Patent Number: 
Section: claims

1. A method of operating a nuclear fission reactor, the method comprising:providing a nuclear fission reactor having a reactor vessel, the reactor vessel having a fission region and a fertile blanket region, wherein the fission region is separate from and interior to the fertile blanket region, and the fertile blanket region is between the fission region and a wall of the reactor vessel;receiving a solution in the fission region and the fertile blanket region of the reactor vessel of the nuclear fission reactor, the solution including a neutronically translucent liquid carrier material and a first fissile nuclear fission fuel material, the first fissile nuclear fission fuel material being dissolved in the neutronically translucent liquid carrier material;disposing an undissolved fertile nuclear fission fuel material in a foam form in the fertile blanket region of the reactor vessel and in direct physical contact with the solution;exposing the undissolved fertile fission fuel material to a neutron flux of the nuclear fission reactor to transmute a portion of the undissolved fertile nuclear fission fuel material into a second fissile nuclear fission fuel material;diffusing the second fissile nuclear fission fuel material to the solution; andreceiving the solution in the fission region and the fertile blanket region of the reactor vessel of the nuclear fission reactor, the solution including the neutronically translucent liquid carrier material, the first fissile nuclear fission fuel material, and the second fissile nuclear fission fuel material, the first and second fissile nuclear fission fuel materials being dissolved in the neutronically translucent liquid carrier material. 2. The method of claim 1, further comprising: diffusing intermediate transmuted material to the solution. 3. The method of claim 1, further comprising:fissioning a portion of the second fissile nuclear fission fuel material. 4. The method of claim 1, wherein diffusing the second fissile nuclear fission fuel material to the solution includes diffusing the second fissile nuclear fission fuel material through the undissolved fertile nuclear fission fuel material. 5. The method of claim 1, wherein disposing the undissolved fertile nuclear fission fuel material in the fertile blanket region includes disposing the undissolved fertile nuclear fission fuel material in the fertile blanket region and not in the fission region. 6. The method of claim 1, wherein providing the nuclear fission reactor having a reactor vessel, the reactor vessel having the fission region and the fertile blanket region, includes providing the reactor vessel with the fission region in fluid communication with the fertile blanket region. 7. The method of claim 1, further comprising, fissioning the second fissile nuclear fuel material to generate a neutron flux, exposing another portion of the undissolved fertile nuclear fission fuel material to the neutron flux of the second fissile nuclear fuel material to transmute the another portion of the undissolved fertile nuclear fission fuel material into additional second fissile nuclear fission fuel material, and diffusing the additional second fissile nuclear fission fuel material to the solution. 8. The method of claim 1, further comprising, adding an additional neutronically translucent liquid carrier material to the solution to reduce concentration of the fissile nuclear fission fuel material in the solution. 9. The method of claim 1, wherein disposing the undissolved fertile nuclear fission fuel material includes forming an annulus in the undissolved fertile nuclear fission fuel material such that natural circulation of the solution is established through a heat exchanger and the annulus.