[en] AECL has developed the design for a next generation of CANDU^R plants by applying a set of enabling technologies to well-established successful CANDU features from the CANDU 6 Reactors in service and the design of the CANDU 9. Advances made in the construction of the Wolsong reactors have been built upon in the current project in China. The basis for the new design is to evolve from the current CANDU units by replicating or adapting existing components for a new core design. Using slightly enriched uranium fuel, a core with light water coolant, and heavy water moderator and reflector has been defined, based on the existing CANDU fuel channel module. This paper summarizes the main features and characteristics of the reference next-generation CANDU design. The progress of the next generation of CANDU design program in meeting challenging cost, schedule and performance targets is described. AECL's cost reduction methodology is summarized as an integral part of the design optimization process. Examples of cost reduction features are given, together with enhancement of design margins

[en] This paper outlines the safety approach being taken in CANDU reactor development The CANDU Pressurized Heavy Water Reactor (PHWR) has been successful both in Canada and internationally. Currently there are twenty-two CANDU plants operating in Canada, and two in Korea and Argentina. There are also five CANDUs under construction in Romania, and three in Korea. In terms of capacity factor, three to four of the top ten reactors in the world have consistently been CANDU. Operating CANDUs span two size ranges: the single-unit 650MWe class CANDU 6 (and its multi-unit variant at Pickering in Canada), and the 900MWe class Bruce/Darlington design. Multiple-unit 900MWe class CANDUs provide over half of the electricity for the Province of Ontario, in Canada; the CANDU 6 class has been used both in Canada and internationally. CANDU design for the future is based on a step-by-step evolutionary approach, building on the strengths of the CANDU concept, and on proven technology. CANDU safety development is consistent with this approach. The priorities for safety development are 'good-neighbour' operation; prevention of accidents; strengthening of CANDU's defence in depth for mitigation of severe accidents. Licensing of CANDU is in keeping with the trend to global consistency. CANDU's versatility is demonstrated by the success being achieved today in achieving and maintaining licensability in widely varying jurisdictions.

[en] CANDU reactor technology was originally developed in Canada as part of the original introduction of peaceful nuclear power in the 1960s and has been continuously evolving and improving ever since. The CANDU reactor system was defined with a requirement to be able to efficiently use natural uranium (NU) without the need for enrichment. This led to the adaptation of the pressure tube approach with heavy water coolant and moderator together with on-power fuelling, all of which contribute to excellent neutron efficiency. Since the beginning, CANDU reactors have used [NU] fuel as the fundamental basis of the design. The standard [NU] fuel bundle for CANDU is a very simple design and the simplicity of the fuel design adds to the cost effectiveness of CANDU fuelling because the fuel is relatively straightforward to manufacture and use. These characteristics -- excellent neutron efficiency and simple, readily-manufactured fuel -- together lead to the unique adaptability of CANDU to alternate fuel types, and advancements in fuel cycles. Europe has been an early pioneer in nuclear power; and over the years has accumulated various waste products from reactor fuelling and fuel reprocessing, all being stored safely but which with passing time and ever increasing stockpiles will become issues for both governments and utilities. Several European countries have also pioneered in fuel reprocessing and recycling (UK, France, Russia) in what can be viewed as a good neighbor policy to make most efficient use of fuel. The fact remains that CANDU is the most fuel efficient thermal reactor available today [NU] more efficient in MW per ton of U compared to LWR's and these same features of CANDU (on-power fuelling, D_2O, etc) also enable flexibility to adapt to other fuel cycles, particularly recycling. Many years of research (including at ICN Pitesti) have shown CANDU capability: best at Thorium utilization; can use RU without re-enrichment; can readily use MOX. Our premise is that CANDU can be deployed in Europe to reduce waste, save money for operating utilities (i.e. Nuclearelectrica) and introduce much more flexible fuel options. This paper provides an update on recent developments in the application of CANDU to important fuel cycle options. More specifically we report on recent developments in three key areas: China NUE uses both RU and DU, two waste products to make fuel. Test irradiations done, moving to full-core implementation, China - Thorium, UK - MOX. CANDU is a leading contender and most efficient practical solution. In the current context where nuclear power expansion remains under consideration for many countries as the primary greenhouse-gas-free energy option, the deployment of CANDU reactors for advanced fuel use provides important potential advantages, both on its own and in synergy with other elements of the global nuclear system. (authors)

