Thorium-based fuel design for pressurized heavy water reactors

A fuel bundle configured to be used in a pressurized heavy water reactor, the fuel bundle comprising:

• a plurality of fuel pins, each of said plurality of fuel pins comprising:
• a sealed tube, and
• a plurality of fuel pellets disposed inside the sealed tube, the plurality of fuel pellets each comprising thorium and uranium fuel,
• wherein a fuel composition of each of the fuel pellets is between 55 and 90 wt % thorium,
• wherein the fuel composition of each of the fuel pellets is between 10 and 45 wt % uranium,
• wherein 235U enrichment of the uranium is between 10.5% and 20%, wherein the fuel composition of at least one of the plurality of fuel pins differs from the fuel composition in at least one other of the plurality of fuel pins, wherein the fuel bundle is shaped and configured to be used in a CANDU PHWR,
• wherein the plurality of fuel pins comprise:
• a first ring of fuel pins,
• a second ring of fuel pins disposed radially outwardly from the first ring of fuel pins, and
• a third ring of fuel ring pins disposed radially outwardly from the second ring of fuel pins;
• wherein thorium weight percentage of the fuel composition of the first ring fuel pins is between 50 and 70 wt %;
• wherein thorium weight percentage of the fuel composition of the second ring fuel pins is between 60 and 90 wt %;
• and
• wherein thorium weight percentage of the fuel composition of the third ring fuel pins is between 75 and 90 wt %.