| 摘要 |
The invention concerns a method which consists in measuring the emission rate of at least one emission spectral line of at least one fission product constituting a combustion rate tracer, less than thirty days after removal of the assembly from the nuclear reactor core, using a high-purity germanium photon detector (8) cooled by a cryogenic system and a collimator (7) having a rectilinear duct (7a) under air extending between a zone proximate the fuel assembly (1) and the photon detector (8); moving the fuel assembly along its longitudinal direction (5) relative to the collimator (7), so as to perform the measurement in each of a number of measuring points. The tracer is one at least among <144>Ce ‰ 2185 keV, <134>Cs to 795 keV <137>Cs to 661 keV and <106>Ru to 622 keV; calculating from calculation and correction software's the combustion rate of the fuel assembly in each of the measuring points based on the measurement of the emission rate. The invention enables the combustion rate of barely cooled fuel assemblies. |
