[en] An experimental program has been undertaken to confirm divers fast neutron spectrum calculations. The verification of calculational methods consists to compare measurements in a highly heterogeneous media to two-dimensional calculations effectuated on approach geometries. The measurements have been carried out in two testing facilities located in the centre of the core and near the reflector of the MELUSINE pool-type reactor. Counting techniques used for the determination of the reaction rate by beta-gamma activity measurements and activation foils are described. The following reactions have been selected: ¹⁹⁷Au(n,γ) ¹⁹⁸Au, ¹¹⁵In(n,n') ¹¹⁵Insub(m), ⁴⁷Ti(n,p) ⁴⁷Sc, ⁵⁸Ni(n,p) ⁵⁸Fe(n,p) ⁵⁴Mn, Ti(n,x) ⁴⁶Sc, ⁵⁶Fe(n,p) ⁵⁶Mn, ⁶³Cu(n,α) ⁶⁰Co, ²⁷Al(n,α)²⁴Na, ⁹²Nb(n,2n) ⁹²Nbsub(m), ⁵⁸Ni(n,2n) ⁵⁷Ni. A spectrum form has been elaborated from such activities by using the unfolding code SAND-II. On other part, spectrum determinations are performed with transport computer codes ANISN and DOT-III. The spectrum obtained from Unfolding and Transport Codes have been compared. Good agreement between the measured (foil activation) and calculated (SAND-II) activities were found with all detectors. Reasonable agreement between transport (DOT-III) and iterative (SAND-II) solutions are observed in the two test cases. This analysis permits to retain a spectrum determination procedure in the actual case of a composite testing facility