Determination of the residual content of fissile materials in fuel from spent fuel assemblies with high initial enrichment by the active neutron method

A stand and procedure for measuring the residual content of fissile materials in spent fuel assemblies from research and propulsion reactors are described. The results of experiments performed with spent and fresh fuel assemblies from the IRT reactor at the Moscow Engineering Physics Institute [MIFI], making it possible to determine the advantages of the proposed procedure, are presented: no need for data on the irradiation history of spent fuel assemblies; possibility of using factory certified fuel assemblies and stand equipment from domestically produced sets; and use of the stand for measurements of spent fuel assemblies with different designs. The error in the measurements of the residual content of fissile materials in the fuel of spent fuel assemblies (<5%) and the time required for the measurements are acceptable, which makes the procedure suitable for mass measurements.