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Description of a Reactivity Measuring Apparatus; Description d'un Type d'Appareil de Mesure de la Reactivite

Conference:

Abstract

Measurement of the reactor period, or doubling time, normally provides the reactor control technician with sufficient data on the behaviour of the installation. The physicist engaged on determining physical parameters cannot be satisfied with these measurements, the concepts of which take no account of the nature of the nuclear fission phenomenon. Normally the physicist must therefore convert period measurement, which has to be carried out over a sufficiently long time in order to eliminate the disturbing transient terms, and to transform this quantity, by means of Nordheim curves, into a reactivity value. This procedure is long and laborious. It therefore seemed desirable to design a type of apparatus capable of evaluating directly and instantaneously the excess multiplication constant {delta}k on the basis of the changes in a physical quantity N assumed to be proportional to the neutron flux prevailing in the reactor core. The coefficient {delta}k is practically coincident with the reactivity near to criticality. This type of apparatus can therefore resolve the relationship which is the inverse of that defined by the system of differential equations with reference to the reactor, by considering the simplified case of a ''point'' reactor in the one-group theory. The application of analog computation  More>>
Authors:
Deiss, M.; Uberschlag, J. [1] 
  1. Centre d'Etudes Nucleaires de Saclay (France)
Publication Date:
Jun 15, 1966
Product Type:
Conference
Report Number:
IAEA-CN-22/11
Resource Relation:
Conference: Conference on Nuclear Electronics, Bombay (India), 22-26 Nov 1965; Other Information: 7 figs.; Related Information: In: Nuclear Electronics. Proceedings of a Conference on Nuclear Electronics| 678 p.
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; CALCULATION METHODS; DIFFERENTIAL EQUATIONS; IMPEDANCE; MATHEMATICAL OPERATORS; NEUTRON FLUX; ONE-GROUP THEORY; OPERATIONAL AMPLIFIERS; POTENTIOMETRY; POWER RANGE; REACTIVITY; REACTOR CONTROL SYSTEMS; REACTOR CORES; REACTOR PERIOD
OSTI ID:
22122942
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
French
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M2114078744
Submitting Site:
INIS
Size:
page(s) 353-363
Announcement Date:
Aug 30, 2013

Conference:

Citation Formats

Deiss, M., and Uberschlag, J. Description of a Reactivity Measuring Apparatus; Description d'un Type d'Appareil de Mesure de la Reactivite. IAEA: N. p., 1966. Web.
Deiss, M., & Uberschlag, J. Description of a Reactivity Measuring Apparatus; Description d'un Type d'Appareil de Mesure de la Reactivite. IAEA.
Deiss, M., and Uberschlag, J. 1966. "Description of a Reactivity Measuring Apparatus; Description d'un Type d'Appareil de Mesure de la Reactivite." IAEA.
@misc{etde_22122942,
title = {Description of a Reactivity Measuring Apparatus; Description d'un Type d'Appareil de Mesure de la Reactivite}
author = {Deiss, M., and Uberschlag, J.}
abstractNote = {Measurement of the reactor period, or doubling time, normally provides the reactor control technician with sufficient data on the behaviour of the installation. The physicist engaged on determining physical parameters cannot be satisfied with these measurements, the concepts of which take no account of the nature of the nuclear fission phenomenon. Normally the physicist must therefore convert period measurement, which has to be carried out over a sufficiently long time in order to eliminate the disturbing transient terms, and to transform this quantity, by means of Nordheim curves, into a reactivity value. This procedure is long and laborious. It therefore seemed desirable to design a type of apparatus capable of evaluating directly and instantaneously the excess multiplication constant {delta}k on the basis of the changes in a physical quantity N assumed to be proportional to the neutron flux prevailing in the reactor core. The coefficient {delta}k is practically coincident with the reactivity near to criticality. This type of apparatus can therefore resolve the relationship which is the inverse of that defined by the system of differential equations with reference to the reactor, by considering the simplified case of a ''point'' reactor in the one-group theory. The application of analog computation techniques leads to the utilization of a Pagels-type network arranged either as an input impedance or as a feed-back impedance of an operational amplifier. This latter structure brings about the inversion of the mathematical operator defining the function of the reactor, and has been adopted for the production of the two apparatuses described. It makes it possible to adapt to the latter the qualities inherent in servo systems and particularly the filtering action of high frequency noise. The output unit of these various types of instrument consists of a divider extracting the term {delta}k from the product N{delta}k supplied by the first stage of the apparatus. The two apparatuses have different dividers in the output unit, in the one case Potentiometric, and in the other electronic. The first apparatus is suitable in principle for most normal measurements. The second, by reason of its shorter response time, is suited both to measurements of higher reactivity values with the reactor level rising, and also with the reactor level falling, even over limited power ranges. (author) [French] La mesure de la periode ou du temps de doublement fournit en general au technicien du controle des reacteurs une information suffisante sur l'evolution du reacteur. Le physicien attache a la determination de parametres physiques ne peut se satisfaire de la mesure ordinaire de ces grandeurs, dont les concepts font abstraction de la nature du phenomene de la fission nucleaire. Habituellement le physicien doit donc convertir la mesure du temps de doublement, effectuee sur un temps suffisamment long, afin d'en eliminer les termes transitoires perturbateurs, et convertir, par intermediaire des courbes de Nordheim, cette mesure en valeur de reactivite. Cette procedure est longue et contraignante. Il a donc semble utile de concevoir un type d'appareil capable d'evaluer directement et instantanement le coefficient de multiplication excedentaire Greek-Small-Letter-Delta K a partir de l'evolution d'une grandeur physique N supposee proportionnelle au flux neutronique regnant dans le coeur du reacteur. Le coefficient Greek-Small-Letter-Delta K est pratiquement assimilable a la reactivite au voisinage de la criticalite. Un appareil de ce type peut en consequence resoudre la relation inverse a celle definie par le systeme des equations differentielles se rapportant au reacteur, en considerant le cas simplifie du reacteur point dans la theorie a un groupe. L'application des techniques du calcul analogique conduit a utiliser un reseau du type Pagels qui sera dispose, soit comme impedance d'entree, soit comme impedance de contre-reaction d'un amplificateur operationnel. Cette derniere structure realise l'inversion de l'operateur mathematique definissant la fonction du reacteur. Celle-ci a ete retenue pour la realisation des deux appareils decrits. Elle permet d'adapter a ceux-ci les qualites propres aux systemes asservis et notamment l'action de filtrage des bruits de haute frequence, L'organe de sortie de ces divers types d'appareils est constitue par un diviseur extrayant le terme Greek-Small-Letter-Delta K du produit N Greek-Small-Letter-Delta K fourni par le premier etage de l'appareil. Les deux appareils different entre eux par la nature de l'organe de sortie constitue par un diviseur, soit potentiometrique, soit electronique. Le premier de ces appareils convient en principe dans la plupart des cas habituels de mesure. Le second en raison de son temps de reponse plus reduit est adapte i la mesure en divergence de reactivites de valeurs plus elevees, ainsi qu'a des mesures en convergence, meme sur des plages de puissance limitees. (author)}
place = {IAEA}
year = {1966}
month = {Jun}
}