Electrical, Control and Information Systems in the Enhanced CANDU 6 ® Electrical, Control and Information Systems in the Enhanced CANDU 6 ® Candu – Official Use Only By Sunil Tikku, presented by Jerry Hopwood SIEN Bucharest, October 2011

Outline Introduction to the Enhanced CANDU 6 I&C design philosophy and architecture –Basic principles and architecture –Drivers for design changes Specific I&C enhancements –Electrical system enhancements –Control room enhancements –Control & Safety system enhancements –Operational support systems (OSS) Generic engineering programs Summary © Copyright 2011, AECL

I&C Architecture © Copyright 2011, AECL

Drivers for EC&I Enhancements compliance with new and more stringent licensing requirements improvements to enhance plant safety margins improvements to address customer feedback improvements for higher plant performance, reduced capital costs and more economic life-cycle operation Compliance to international I&C standards changes to address obsolescence other opportunities for improvement © Copyright 2011, AECL

Electrical Power System Enhancements Each unit has dedicated pair of redundant standby generators with auto start Seismically qualified uninterruptible power supplies (UPSs) added with automatic start-up of essential loads Manual tie-in circuit breakers between the redundant buses of the two units to enhance availability © Copyright 2011, AECL

EC6 MCR Enhancements Similar to C6 panel layout (some improvements) Preserves “operate at panel” philosophy Incorporates advantages of digital systems Avoids over-reliance on complex software Centralized operator console provides monitoring, test and supervisory support functions Digital device controls (where appropriate) Computerized safety system testing © Copyright 2011, AECL

EC6 MCR Enhancements (2) Seismically qualified MCR Computerized and seismically qualified Safety Monitoring System (includes PAM, h/w back-ups) Advanced alarm annunciation with h/w back-ups Computer based procedures (including safety system testing, EOPs) © Copyright 2011, AECL

Digital Safety Systems SDS 1 &2 remain independent and diverse: –fully separate and diverse voting, actuation and shut-down mechanisms –each employs triplicated computerized trip channels –both on new digital platforms (diverse design) –two out of three voting logic in each SDS –adding digital neutronics trips –adding two faster rate trips on each SDS Digital emergency core cooling system (ECC) Digital emergency heat removal system (EHRS) Containment systems remain as relay logic © Copyright 2011, AECL

Reactor Instrumentation Enhancements Adding more in-core flux detectors Additional SDS 2 in-core detectors in lower core (eliminates difference compensation) Replacing ion chambers with fission chambers –Eliminate lead shielding (reduced seismic load) –Improved detector range –Reduced reliance on start-up instrumentation Adding fission chambers on both sides of core for both shut-down systems

Control System Enhancements Modern DCS technology to replace Digital Control Computers (DCCs) –Design for safety, reliability, and maintenance –Tighter integration of device and group control –Separate mitigating controller (credited class 2) –Increased use of local controllers –Reduction in wiring and signal marshalling –Separate Fuel-Handling DCS & display system –Separate digital Fuel-Handling protective system © Copyright 2011, AECL

Display System Enhancements Safety qualified display systems (ACCIS ® platform) Supervisory functions in Plant Display System (PDS) Use of local panel displays (touch panel VDUs and display-only VDUs) Advanced alarm annunciation (intelligent alarm conditioning and management) Robust PDS system architecture Design for safety, maintainability and reliability

Operational Support Systems Plant information systems to help meet plant performance targets (94% annual capacity factor, 1% forced loss rate) Increased equipment and system health monitoring –Single points of vulnerability (SPV) and critical components –Smart CANDU ® applications Provision of online safety/reliability monitors Provision of an equipment status monitor (ESM) Provision of an historical data system (HDS) Improved data exchange and integration, plant configuration management

EC&I Enhancements for Severe Accidents Dedicated diesel generator / batteries and power distribution system to handle severe accident recovery and heat removal Monitoring to deal with SA available in both MCR and SCA (in form of hardwired and computerized safety parameter display) All related instrumentation evaluated / enhanced to cover the measurement ranges expected for SA Instrumentation assessed for layout and power source considerations for post SA effectiveness Instrumentation EQ’ed and assessed for survivability under SA conditions © Copyright 2011, AECL

Generic Engineering Programs These are applied to the design of all or many plant systems and include: –Increased use of simulation (“EC6Sim” Dynamic Simulator for design assist, plant dynamics, Anticipated Operation Occurrence analysis etc.) –Functional MCR mock-up facility –IEC standards for I&C system life cycle design –Human factors engineering program –Operating experience feedback program –Equipment qualification (EQ) program –Integrated cyber security program © Copyright 2011, AECL

Summary EC6 builds on proven success of CANDU 6 Design to meet or exceed current new build requirements EC&I enhancements provide improvements: –in safety margin –in plant performance –to address OPEX and customer feedback issues –in life-cycle cost reduction (improved maintainability, reliability, reduced obsolescence issues)