Enhanced CANDU 6

EC6 2-unit -October 30 2012 254x180 72dpiThe Enhanced CANDU 6 (EC6) Generation III reactor design is the only reactor that offers:

  • natural uranium fuelling
  • a design based on our 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 pressure tube reactor. Heavy water is a natural form of water used as a moderator to slow down the fission chain reaction neutrons in the reactor. It is one of the most efficient moderators and enables the CANDU design to use natural uranium as fuel, which is unique to CANDU reactors. The use of natural uranium increases a country’s energy independence as fuel can be manufactured locally, and reprocessing and associated issues can be avoided.

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 based on the Qinshan Phase III CANDU 6 plant in China, designed to meet industry and public expectations of nuclear power generation that is safe, reliable and environmentally friendly.

It has been enhanced by using the experience and feedback that AECL gained in the development, design, construction and operation of 11 CANDU 6 units operating in five countries. CANDU 6 reactors are performing well on four continents with over 150 reactor-years of excellent and safe operation.

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, operation 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 projected an average annual operational performance factor of 94% and 92% lifetime including mid-life retubing. The performance factor is the ratio of available capacity to the theoretically possible capacity, and this characterizes 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 list 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
  • Modular, horizontal fuel channel core
  • 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
  • Reactor vault that is filled with cool light water that surrounds the reactor core and provides an additional passive heat sink for mitigation of severe accidents
  • Reactor building access for maintenance activities during on-power operation

Our EC6 Technical Summary discusses the EC6 in more detail.