%A"Bourgeois, J" %A"Lafore, P" %A"Millot, J P" %A"Rastoin, J" %A"Vathaire, F de [Commissariat a l'Energie Atomique, Saclay (France).Centre d'Etudes Nucleaires]" %D1959 %I; CEA Saclay, 91 - Gif-sur-Yvette (France) %2 %J[] %K22 GENERAL STUDIES OF NUCLEAR REACTORS, BOLTZMANN EQUATION, CONCRETES, CROSS SECTIONS, EL-1 REACTOR, FERMI AGE THEORY, GAMMA RADIATION, GRAPHITE, IRON, LEAD, MILNE PROBLEM, NEUTRON AGE, NEUTRON FLUX, NEUTRON SPECTRA, NEUTRON TRANSPORT THEORY, RADIATION ATTENUATION TESTING, RADIATION PROTECTION, REACTOR EXPERIMENTAL FACILITIES, SHIELDING MATERIALS, THICKNESS, WATER %PMedium: ED; Size: 38 pages %TMethods and experimental coefficients used in the computation of reactor shielding; Methodes et coefficients experimentaux pour le calcul des protections de reacteurs %X1) The concept of an effective removal cross section has been developed in order more easily to compute reactor shielding thicknesses. We have built an experimental facility for the purpose of measuring effective removal cross sections, the value of which had not been published at that time. The first part of this paper describes the device or facility used, the computation method applied, and the results obtained. 2) Starting from this concept, we endeavoured to define a removal cross section as a function of energy. This enabled us to use the method for computations bearing on the attenuation of fast neutrons of any spectrum. An experimental verification was carried out for the case of fission neutrons filtered by a substantial thickness of graphite. 3) Finally, we outline a computation method enabling us to determine the sources of captured gamma rays by the age theory and we give an example of the application in a composite shield. (author) [French] 1) La notion de section efficace effective de deplacement a ete introduite pour calculer commodement les epaisseurs de protection des reacteurs. Nous avons construit un dispositif experimental destine a mesurer les sections efficaces effectives de deplacement dont la valeur n'avait pas ete publiee a cette epoque. La premiere partie de cette communication decrit le dispositif utilise, la methode de calcul employee et les resultats obtenus. 2) A partir de cette notion, nous avons essaye de definir une section efficace de deplacement fonction de l'energie. Ceci permet d'utiliser la methode du deplacement pour des calculs d'attenuation de neutrons rapides dont le spectre est quelconque. Une verification experimentale a ete faite dans le cas de neutrons de fission filtres par une epaisseur notable de graphite. 3) Enfin une methode de calcul permettant de determiner les sources de gamma de capture par la theorie de l'age est exposee et un exemple d'application donne dans une protection composite. (auteur) %0Technical Report %NCEA-R-1307;TRN: FR07R1307096411 %1 %CFrance %Rhttps://doi.org/ TRN: FR07R1307096411 FRN %GFrench