Advanced CANDU Reactor ACR-1000 ACR 1000

Advanced CANDU Reactor
ACR-1000 ACR 1000 - Design Overview
Bob Munro
ACCOUNT MANAGER, CERNAVODA
Budapest, Hungary
March, 2007

Atomic Energy of Canada Limited
• Commercial Crown Corporation,
established in 1952 to lead the
Canadian nuclear industry
• CANDU designer, invented cancer
therapy machines and is largest
supplier of medical isotopes
• CANDU recognized as one of the top
10 major engineering achievements
of the past century in Canada
• Established world records in
construction and commissioning
2

A Total Nuclear Solution Company
• Involved in all aspects of nuclear power design and
construction
• Full lifecycle service packages
– Design, build, and service reactors in Canada and around
world
• Bundled services
– O&M support, plant life management programs, waste
management
• World Class R&D facilities at Chalk River Laboratories
3

World Class Nuclear R&D
More than 400
laboratories with
uniquely specialized
test facilities provide
the breadth of
capabilities to
support CANDU
platform
4

Products
• The CANDU Reactor is AECL’s flagship
product
– CANDU 6
– Enhanced CANDU 6
– ACR-1000
• AECL also delivers solutions to the PWR
industry
– MACSTOR (Modular Air Cooled Storage)
– ECC (Emergency Core Cooling) Strainers
– Pump Seals
– Hydrogen Recombiners
5

Power (MWe)
900
800
700
600
500
200
100
CANDU Development Builds on a Strong History
-
900MW Class Reactors
700MW Class Reactors
ZEEP
NRX
NRU
NPD
Douglas Point
Bruce A
Pt Lepreau Embalse
CANDU 6
Pickering A Pickering B
RAPP 1,2
KANUPP
1950 1960 1970
1980 1990 2000
Years
Darlington
Bruce B
Gentilly 2 Wolsong 1
Cernavoda
CANDU 9
Qinshan 1&2
Wolsong
2,3,4
Research &Prototype Reactors
ACR
and beyond
Enhanced
CANDU 6
2010
6

Integrated two-unit two unit ACR-1000 ACR 1000 Plant
7

AECL’s Reactor Product for New Build
ACR-1000:
• 1200 MWe class
• Generation III+ technology
• Combines experience of CANDU 6
with new CANDU concepts
• Enhanced safety, economics,
operability
8

Keeping the CANDU Tradition…
ACR evolves from the successful
CANDU 6 family of units:
• Modular horizontal fuel channels
• Simple fuel bundle design
• Separated coolant from moderator
• Cool, low pressure heavy water
moderator
• On-power fuelling
• Passive shutdown systems
• Established equipment
Qinshan Phase III, China
Most recent CANDU 6 plant
completed in 2002/3, ahead
of time and under budget
9

Nuclear Steam Plant Overview
• Nominal gross/net output
~1165/1085 MWe
• 520 parallel, horizontal
pressure tubes located
within the calandria
tubes
• Calandria filled with
heavy water moderator
• Light water reactor
coolant system
• Low Enriched Fuel (LEU)
Steam
Feedwater
Light Water Coolant
Heavy Water Moderator
1 Main Steam Pipes
2 Pressurizer
3 Steam Generators
4 Heat Transport Pumps
5 Headers
6 Calandria
7 Fuel
8 Moderator Pumps
9 Moderator Heat Exchangers 10
10 Fuelling Machines

ACR-1000
ACR-1000 Major Changes:
• Low enriched fuel, light water coolant,
reduced D 2O inventory
• Higher steam pressure for increased
efficiency
• Smaller reactor core with improved
stability enables higher output
• Design optimized for high capacity factor,
operability and maintainability over 60
year life
• Larger thermal margins - designed for
end-of-life conditions
11

ACR-1000 Reactor Assembly
12

Reactor Core Design Comparison
• Calandria 7.6 m
(similar to EC6)
• Lattice 26 x 26
• Heavy water hold-up
reduced
EC6 ACR - 1000
EC6 ACR-1000
Number of Channels 380 520
Reactor Core Diameter (m) 7.6 7.6
Lattice Pitch (mm) 286 240
Vol of D 2O in Moderator (m 3)
265 250
Vol of D 2O in HTS (m 3 ) 192 0
Total Vol of D 2O (m 3 ) 457 250
13

ACR Compact Core Design
• Reduced lattice pitch
• Reduced heavy water inventory
• Flat core neutron flux with increased
stability
• Increased safety margins via optimized
power profile and reactivity coefficients
14

Heat Transport System
• Heat Transport System – 2 loop
arrangement, same as EC6
• Increased thermal margin
• Higher HT System operating
conditions
• ROH pressure 11.1 MPa(g)
• ROH temp 319 o C
• Higher steam pressure for
increased thermal efficiency,
• SG pressure 5.9 MPa(g)
• SG Temperature 275 o C
• Feedwater temperature 217 o C
• Turbine cycle efficiency 36.6%
Reactor Assembly
Reactor Outlet
Header (ROH)
15

