Improvement of CANDU-1000 MW(e) power cycle by moderator heat recovery

Four different moderator heat recovery circuits are proposed for CANDU-1000 MW (e) reactors. The proposed circuits utilize all, or part, of the 155 MW(th) moderator heat load (at 70°C moderator outlet temperature from calandria) to the first stage of the water heating system. An economics study was carried out and indicated that the direct circulation of feed water through the moderator heat exchanger (with full heat recovery) is the most economical scheme. For this scheme the saved steam from the turbine extraction was found to produce additional electric power of 8 MW(e). This additional power represents a 0.7% increase in the plants nominal electric output. The outstanding features and advantages of the selected scheme are also presented.