[en] Various mathematical algorithms and computer codes may be used to study time dependencies of isotopic compositions and maximal temperatures in fuel rods of nuclear reactors. In connection with designing of new-generation fuel assemblies (FA) and upgrading of computer engineering techniques, the problem related with achieving better accuracy in mathematical simulation of these FA parameters becomes more actual one. Development of new mathematical algorithms and computer codes for modeling time-dependent behavior of isotopic compositions of maximal temperatures in all fuel rod components requires availability of some benchmark tasks for verification of the algorithms and codes. The presentation describes a set of the benchmark tasks needed to verify the algorithms for determination of maximal temperatures in fuel rods of VVER-type reactors at various phases of fuel burn-up. If the benchmark tasks are resolved with application of different high-precision computer codes, then systematization of these solutions makes it possible to evaluate the uncertainty range of maximal temperatures obtained with application of different modeling approaches. (authors)