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Nuclear Calculations of Light-Water Moderated Reactors and Experimental Correlations; Calculs de Riacteurs Ralentis a l'Eau Ordinaire et Comparaison avec les Risultats Expirimentaux; Raschet reaktorov s zamedlitelem iz obychnoj vody i sravnenie s ehksperimental'nymi rezul'tatami; Calculos Nucleares de Reactores Moderados por Agua Ligera y Correlacion Experimental

Conference:

Abstract

Using the theory of two groups modified by epithermal fissions, we analysed a set of critical systems comprising a reflector and light-water moderator and nuclear fuel consisting of U{sup 235} in various degrees of enrichment. The cross-sections of the thermal group used are those listed in the Tables of Amster for hydrogenated mixtures at different temperatures, U{sup 235} concentrations and 1/v absorbers. The effect of heterogeneity in the cross-sections was dealt with by approximation, modifying the concentrations of the absorbers by spatial variation of the thermal flux in the elementary cell. The disadvantage factor was calculated using the formula of Amouyal-Benoist. The thermal diffusion coefficient was defined as the reciprocal of three times the macroscopic transport cross-section homogenized over the volume of the elementary cell. The constants of the fast group were calculated in accordance with Ombrellaro's scheme for three fast diffusion groups (10 MeV to 0.821 MeV; 0.821 MeV to 5.5 keV; 5.5 keV to 0.625 eV) with microscopic cross-sections fitted for each group. Ombrellaro's definition of the neutron constants for the three fast groups as a function of the fitted cross-sections was modified for the third group in accordance with Hick's treatment of the effective resonance absorption of  More>>
Authors:
Solanilla, R. [1] 
  1. Comision Nacional de Energia Atomica, Buenos Aires (Argentina)
Publication Date:
Feb 15, 1964
Product Type:
Conference
Report Number:
IAEA-SM-42/25
Resource Relation:
Conference: Symposium on Exponential and Critical Experiments, Amsterdam (Netherlands), 2-6 Sep 1963; Other Information: 30 refs., 6 tabs., 9 figs.; Related Information: In: Exponential and Critical Experiments Vol. II. Proceedings of the Symposium on Exponential and Critical Experiments| 494 p.
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 22 GENERAL STUDIES OF NUCLEAR REACTORS; CONCENTRATION RATIO; CROSS SECTIONS; DANCOFF CORRECTION; DISADVANTAGE FACTOR; EPITHERMAL NEUTRONS; EXPERIMENTAL DATA; FISSION; NEUTRON DIFFUSION EQUATION; NEUTRON TRANSPORT; NUCLEAR FUELS; RECIPROCAL V LAW; RESONANCE ABSORPTION; RESONANCE INTEGRALS; SCATTERING; THEORETICAL DATA; THERMAL DIFFUSION; URANIUM 235; URANIUM 238; WATER MODERATED REACTORS
OSTI ID:
22123043
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
Spanish
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M2690078845
Submitting Site:
INIS
Size:
page(s) 361-389
Announcement Date:
Aug 30, 2013

Conference:

