8.0 Instrumentation & Control

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Objectives

1. State the purposes of the following:

a. Safety Information and Control Systemb. Process Information and Control Systemc. Protection System

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c. Protection Systemd. Process Automation Systeme. Diverse Actuation System

2. Describe the major differences between the I&C design of the US-EPR and those of currently operating PWRs.

CRDCS – Control Rod Drive Control Sys.DAS – Diverse Actuation SystemMCR - Main Control RoomPACS – Priority & Actuator Control SystemPAS – Process Automation SystemPICS – Process Information & Control SystemPS – Protection SystemRCSLS – Reactor Control, Surveillance, &

Limitation SystemRSS – Remote Shutdown StationSAS – Safety Automation SystemSCDS – Signal Conditioning & Distribution SystemSICS – Safety Information & Control SystemTG I&C – Turbine-Generator Instr. & Control 3

Figure 8-1I&C Architecture

Human-Machine Interface (HMI): Safety Information & Control System

Controls & indications for:

• Mitigation of AOOs & accidents (manual reactor trips & ESF actuations)

• Reaching & maintaining safe shutdown

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shutdown• Mitigation of severe accidents• Display of PAM variables

• Implemented with dedicated, hardwired equipment

• Powered from EUPS (safety) & 12UPS (nonsafety)

HMI:Process Information & Control System

• Equipment for monitoring & control of process systems during normal ops

• Workstations in MCR, RSS • Data connections to RCSLS (core

control), PAS (plant control)

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• Implemented with industrial I&C platform

• Powered from 12UPS

Automation Systems:

Protection System

• Auto reactor trips & ESF actuations

• TELEPERM XS platform• 4 divisions in safeguard

buildings • Powered from EUPS

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Safety Automation System

• Performs auto & manual grouped safety-related control functions

• TELEPERM XS platform• 4 divisions in SCI buildings • Powered from EUPS

APU - Acquisition & Processing Unit

ALU - Actuation & Logic Unit

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Figure 8-4 Typical Reactor Trip Actuation

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Figure 8-5 ManualReactor Trip

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Figure 8-3 Safety-Related Reactor Trip Devices

Table 8-2

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Table 8-2 (cont’d)

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12Figure 8-6 Typical ESF Actuation

Table 8-4

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Table 8-4 (cont’d)Table 8-4 (cont’d)

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Table 8-4 (cont’d)

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Table 8-4 (cont’d)

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Automation System:Priority & Actuator Control System

• Prioritizes actuation signals from different I&C systems

• Interfaces with actuation devices & actuated equipment via (mostly) hardwired connections

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• Implemented with priority & communication modules (1 set per actuator)

• 4 divisions in SCI buildings• Powered from EUPS (safety)

& 12UPS (nonsafety)

18Figure 8-2 Priority & Actuator Control System

Automation System:Signal Conditioning & Distribution System

• Performs signal conditioning & distribution of signals from sensors, black boxes

• Receives hardwired inputs & sends hardwired signal outputs to various systems

• Implemented with TELEPERM XS signal conditioning & distribution equipment

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g q p(diverse from TELEPERM XS digital function processors)

• 4 divisions in SCI buildings• Powered from EUPS (safety) & 12UPS

(nonsafety)

Automation System:Reactor Control, Surveillance, & Limitation System

• Performs reactivity-related control & limitation functions

• Provides orders to CRDCS for rod motion, to PAS for boration or dilution

• Implemented with TELEPERM XS l tf 4 di i i i f d

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platform, 4 divisions in safeguard buildings

• Powered from 12UPS

Core Control• RCSLS implements automation-level

I&C functions:

– Tavg control using rod motion– Tavg control adjusting boron concentration

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– Neutron flux control– Axial offset control

• Control Rod Drive Control System (CRDCS) provides interface to CRDM coils (controls currents).

25%, 587

35%, 587

60%, 594 100%, 594

585

590

595

600T

EM

PE

RA

TU

RE

(F

)

Fig. 8-7 RCS Temperature Program

100% values:

• Th ~ 625°F

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0%, 578

570

575

580

0% 20% 40% 60% 80% 100%

POWER LEVEL (% OF RATED THERMAL POWER)

AV

ER

AG

E R

C T • Tavg ~ 594°F

• Tc ~ 563°F

• ΔT ~ 62°F

Fig. 8-8Rod Speed Control

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Automation System:Process Automation System

• Nonsafety-related automation & control system for plant

• Redundant control units acquire hardwired inputs from various sources

• Outputs sent directly to nonsafetyactuators or to PACS

I l t d ith i d t i l

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• Implemented with industrial, commercial-grade digital I&C platform

• 4 divisions for most functions, 2 trains for others in various buildings

• Powered from various nonsafetysources

Plant Control• RCS Pressure Control: Controls PZR

heaters & spray

• Pressurizer Level Control: Modulates CVCS letdown

• Steam Generator Level Control: Maintains

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• Steam Generator Level Control: Maintains SG levels by modulating MFW control valves

• Main Steam Pressure Control: Modulates turbine bypass valves to provide main steam overpressure control

Diverse Performance of Safety Functions

• SICS: Manual reactor trip; initiation of system-level safety functions via DAS

• DAS: Executes manual functions from SICS & auto functions to mitigate ATWS, software CCF of PS– Reactor trips

ESF t ti

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– ESF actuations– Display of post-accident monitoring variables

• PACS: Supports execution of auto & manual functions to mitigate ATWS, software CCF of PS; diverse in operation from the PS

• SCDS: Outputs are hardwired & sent independently to each system

Diverse Actuation System Functions

• Acquires sensor info from SCDS & executes logic for several reactor trip & ESF actuation functions

• For trips, DAS outputs go to breaker shunt trip coils (PS affects undervoltage coils), control

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( g ),units of CRDCS to interrupt power to CRDM coils

• For ESF actuations, DAS outputs go directly to PACS (bypassing PS & SAS)

• Designed so that DAS should not interfere with PS; PS should actuate first

Automation System:Diverse Actuation System

• Nonsafety-related system for mitigating AOO or accident concurrent with common-cause PS failure

• Hardwired inputs & ouputs• Hardwired interface with SICS for

receipt of manual system-level d

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commands

• Implemented with something other than microprocessor-based technology

• 4 divisions in safeguard buildings• Powered from 12UPS

DAS Protection Functions• Reactor Trips

– High neutron flux

– Low RCS flow (2 loops)

– Low-low RCS flow (1 l )

• ESF Actuations– SIS actuation

– EFWS actuation

– Main steam isolation

– Containment isolation

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loop)

– High PZR pressure

– Low hot leg pressure

– Low SG pressure

– High SG level

– Low SG level

– Turbine trip on reactor trip

– MFW isolation

– Opening of containment H2 mixing dampers

– Starting of SBODGs