[en] AECL's advanced CANDU reactor strategy is based on an aggressive development programme which builds on the company's current products to create a future-generation reactor concept that meets the needs of world markets. Concurrently, evolutionary improvements are being spun off to existing designs. These emphasise safety, reduced capital and O and M costs, and low project risk. (author)

[en] This paper outlines the continuous evolution of the CANDU reactor and the premise and promise of the CANDU design. The objective of the CANDU development program is to introduce innovative design features for improving the performance, reducing the cost, and enhancing the safety of CANDU reactors. The current CANDU products are the 700 MW Class CANDU 6 reactor and the 900 MW Class CANDU 9 reactor. The CANDU development program is aimed at enhancing these two reactor designs. This development program has 3 parts: The CANDU 6 and 9 enhancement programs involve a detailed evaluation of technologies and features that can be incorporated into the CANDU products in the near term. The Advanced CANDU 6 and 9 programs involve concepts that can be incorporated into the CANDU products in the medium term. The CANDU X program explores the natural extension of the CANDU technology into the long term, beyond the advanced CANDU products. When these three program elements are taken together and supported by a strong underlying Research program, the result is a comprehensive program to support CANDU designs well into the next century. While the CANDU X program defines the extreme performance limits for a feasible and competitive pressure-tube reactor, the program also continually spins off technological design improvements to enhance short- and medium-term plant performance. To date, potential spin-offs include the following concepts that have potential for improving the performance and safety in the near term: the insulated fuel channel, advanced CANFLEX fuel bundle concepts, corrosion-resistant high-temperature fuel cladding, fuel channel bore seals, simplified fuelling machine, and enhanced natural circulation in the cooling system. A key part of the longer-term development program is the ability to increase the reactor coolant operating temperature to increase the thermodynamic efficiency and, hence, produce more electricity for a given reactor output. At the same time, simplifying the design will further reduce cost and enhance safety. As the reactor coolant temperatures increase, the eventual transition to supercritical water (SCW) conditions could be a logical adaptation from existing designs. (author)

[en] Nuclear Plants have a nominal 'design life' that forms the basis of equipment specification, economic evaluations and licensing for some jurisdictions. Some component in the plant may require replacement, refurbishing and or rehabilitation during the plant 'design life'. Components which are extremely difficult or economically impossible to replace will place a limit on plant life. Rehabilitation programs completed to date on older CANDU plants to improve reliability of plant components, coupled with R and D programs, experimental data and advanced analytical methods form the basis for CANDU plant component life assurance. Life assurance is verified during plant operation by comprehensive in-service inspection programs and laboratory examinations. The paper provides an overview of the experiences to date on Refurbishment and Rehabilitation programs and some Canadian approaches on the main activities involved in scoping and managing nuclear plant life assurance. A number of proactive programs are underway to anticipate, detect and mitigate potential aging degradation at an early stage to ensure plant safety and reliability. Some of these programs include; systematic plant condition assessment, refurbishment and upgrading programs, environmental qualification programs and a program of examination of components from decommissioned reactors. These programs are part of an overall nuclear power plant maintenance strategy. Beyond life assurance, a longer term approach would be geared towards life extension as a viable option for the future. Recent CANDU designs have benefited from the early CANDU experience and are expected to require less rehabilitation. Examples of changes in CANDU 6 include fuel channel design and adopting a closed component cooling water system. New designs are based on 'design life' longer than that used for economic evaluations. The approach is to design for easy replace ability for components that can be economically replaced. Specific examples include design provisions to replace fuel channels and steam generators. Difficult to replace components such as reactor building structures and calandria/shield tank assembly are designed for much beyond 40 years. Given the performance of CND's to date and the successfully completed rehabilitations and the lessons learned from older plants, a newly committed CANDU will have an economic service life significantly longer than 40 years. The CANDU design life was initially set at thirty years. The key components of a CANDU nuclear steam plant are the calandria vessel, the fuel channels, the reactivity control mechanisms, and the primary heat transport components including piping and steam generators. The calandria vessel, a large stainless steel tank, experiences conditions of relatively low temperature and pressure and is designed for a very long life. Experience to date shows that of the remaining components, fuel channels and reactivity control mechanisms are replaceable. Given that other refurbishments and/or replacements can be done to existing plants, a minimum of 40 year operating life can be achieved. Large scale fuel channel replacement was dictated by Station Life Assurance rather than Life Extension considerations. This major rehabilitation program has been successfully implemented for three of the Pickering A reactors to achieve a minimum 40 year operating life. In this program steady flow of successful design and process improvements have contributed to the knowledge base and know how of the CANDU industry. Over the next few years, retuning of the fourth Pickering A unit and the first of the Bruce A units will be undertaken providing the opportunity for Life extension of these units. Steam Generators in most CANDU plants continue to perform, with relatively low tube failures and plugging rates. Remedial measures are being taken, with solutions being evaluated by Ontario Hydro to address current degradation problems due to tube fouling and sludge deposition. R and D programs are underway to develop analytical deposition models and mechanical/chemical cleaning techniques to minimize and/or control degradation. In summarizing, an integrated approach to plant life management and assurance. Life expectancy is verified during plant operation by a comprehensive inservice inspection program, which includes periodic removal of a fuel channel for laboratory inspection. New CANDU designs continue to build on the above aspects incorporating innovative features resulting from Canadian research, international cooperation and technological developments