Citation Formats

Solanilla, R. Nuclear Calculations of Light-Water Moderated Reactors and Experimental Correlations; Calculs de Riacteurs Ralentis a l'Eau Ordinaire et Comparaison avec les Risultats Expirimentaux; Raschet reaktorov s zamedlitelem iz obychnoj vody i sravnenie s ehksperimental'nymi rezul'tatami; Calculos Nucleares de Reactores Moderados por Agua Ligera y Correlacion Experimental. IAEA: N. p., 1964. Web.
Solanilla, R. Nuclear Calculations of Light-Water Moderated Reactors and Experimental Correlations; Calculs de Riacteurs Ralentis a l'Eau Ordinaire et Comparaison avec les Risultats Expirimentaux; Raschet reaktorov s zamedlitelem iz obychnoj vody i sravnenie s ehksperimental'nymi rezul'tatami; Calculos Nucleares de Reactores Moderados por Agua Ligera y Correlacion Experimental. IAEA.
Solanilla, R. 1964. "Nuclear Calculations of Light-Water Moderated Reactors and Experimental Correlations; Calculs de Riacteurs Ralentis a l'Eau Ordinaire et Comparaison avec les Risultats Expirimentaux; Raschet reaktorov s zamedlitelem iz obychnoj vody i sravnenie s ehksperimental'nymi rezul'tatami; Calculos Nucleares de Reactores Moderados por Agua Ligera y Correlacion Experimental." IAEA.
@misc{etde_22123043,
title = {Nuclear Calculations of Light-Water Moderated Reactors and Experimental Correlations; Calculs de Riacteurs Ralentis a l'Eau Ordinaire et Comparaison avec les Risultats Expirimentaux; Raschet reaktorov s zamedlitelem iz obychnoj vody i sravnenie s ehksperimental'nymi rezul'tatami; Calculos Nucleares de Reactores Moderados por Agua Ligera y Correlacion Experimental}
author = {Solanilla, R.}
abstractNote = {Using the theory of two groups modified by epithermal fissions, we analysed a set of critical systems comprising a reflector and light-water moderator and nuclear fuel consisting of U{sup 235} in various degrees of enrichment. The cross-sections of the thermal group used are those listed in the Tables of Amster for hydrogenated mixtures at different temperatures, U{sup 235} concentrations and 1/v absorbers. The effect of heterogeneity in the cross-sections was dealt with by approximation, modifying the concentrations of the absorbers by spatial variation of the thermal flux in the elementary cell. The disadvantage factor was calculated using the formula of Amouyal-Benoist. The thermal diffusion coefficient was defined as the reciprocal of three times the macroscopic transport cross-section homogenized over the volume of the elementary cell. The constants of the fast group were calculated in accordance with Ombrellaro's scheme for three fast diffusion groups (10 MeV to 0.821 MeV; 0.821 MeV to 5.5 keV; 5.5 keV to 0.625 eV) with microscopic cross-sections fitted for each group. Ombrellaro's definition of the neutron constants for the three fast groups as a function of the fitted cross-sections was modified for the third group in accordance with Hick's treatment of the effective resonance absorption of U{sup 238} , based on the calculation of the effective resonance integral. The calculations were performed by computing the effective resonance integral of U{sup 238} by the formula obtained theoretically by the author and involving reduction of the S/M relationship in accordance with Bell's approximation of the ''Dancoff'' effect. The correlation with the available experimental results, which extend to a wide range of moderation, composition of materials and geometry and which was carried out by comparing some of the main parameters of a lattice and/or effective multiplication, shows satisfactory results, with scattering of generally not more than 2% between calculated and experimental reactivity. (author) [French] En appliquant la theorie a deux groupes modifiee pour tenir compte des fissions epithermiques, on a analyse une serie d'assemblages critiques avec reflecteur et ralentisseur a l'eau ordinaire, qui differaient par le degre d'enrichissement en {sup 235}U. Les sections efficaces du groupe thermique sont celles qui figurent dans les tables d'Amster pour les melanges hydrogenes a differentes temperatures et pour differentes concentrations de {sup 235}U et des absorbants en l/v. L'effet de l'heterogeneite des sections efficaces a ete traite approximativement en modifiant la concentration de l'absorbant par variation spatiale du flux thermique dans la cellule. On a calcule le facteur de desavantage en appliquant la formule d'Amouyal-Benoist. Par definition, le coefficient de diffusion thermique est l'inverse du triple de la section efficace macroscopique de transport, homogeneise sur tout le volume de la cellule. On a calcule les constantes du groupe rapide conformement au systeme d'Ombrellaro a trois groupes rapides de diffusion (de 10 MeV a 0,821 MeV; de 0,821 MeV a 5,5 keV; 5,5keV a 0,625 eV) avec des sections efficaces microscopiques adaptees a chaque groupe. La definition que donne Ombrellaro pour les constantes neutioniques des trois groupes rapides en fonction des sections efficaces ajustees a ete modifiee pour le troisieme groupe conformement au traitement de l'absorption effective de resonance de {sup 238}U, proposee par Hick, et fondee