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Measurements with a Pulsed and Modulated Source in a Reactor; Mesures au Moyen d'une Source Pulsee et Modulee dans un Reacteur; Izmereniya v reaktore s pomoshch'yu impul'snogo i moduliruemogo is tochnika; Mediciones Efectuadas en Reactor con una Fuente Pulsada y Modulada

Conference:

Abstract

A generator with a neutron level variable in terms of any time factor has been developed by Philips Research Laboratories. Its practical use. in reactor physics has been demonstrated through a series of measurements carried out in the BRO2 reactor when subcritical. The stability of this generator, and the possibility of introducing sharp variations in the neutron intensity and of pulsing the flux or modulating it sinusoidally, makes it a very versatile instrument. It enables reactivity ({rho} = {Delta}k/{beta}) and neutron lifetime ( Script-Small-L /{beta}) to be determined by different independent methods. An exact comparison can be made of these methods since they can be employed without changing the conditions under which measurements are carried out. The following were determined: (1) {rho} based on delayed neutrons, by a sudden reduction of neutron level, (2) {rho} based on prompt neutrons by neutron pulses, (3) ( Script-Small-L /{beta}) by a combination of (1) and (2) for 0.5$ < {rho} < 2$; and (4) Script-Small-L /{beta} based on the transfer function of the reactor for a modulated source. The transfer functions for a reactivity oscillator and for a sinusoidally modulated source are discussed. It is shown that the measurement of Script-Small-L /{beta} is  More>>
Authors:
Rotter, W. [1] 
  1. Centre d'Etude de l'Energie Nucleaire, Mol (Belgium)
Publication Date:
Oct 15, 1965
Product Type:
Conference
Report Number:
IAEA-SM-62/38
Resource Relation:
Conference: Symposium on Pulsed Neutron Research, Karlsruhe (Germany), 10-14 May 1965; Other Information: 10 refs., 8 figs., 2 tabs.; Related Information: In: Pulsed Neutron Research. Vol. II. Proceedings of the Symposium on Pulsed Neutron Research| 934 p.
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; BR-2 REACTOR; COMPARATIVE EVALUATIONS; DELAYED NEUTRONS; DIGITAL COMPUTERS; MODULATION; MULTI-CHANNEL ANALYZERS; NEUTRON GENERATORS; OSCILLATORS; PROMPT NEUTRONS; PULSED NEUTRON TECHNIQUES; REACTIVITY; STATISTICS; TRANSFER FUNCTIONS
OSTI ID:
22123036
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
French
Contract Number:
Contract 006/60/5 BRAB
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M2645078838
Submitting Site:
INIS
Size:
page(s) 775-793
Announcement Date:
Aug 30, 2013

Conference:

