Patent Number: 
Section: claims

1. A method of stabilizing a fuel containing a reactive sodium metal, comprising:puncturing a cladding of a fuel pin enclosing the fuel containing the reactive sodium metal to form an injection passage and an extraction passage;injecting a reaction gas into the fuel pin through the injection passage to react with the reactive sodium metal to form a stable sodium compound;measuring a ratio of a product gas and a remaining quantity of the reaction gas exiting the fuel pin through the extraction passage, the product gas being a reaction product of the reaction gas and the reactive sodium metal within the fuel pin; andsealing the injection passage and the extraction passage so as to confine the stable sodium compound within the fuel pin once the ratio indicates that a reaction between the reaction gas and the reactive sodium metal is complete. 2. The method of claim 1, wherein the puncturing includes orienting the fuel pin in a vertical position such that the injection passage and the extraction passage are formed on a planar end of the fuel pin. 3. The method of claim 1, wherein the puncturing includes orienting the fuel pin in a horizontal or vertical position such that the injection passage and the extraction passage are formed on a curved surface of the fuel pin. 4. The method of claim 1, wherein the injecting a reaction gas includes introducing at least one of an oxygen-containing gas and a halogen gas. 5. The method of claim 1, wherein the injecting a reaction gas includes introducing at least one of carbon dioxide (CO2), oxygen (O2), methane (CH4), and chlorine (Cl2). 6. The method of claim 1, wherein the injecting involves forming at least one of Na2O and NaCl from the reactive sodium metal. 7. The method of claim 1, wherein the sealing includes closing the injection passage and the extraction passage by welding. 8. The method of claim 1, further comprising:venting an existing gas from the fuel pin after the puncturing a cladding and prior to the injecting a reaction gas. 9. The method of claim 8, wherein the venting an existing gas includes extracting a radioactive gas from the fuel pin. 10. The method of claim 8, wherein the venting an existing gas includes removing fission product gases from the fuel pin. 11. The method of claim 1, further comprising:purging the fuel pin with an inert gas after the measuring a ratio and prior to the sealing the injection passage and the extraction passage. 12. The method of claim 11, wherein the purging includes introducing at least one of argon, nitrogen, and helium.