An advancement or variety of PWR cores by introducing MOX fuel, burnable poison and so on, increases a heterogeneity in a core or an assembly. For the evaluation of the pin power distribution, the fine mesh flux reconstruction is required with the combination of an assembly calculation and a three dimensional core calculation with coarse mesh, instead of the combination of a two dimensional X-Y core calculation with fine mesh and a one dimensional axial core calculation for the conventional PWR core. The main purpose of the NEANSC benchmark problems entitled `Power Distribution within Assemblies` is to compare the technique of the fine mesh flux reconstruction based on coarse mesh core calculation. In this report, we examine the validity of the reconstruction technique based on the coarse mesh core calculation using the Spline function, assembly calculation and heterogeneous fine mesh core calculation by built-in programs in the SRAC code using the groupwise Monte Carlo calculation with the GMVP code as reference. (author).