Heterogeneous core designs and thorium based fuels for heavy water reactors

A channel type heterogeneous reactor core for a heavy water reactor for burnup of thorium based fuel, the heterogeneous reactor core comprising:

• at least one seed fuel channel region comprising seed fuel channels for receiving seed fuel bundles of thorium based fuel;
• and
• at least one blanket fuel channel region comprising blanket fuel channels for receiving blanket fuel bundles of thorium based fuel;
• wherein the seed fuel bundles have a higher percentage content of fissile fuel than the blanket fuel bundles;
• wherein the at least one seed fuel channel region and the at least one blanket fuel channel region are each substantially circular in cross-section and arranged in an annular pattern within the heterogeneous reactor core, an outermost ring of the heterogeneous reactor core comprising the at least one blanket fuel channel region;
• wherein the channel type heterogeneous reactor core is a CANDU reactor core;
• and
• wherein 49-51% of the channel type heterogeneous reactor core comprises the seed fuel channel region while the balance comprises the blanket fuel channel region.