Patent Number: 
Section: claims

1. A method of fabricating a liquid-metal coolant for a nuclear reactor, the method comprising:adding nanoparticles to the liquid-metal coolant to change neutronic properties of the liquid-metal coolant,the nanoparticles including a metal having neutronic properties different from that of the liquid-metal coolant prior to the adding nanoparticles, the metal including one of hafnium, boron and gadolinium. 2. The method of claim 1, wherein the adding nanoparticles includes adding the metal having the neutronic properties including at least one of a neutron cross-section and an atomic weight different from a metal of the liquid-metal coolant. 3. The method of claim 2, wherein the adding a metal to the liquid-metal coolant includes adding the metal to one of a liquid sodium coolant, a lead-bismuth coolant and a sodium-potassium coolant. 4. The method of claim 1, wherein the neutronic properties include one of neutron absorption cross-section, neutron moderation characteristics, and a neutron scattering cross-section. 5. The method of claim 1, wherein the adding nanoparticles includes measuring a concentration of the nanoparticles by one of direct methods and continuous on-line methods. 6. The method of claim 5, wherein the measuring a concentration of the nanoparticles includes sampling the liquid-metal coolant using a mass spectrometer. 7. The method of claim 5, wherein the measuring a concentration of the nanoparticles includes measuring intensity of a gamma signal from decay of a metal present in the nanoparticles to determine the content of the metal in the liquid-metal coolant. 8. The method of claim 1, wherein the metal includes one of boron and gadolinium. 9. The method of claim 1, wherein the nanoparticles consist essentially of the metal.