[en] As air quality and climate change issues receive increasing attention, the opportunity for nuclear to play a larger role in the coming decades also increases. The good performance of the current fleet of nuclear plants is crucial evidence of nuclear's potential. The excellent record of Cernavoda-1 is an important part of this, and demonstrates the maturity of the Romanian program and of the CANDU design approach. However, the emerging energy market also presents a stringent economic challenge. Current NPP designs, while established as reliable electricity producers, are seen as limited by high capital costs. In some cases, the response to the economic challenge is to consider radical changes to new design concepts, with attendant development risks from lack of provenness. Because of the flexibility of the CANDU system, it is possible to significantly extend the mid-size CANDU design, creating a Next Generation product, without sacrificing the extensive design, delivery and operations information base for CANDU. This enables a design with superior safety characteristics while at the same time meeting the economic challenge of emerging markets. The Romanian nuclear program has progressed successfully forward, leading to the successful operation of Cernavoda-1, and the project to bring Cernavoda-2 to commercial operation. The Romanian nuclear industry has become a full-fledged member of the CANDU community, with all areas of nuclear technology well established and benefiting from international cooperation with other CANDU organizations. AECL is an active partner with Romanian nuclear organizations, both through cooperative development programs, commercial contracts, and also through the activities of the CANDU owners' Group (COG). The Cernavoda project is part of the CANDU 6 family of nuclear power plants developed by AECL. The modular fuel channel reactor concept can be modified extensively, through a series of incremental changes, to improve economics, safety margins and performance. The CANDU 6 design has evolved in both design and project delivery, so that the current CANDU 6 construction project at Qinshan Phase 3, in China, represents the nuclear project state-of-the-art. Experience with current plants, such as Cernavoda, is an important input to the development of improved designs for the future. Building on the strong CANDU knowledge base, AECL is continuing to adapt the CANDU design to develop the Next Generation CANDU medium-sized fuel channel reactor. This paper discusses the next generation of CANDU designs featuring major improvements in economics, inherent safety characteristics and performance, while retaining the proven benefits of the CANDU family of nuclear power plants. This leads to a seamless evolution which ensures that innovation is introduced in a way which minimizes project or operations uncertainties. (authors)

[en] The CANDU 6 Pressurized Heavy Water Reactor system, featuring horizontal fuel channels and heavy water moderator continues to evolve, supported by AECL's strong commitment to comprehensive R and D programs. The initial CANDU 6 design started in the 1970's. The first plants went into service in 1983, and the latest version of the plant is under construction in China. With each plant the technology has evolved giving the dual advantages of proveness and modern technology. CANDU 6 delivers important advantages of the CANDU system with benefit to small and medium-sized grids. This technology has been successfully adopted by, and localized to varying extents in, each of the CANDU 6 markets. For example, all CANDU owners obtain their fuel from domestic suppliers. Progressive CANDU development continues at AECL to enhance this medium size product CANDU 6. There are three key CANDU development strategic thrusts: improved economics, fuel cycle flexibility, and enhanced safety. The CANDU 6 product is also enhanced by incorporating improvements and advanced features that will be arising from our CANDU Technology R and D programs in areas such as heavy water and tritium, control and instrumentation, fuel and fuel cycles, systems and equipment and safety and constructability. (author)

[en] The CANDU 9 is a family of single-unit Nuclear Power Plant designs based on proven CANDU concepts and equipment from operating CANDU plants capable of generating 900 MWe to 1300 MWe depending on the number of fuel channel used and the type of fuel, either natural uranium fuel or slightly enriched uranium fuel. The basic design, the CANDU 9 480/NU, uses the 480 fuel channel Darlington reactor and employs Natural Uranium (NU) fuel Darlington, the latest of the 900 MWe Class CANDU plants, consists of four integrated units with a total output of approximately 3740 MWe located in Ontario, Canada. AECL has completed the concept definition engineering for this design, and will be completing the design integration engineering by the end of 1996. AECL's design philosophy is to build-in product improvements in evolutionary from the initial prototype plants, NPD and Douglas Point, to today's operating CANDU's construction projects and advanced designs. CANDU 9 safety design follows the evolutionary path, including simple improvements based on existing well-proven CANDU safety concepts. The CANDU 9 builds on the experience base for the Darlington reference plant, and on AECL's extensive safety design experience with single unit CANDU 6 power plants. The latest CANDU 6 plants are being built in Korea by KEPCO at Wolsong 2,3 and 4. The Safety improvements for the CANDU 9 power plant are intended to provide the owner-operator with increased assurance of reliable, trouble-free operation, with greater safety margin, with improved public acceptance, and with ease of licensibility

