Possibility of identifying the fuel elements and fuel assemblies of first-generation USA and USSR research reactors

The possibilities of identifying the fuel elements and fuel assemblies from the cores of first-generation research reactors in the USSR (F1, TVR, RFT, IGR, SM-2, and IVG.1) and USA (CR-1, X-10, BGRR, EBR I, MTR, ARE, and TREAT) are examined. The fuel elements and assemblies are described and the cross section and characteristic dimensions are presented. It is shown that the fuel elements and fuel assemblies are different and that in order to identify them in most cases only the geometric dimensions need by examined and measured. However, if a reactor fuel element or assembly is completely destroyed, then the uranium enrichment and isotopic composition as well as the impurity composition must be measured.