Patent Number: 056384149
Section: claims

1. A method for detecting failure of a nuclear reactor fuel comprising the steps of: (a) identifying one or more failed fuel assemblies; and  (b) identifying one or more failed fuel elements in each identified failed fuel assembly, including the substeps of  (b1) detecting gamma radiation emitted by the identified fuel assembly with a gamma radiation detector and acquiring detector data, while relatively rotating and translating the identified fuel assembly about the gamma radiation detector,  (b2) constructing a tomographic image of the radiation intensity distribution over a cross section of the identified fuel assembly based upon the detector data, and  (b3) determining said one or more failed fuel elements by variations in the radiation intensity in the tomographic image. 2. A method for detecting failure in fuel for a nuclear reactor according to claim 1, wherein the radiation detector is placed opposite to a gas plenum of the fuel element of the fuel assembly, and radiation emitted from fission product nuclides in the gas plenum is detected.