Heat Transport System Pump
Steam Generator
16

On-Power Fuelling – Basic Operation
• Each fuel channel contains 12
fuel bundles
• Two fuelling machines are
connected to each end of a
channel at the same time
• The fuelling machines also
connect to the new and
irradiated fuel ports and fuels
channels in sequence.
17

On-Power On Power Fuelling - Benefits
• No re-flueling outage
(flexibility in planned
outage timing)
• Permit reduced
planned outage
frequency
• Can detect and
remove failed fuel onpower
Fuelling Machine
18

ACR-1000 Improvement Areas
• Safety Enhancements
• Enhanced passive safety
• Factor of ten improvement in severe core damage frequency
• Operational Enhancements
• Capacity Factor >90% over 60-year lifetime
• Operating margins maintained to End of Life
• Maintenance based design
• Target: event-free operation
• Improved Construction
• Shorter construction schedule
• Reduce cost by 25% or more
19

ACR-1000 ACR 1000 Safety Enhancements
20

ACR-1000 Safety Enhancements
• Meets IAEA standards (e.g., for safeguards, IAEA
Safety Standard NSR-1 including single failure
criterion)
• Meets Canadian regulations, codes and standards
• Incorporates and enhances established CANDU
advantages:
– Two independent shutdown systems
– Inherent passive heat sinks
– High degree of automation lessens operator burden
– Improved separation and redundancy of safety and
safety support systems to facilitate maintenance and
improve operating reliability (e.g., four safety channels)
21

ACR-1000 Safety Enhancements
• Enhanced resistance to severe core
damage through passive mitigation such
as passive makeup to moderator and
calandria vault heat sinks
• Core damage and large release mitigation
going beyond international standard for
advanced plants
• Robust steel-lined reactor building
structure to address evolving safety and
security licensing basis (aircraft crash,
etc.)
22

Dual Fast Acting Shutdown Systems
• Shutdown system 1 (SDS1)
Shut-off rods fall vertically
into the low pressure
moderator by gravity drop
• Shutdown system 2 (SDS2)
Liquid neutron absorber
injected horizontally by
gas pressure into the
moderator
Shutdown System Number 2
Shutdown System Number 1
ACR-1000 Shutdown Systems 1 & 2
23

Emergency Core Cooling (ECC) System
• Two Stage ECC System:
Initial injection from pressurized
ECI tanks located inside
Reactor Building (RB)
Long Term Cooling (LTC)
System provides pumped
recovery
LTC System also provides
maintenance cooling after
normal shutdown
LTC pumps and heat
exchangers located in Reactor
Auxiliary Building (RAB)
adjacent to RB sumps
24

3. Reserve Water
Tank fills fuel
channels,
moderator vessel,
and calandria
vault by gravity
Three Major Passive Heat Sinks
1. Moderator
Vessel Water
2. Calandria Vault
Water
25

ACR-1000 Reactor Building
26

Strong Containment and Quadrant Design
Steel-lined, 1.8 meter thick
pre-stressed concrete walls
Safety support systems in
quadrants around Reactor Building
27

Reactor Building Structure
• Additional loads are considered
in the design. Steam Line Break
sets design pressure (approx.
350 kPa)
• Robust reactor building structure
upgraded to address evolving
security licensing basis
• Reactor Building structure
designed for aircraft crash
• RB equipment is accessible on-
REACTOR
power through 2 airlocks LTC GRADE
COOLING
COILS
SG VAULT
LACS
FANS
LTC GRADE
LEVEL TANK
SPRAYS
RESERVE WATER TANK
SPRAY HEADER SPRAYS
DOME
LACS
COOLING
COILS
LEVEL TANK
28
SG VAULT
LACS
FANS

For accident prevention &
mitigation of consequences:
• High-quality process systems to
minimize likelihood of accidents
• Reliable safety systems for reactor
shutdown, ECCS and containment
• Reliable safety support systems to
provide services to safety systems
and other mitigation systems
• Backup systems for heat sinks and
essential controls
• Passive heat sinks to increase
resistance against both design
accidents and severe accidents
Defense-in-Depth
29

Severe Accidents
• ACR-1000 includes the following features
for severe accident mitigation:
• Passive Core Make-Up Tanks keep HTS full to
assure thermosyphoning capability
• Reserve Water System (RWS) supply by gravity to
SGs provides inventory for long-term
thermosyphoning
• Passive make-up to HTS from ECI and RWS delay
accident progression
• Passive make-up to moderator and calandria vault
from RWS delay accident progression
• Passive spray system supplied from RWS delays
containment failure
30

Operational Improvements
31

Operation and Maintenance
• Designed for >90% average lifetime capacity factor
• Advanced Control Center design
• Low forced outage frequency
• Three-year planned outage frequency
• General design for maintenance
• 21-day standard planned outage duration
• Mid-life (30 years) pressure tube re-tubing outage
• SMART CANDU TM plant life cycle information tools
32

