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Neutron moderation at very low temperatures (1691); Moderation des neutrons aux tres basses temperatures (1961)

Abstract

Starting from Harwell experiment carried out inside a low-power reactor, we intended to maintain a liquid hydrogen cell in a channel of the EL3 reactor (at Saclay) whose thermal neutrons flux is 10{sup 14} neutrons/cm{sup 2}/s. We tried to work out a device giving off an important beam of cold neutrons and able to operate in a way as automatic as possible during many consecutive day without a stop. Several circuits have already been achieved at very low temperatures but they brought out volumes and fluxes much lower than those we used this time. The difficulties we have met in carrying out such a device arose on the one hand from the very high energy release to which any kind of experiment is inevitably submitted when placed near the core of the reactor, on the other, hand from the very little room which is available in experimental channels of reactors. In such condition, it is necessary to use a moderator as effective as possible. This study is divided into three parts ; in the first part, we try to determine: a) conditions in which moderation takes place, hence the volume of the cell; b) materials likely to be used at  More>>
Authors:
Lacaze, A [1] 
  1. Commissariat a l'Energie Atomique, Grenoble (France). Centre d'Etudes Nucleaires
Publication Date:
Apr 15, 1961
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-2012
Resource Relation:
Other Information: TH: These sciences; 61 refs
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; COLD NEUTRONS; COOLING SYSTEMS; CRYOGENIC FLUIDS; EL-3 REACTOR; NEUTRON FLUX; TEMPERATURE RANGE 0013-0065 K
OSTI ID:
20734772
Research Organizations:
CEA Grenoble, 38 (France); Faculte des Sciences de l'Universite de Grenoble, 38 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR06R2012045181
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
[104] pages
Announcement Date:
Jun 09, 2006

Citation Formats

Lacaze, A. Neutron moderation at very low temperatures (1691); Moderation des neutrons aux tres basses temperatures (1961). France: N. p., 1961. Web.
Lacaze, A. Neutron moderation at very low temperatures (1691); Moderation des neutrons aux tres basses temperatures (1961). France.
Lacaze, A. 1961. "Neutron moderation at very low temperatures (1691); Moderation des neutrons aux tres basses temperatures (1961)." France.
@misc{etde_20734772,
title = {Neutron moderation at very low temperatures (1691); Moderation des neutrons aux tres basses temperatures (1961)}
author = {Lacaze, A}
abstractNote = {Starting from Harwell experiment carried out inside a low-power reactor, we intended to maintain a liquid hydrogen cell in a channel of the EL3 reactor (at Saclay) whose thermal neutrons flux is 10{sup 14} neutrons/cm{sup 2}/s. We tried to work out a device giving off an important beam of cold neutrons and able to operate in a way as automatic as possible during many consecutive day without a stop. Several circuits have already been achieved at very low temperatures but they brought out volumes and fluxes much lower than those we used this time. The difficulties we have met in carrying out such a device arose on the one hand from the very high energy release to which any kind of experiment is inevitably submitted when placed near the core of the reactor, on the other, hand from the very little room which is available in experimental channels of reactors. In such condition, it is necessary to use a moderator as effective as possible. This study is divided into three parts ; in the first part, we try to determine: a) conditions in which moderation takes place, hence the volume of the cell; b) materials likely to be used at low temperature and in pile; c) cooling system; hence we had to study fluid flow conditions at very low temperatures in very long ducts. The second part is devoted to the description of the device. The third part ventilates the results we have obtained. (author) [French] Partant de l'experience de Harwell faite dans une pile de faible puissance, nous nous sommes propose de maintenir une cellule d'hydrogene liquide dans un canal de la pile EL3 de Saclay dont le flux de neutrons thermiques est de 10{sup 14} neutrons par seconde et par cm{sup 2}. Nous avons cherche a realiser une installation donnant un faisceau de neutrons froids important, et pouvant fonctionner d'une maniere aussi automatique que possible, pendant des periodes de plusieurs jours sans arret. Plusieurs circuits aux tres basses temperatures ont deja ete realises, mais ils ne mettaient en oeuvre que des volumes et des flux beaucoup plus faibles que ceux que nous avons utilises. Les difficultes de realisation d'un tel systeme proviennent d'une part du degagement de chaleur intense que subit tout dispositif place pres du coeur de pile, d'autre part de la faible place dont on dispose dans les canaux experimentaux des reacteurs. Il est alors important d'utiliser le moderateur le plus efficace possible. Cette etude comprendra trois parties; dans la premiere nous determinerons: a) les conditions de moderation, ce qui nous permettra de fixer le volume a donner a la cellule; b) les materiaux a employer aux basses temperatures et en pile; c) le circuit de refrigeration, ce qui nous amenera a etudier les conditions d'ecoulement des fluides aux/tres basses temperatures dans des conduites de grandes longueurs. La deuxieme partie sera consacree a la description du montage realise. Enfin dans la troisieme partie, nous discuterons les resultats obtenus. (auteur)}
place = {France}
year = {1961}
month = {Apr}
}