Published March 1962 | Version v1
Book Metadata-only

Reactivity coefficients of sodium in some large fast reactors

Creators

  • 1. Atomic Energy Establishment, Trombay, Bombay (India)
  • 2. Argonne National Laboratory, Argonne, IL (United States)

Description

Several studies have been made regarding the change of reactivity in fast reactors with the temperature of sodium or with the loss of coolant. In this paper, the effect on the sodium void-coefficient of taking into account more accurately the effect of elastic resonance scattering by light and medium atomic-weight materials is studied for some large fast systems. Fundamental-mode calculations were performed for the different sodium concentrations in the systems using 574 energy groups from 3.7 MeV to 25 keV. The elastic removal cross-sections and transport cross-sections were re- evaluated for a 16-group cross-section set and the reactivity coefficients were calculated using a one-dimensional diffusion-theory code for the idealized spherical systems. A more accurate calculation of the very-low-energy flux is provided by this method. This flux has been found to be very important for calculation of the Doppler effect in large reactors. (author)

Abstract (French)

Les variations de reactivite provoquees dans les reacteurs a neutrons rapides par les variations de la temperature du sodium ou par la perte de fluide de refroidissement ont fait l'objet de plusieurs etudes. Les auteurs etudient, pour quelques grands reacteurs a neutrons rapides, ce que devient le coefficient cavitaire du sodium lorsqu'on serre de plus pres l'effet de diffusion elastique par resonance dans les materiaux de masse atomique faible ou intermediaire. On a calcule les modes fondamentaux pour les differentes concentrations de sodium dans les systemes, en utilisant 574 groupes d'energie allant de 25 keV a 3,7 MeV. On a procede a une nouvelle evaluation des sections efficaces de deplacement elastique et des sections efficaces de transport pour un ensemble de 16 groupes de sections efficaces et au calcul des coefficients de reactivite a partir d'un programme de diffusion a une dimension dans le cas de systemes spheriques ideaux. Il est ainsi possible de calculer avec plus de precision le flux des neutrons de tres faible energie. On a constate que ce flux joue un role tres important dans le calcul de l'effet Doppler dans les grands reacteurs. (author)

Abstract (Spanish)

En el caso de los reactores rapidos, se han efectuado diversos estudios acerca de la variacion de la reactividad en funcion de la temperatura del sodio o de la perdida de refrigerante. En el presente trabajo, los autores estudian las consecuencias que se derivan del hecho de evaluar con mayor precision el efecto que la dispersion elastica por resonancia ejerce, en los materiales de peso atomico bajo y mediano, sobre el coeficiente de vacio del sodio, en el caso de algunos reactores rapidos de gran tamano. Calcularon los modos fundamentales para las diferentes concentracione s del sodio en los sistemas, utilizando 574 grupos de energias, que abarcan desde 25 keV hasta 3,7 MeV. Procedieron a una nueva evaluacion de las secciones eficaces de eliminacion elastica y de las secciones eficaces de transporte para un conjunto de secciones eficaces de 16 grupos y calcularon los coeficientes de reactividad usando una clave unidimensional de difusion para sistemas esfericos ideales. Con este metodo, es posible calcular eon mayor precision flujos neutronicos de energias muy bajas. Se ha comprobado que el conocimiento de estos flujos reviste mucha importancia para el calculo del efecto Doppler en los reactores de gran tamano. (author)

Abstract (Russian)

Byli provedeny nekotorye raboty, izuchayushchie izmenenie reaktivnosti v reaktorakh na bystrykh nejtronakh s temperaturoj natriya ili s poterej okhladitelya. V ehtoj rabote izuchaetsya ehffekt pustotnogo koehffitsienta natriya s bolee tshchatel'nym primeneniem ehffekta uprugogo rezonansnogo rasseyaniya materialami s legkimi i srednimi atomnymi vesami dlya nekotorykh bol'shikh sistem na bystrykh nejtronakh. Raschety osnovnogo sostoyaniya byli provedeny dlya razlichnykh kontsentratsij natriya v sistemakh, ispol'zuya 574 ehnergeticheskie gruppy ot 3,7 megaehlektronvol' t do 25 kiloehlektronvol't. Secheniya uprugogo protsessa vyvedeniya i transportnoe sechenie byli pereotseneny dlya nabora 16-gruppovykh poperechnykh sechenij i koehffitsienty reaktivnosti byli rasschitany s ispol'zovaniem odnorazmernog o koda teorii diffuzii dlya ideal'nykh sfericheskikh sistem. Ehtot metod predusmatrivaet bolee tochnyj raschet potoka nejtronov samykh malykh ehnergij. Ehtot potok okazalsya ochen' vazhnym dlya rascheta ehffekta Dopplera v bol'shikh reaktorakh. (author)
Part of:
Physics of Fast and Intermediate Reactors. Vol. II. Proceedings of the Seminar on the Physics of Fast and Intermediate Reactors. Vol. II

Additional details

Additional titles

Original title (English)
Coefficients de reactivite du sodium dans certains grands reacteurs a neutrons rapides; Koehffitsienty reaktivnosti natriya v nekotorykh bol'shikh reaktorakh na bystrykh nejtronakh; Coeficientes de reactividad del sodio en algunos reactores rapidos de gran tamano

Publishing Information

Publisher
Globus, Druck- und Verlagsanstalt, Vienna
Imprint Place
Vienna (International Atomic Energy Agency (IAEA))
Imprint Title
Physics of Fast and Intermediate Reactors. Vol. II. Proceedings of the Seminar on the Physics of Fast and Intermediate Reactors. Vol. II.
Imprint Pagination
418 p.
Series
Proceedings Series
Journal Page Range
p. 177-186
ISSN
0074-1884

Conference

Title
Seminar on Physics of Fast and Intermediate Reactors
Dates
3-11 Aug 1961
Place
Vienna (Austria)

INIS

Country of Publication
International Atomic Energy Agency (IAEA)
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
44035062
Subject category
S21: SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS;
Resource subtype / Literary indicator
Conference
Descriptors DEI
CROSS SECTIONS; DOPPLER EFFECT; FAST REACTORS; KEV RANGE; LOSS OF COOLANT; MEV RANGE; MULTIGROUP THEORY; NEUTRON DIFFUSION EQUATION; NEUTRON TRANSPORT; ONE-DIMENSIONAL CALCULATIONS; RESONANCE SCATTERING; SODIUM; SPHERICAL CONFIGURATION; VOID COEFFICIENT
Descriptors DEC
ACCIDENTS; ALKALI METALS; CONFIGURATION; DIFFERENTIAL EQUATIONS; DIFFUSION EQUATIONS; ELEMENTS; ENERGY RANGE; EPITHERMAL REACTORS; EQUATIONS; INELASTIC SCATTERING; METALS; NEUTRAL-PARTICLE TRANSPORT; NEUTRON TRANSPORT THEORY; PARTIAL DIFFERENTIAL EQUATIONS; RADIATION TRANSPORT; REACTIVITY COEFFICIENTS; REACTOR ACCIDENTS; REACTORS; SCATTERING; TRANSPORT THEORY

Optional Information

Notes
7 refs, 2 figs, 5 tabs Imprint:In three volumes
Secondary number(s)
STI/PUB--49(V.2); IAEA-SM--18