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Construction, Cost and Use of an Enriched Uranium, Light-Water Subcritical Assembly; Assemblage Sous-Critique a Uranium Enrichi et Eau Legere; Realisation, Cout et Application; Realizatsiya i stoimost' podkriticheskoj sborki na obogashchennom urane i legkoj vode; Construccion, Coste y Aplicacion de un Conjunto Subcritico de Uranio Enriquecido

Conference:

Abstract

Designed for the experimental investigation of multiplying lattices, the Lausanne subcritical assembly is also used for teaching purposes. It is extremely versatile. The authors explain why the Nuclear Engineering Laboratory of the Ecole Polytechnique, University of Lausanne, decided to construct a subcritical assembly, relying as far as possible on its own resources, and why a slightly enriched uranium, light-water lattice was selected. The construction and arrangements are such that the lattice and neutron input parameters can be varied quickly and easily. 1. The uranium rods are vertically suspended and each suspension point has two degrees of freedom and can be continuously varied. Hence the lattice spacing, for example, can also be continuously varied. 2. The neutron input is provided by five Pu-Be sources placed in a graphite base. The spacing of these sources can also be continuously regulated. The paper discusses the safety problems the facility involves because of the fact that the reactivity can vary a great deal from one configuration to the other. It also explains the general construction and operational costs. The facility is used, inter alia, to study a non-periodic lattice with a view to obtaining a uniform flux. For this purpose the heterogeneous theory developed  More>>
Authors:
Vittoz, B.; Berthet, P.; Gavin, P.; Mandrin, C.; Robert, P.; Thurnheer, J. [1] 
  1. Ecole Polytechnique de l'Universite de Lausanne (Switzerland)
Publication Date:
Feb 15, 1964
Product Type:
Conference
Report Number:
IAEA-SM-42/8
Resource Relation:
Conference: Symposium on Exponential and Critical Experiments, Amsterdam (Netherlands), 2-6 Sep 1963; Other Information: 4 refs., 12 figs., 1 tab.; Related Information: In: Exponential and Critical Experiments Vol. I. Proceedings of the Symposium on Exponential and Critical Experiments| 494 p.
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; DEGREES OF FREEDOM; FAST NEUTRONS; GRAPHITE; NEUTRON DIFFUSION EQUATION; NEUTRON FLUX; NEUTRON SOURCES; OPERATING COST; REACTIVITY COEFFICIENTS; REACTOR SAFETY; SLIGHTLY ENRICHED URANIUM; SUBCRITICAL ASSEMBLIES; THERMAL NEUTRONS; WATER MODERATED REACTORS
OSTI ID:
22121979
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
French
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M2667078090
Submitting Site:
INIS
Size:
page(s) 355-369
Announcement Date:
Aug 27, 2013

Conference:

