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Reheating experiment in the 35-ton pile; Experience de rechauffage sur la pile de 35 tonnes

Abstract

When the 35-ton pile was started up it was necessary for us, in order to study certain effects (xenon for example), to know the anti reactivity value of the rods as a function of their dimensions. We have made use of the possibility, in the reheating experiment, of raising the temperature of the graphite-uranium block by simple heating, in order to determine the anti reactivity curves of the rods, and from that the overall temperature coefficient. For the latter we have considered two solutions: first, one in which the average temperature of the pile is defined as our arithmetical mean of the different values given by the 28 thermocouples distributed throughout the pile; a second in which the temperature in likened to a poisoning and is balanced by the square of the flux. The way in which the measurements have been made is indicated, and the different instruments used are described. The method of reheating does not permit the separation of the temperature coefficients of uranium and of graphite. The precision obtained is only moderate, and suffers from the changes of various parameters necessary to other manipulations carried out simultaneously (life time modulators for example), and finally it is a  More>>
Authors:
Cherot, J; Girard, Y [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1957
Product Type:
Technical Report
Report Number:
CEA-R-670-L
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; BLOWERS; CALIBRATION; CONFIGURATION; CONTROL ELEMENTS; DUSTS; FUEL RODS; G-1 REACTOR; GRAPHITE; HEATING; POISONING; POSITIONING; PRESSURE COEFFICIENT; REACTIVITY; REACTOR CONTROL SYSTEMS; REACTOR LATTICE PARAMETERS; REACTOR START-UP; TEMPERATURE COEFFICIENT; THERMOCOUPLES; URANIUM; VAPOR CONDENSATION
OSTI ID:
20889973
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR07RL670054592
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
15 pages
Announcement Date:
Aug 10, 2007

Citation Formats

Cherot, J, and Girard, Y. Reheating experiment in the 35-ton pile; Experience de rechauffage sur la pile de 35 tonnes. France: N. p., 1957. Web.
Cherot, J, & Girard, Y. Reheating experiment in the 35-ton pile; Experience de rechauffage sur la pile de 35 tonnes. France.
Cherot, J, and Girard, Y. 1957. "Reheating experiment in the 35-ton pile; Experience de rechauffage sur la pile de 35 tonnes." France.
@misc{etde_20889973,
title = {Reheating experiment in the 35-ton pile; Experience de rechauffage sur la pile de 35 tonnes}
author = {Cherot, J, and Girard, Y}
abstractNote = {When the 35-ton pile was started up it was necessary for us, in order to study certain effects (xenon for example), to know the anti reactivity value of the rods as a function of their dimensions. We have made use of the possibility, in the reheating experiment, of raising the temperature of the graphite-uranium block by simple heating, in order to determine the anti reactivity curves of the rods, and from that the overall temperature coefficient. For the latter we have considered two solutions: first, one in which the average temperature of the pile is defined as our arithmetical mean of the different values given by the 28 thermocouples distributed throughout the pile; a second in which the temperature in likened to a poisoning and is balanced by the square of the flux. The way in which the measurements have been made is indicated, and the different instruments used are described. The method of reheating does not permit the separation of the temperature coefficients of uranium and of graphite. The precision obtained is only moderate, and suffers from the changes of various parameters necessary to other manipulations carried out simultaneously (life time modulators for example), and finally it is a function of the comparatively restricted time allowed. It is evident of course that more careful stabilisation at the different plateaux chosen would have necessitated long periods of reheating. (author) [French] Nous avions besoin lors de la montee en puissance de la pile de 35 tonnes, pour l'elude de divers effets (xenon par ex.) de la valeur de l'antireactivite des barres en fonction de leurs cotes. Nous avons profite dans l'experience rechauffage de la possibilite de monter en temperature, non nucleairement, le bloc graphite uranium, pour determiner les courbes d'antireactivite des barres et de la le coefficient global de temperature. Nous avons considere pour ce dernier deux solutions. Une premiere dans laquelle la temperature moyenne de la pile est definie comme moyenne arithmetique des differentes valeurs donnees par les 28 thermocouples eparpilles dans la pile. Une seconde dans laquelle la temperature est assimilee a un empoisonnement et se trouve ponderee par le carre du flux. Nous indiquons la fa n dont les mesures ont ete faites et citons les differents appareils utilises. Le mode de rechauffage ne permet pas la separation des coefficients de temperature de l'uranium et du graphite. La precision obtenue est mediocre et souffre des changements de divers parametres necessaires a d'autres manipulations realisees simultanement (modulateurs a temps de vie, par ex.), et enfin est fonction du temps relativement restreint accorde. Il est bien sur evident qu'une excellente stabilisation aux differents paliers choisis aurait entraine des durees de rechauffage considerables. (auteur)}
place = {France}
year = {1957}
month = {Jul}
}