UBC Theses and Dissertations
The feasibility of using supercritical carbon dioxide as a coolant for the CANDU reactor Tom, Samsun Kwok-Sun
This study indicates the technical feasibility of using supercritical carbon dioxide as a coolant for a CANDU-type reactor. A new concept of supercritical cooling loop is proposed in this study. The reactor is cooled by a single phase coolant, which is pumped at a high density liquid-like state. The supercritical-fluid-cooled reactor has the advantage of avoiding dryout as in gas-cooled reactors, and the advantage of low coolant-circulation power as for liquid-cooled reactors. As a result of eliminating dryout, the maximum operating temperature of the fuel sheath can be increased to 1021°F (550°C) for existing Canadian fuel bundles. Accordingly, the coolant temperature in the case study of this work was calculated to be 855°F. This high temperature coolant can produce steam at a temperature and pressure comparable to that of conventional fossil-fuel plants. However, since the exit coolant temperature from the steam generator may be as low as 280°F, a portion of the supercritical carbon dioxide coolant is used to produce low-pressure steam. A new dual-reheat cycle is proposed to reduce the high degree of irreversibility in the steam generation process. In the new dual-reheat cycle, the coolant heats the low and high pressure feeds in a parallel manner instead of alternative heating as in dual-pressure cycles. The ideal overall plant efficiency of the new proposed dual-reheat cycle is 33.02%, which is comparable to that of the Pickering generating station.
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