Patent Number: 
Section: claims

1. A pressurized water nuclear reactor, comprising:a core comprising a containment shield surrounding a reactor vessel having fuel assemblies that contain control rods and fuel rods filled with fuel pellets, and a steam generator thermally coupled to said reactor vessel via a primary flow loop;a secondary flow loop comprising said steam generator, a turbine, a condenser, and a pump for circulating a water-based heat transfer fluid in said secondary flow loop, wherein said heat transfer fluid comprises a plurality of nanoparticles comprising at least one carbon allotrope or related carbon material dispersed therein. 2. The pressurized water nuclear reactor of claim 1, wherein said at least one carbon allotrope or related carbon material comprises diamond nanoparticles. 3. The pressurized water nuclear reactor of claim 2, wherein said diamond nanoparticles are primarily colloidal. 4. The pressurized water nuclear reactor of claim 2, wherein said diamond nanoparticles have a mean size that is in a range from 0.5 nm to 200 nanometers. 5. The pressurized water nuclear reactor of claim 4, wherein said mean size is in a range from 1 nm to 100 nm. 6. The pressurized water nuclear reactor of claim 4, wherein said mean size of said plurality of nanoparticles is in a range from 40 nm to 100 nm. 7. The pressurized water nuclear reactor of claim 1, wherein said at least one carbon allotrope or related carbon material comprises fullerenes. 8. The pressurized water nuclear reactor of claim 1, wherein said at least one carbon allotrope or related carbon material comprises carbon nanotubes. 9. The pressurized water nuclear reactor of claim 1, wherein a concentration of said plurality of nanoparticles in said heat transfer fluid is in a range from 0.0001 to 10 volume percent of said heat transfer fluid. 10. The pressurized water nuclear reactor of claim 9, wherein said concentration of said plurality of nanoparticles in said heat transfer fluid is in a range from 0.1 to 3 volume percent of said heat transfer fluid.