[en] Building CANDU 6 units at Qinshan Phase III in China is contributed to the impressive schedule accomplishments. The ACR1000 is a 1200 MWe-class Generation III+ nuclear power plant with a 60-year design life. It is a light-water-cooled, heavy-water-moderated pressure-tube reactor, which has evolved from the well-established Candu line. It retains basic, proven, CANDU design features while incorporating innovations and state-of-the-art technologies to optimize safety, operation, performance and economics. These technical improvements, along with system simplifications and advancements in project engineering, manufacturing, and construction, result in a reduced capital cost and construction schedule, while enhancing the inherent safety and operating performance of the ACR1000 design. Maximum use of modularization and 'open-top', parallel construction - which have already been demonstrated at the Qinshan Phase III units, both delivered under budget and ahead of schedule - are key to AECL's ACR1000 project model. The ACR1000 has been chosen for generic design assessment in the United Kingdom. Additionally, there are active ACR1000 initiatives in Canada - in Ontario, where the ACR1000 has been short-listed for new build-Alberta and New Brunswick

[en] The Advanced CANDU Reactor (ACR^TM) is the 'Next Generation' CANDU^R reactor, aimed at safe, reliable power production at a capital cost significantly less than that of current reactors such as the very successful CANDU 6 reactors (e.g., Wolsong 1-4). The Wolsong 1-4 units are being joined by the Qinshan Phase 3 units in China as the current successful examples of CANDU technology. The ACR design builds on this knowledge base, adding a selected group of innovations to obtain substantial cost reduction while retaining a proven design basis. The ACR maximizes the use of components and equipment applications that are well proven through CANDU and other nuclear experience. Joint development of equipment designs and specifications with manufactures has been emphasized. Similarly, the ACR design emphasizes constructability, and takes advantage of inherent CANDU features to enable short project and construction schedules. Overall, the ACR design represents a balance of proven design basis and innovations to give step improvements in safety, reliability and economics. The ACR development program, now well into the detail design stage, includes parallel formal licensing in the USA and Canada

[en] The Enhanced CANDU 6^R (ECo^R) is the updated version of the well established CANDU 6 family of units incorporating improved safety characteristics designed to meet or exceed Generation III nuclear power plant expectations. The EC6 retains the excellent neutron economy and fuel cycle flexibility that are inherent in the CANDU reactor design. The reference design is based on natural uranium fuel, but the EC6 is also able to utilize additional fuel options, including the use of Recovered Uranium (RU) and Thorium based fuels, without requiring major hardware upgrades to the existing control and safety systems. This paper outlines the major changes in the EC6 core design from the existing C6 design that significantly enhance the safety characteristics and operating efficiency of the reactor. The use of RU fuel as a transparent replacement fuel for the standard 37-el NU fuel, and several RU based advanced fuel designs that give significant improvements in fuel burnup and inherent safety characteristics are also discussed in the paper. In addition, the suitability of the EC6 to use MOX and related Pu-based fuels will also be discussed. (authors)

[en] AECL has developed the design for a new generation of CANDU nuclear power plants, the Advance CANDU Reactor or ACR. The ACR combines a set of underlying enabling technologies with well-established successful CANDU features in an optimized design with significantly lower costs. By adopting slightly enriched uranium fuel, an optimized core design with light water coolant, heavy water moderator and reflector has been defined based on the existing CANDU fuel channel module. The basic design for the complete reference ACR power plant has now been completed. This paper summarizes the main features and characteristics of the reference ACR-700 power plant design. The progress of the ACR design program in meeting challenging cost, schedule and performance targets is described. AECL's cost reduction methodology is summarized as an integral part of the design optimization process. Examples are given of cost reduction features together with the enhancement of design margins. AECL expects the detailed design and testing of ACR to be complete and pre-project licensing evaluation carried out to enable regulatory endorsement in key markets by the middle of the decade. (authors)