Resumen
Using a burnup credit as safety criteria in a spent nuclear fuel (SNF) criticality calculations required accuracy isotopes composition preparation approach. Comparisons between calculation results and existing experimental data are one effective way for this calculation approach development. Moreover some studies devoted to determination of the SNF isotopes composition do not provide the information about the fuel irradiation history, cooling time at all. In this case some complicacy can appear during initial data preparation and calculation results interpretation. In present work the verify calculations for 137Cs concentration proposed dependence were made use experimental data for several pressurize water reactor (PWR) and boiling water reactor (BWR) spent fuel assembly. The calculations of the 137Cs concentration using the proposed formula have a good agreement with the experimental data, which is available to the authors.