ACR-1000 Control Centre
Major focus of the ACR-1000 Advanced Control
Centre design is:
• Build on the improved display and layout used in the
Qinshan CANDU 6 Main Control Room
• Improve operability of the plant and build on past
experience
• Systematically integrate human factors into the design
process
• Decrease likelihood of operator or maintainer errors
• Improve the operator’s awareness of system and plant
status through Human Factors engineering analysis
• Provide improved maintenance/diagnostic capabilities
33

Control Centre Mockup
Ergonomic operator console, touch displays, large screens,
smart annunciation.…
34

Low Forced Outage Frequency
• Well maintained quality equipment
• Increased access for on-line maintenance
• 4 divisions of major safety & safety support systems
provides additional redundancy and reliability to allow
on-power maintenance of one division
• 4 channel safety systems, minimizes risk of spurious
trips
• Increased automation of shutdown system testing
• Operability, maintainability and human factors
designed in
• Increased automation of unit operations
• Better information tools
35

3-Year Planned Outage Intervals
• Maximum on-line maintenance access
– Reactor building accessible areas
– Shielding of inaccessible areas
• Use of AECL Feedback Management System
information
• Selection and design of critical equipment and
components for O&M
• “Systematic Approach to Maintenance” tools
used to define maintenance strategy
36

General Design for Maintenance
• Equipment transfer routes and sufficient space
around equipment (3-D modelling)
• Equipment and component lay down areas especially
for outages
• Permanent platforms and lifting facilities for
inspection and maintenance
• Outage services such as air, water and electrical
supplies
• Specialized tools for fast inspection, disassembly,
replacement
37

Fast & Simplified Outages
• Faster application and removal of GSS – current efforts
on Rod based
• 4-division power supply and heat sinks
– Electrical distribution and heat sink maintenance not critical
path
– Steam generators (SG) not required as back-up heat sink
– Fuel channel and SG inspections in parallel
• Back-up power for essential outage equipment
• More walkways and hoists, few temporary scaffolds
• R/B elevator for personel, tools and equipment
• Air, power and water for outage maintenance areas
38

Fast & Simplified Outages
• Elimination of legacy problems less inspections
• Maximize on-line maintenance
• T/G design and tooling minimize disassembly,
reassembly and inspection time
• R/B ventilation design enables open airlocks during
outage
• Zone shielding and ventilation speeds up
maintenance and inspection
• Start-up and shut-down primarily computer
controlled
39

SMART CANDU TM Information Tools
• Advanced Computer Control and Information
System
• Two process system health monitoring tools
(ChemAND and ThermAND)
• Equipment monitoring and reporting tool
(MIMC)
• Configuration management tools (Plant Data
Historian, Document Management, Equipment
Database)
40

DATA
ChemAND – Performance Monitor for
Plant Chemistry
ACTION
KNOWLEDGE
INFORMATION
41

Improved Construction
42

Construction Strategy
• Prefabrication / Modularization
• RB Open Top Construction using Very Heavy Lift
(VHL) Crane
• Parallel construction and module fabrication
• Use of up-to-date technologies
– Use of 3-D modeling and wiring databases in the field
– Large volume concrete pours
– High performance and low heat concrete
– Prefabricated rebar
– Concrete climbing forming
– Bridging systems and prefabricated permanent formwork
– Composite structures
– Pipe bending and pre-fabrication
– Automatic welding
43

ACR Modularization Strategy
• Qinshan demonstrated large potential for
significant schedule and cost reduction through
planned use of modules
• ACR design and construction strategy further
extends use of modules to increase parallel
construction
• Extensive Modularization coupled with “Vertical
Installation Compartment” used in Reactor
Building construction
• ACR is designed to employ more than 165
modules in the Reactor Building
• Input from Module Fabricators and Construction
have been incorporated into the module design
44

ACR Module Types
• Piping Valve/ Modules Pre-Assembled on Skids
− Pre-assembled in Supplier/ Fabricators shop
− Shipped by road/ rail/ sea
• Instrumentation Racks/ Pre-assembled Panels
− Pre-assembled in Suppliers shop
− Shipped by road/ rail/ sea
- Images taken from 3L Filters
45

Walkways
ACR Feeder Header Module
46

1st
1st Unit Project Schedule 66 m.
Unit 12 m
46 m 8 m
CED
Nth
Unit
CED
6 m
ACR-1000 Project Schedule
F/C F/L I/S
F/C
Nth Unit Project Schedule 54 m.
42 m 6 m
F/L I/S
47

Summary of ACR Design
• AECL has invested significantly in the “Generic ACR
Technology Development” Program for the ACR-1000
– Generic ACR program ongoing since 2000
– The ACR design has undergone extensive program review to serve
as a foundation for ACR-1000 basic engineering and pre-licensing
• Activities being carried out:
– Design
– Licensing
– Development and Testing
– Supply Chain Management
– Commissioning and Operations assessment
48

Summary of ACR Design
• Significant design enhancements have been
made for the benefit of the Customer:
– Safety
– Performance
– Operability
– Maintainability
– Constructability
49