Post on 27-May-2017
Overview of CANDU Pressurized Heavy Water Reactor (PHWR)and the Canadian Nuclear Industry
Mikko I. Jyrkama and Mahesh D. PandeyDepartment of Civil Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
Steam (light water)
SteamGenerator
PressurizerPump/MotorAssembly
Feedwater(light water)
Calandria
Fueling MachineFueling Machine
Moderator (heavy water)Fuel Channels
Feeders
From FuelChannels
High PresureTurbine
FeedwaterPump
Assembly
Condenser
ModeratorPump
ModeratorHeat Exchanger
Low Pressure Turbines
CoolingWater
Generator
Switchyard
Powerto Grid
To FuelChannels
Fuel
CANDU® - CANada Deuterium Uranium
CalandriaEnd Shield
Tubesheet
End Fitting
Feeder Pipe
ChannelClosure
Liner Tube
PositioningAssembly
Heavy Water Moderator
Fuel Bundles
Shield Plug
Fuel ChannelLattice Tube
Calandria Tube Pressure Tube
Annulus Gas (CO2)Fuel Bundle
Heavy Water CoolantAnnulus Spacer
2005
2007
2008
2009
2010
2006
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
Pickering 2,3Restart
IMO Median Demand Growth ~0.9% p.a.
MW Dispatchable (after avg. Capacity Factors applied)36,000
34,000
32,000
30,000
28,000
26,000
24,000
22,000
20,000
18,000
16,000
14,000
12,000
10,000
Res
ou
rces
(M
W)
Coal (as shutdown)
New Hydro(incl. ~1,400 MW from Manitoba)
Existing Resources (2005)11,000 MW
7,700 MW7,600 MW5,100 MW
NuclearHydroCoalGas
Total Gas ~12,000 MW (~30% of Installed MW)New Gas Builds ~7,000 MW Installed
Nuclear RefurbishmentBruce & Darlington
(Pickering A&B run toend of current life)
New Nuclear (6,100 MW net)Six ACR-1000 units
Wind/Renewable ~10% of Installed MW
Reactor Assembly
AcknowledgementsThis work is part of the NSERC-UNENE Industrial Research Chair (IRC) program at the University of Waterloo. The Chair is one of the sixuniversity professorships established by UNENE in Ontario. The program is funded by UNENE in partnership with NSERC. Industrial sponsorship is provided by Ontario Power Generation, Bruce Power, and Atomic Energy of Canada Limited.
Regulation
1
2
3
4
5
6
7
Steam Outlet Nozzle
Shroud Cone
Tube Bundle
Tube Bundle Hot Leg
Tubesheet
D2O InletD2O Outlet
Feedwater Inlet Nozzle
Preheater Section
Tube Bundle Cold Leg
Grid Tube Support Plate
Shroud
U Bend
Primary Cyclone Separators
Secondary Cyclone Separators
Manway
CANDU Evolution
800
700
600
500
400
300
200
100
900
1950 1960 1970 1980 1990 2000 2010Years
Po
wer
(M
We)
900 MW ClassReactors
600 MW ClassReactors
Research & PrototypeReactors
ZEEPNRX NPD
NRU
RAPP 1,2
Douglas Point
KANUPP
Pickering A Pickering B
Gentilly 2
EmbalsePt. Lepreau
Wolsong 1 Cernavoda 1
Wolsong 2,3,4
Qinshan 1,2
Bruce A Bruce B
Darlington
CANDU 9
Demand for Electricity UNENE
NuclearNucléaire
Gross Capacity (per unit)Net Capacity (per unit)
Construction StartStart-up
Fuel:Elements in bundle/bundles per channelTotal number of fuel bundles in core
Fuel Channels:NumberCalandria tube materialCalandria tube ID/wall thickness (mm)Pressure tube materialPressure tube ID/wall thickness (mm)
Heat Transport SystemNumber of loopsReactor inlet/outlet temperature (°C)Number of heat transport pumpsNumber of steam generatorsNumber of SG tubes/material
791 MW740 MW
Operator
Reactor
Unit
Bruce A Bruce B
1-4
Dec 1970Jul 1976
37/136240
480a. Zircaloy-2129/1.37cw. Zr-2.5%Nb103.4/4.06
4250-265/30448*4200/Inconel 600
4250-265/30448*4200/Inconel 600
* Bruce A and B steam generators have separate preheaters
807 MW750 MW
5-8
Jan 1978May 1984
37/136240
480a. Zircaloy-2129/1.37cw. Zr-2.5%Nb103.4/4.11
Pickering A
2249/29312 plus 4 spare122600/Monel
542 MW508 MW
1-4
Jun 1966Feb 1971
28/124680
390a. Zircaloy-2130.8/1.55cw. Zr-2.5%Nb103.4/4.06
Pickering B
540 MW508 MW
5-8
Nov 1974Oct 1982
Darlington
4267/310444663/Incoloy 800
935 MW881 MW
1-4
Sep 1981Nov 1989
37/136240
480a. Zircaloy-2129/1.37cw. Zr-2.5%Nb103.4/4.19
Point Lepreau
2266/310443542/Incoloy 800
680 MW635 MW
N/A
May 1975Jul 1982
37/124560
380a. Zircaloy-2129/1.37cw. Zr-2.5%Nb103.4/4.19
Gentilly
2266/310443542/Inconel 600
675 MW640 MW
2
Apr 1974Sep 1982
37/124560
380a. Zircaloy-2129/1.37cw. Zr-2.5%Nb103.4/4.19
2249/29312 plus 4 spare122573/Monel
28/124560
380a. Zircaloy-2129/1.37cw. Zr-2.5%Nb103.4/4.01
Cross-Section
Steam Generator
Uses natural uranium as fuel and deuterium oxide (D2O) or "heavy water" as coolant and moderatorStarted as the Canadian contribution to the War effortDesigned by AECL (Atomic Energy of Canada Limited)All nuclear power reactors in Canada are CANDUsCan be refuelled at full powerMultiple shutdown systems for added safety
The steam turns tthe turbines and the turbines turn the generator to produce electricity.
