GENERATION III AND III+ NUCLEAR POWER PLANT DESIGNS ACR-1000 (Advanced CANDU Reactor) Dr. Şule Ergün Hacettepe University Department of Nuclear Engineering March 2008, Istanbul

Outline CANDU Concept CANDU Development ACR-1000 –Technical Description Conclusion

CANDU Concept Pressurized Heavy Water Reactor (CANadian Deterium Uranium)

CANDU6 ACR-700 ACR-1000 CANDU Development

The CANDU Design: –Modular horizontal fuel channels –Simple fuel bundle design –Separated coolant from moderator –Cool, low pressure heavy water moderator –On-power fuelling –Passive shutdown systems

ACR-1000 Low enriched fuel Light water coolant Higher steam pressure Smaller reactor core High capacity factor Over 60 year life Larger thermal margins

ACR-1000 Evolution in Core Size CANFLEX Fuel Bundle

ACR-1000 Safety Enhancements –Enhanced passive safety –Factor of ten improvement in severe core damage frequency Improved Construction –Shorter construction schedule –Reduce cost by 25% or more

ACR-1000 ECC System: –Initial injection from pressurized ECI tanks located inside Reactor Building (RB) –Long Term Cooling (LTC) System provides pumped recovery –LTC System also provides maintenance cooling after normal shutdown

ACR-1000 Frequency for internal events: ~ 3 x / reactor year

ACR-1000 Severe accident mitigation: –Passive Core Make-Up Tanks keep HTS full to assure thermosyphoning capability –Reserve Water System (RWS) supply by gravity to SGs provides inventory for long-term thermosyphoning –Passive make-up to HTS from ECI and RWS delay accident progression –Passive make-up to moderator and calandria vault from RWS delay accident progression –Passive spray system supplied from RWS delays containment failure

Conclusion The ACR-1000 innovations include: –A compact core design which reduces heavy water inventory and results in lower costs and reduced emissions –Use of light water as reactor coolant, resulting in reduction of systems for heavy water coolant cleanup and recovery and simplification of containment atmosphere cleanup systems –Use of low enriched uranium fuel, contained in advanced CANFLEX ACR fuel bundles

Conclusion –Efficient means for burning other fuel types such as mixed oxides (MOX) and thorium fuels –Increased fuel safety margins –Improved plant thermal efficiency through use of higher pressures and higher temperatures in the coolant and steam supply systems –Enhanced accident resistance and core damage prevention features –Enhanced operability and maintainability