADFCS – Design OverviewADFCS Design Overview

● Improved system reliability via signal selectors– Narrow Range Level– Wide Range Level– Feedwater Flow– Steam Flow– Steam Pressure– Feedwater Temperaturep– Turbine Impulse Pressure or Nuclear Power– Feedwater Header Pressure

(FP turbine runback)( )● Improve System performance by integrating feed

pump governor controls

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ADFCS – Design OverviewADFCS Design Overview●Proven Control Application – third generation

design consistent with AP1000design consistent with AP1000– Low and High Power ControllersBumpless Transfer between Low Power and High

P C t l M dPower Control Mode – Feedwater Temperature CompensationLow Power Level Controller gain & reset adjustedLow Power Level Controller gain & reset adjusted

based on feedwater temperatureCompensates for the effects of shrink and swell in

l l t f d t fl i tilevel response to feedwater flow variations– High Power Level Controller proportional gain and

integral time adjusted based on steam flow

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integral time adjusted based on steam flow



●Proven Control Application (cont’d)Load Index– Load Index Wide Range LevelAnticipates need for flow change at low power

Automatic transition from bypass valve to main feed– Automatic transition from bypass valve to main feed water regulation valve

– Capability of operating with one valve in manual and other in autoother in auto

– Control Valve Linearization & PerformanceCompensates for non-linearities in valve

characteristics and ensures an effective and stable control response

Position feedback provides means to detect sticking or sluggish valve response and alert the operator

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●Proven Control Application (cont’d)F d d d d i l l t d f ti f– Feed pump speed demand is calculated as a function of feed water flow demand Provide adequate pump head to ensure flow to the

steam generators is maintained during transientsCoordinated automatic control of steam driven feed

pumps when integrated into ADFCS p p g

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ADFCS – Design OverviewADFCS – Design Overview●Proven Control Application (cont’d)

S it h t M l d i t l ith– Switch to Manual mode in new system only occurs with complete Narrow Range Level failure; otherwise system remains in Automatic for all other failuresSteam or feedwater flow input failure; system revertsSteam or feedwater flow input failure; system reverts

to single element control with a reduced steam generator narrow range level error input to the flow controller PID.controller PID.

Steam pressure, feedwater temperature and feedwater header pressure input failures; system uses a constant value of the signal that is grepresentative of the signal prior to the failure.

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Advanced Digital Feed WaterAdvanced Digital Feed Water

●Benefits– Proven 3rd Generation Design used on Westinghouse and CE plants, deployed

in eleven units with two additional in next two years; common design with AP1000

– Standardized proven and enhanced control logic used for highly reliableStandardized, proven and enhanced control logic used for highly reliable operational performance allowing operational maneuvers with no level deviation

– Auto control over full power range (1-100%), heatup/cooldown (optional)– Auto, seamless transition between main/bypass feed water regulation valves – Bumpless transition from Automatic mode to Manual mode and back– Allows Integrated governor control and protection of main feed water pump

speedPlant specific dynamic analysis per SWIL addresses plant components &– Plant-specific dynamic analysis per SWIL addresses plant components & operational conditions

– Supports transient capability with reduced risk of reactor trip– Minimized field tuning and risk of delays at startup

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g y p


Advanced Digital Feed WaterAdvanced Digital Feed Water Benefits (cont)

– Integrated governor control and protection of– Integrated governor control and protection of main feed water pump speed governor

– Operational maneuvers with no narrow range level deviation

– Output redundancy to control valves available that provides additional layer of protection against SPV and loss of

d d t t llredundant controllers– SLIM hard interface operates seamlessly

with Soft Control Interface graphicsA tomatics s itch to man al and alternate– Automatics switch to manual and alternate actions

– SONG’s and Almaraz have tripped a feed pump at power and stayed on line

Almaraz Feed Pump Turbine

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pump at power and stayed on line


Advanced Digital Feed WaterAdvanced Digital Feed Water

●Benefits (cont)– Eliminates Single Point Vulnerabilities – establish system reliabilities >

99.99%– Internal diagnostics can extend if not eliminate surveillances of the system

Advanced diagnostics making the system easier to troubleshoot and– Advanced diagnostics making the system easier to troubleshoot and maintain

– Standardization with a common platform across multiple applications simplifies spare parts, training and eliminates need for system experts

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Digital ADFCSLessons Learned

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Digital Feed Water Lessons LearnedDigital Feed Water Lessons Learned● Air Supply system to main and bypass valves should be

sized properly with enough volume so valves strokesized properly with enough volume so valves stroke smoothly in required time less than 20-30 secs Air Booster/Accumulator - stroking of any valve should

t ff t th lnot affect other valves Check Pre-load on Bypass & Main Valve actuators to

ensure spring constants have not changedp g g Check diaphragms on Bypass & Main Valves actuators

● Control valve trim should be designed/sized properly and there should be no valve sticking or bindingthere should be no valve sticking or binding New digital control system will not fix valve design issues

or operational problems

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Digital Feed Water Lessons LearnedDigital Feed Water Lessons Learned● Replacement Digital Positioners have internal PID control

and form an outer control loop p Positioner acts as a small control system Positioner/valve sub-loop has effective closed-loop response Overall response of outer flow/level controller is dependant upon the Overall response of outer flow/level controller is dependant upon the

sub-loop response Digital positioners have capability to significantly alter gain and/or time

response for the positioner/valve combinationp p● Utilize “experienced” personnel teams from vendor and

utility – include key stakeholders Utilize personnel that know the plant, interfaces and processesp p , p Involve plant operations personnel from the start and till the end of the

project and identify an operations focal point that “speaks” for Operation Department.

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Digital Feed Water Lessons LearnedDigital Feed Water Lessons Learned● Review and challenge scope of modification will fit in

outage window with minimal riskg Perform work that can be done on line to reduce risk Upgrade solutions should be designed to maximize installation

efficiencyy Use phased upgrade approach

● Carefully evaluate SPVs for cost to improvement benefits Deploy some level of output redundancy Deploy some level of output redundancy

● Take into account scenario of controller redundancy failure - human error What happens to the plant, if control processing stops What happens to the plant, if control processing stops Is there a backup layer of redundancy

● Digital Systems provide configuration management challenges – product offerings should provide levels of self

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challenges product offerings should provide levels of self documenting


Digital Feed Water Lessons LearnedDigital Feed Water Lessons Learned● Digital Systems provide configuration management

challenges – product offerings should provide levels of selfchallenges product offerings should provide levels of self documenting

● Utilize proven designs to minimize project and outage risks● Utilize a robust testing & validation plan that incorporatesUtilize a robust testing & validation plan that incorporates

closed loop engineering models to ensure startup tuning is not required

● With Hi-fidelity engineering models it will be very likely that y g g y ythe plant simulator models will need to be revised

● Ensure that upgrade system design meets current dynamic regulatory environment and requirementsSoftware HazardsFailure Modes and EffectsSystem Security & Cyber Security

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y y y y

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