Patent Number: 
Section: claims

1. 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; andat 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; andwherein 49-51% of the channel type heterogeneous reactor core comprises the seed fuel channel region while the balance comprises the blanket fuel channel region. 2. The channel type heterogeneous reactor core of claim 1, wherein the seed fuel bundle comprises 35% or more UO2 and 65% or less ThO2. 3. The channel type heterogeneous reactor core of claim 1, wherein the seed fuel bundle comprises 3% or more PuO2 and 97% or less ThO2. 4. The channel type heterogeneous reactor core of claim 1, wherein the blanket fuel bundle comprises 30% or less UO2 and 70% or more ThO2. 5. The channel type heterogeneous reactor core of claim 1, wherein the blanket fuel bundle comprises 2% or less PuO2 and 98% or more ThO2. 6. The channel type heterogeneous reactor core of claim 1, wherein each seed fuel channel comprises 12 seed fuel bundles and each blanket fuel channel comprises 12 blanket fuel bundles. 7. The channel type heterogeneous reactor core of claim 1, wherein a total number of seed fuel channels and blanket fuel channels is 380. 8. The channel type heterogeneous reactor core of claim 1, wherein the channel type heterogeneous core comprises a square lattice pitch of 28.575 cm. 9. The channel type heterogeneous reactor core of claim 1, wherein the CANDU reactor core is an enhanced CANDU-6 (EC-6) reactor core. 10. A heavy water reactor comprising:a channel type heterogeneous reactor core comprising:at least one seed fuel channel region comprising seed fuel channels for receiving seed fuel bundles of thorium based fuel; andat 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; andwherein 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 annular pattern heterogeneous reactor core comprising the at least one blanket fuel channel region;wherein the heavy water reactor is an enhanced CANDU-6 (EC-6) reactor; andwherein 49-51% of the channel type heterogeneous reactor core comprises the seed fuel channel region while the balance comprises the blanket fuel channel region.