Published 1970 | Version v1
Report Open

Fast neutron spectrum in the reflector of swimming pool reactor behind metallics slabs

Creators

  • 1. Commissariat a l'Energie Atomique, Grenoble (France). Centre d'Etudes Nucleaires

Description

The large perturbations of fast neutron spectrum were measured behind lead, aluminium and iron slabs in the Siloette reflector at the CENG. The neutron slowing down is chiefly depending of the inelastic reaction. The reaction cross section increases with energy; a spectrum softening is deduced. This is verified. We tried to determine the spectrum shape by calculation to fit the measurements. Calculations were firstly made in unidimensional geometry by the NIOBE transport equation resolution code and by the SANE Monte-Carlo code. The results does not agree with the experimental determined values. Finally a semi-empirical method for studying a tridimensional geometry was chosen. We have obtained calculation results in a perfect agreement with measurements. The method is described. (author)

Availability note (English)

Available from INIS in electronic form

Abstract (French)

Les experiences realisees dans le reflecteur de la pile a eau legere SILOETTE du CENG avec des ecrans de plomb, d'aluminium et de fer, nous ont permis de caracteriser les deformations importantes du spectre des neutrons rapides par ces materiaux. Nous avons verifie que la loi de ralentissement preponderante est la reaction de diffusion inelastique dont la section efficace croit avec l'energie, ce qui entraine un amollissement du spectre. Nous avons cherche a determiner par le calcul la trace des spectres de neutrons rapides correspondant aux points de mesure. Les premiers calculs effectues en geometrie unidimensionnelle a l'aide d'un code de resolution de l'equation du transport (NIOBE) et d'un code de Monte-Carlo (SANE) nous ont donne des resultats imparfaits. On a alors choisi une methode de calcul approche capable d'etudier une geometrie tridimensionnelle. Cette methode nous a donne des resultats de calcul qui s'approchaient a quelques pour cent des resultats experimentaux. La methode est decrite. (auteur)

Files

36002852.pdf

Files (3.5 MB)

Name Size Download all
md5:7aa6b020a13f98d7ccdc93e52af3206d
3.5 MB Preview Download

Additional details

Additional titles

Original title (French)
Spectre des neutrons rapides dans le reflecteur d'une pile a eau legere derriere des ecrans metalliques

Publishing Information

Imprint Pagination
[170 p.]
Report number
CEA-R--3799

INIS

Country of Publication
France
Country of Input or Organization
France
INIS RN
36002852
Subject category
S21: SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS;
Resource subtype / Literary indicator
Numerical Data, Thesis
Descriptors DEI
ALUMINIUM; COMPARATIVE EVALUATIONS; COMPUTER CODES; CROSS SECTIONS; EXPERIMENTAL DATA; FAST NEUTRONS; IRON; LEAD; MONTE CARLO METHOD; NEUTRON REFLECTORS; NEUTRON SLOWING-DOWN THEORY; NEUTRON SPECTRA; NEUTRON TRANSPORT THEORY; SHIELDING MATERIALS; SILOETTE REACTOR; THREE-DIMENSIONAL CALCULATIONS
Descriptors DEC
BARYONS; CALCULATION METHODS; DATA; ELEMENTARY PARTICLES; ELEMENTS; ENRICHED URANIUM REACTORS; EVALUATION; EXPERIMENTAL REACTORS; FERMIONS; HADRONS; INFORMATION; MATERIALS; METALS; NEUTRONS; NUCLEONS; NUMERICAL DATA; POOL TYPE REACTORS; REACTORS; RESEARCH AND TEST REACTORS; SPECTRA; THERMAL REACTORS; TRANSITION ELEMENTS; TRANSPORT THEORY; WATER COOLED REACTORS; WATER MODERATED REACTORS; ZERO POWER REACTORS

Optional Information

Notes
25 refs.