Citation Formats

Vittoz, B., Berthet, P., Gavin, P., Mandrin, C., Robert, P., and Thurnheer, J. Construction, Cost and Use of an Enriched Uranium, Light-Water Subcritical Assembly; Assemblage Sous-Critique a Uranium Enrichi et Eau Legere; Realisation, Cout et Application; Realizatsiya i stoimost' podkriticheskoj sborki na obogashchennom urane i legkoj vode; Construccion, Coste y Aplicacion de un Conjunto Subcritico de Uranio Enriquecido. IAEA: N. p., 1964. Web.
Vittoz, B., Berthet, P., Gavin, P., Mandrin, C., Robert, P., & Thurnheer, J. Construction, Cost and Use of an Enriched Uranium, Light-Water Subcritical Assembly; Assemblage Sous-Critique a Uranium Enrichi et Eau Legere; Realisation, Cout et Application; Realizatsiya i stoimost' podkriticheskoj sborki na obogashchennom urane i legkoj vode; Construccion, Coste y Aplicacion de un Conjunto Subcritico de Uranio Enriquecido. IAEA.
Vittoz, B., Berthet, P., Gavin, P., Mandrin, C., Robert, P., and Thurnheer, J. 1964. "Construction, Cost and Use of an Enriched Uranium, Light-Water Subcritical Assembly; Assemblage Sous-Critique a Uranium Enrichi et Eau Legere; Realisation, Cout et Application; Realizatsiya i stoimost' podkriticheskoj sborki na obogashchennom urane i legkoj vode; Construccion, Coste y Aplicacion de un Conjunto Subcritico de Uranio Enriquecido." IAEA.
@misc{etde_22121979,
title = {Construction, Cost and Use of an Enriched Uranium, Light-Water Subcritical Assembly; Assemblage Sous-Critique a Uranium Enrichi et Eau Legere; Realisation, Cout et Application; Realizatsiya i stoimost' podkriticheskoj sborki na obogashchennom urane i legkoj vode; Construccion, Coste y Aplicacion de un Conjunto Subcritico de Uranio Enriquecido}
author = {Vittoz, B., Berthet, P., Gavin, P., Mandrin, C., Robert, P., and Thurnheer, J.}
abstractNote = {Designed for the experimental investigation of multiplying lattices, the Lausanne subcritical assembly is also used for teaching purposes. It is extremely versatile. The authors explain why the Nuclear Engineering Laboratory of the Ecole Polytechnique, University of Lausanne, decided to construct a subcritical assembly, relying as far as possible on its own resources, and why a slightly enriched uranium, light-water lattice was selected. The construction and arrangements are such that the lattice and neutron input parameters can be varied quickly and easily. 1. The uranium rods are vertically suspended and each suspension point has two degrees of freedom and can be continuously varied. Hence the lattice spacing, for example, can also be continuously varied. 2. The neutron input is provided by five Pu-Be sources placed in a graphite base. The spacing of these sources can also be continuously regulated. The paper discusses the safety problems the facility involves because of the fact that the reactivity can vary a great deal from one configuration to the other. It also explains the general construction and operational costs. The facility is used, inter alia, to study a non-periodic lattice with a view to obtaining a uniform flux. For this purpose the heterogeneous theory developed by Feinberg and Horning is used. A lattice in which the rods are identically arranged in non-equidistant, parallel n-planes is first considered. Each plane is a fast- neutron source and an absorber of thermal neutrons. Outside these planes, two-group diffusion equations are used. If the characteristics of a single plane are known the neutron flux for the n- planes can be forecast. These characteristics are determined experimentally, with due regard to the vertical variation of the neutron flux. The role played by the distance between the rods in a given plane is also investigated. (author) [French] Destine a l'etude experimentale des reseaux ienultiplicateurs, l'assemblage sous-critique de Lausanne est egalement employe pour renseignement. Cette installation presente une grande souplesse d'utilisation. Les auteurs exposent les raisons qui ont amene le Laboratoire de genie atomique de l'Ecole polytechnique de l'Universite de Lausanne a realiser l'assemblage sous-critique, autant que possible par ses propres moyens, et a choisir un reseau uranium faiblement enrichi-eau legere. Ils decrivent le principe et la realisation des dispositifs qui permettent de faire varier commodement et rapidement les parametres relatifs au reseau et a l'alimentation en neutrons: 1. Les barres d'uranium sont suspendues verticalement, chaque point de suspension est a deux degres de liberte sans restriction de continuite. Ce principe permet par exemple de faire varier de facon , continue te pas de reseau. 