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Recent progress in the detection of bursts in the canning in French reactors; Progres recents de la detection des ruptures de gaines dans les reacteurs francais G1, EL2, G3, EL3

Abstract

In piles cooled by pressurized carbon dioxide, type G{sub 3}, the chief radioactivity of the gas is that of nitrogen - 16 created by {sup 16}O (n, p) {sup 16}N reaction of the fact neutrons on the oxygen. This activity short-lived and with a high {beta} energy, masks the activity of fission gases escaping through a crack in the canning into the carbon dioxide, and makes it necessary to use a material method to separate the solid fission products before the detection proper. This detection is carried out by means of a special electronic system whose input is a scintillator associated with a photomultiplier. A system for measuring the evolution of a crack with compensation for power variations allows the speed of development of a crack to be followed. This instrument, baptised 'evolution-meter', is designed to make the measurement of the activity of the cooling gas in the canals by a zero method, and thus to be independent of: 1) the activity of the gas itself, left after discrimination of the fission products; 2) uranium pollution of the canning and eventual pollution of the canals after rapid splits in the canning. The 'evolution-meter' consists of a memory which stores canal  More>>
Authors:
Goupil, J; Grenon, M; Raffailhac, J; Roguin, A [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1959
Product Type:
Technical Report
Report Number:
CEA-R-1162
Resource Relation:
Other Information: 12 refs
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; ACTIVITY METERS; CARBON DIOXIDE; COUNTING RATES; CYCLONE SEPARATORS; DEGASSING; EL-2 REACTOR; EL-3 REACTOR; FAILED ELEMENT DETECTION; FISSION PRODUCT RELEASE; FUEL CANS; FUEL CHANNELS; FUEL ELEMENT FAILURE; G-1 REACTOR; G-3 REACTOR; GEIGER-MUELLER COUNTERS; PHOTOMULTIPLIERS; PLASTIC SCINTILLATION DETECTORS; PRIMARY COOLANT CIRCUITS; RADIATION MONITORS; REACTOR SAFETY
OSTI ID:
20912794
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR07R1162073970
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
51 pages
Announcement Date:
Sep 22, 2007

