A method for evaluation of fuel can temperature using the large-scale profilometry data based on the inverse problem solution, is developed. Temperature values, which can explain the values of can diameter measured in post-reactor analysis, are determined. It is assumed that relative distribution of neutron flux is known exactly. Parameters of the shape change model are calculated on the basis of the same profilometric data. Sufficiently iteration character of these calculations is taken into account. Orthogonal Tchebyshev polinomials are used for description of dose-temperature dependence of shape change. A special selection of fuel elements is conducted by means of their grouping according to can diameter by the method of k-averages of cluster analysis, when the matrix for calculating the parameters of this dependence is formed. 4 refs.; 1 fig.