sur le calcul de l'integrale de resonance effective. On a calcule l'integrale de resonance effective de {sup 238}U a l'aide de la formule deduite de la theorie par l'auteur, la relation S/M etant reduite conformement a l'approximation de Bell pour l'effet 'Dancoff' . La correlation entre les resultats du calcul et les donnees experimentales disponibles - qui correspondent a de nombreuses valeurs pour les caracteristiques du ralentisseur et pour la composition des matieres et a de nombreuses geometries - faite par comparaison avec certains des principaux parametres d'un reseau y/o de multiplication effective, est satisfaisante, l'ecart entre la reactivite obtenue par le calcul et le chiffre donne par l'experience,n'etant pas, en general, superieur a 2%. (author) [Spanish] Con el empleo de la teoria de dos grupos modificados por fisiones epitermales, se ha analizado un conjunto de sistemas criticos dotados de reflector y moderador de agiia liviana y variado enriquecimiento en {sup 235}U del combustible nuclear. Las secciones eficaces del grupo termal empleadas son las consignadas en las Tablas de Amster para mezclas hidrogenadas a diferentes temperaturas; concentraciones de {sup 235}U y absorbedores en 1/v. El efecto de heterogeneidad en las secciones eficaces ha sido tratado aproximadamente modificando las concentraciones de los absorbedores por variacion espacial del flujo termico en la celda elemental. El factor de desventaja ha sido calculado empleando la formula de Amouyal-Benoist. El coeficiente de difusion termal ha sido definido como la inversa del triple de la seccion eficaz macroscopica de transporte homogeneizada sobre el volumen de la celda elemental. Las constantes del grupo rapido han sido calculadas'de acuerdo al esquema de Ombrellaro de tres grupos rapidos de difusion (10 MeV a 0,821 MeV; 0,821 MeV a 5,5 keV; 5,5 keV a 0,625 eV) con secciones eficacesmicroscopicas ajustadas para cada grupo. La definicion de Ombrellaro de las constantes neutionicas de los tres,grupos rapidos en funcion de las secciones eficaces ajustadas ha sido modificada para el tercer grupo de acuerdo al tratamiento de Hick de la absorcion efectiva de resonancia del {sup 238}U, basada en el computo de la integral de resonancia efectiva. Los calculos han sido realizadas computando la integral de resonancia efectiva del: {sup 238}U por la formula obtenida, por el autor, del calculo teorico, con reduccion de la relacion S/M de acuerdo a la aproximacion del Bell del efecto 'Daneoff' . La La correlacion con los resultados experimentales disponibles, que comprenden un vasto campo de moderacion, composicion de materiales y geometria, realizada, a traves de la comparacion con algunos de los. principales parametros de un reticulado y/o de la multiplication efectiva, muestra resultados satisfactorios, consiguiendose dispersiones entre reactividad calculada y experimental que en general no superan el 2%. (author) [Russian] S pomoshh'ju teorii dvuh grupp, izmenennoj s uchetom nadteplovyh delenij, byla proanalizirovana serija kriticheskih sborok s otrazha- telem i zamedlitelem iz obychnoj vody. Otlichie sostojalo v stepeni obogashhenija uranom-235. Jeffektivnye sechenija teplovoj gruppy te zhe, chto i v tablicah Amstera dlja vodorodnyh smesej pri razlichnyh temperaturah, a takzhe dlja razlichnyh koncentracij urana-235 i poglo- titelej v 1/v. Vozdejstvie geterogennosti jeffektivnyh sechenij bylo opredeleno pribli- zitel'no putem izmenenija koncentracii poglotitelja s pomoshh'ju prostranstvennyh otklonenij teplovogo potoka v kamere. S primeneniem formuly Amuajjalja-Benoista byl rasschitan kojefficient proigrysha. Po sushhestvu kojefficient termodiffuzii vtroe men'she makrosko- picheskogo jeffektivnogo sechenija perenosa, kotoryj byl gomogenizirovan po vsej kamere. V sootvetstvii s sistemoj Ombrellaro byli rasschitany parametry gruppy bystryh chastic po trem diffuzionnym gruppam bystryh chastic (ot 10 do 0,821 Mjev; ot 0,821 Mjev do 5,5 kjev; ot 5,5 kjev do 0,625 jev) vmeste s mikroskopicheskimi jeffektivnymi sechenijami, prime- nimymi dlja kazhdoj gruppy. Opredelenie, kotoroe dajot Ombrellaro dlja nejtronnyh para- metrov treh grupp bystryh chastic v zavisimosti ot ustanovlennyh jeffektivnyh sechenij, bylo izmeneno dlja tret'ej gruppy v sootvetstvii s rezul'tatami obrabotki jeffektivnogo rezonansnogo pogloshhenija urana-238. Jeto predlozhennoe Nikom opredelenie bylo osnovano na raschete jeffektivnogo rezonansnogo integrala. Jeffektivnyj rezonansnyj integral urana-238 byl rasschitan s pomoshh'ju formuly, vy- vedennoj avtorom iz teorii sokrashhenija otnoshenija S/M v srotvetstvii s priblizheniem Bella dlja ''jeffekta Dankova''. Korreljacija rezul'tatov rascheta i poluchennyh jeksperimental'nyh dannyh, kotorye so- otvetstvujut mnogim znachenijam harakteristik zamedlitelja i sostavov veshhestv, a takzhe mno- gim geometrijam, byla provedena putem sravnenija s nekotorymi iz osnovnyh parametrov re- shetki jeffektivnogo razmnozhenija i javljaetsja udovletvoritel'noj. Rashozhdenie mezhdu ras- chetom i dannymi opyta v osnovnom ne prevyshaet 2%. (author)}
place = {IAEA}
year = {1964}
month = {Feb}
}