Patent Number: 
Section: claims

1. A method of detecting defects in nuclear fuel within a fuel rod comprising the steps of:heating the fuel rod to a temperature range substantially above an ambient temperature;measuring the temperature over a surface of the rod as the rod is allowed to cool; andnoting over a preselected time period variations in the temperature decrease measured over the surface of the rod as the rod is allowed to cool. 2. The method of claim 1 wherein the heating step is performed soaking chamber. 3. The method of claim 1 wherein the heating step simultaneously heats substantially an entire area of a cladding of the rod that extends over a stack of fuel pellets within the rod, to a temperature in the range of 80 to 120 degrees centigrade. 4. The method of claim 1 wherein the fuel rod is allowed to cool substantially at the ambient temperature. 5. The method of claim 1 wherein the temperature is measured with an infrared receiver. 6. The method of claim 5 wherein the infrared receiver is an infrared camera. 7. The method of claim 5 including a step of rotating the fuel rod in front of the infrared receiver. 8. The method of claim 1 including a second heating step after the initial heating step and before the measuring step wherein the second heating step heats the surface of the rod for a time period substantially shorter than the initial heating step. 9. The method of claim 8 wherein the second heating step is performed by a radiant heat source. 10. The of claim 9 including a step of moving the rod past the radiant heat source. 11. The method of claim 1 wherein the measuring step is performed in a reduced pressure environment that is below atmospheric pressure. 12. The method of claim 1 wherein the noting step occurs at approximately at or between sixty and one hundred eighty seconds after the heating step is completed.