Citation Formats

Goupil, J, Grenon, M, Raffailhac, J, and Roguin, A. Recent progress in the detection of bursts in the canning in French reactors; Progres recents de la detection des ruptures de gaines dans les reacteurs francais G1, EL2, G3, EL3. France: N. p., 1959. Web.
Goupil, J, Grenon, M, Raffailhac, J, & Roguin, A. Recent progress in the detection of bursts in the canning in French reactors; Progres recents de la detection des ruptures de gaines dans les reacteurs francais G1, EL2, G3, EL3. France.
Goupil, J, Grenon, M, Raffailhac, J, and Roguin, A. 1959. "Recent progress in the detection of bursts in the canning in French reactors; Progres recents de la detection des ruptures de gaines dans les reacteurs francais G1, EL2, G3, EL3." France.
@misc{etde_20912794,
title = {Recent progress in the detection of bursts in the canning in French reactors; Progres recents de la detection des ruptures de gaines dans les reacteurs francais G1, EL2, G3, EL3}
author = {Goupil, J, Grenon, M, Raffailhac, J, and Roguin, A}
abstractNote = {In piles cooled by pressurized carbon dioxide, type G{sub 3}, the chief radioactivity of the gas is that of nitrogen - 16 created by {sup 16}O (n, p) {sup 16}N reaction of the fact neutrons on the oxygen. This activity short-lived and with a high {beta} energy, masks the activity of fission gases escaping through a crack in the canning into the carbon dioxide, and makes it necessary to use a material method to separate the solid fission products before the detection proper. This detection is carried out by means of a special electronic system whose input is a scintillator associated with a photomultiplier. A system for measuring the evolution of a crack with compensation for power variations allows the speed of development of a crack to be followed. This instrument, baptised 'evolution-meter', is designed to make the measurement of the activity of the cooling gas in the canals by a zero method, and thus to be independent of: 1) the activity of the gas itself, left after discrimination of the fission products; 2) uranium pollution of the canning and eventual pollution of the canals after rapid splits in the canning. The 'evolution-meter' consists of a memory which stores canal activity values taken at a given moment considered as a reference. The values of canal activity during the course of prospection are compared to this memory. A difference between the values indicates the appearance or the evolution of a crack in the canning. To account for the variations of thermodynamic running conditions in the canals, the values taken from the memory are corrected by a signal from an activity detector placed in the general circuit of gas leaving the pile. In the case of the pile EL{sub 2}, also cooled by pressurized CO{sub 2}, a method similar to that of G{sub 3}, has been used. Samples of cooling gas are taken successively in each of the 133 pile cells by the opening of electro-valves. The gas is filtered and the fission products extracted by an electrostatic collecting method. A scintillator and an electronic system provide a specific signal of the fission products which is then marked on a recorder. In a case where the activity threshold is exceeded, the cell involved is isolated from the prospection system and taker, over by a 'follow-up' detector which follows the evolution of the crack. A year of working on the pile G{sub 1}, which is cooled by air at atmospheric pressure, has made it possible to obtain results on the operation of the canning-burst detection appliance, which has led us to perfect the original device by installing an 'evolution-meter' of the type described above for G{sub 3}. The reactor EL{sub 3}, cooled by heavy water, uses a detection system based on the measurement by GM counters of the activity of the fission gases carried by diluted helium into the heavy water, then extracted by hydro-cyclones. The selectivity of the system gives it a low sensitivity to parasite activities, and an excellent performance. (author) [French] Dans les piles refroidies par gaz carbonique sous pression, du type G{sub 3}, la radioactivite principale du gaz est celle de l'azote 16 creee par reaction {sup 16}O(n, p) {sup 16}N des neutrons rapides sur l'oxygene. Cette activite, de vie courte et de forte energie {beta}, masque l'activite des gaz de fission s'echappant par une fissure de gaine dans le gaz carbonique et oblige a utiliser une methode de separation materielle des produits de fission solides avant la detection proprement dite. Cette detection est faite par une chaine electronique speciale dont l'entree est un scintillateur associe a un photomultiplicateur. Un systeme de mesure d'evolution de fissure avec compensation des variations de puissance permet de suivre la vitesse d'evolution d'une fissure. Cet appareil, baptise evolumetre, est destine a ramener a une methode de zero la mesure de l'activite du gaz de refroidissement des canaux, il permet de s'affranchir: 1) de l'activite propre du gaz restant apres la discrimination des produits de fission, 2) de la pollution d'uranium des gaines et de la pollution eventuelle des canaux apres ruptures de gaines rapides. L'evolumetre est constitue par une memoire qui stocke les valeurs de l'activite des canaux prises a un instant considere comme reference. A cette memoire, on vient comparer les valeurs de l'activite des canaux en cours de prospection. Une difference entre ces valeurs indique l'apparition ou l'evolution d'une fissure de gaine. Pour tenir compte des variations du regime thermodynamique dans les canaux, les valeurs extraites de la memoire sont corrigees par un signal provenant d'un detecteur d'activite place dans le circuit general de sortie du gaz de la pile. Dans le cas de la pile EL{sub 2}, egalement a refroidissement par CO{sub 2}, sous pression, une methode analogue a celle de G{sub 3} a ete utilisee. Des echantillons de gaz de refroidissement sont preleves dans chacune des 133 cellules de la pile successivement par l'ouverture d'electrovannes. Le gaz est filtre et les produits de fission sont extraits par une methode de collection electrostatique. Un scintillateur et une chaine electronique fournissent un signal specifique des produits de fission qui s'inscrit sur un enregistreur. Dans le cas d'un depassement du seuil d'activite, la cellule incriminee est isolee du systeme de prospection et prise en charge par un detecteur 'suiveur' qui permet de suivre l'evolution de la fissure. Une annee d'exploitation de la pile G1 qui est refroidie a l'air a la pression atmospherique a permis d'obtenir des resultats sur le fonctionnement du dispositif D.R.G. ce qui nous a amenes a perfectionner le dispositif initial en installant un evolumetre du type decrit ci-dessus pour G{sub 3}. Le reacteur EL{sub 3}, refroidi a l'eau lourde, utilise un systeme de detection base sur la mesure, au moyen de compteurs G.M., de l'activite des gaz de fission entraines par de l'helium dilue dans l'eau lourde puis extraits de celle-ci par des hydrocyclones. La selectivite du systeme lui confere une bonne insensibilite aux activites parasites et d'excellentes performances. (auteur)}
place = {France}
year = {1959}
month = {Jul}
}