Citation Formats

Rotter, W. Measurements with a Pulsed and Modulated Source in a Reactor; Mesures au Moyen d'une Source Pulsee et Modulee dans un Reacteur; Izmereniya v reaktore s pomoshch'yu impul'snogo i moduliruemogo is tochnika; Mediciones Efectuadas en Reactor con una Fuente Pulsada y Modulada. IAEA: N. p., 1965. Web.
Rotter, W. Measurements with a Pulsed and Modulated Source in a Reactor; Mesures au Moyen d'une Source Pulsee et Modulee dans un Reacteur; Izmereniya v reaktore s pomoshch'yu impul'snogo i moduliruemogo is tochnika; Mediciones Efectuadas en Reactor con una Fuente Pulsada y Modulada. IAEA.
Rotter, W. 1965. "Measurements with a Pulsed and Modulated Source in a Reactor; Mesures au Moyen d'une Source Pulsee et Modulee dans un Reacteur; Izmereniya v reaktore s pomoshch'yu impul'snogo i moduliruemogo is tochnika; Mediciones Efectuadas en Reactor con una Fuente Pulsada y Modulada." IAEA.
@misc{etde_22123036,
title = {Measurements with a Pulsed and Modulated Source in a Reactor; Mesures au Moyen d'une Source Pulsee et Modulee dans un Reacteur; Izmereniya v reaktore s pomoshch'yu impul'snogo i moduliruemogo is tochnika; Mediciones Efectuadas en Reactor con una Fuente Pulsada y Modulada}
author = {Rotter, W.}
abstractNote = {A generator with a neutron level variable in terms of any time factor has been developed by Philips Research Laboratories. Its practical use. in reactor physics has been demonstrated through a series of measurements carried out in the BRO2 reactor when subcritical. The stability of this generator, and the possibility of introducing sharp variations in the neutron intensity and of pulsing the flux or modulating it sinusoidally, makes it a very versatile instrument. It enables reactivity ({rho} = {Delta}k/{beta}) and neutron lifetime ( Script-Small-L /{beta}) to be determined by different independent methods. An exact comparison can be made of these methods since they can be employed without changing the conditions under which measurements are carried out. The following were determined: (1) {rho} based on delayed neutrons, by a sudden reduction of neutron level, (2) {rho} based on prompt neutrons by neutron pulses, (3) ( Script-Small-L /{beta}) by a combination of (1) and (2) for 0.5$ < {rho} < 2$; and (4) Script-Small-L /{beta} based on the transfer function of the reactor for a modulated source. The transfer functions for a reactivity oscillator and for a sinusoidally modulated source are discussed. It is shown that the measurement of Script-Small-L /{beta} is possible for 0.1 $ < {rho} < 10 $ by using a modulated source. The same method also gives the reactivity on the basis of the ratio of prompt neutrons to delayed neutrons for an optimal frequency, practically independently of the data for delayed neutrons and of the value of Script-Small-L /{beta}. By accumulating a large number of cycles in the multi-channel analyser, better statistics for each method can be obtained. Since the neutron level from the generator is in fact sinusoidal, the response of the reactor may be integrated over each quarter of a period, as the measurement sequence is controlled by the generator; measurement time is then minimal. Observations recorded on a perforated tape are analysed by a digital computer [French] Un generateur dont le debit neutronique est variable selon une fonction du temps quelconque a ete mis au point par les Laboratoires de recherches Philips. Son utilite pratique dans le domaine de la physique des reacteurs a ete demontree par une serie de mesures effectuees dans le reacteur BRO2 a fotat sous-critique. Sa bonne stabilite, la possibilite de faire varier brusquement l'intensite neutronique, de puiser le debit ou de le moduler sinusoldalement, rend ce generateur tres souple. Il permet de determiner la reactivite ({rho} = {Delta}k/{beta}) et le temps de vie des neutrons ( Script-Small-L /{beta}) d'apres differentes methodes independantes. Une comparaison exacte de ces methodes est possible puisqu'elles peuvent etre employees sans modifier les conditions de mesure. On a determine: a) {rho} sur la base des neutrons retardes, par une reduction instantanee du debit de neutrons; b) {rho} sur la base des neutrons instantanes par des bouffees de neutrons; c) Script-Small-L /{beta} par combinaison de a) et b) pour 0,5 $ < {rho} <2 $; d) Script-Small-L /{beta} sur la base de la fonction de transfert du reacteur pour une source modulee. Les fonctions de transfert pour un oscillateur de reactivite et pour une source modulee sinusoldalement sont discutees. Il est montre que la mesure de Script-Small-L /{beta} est possible pour 0,1 $ < {rho} < 10 $ en utilisant une source modulee. La meme methode fournit aussi la reactivite a l'aide du rapport des neutrons instantanes aux neutrons retardes pour une frequence optimale, pratiquement independamment des donnees relatives aux neutrons retardes et de la valeur de f Script-Small-L /{beta}. Par accumulation d'un grand nombre de cycles dans l'analyseur multicanal, la statistique peut etre amelioree pour chaque methode. Le debit du generateur etant bien sinusoiedal, la reponse du reacteur peut etre integree sur chaque quart d'une periode, etant donne que la chafhe de mesure est pilotee par le generateur: le temps de mesure est donc minimum. Les observations enregistrees sur bande perforee sont depouillees par une calculatrice numerique. (author) [Spanish] Los laboratorios de investigacion Philips han construido un generador neutronico de flujo variable en funcion del tiempo. Con una serie de mediciones efectuadas en el reactor BRO2 en estado subcrftico, se ha demostrado su utililidad practica en la esfera de la fisica de los reactores. El funcionamiento del generador es muy flexible debido a su alta estabilidad, a la posibilidad de variar bruscamente la intensidad neutronica, y de pulsar el flujo o modularlo de manera sinusoidal. El generador permite determinar la reactividad ({rho} = {Delta}k/{beta}) y la vida media de los neutrones ( Script-Small-L /{beta}) segun varios metodos independientes. Es posible proceder a una comparacion exacta de esos metodos, dado que pueden aplicarse sin modificar las condiciones de medicion. El autor ha calculado los siguientes valores: a) p, sobre la base de los neutrones retardados, por reduccion instantanea del flujo neutronico; b) p, sobre la base de los neutrones inmediatos, por impulsos neutronicos; c) Script-Small-L /{beta}, combinando 1) y 2), cuando 0, 5 dolares < {rho} < 2 dolares, y d) Script-Small-L /{beta}, sobre la base de la funcion de transferencia del reactor para una fuente modulada. En la memoria se examinan las funciones de transferencia correspondientes a un oscilador de reactividad y a una fuente de modulacion sinusoidal. Se demuestra que es posible medir Script-Small-L /{beta}, cuando 0,1 dolar < {rho} < 10 dolares utilizando una fuente modulada. Por el mismo metodo se obtiene tambien la reactividad partiendo de la razon neutrones inmediatos/neutrones retardados para una frecuencia optima que es practicamente independiente de los datos relativos a los neutrones retardados y del cociente Script-Small-L /{beta}. La precision estadistica de cada metodo puede aumentarse acumulando un gran numero de ciclos en el analizador multicanal. Como el flujo del generador es perfectamente sinusoidal, la respuesta del reactor puede integrarse en cada cuarto de perfodo, puesto que el circuito de medicion esta gobernado por el generador; por consiguiente, el tiempo de medicion es minimo. Los datos registrados sobre cinta perforada se analizan con ayuda de una calculadora numerica. (author) [Russian] Generator, vyhod nejtronov kotorogo izmenjaetsja v zavisimosti ot funkcii kakogo-to vremeni, byl razrabotan v issledovatel'skih laboratorijah Filipsa. Ego prakticheskaja pol'za v oblasti fiziki reaktorov byla prodemonstrirovana na serii izmerenij, provedennyh v reaktore BR-O 2 v podkriticheskom sostojanii. Horoshaja ustojchivost', vozmozhnost' proizvodit' rezkie izmenenija intensivnosti nejtronnogo potoka, impul'sirovat' vyhod ili modulirovat' ego sinusoidal'no, - vse jeto delaet takoj generator ochen' gibkim. On pozvoljaet ustanavlivat' reaktivnost' ({rho} = {Delta}k/{beta}) i vremja zhizni nejtronov ( Script-Small-L /{beta}) po razlichnym nezavisimym metodam. Tochnoe sravnenie jetih metodov vozmozhno, poskol'ku poslednie mogut byt' ispol'zovany bez izmenenija uslovij izmerenija. Ustanovleno: 1) {rho} na osnove zapazdyvajushhih nejtronov putem mgnovennogo umen'shenija vyhoda nejtronov; 2) {rho} na osnove mgnovennyh nejtronov putem ispol'zovanija impul'sov nejtronov; 3) Script-Small-L /{beta} putem soedinenija 1) i 2) dlja 0,5 $ < {rho} < 2 $ ; 4) Script-Small-L /{beta} na osnove peredatochnoj funkcii reaktora dlja moduliruemogo istochnika. Obsuzhdajutsja peredatochnye funkcii dlja oscilljatora reaktivnosti i dlja sinusoidal'no moduliruemogo istochnika. Pokazano, chto izmerenie Script-Small-L /{beta} vozmozhno dlja 0,1 $< {rho} < $ s uchetom primenenija moduliruemogo istochnika. Tot zhe metod takzhe daet reaktivnost' s pomoshh'ju otnoshenija mgnovennyh nejtronov k zapazdyvajushhim nejtronam dlja optimal'noj chastoty, prichem na praktike jeto proishodit nezavisimo ot dannyh, otnosjashhihsja k zapazdyvajushhim nejtronam, i ot znachenija Script-Small-L /{beta}. Statistika mozhet byt' uluchshena dlja kazhdogo metoda v rezul'tate nakoplenija bol'shogo kolichestva ciklov v mnogokanal'nom analizatore. Esli vyhod s generatora dostatochno sinusoidalen, to chuvstvitel'nost' reaktora mozhet byt' integrirovana dlja kazhdoj chetverti perioda pri uslovii, chto cep' izmerenij upravljaetsja generatorom; pojetomu vremja izmerenija minimal'no. Zaregistrirovannye na perforirovannoj lente nabljudenija rasshifrovyvajutsja na cifrovom vychislitel'nom ustrojstve. (author)}
place = {IAEA}
year = {1965}
month = {Oct}
}