Uranium atoms are split in the core under controlled conditions to produce a chain reaction, providing large amounts of energy in the form of heat.
Heavy water coolant circulates in the Primary Heat TransportSystem through the reactor core.
The hot heavy water coolant from the reactor istransferred to the steam generators to produce steam.
Feeders - inlet and outlet feeders connect each fuel channel individually to connectors (headers) above the core and then to the steam generators
Calandria - a horizontal, cylindrical, single-walled, 6 m long stepped shell enclosed at each end by tubesheets and spanned by calandria tubes and filled with the heavy water moderatorModerator - consists of heavy water at near atmospheric pressure and at a temperature of 70°C, used for moderating (slowing down) the high energy fission neutronsCalandria Tubes - provide access through the calandria for the fuel channel assemblies and also support the pressure tubes by means of four garter spring spacers per channelFuel Channels - the fuel channels contain the pressure tubes that hold the fuel bundles in the neutron flux of the reactor core
1. Calandria2. Calandria end shield3. Shut-off and control rods4. Poison injection5. Fuel channel assemblies6. Feeder pipes7. Vault
CANDU Nuclear PowerPlant Schematic
The condenser turns the steam back into water which is then returned to the steam generators through the feedwater system.
The heavy water coolant in the primary heat transport system removes heat from the reactor core by circulating in the pressure tubes and cooling the fuel bundlesThe HTS operating pressure is ~10 MPa and the typical variation of coolant temperature is from 266°C at the channel inlet to 312°C at the channel outletThe HT water has a pH above 10 and a very low oxidation potential in order to protect the HT piping such as pressure tubes, steam generator tubes, feeders, and fuel Steam Generators - transfer the heat from the hot heavy water (D2O) circulating in the primary heat transport system to ordinary "light" water in the steam generator
The CANDU fuel consists of natural uranium, which contains a fraction of 0.72 % (isotopic abundance) of isotope 235U, with the remaining fraction in the form of 238UThe fuel is fabricated into small UO2 pellets which are then placed inside 0.5 m long fuel rods (small Zircaloy tubes)The tubes are then arranged into fuel bundles consisting of an assembly of 37 elementsSpacer pads on the surface of the tubes prevent direct contact of the fuel rods with the pressure tube walls and allow space for coolant flow through the bundles
Heat Transport System
Fuel
Close-up
Fuel Bundle Zircaloy Fuel Rod(fuel sheath)
UO2 Fuel Pellet
End Plate
End Cap
Spacer Pad
(Sources: Atomic Energy of Canada Limited AECL and Canadian Nuclear Association CNA)
U N E N EUniversity Network of Excellence
in Nuclear Engineering
Point Lepreau Turbine-Generator
(image courtesy of AECL)
(image courtesy of AECL)
CANDU Reactor Assembly(during construction)
(image courtesy of AECL)
The Canadian Nuclear Safety Commission (CNSC), an independent agency of the Government of Canada operates and enforces regulations under the Nuclear Safety and Control Act (NSC Act)As the federal regulator, the CNSC
executes licensing decisions made by the Commission or its designatescontinually monitors licensees to ensure they comply with safety requirements that protect workers, the public, and the environmentuphold Canada’s international commitments on the peaceful use of nuclear energy
The CNSC functions as a tribunal, taking into account the views, concerns and opinions of interested parties and intervenors when establishing regulatory policy, making licensing decisions and implementing programs
In addition to the NSC Act, the CNSC also administers other nuclear related regulations and bylaws in the form of policies, standards, guides and notices
Current energy infrastructure in Ontario will be unable to meet futuresupply requirements
coal phase-out will place additional strains on supplyimports can only meet fluctuations in demand
Future demand can be met with a mix of sources, including Nuclear
(Source: Atomic Energy of Canada Limited)
(Sources: International Atomic Energy Agency IAEA and Canadian Nuclear Safety Commission CNSC)
(image courtesy of CANTEACH)
(image courtesy of CANTEACH)
(image courtesy of AECL)
(CANDU 6’s)
ACRAdvanced CANDU
Reactor
Gas Annulus - the gap between the fuel channel pressure tubes and the calandria tubes insulates the hot pressure tubes from the relatively cool moderator
University Network of Excellence in Nuclear Engineering
UNENE is an alliance of universities, nuclear power utilities, research and regulatory agencies for the support and development of nuclear education and R&D capability in Canadian universitiesThe main purpose of UNENE is to assure a sustainable supply of qualified nuclear engineers and scientists to meet the current and future needs of the Canadian nuclear industry
UNENE has created a fully accredited course-based Master's of Engineering (MEng) program in Nuclear Engineering which is offered jointly by the member universities
UNENE has established Industrial Research Chairs (professorships) in six Ontario universities through a partnership with NSERC and generous support from the Canadian nuclear industry
Nuclear Research and Development
Nuclear Engineering Education Program