2. L'alimentation en neutrons est assuree par 5 sources Pu-Be placees dans un socle de graphite. L'ecartement de ces sources peut aussi etre regle de facon continue. Les auteurs examinent les problemes de securite que pose l'installation par le fait que la reactivite peut beaucoup varier d'une configuration a l'autre. Enfin, les auteurs presentent l'ensemble des depenses occasionnees par la construction et l'exploitation de cet assemblage sous-critique. L'une des recherches faites avec le sous-critique est l'etude d'un reseau non periodique ou l'on cherche a obtenir un flux uniforme. On utilise a cet effet la theorie heterogene developpee par Feinberg et Horning ea considerant d'abord un reseau de barres disposees de facon identique dans n plans paralleles non equidistants. Chaque plan de barres est une source de neutrons rapides et un absorbeur de neutrons thermiques. En dehors de ces plans, les equations de diffusion a deux groupes sont utilisees. La connaissance des caracteristiques d'un seul plan de barres est suffisante pour prevoir le flux de neutrons du aux n plans. La determination experimentale de ces caracteristiques est faite en tenant compte de la variation verticale du flux de neutrons. L'etude est poursuivie en etudiant l'influence de la distance entre les barres d'un meme plan. (author) [Spanish] El conjunto subcritico de la Escuela Politecnica de la Universidad de Lausana esta destinado al estudio experimental de los reticulados multiplicadores, pero se emplea tambien para fines de enseflanza. La instalacion se presta a usos multiples. Los autores exponen los motivos que indujeron al Laboratorio de Ingenieria Nuclear de la citada Escuela Politecnica a construir el conjunto subcritico, por sus propios medios en toda la medida de lo posible, y a elegir un reticulado de uranio poco enriquecido-agua ligera. Describen el principio y la construccion de los dispositivos que permiten variar comoda y rapidamente los parametros relativos al reticulado y a la alimentacion neutronica: 1. Las barras de uranio estan suspendidas verticalmente; cada punto de suspension posee dos grados de libertad sin restriccion de continuidad. Este principio permite, por ejemplo, variar de forma continua el paso del reticulado. 2. La alimentacion neutronica queda asegurada por cinco fuentes de Pu-Be colocadas sobre un pedestal de grafito. La separacion entre estas fuentes tambien se puede regular de forma continua. Los autores examinan los problemas de seguridad que plantea la instalacion, yaque la reactividad puede variar en gran medida de una configuracion a otra. Por ultimo, informan sobre el costo de la construccion y de los gastos de explotacion de este conjunto subcritico. Una de las investigaciones llevadas a cabo en el conjunto es el estudio de un reticulado aperiodico en el que se procura obtener un flujo uniforme. A este efecto se recurre a la teoria heterogenea establecida por Feinberg y Horning, considerando primero un reticulado de barras distribuidas de forma identica en n planos paralelos no equidistantes. Cada plano de barras constituye una fuente de neutrones rapidos y un absorbedor de neutrones termicos. Fuera de estos planos se utilizan las ecuaciones de dispersion en teoria de dos grupos. Basta conocer las caracteristicas de un solo plano de barras para prever el flujo neutronico debido a los n planos. Estas caracteristicas se determinan experimentalmente teniendo en cuenta la variacion vertical del flujo neutronico. El estudio se prosigue por evaluacion de la influencia de la distancia entre las banas pertenecientes a un mismo plano. (author) [Russian] Prednaznachennaja dlja jeksperimental'nogo izuchenija reshetok umnozhitelja podkriticheskaja sborka ispol'zuetsja takzhe dlja celej obuchenija. Ustanovka obladaet bol'shimi vozmozhnostjami ispol'zovanija. Izlagajutsja prichiny, po kotorym laboratorija jadernoj tehniki Politehnicheskoj shkoly Lozannskogo universiteta reshila realizovat', naskol'ko jeto vozmozhno, podkriticheskuju sborku svoimi sobstvennymi sredstvami i izbrat' reshetku slaboobogashennyj uran-legkaja voda. Daetsja opisanie principa i realizacii ustrojstv, kotorye pozvoljajut udobno i bystro izmenjat' parametry reshetki i nejtronnogo pitanija: 1. Uranovye sterzhni podveshivajutsja vertikal'no, i kazhdaja tochka podveski imeet dva gradusa svobodnogo hoda bez ogranichenija samogo processa. Jetot princip pozvoljaet, naprimer, var'irovat' posledovatel'no shag reshetki. 2. Nejtronnoe pitanie obespechivaetsja pjat'ju istochnikami, kotorye pomeshajutsja v grafitovom cokole. Rasstojanie jetih istochnikov mozhet takzhe regulirovat'sja posledovatel'nym obrazom. Rassmatrivajutsja problemy bezopasnosti, kotorye sozdaet ustanovka, tem. chto reaktivnost' mozhet sil'no izmenjat'sja ot odnoj konfiguracii k drugoj. Nakonec, privodjatsja rashody po stroitel'stvu i jekspluatacii jetoj podkriticheskoj sborki. S pomoshh'ju podkriticheskoj sborki izuchalas' neperiodicheskaja reshetka, kogda byla predprinjata popytka poluchit' odnorodnyj potok. S jetoj cel'ju ispol'zovana geterogennaja teorija Fajnberga i Horninga. Vnachale rassmatrivaetsja reshetka sterzhnej, raspolozhennyh odinakovym obrazom v n-parallel'nyh planah na raznovelikih rasstojanijah. Kazhdyj plan sterzhnej javljaetsja istochnikom bystryh nejtronov i poglotitelem teplovyh. Za jetimi planami ispol'zujutsja diffuzionnye uravnenija dvuh grupp. Dostatochno znat' harakteristiki odnogo plana sterzhnej, chtoby opredelit' potok nejtronov po n-planam. Jeksperimental'noe opredelenie jetih harakteristik provedeno s uchetom vertikal'nogo izmenenija potoka nejtronov. Issledovanie prodolzhaetsja paralell'no s izucheniem vlijanija rasstojanija mezhdu sterzhnjami odnogo i togo zhe plana. (author)}
place = {IAEA}
year = {1964}
month = {Feb}
}