回复15楼:早期设计是
后来的设计用slightly enriched 铀的来增加功率
The Candu 9 design had flexible fuel requirements ranging from natural uranium through slightly-enriched uranium, recovered uranium from reprocessing spent PWR fuel, mixed uranium and plutonium oxide (MOX) fuel, direct use of spent PWR fuel, to thorium.

Candu 9还只存在于PPT上呢,现在运行的Candu全是用天然铀。