CANDU 6
The CANDU 6 power reactor offers proven, state-of-the-art technology. It was designed specifically for electricity production, unlike other major reactor types, which evolved from other uses. This focused development is one of the reasons that CANDU reactors have such high fuel efficiency.
The CANDU 6 is our 700 MWe class nuclear power reactor. The first CANDU 6 plants went into service in the early 1980s, and the design has continued to evolve to maintain superior technology and performance.
The CANDU 6 was licensed in the early 1980s in Canada, Argentina and the Republic of Korea. In 1996, Cernavoda Unit 1 was licensed in Romania, and Wolsong Unit 2 was licensed in Korea. Wolsong Units 3 and 4 were licensed in Korea in 1997 and 1999 respectively; Qinshan Units 1 and 2 were licensed in China in 2002 and 2003 respectively; and, in 2007, Cernavoda Unit 2 was licensed in Romania. These units all came into service ahead of schedule and on budget. To date, there are 11 CANDU 6 units in operation.
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EC6
The Enhanced CANDU 6® (EC6®) Generation III reactor design offers:
- Natural uranium fuel cycle
- A design based on the highly successful CANDU 6 reactors
- Superior safety performance and economics
- Very high localization
- Suitability for small and medium electric grids
The EC6 is a 700 MWe class heavy-water moderated and heavy-water cooled reactor. Heavy water is a natural form of water that is used as a moderator to slow the fission chain reaction neutrons. It enables CANDU reactors to use natural uranium as fuel, a unique capability. The use of natural uranium increases a country’s energy independence, as fuel can be manufactured locally, mitigating issues connected with enriched uranium.
Heavy water coolant passes through the reactor core and removes the heat generated by the fission chain reactions. This heated reactor coolant heats light (ordinary) water and converts it to steam, which drives a turbine-generator to produce electricity.
The EC6 reactor is the evolution of the proven CANDU 6 design. It is designed to meet industry and public expectations of nuclear power generation that is safe, reliable, economical and environmentally friendly. The design has been enhanced and refined based on the experience and feedback Candu has gained in the development, design, construction and operation of CANDU 6 units operating in five countries.
While retaining the basic features of the CANDU 6 design, the EC6 reactor incorporates innovative features and state-of-the-art technologies that enhance safety, operations and performance.
The latest CADDS tools and innovative integrated systems linking material management, documentation, safety analysis and project execution databases are used to ensure that accurate and complete configuration management can be readily maintained by the plant owner.
The EC6 reactor has a projected annual performance factor of over 90%. The performance factor is the ratio of available capacity to the theoretically possible capacity, which reflects the reliability of the plant. In recent years, the global CANDU 6 fleet achieved an average lifetime performance factor of 89%, which ranked the fleet in the world’s top reactor performance echelons. In the last decade, three of the CANDU units in South Korea ranked in the top 10 for world reactors.
Enhanced CANDU 6 Design Features
The EC6 reactor design benefits from the proven principles and characteristics of the CANDU 6 design and decades of operation.
Proven CANDU strengths include:
- Two independent safety shutdown systems
- Refuelling during on-power operation
- Passive water tank located in the containment
- Separate low-temperature, low-pressure moderator that provides inherently passive heat sinks by permitting heat to be removed from the reactor core under abnormal conditions
- Modular, horizontal fuel channel core
- Reactor vault that is filled with cool light water, that surrounds the reactor core
- Reactor building access for maintenance activities during on-power operation
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CANDU Fuel Cycles
Unique Fuel Cycle Capability
CANDU technology has had a continuous fuel cycle program and vision for more than 40 years, including reactor physics and core design, fuel design and fabrication, irradiation demonstration and examination, reprocessing and separation, cycle optimization and commercial deployment options. The advanced CANFLEX® fuel bundle was developed as the optimal advanced fuel carrier.
One of the unique features of CANDU reactor design is its ability to use alternative fuels such as recovered uranium (RU) from the reprocessing of used light water reactor fuel, low-enriched uranium (LEU) and plutonium (Pu) mixed oxide, thorium and actinides, in addition to the conventional natural uranium. Options with thorium include Th-Pu and Th-LEU. The design’s high neutron efficiency and on-power refuelling uniquely positions CANDU as the solution for customers seeking to extend fuel resources, reduce used fuel volume and enhance non-proliferation.
Candu Energy Inc. is participating in the demonstration of RU in China, using an option that blends RU with depleted uranium (DU) to produce a natural-uranium equivalent (NUE) fuel. Additionally, an expert panel appointed by the China National Nuclear Corporation (CNNC) recently concluded that CANDU technology “is the ideal nuclear reactor design to further China’s nuclear power program using thorium as an alternative nuclear fuel source.”
The panel unanimously recommended that China consider building two new CANDU units to take advantage of CANDU technology’s unique capabilities in utilizing alternative fuels.
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