[en] Reducing costs is a clear priority in nuclear markets where capital reaches billions and financing is hard-won. To address that priority, AECL introduced the use of advanced construction techniques. This has been one of the key thrusts behind its development of CANDU 9. (author)

[en] AECL has adopted an evolutionary approach to the development of the CANDU 6 and CANDU 9 Nuclear Power Plant (NPP) designs. Each new NPP project benefits from previous projects and contains an increasing number of fully proven enhancements. In accordance with this evolutionary design approach, AECL has built on the Wolsong and Qinshan successes and the solid performance of the reference CANDU stations to define, review and implement the enhancements for the CANDU 9 NPP. Some of these enhancements include fully integrated project information systems and databases, safety enhancements coming from PSA studies and licensing activities, distributed control systems for plant-wide control and an advanced control center which addresses human factors engineering concepts. Examples of the Qinshan CANDU project delivery enhancements are the utilization of electronic engineering tools for the complete plant, and the linking of these tools with the project material management system and document management systems. The project information is reviewed and approved at the engineering office in Canada and then transmitted to site electronically. Once the electronic data is at site the information packages are extracted as necessary to enable construction and facilitate contract needs with minimum effort. This paper will provide details of the CANDU Qinshan project experiences as well as describing some of the corresponding CANDU 9 enhancements. (author)

[en] This paper describes the role of MDS Nordion and AECL in ensuring a reliable global supply of medical isotopes. The First part of the paper discusses the uses of medical isotopes, their importance to the medical community, and the benefits to patients of a secure supply of medical isotopes. The second part describes the role of the NRU reactor and the future role of the MAPLE reactors and New Processing Facility being commissioned at AECL's Chalk River Laboratories for production of medical isotopes to meet the world market demand for the next 40 years. MDS Nordion is the world's leading supplier of medical isotopes. These isotopes are used to conduct some 34,000 nuclear medicine procedures performed every day around the world, such as determining the severity of heart disease, the spread of cancer, and diagnosing brain disorders. These medical isotopes are currently produced primarily by AECL in the NRU reactor at Chalk River, Ontario, Canada. (author)

[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 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 CANDU 9 design has followed the evolutionary product development approach that has characterized the CANDU family of nuclear power plants. In addition to utilizing proven equipment and systems from operating stations, the CANDU 9 design has looked ahead to incorporate design and safety enhancements necessary to meet evolving utility and licensing requirements. With the requirement that the CANDU 9 design should be licensable for both domestic and foreign potential users, the pre-project Basic Design Engineering program included a two year formal extensive review by the Canadian Regulatory Agency, the Atomic Energy Control Board . Documentation submitted for the licensing review included the licensing basis, safety requirements and safety analyses necessary to demonstrate compliance with regulations and to assess system design and performance