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Part 1: The detection of criticality accidents in the Commissariat a l'Energie Atomique. Part 2: The Burst Slug Detection; 1. partie: la detection des accidents de criticite au Commissariat a l'Energie Atomique. 2. partie.: la detection des ruptures de gaines

Abstract

In all installations where fissionable materials are handled in quantities virtually greater than the critical mass, there exists permanent risk of accidental nuclear excursion entailing a serious irradiation hazard to the personnel, in spite of all the precautions that might be taken. Immediate detection followed by rapid evacuation greatly limits the risks of irradiation due to the fission products or to the sustained nuclear reaction. The necessity for a suitable equipment for the detection of accidents of criticality is imposed by the fact that the physical phenomena accompanying a nuclear, excursion are insufficient to follow the alarm, and may lead to confusion. Taking into account the accidents which have occurred and the role expected from a detector, we choose a dose integration device for the detecting probe proper, and a system based on the coincidence of several information to trigger the alarm. At the demand of the Commission des Masses Critiques, the minimal physical and electronic features required to obtain a very reliable system with minimal risk of false alarm has been established. These features are described in some detail. The equipment constructed at the Commissariat a l'Energie Atomique on the basis of these recommendations has been tested systematically under  More>>
Authors:
Debrie, G; Lavie, J; Planque, M [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1964
Product Type:
Technical Report
Report Number:
CEA-R-2652
Resource Relation:
Other Information: 9 refs
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; CEA; CRITICALITY; FAILED ELEMENT DETECTION; FUEL RODS; GAS COOLED REACTORS; RADIATION ACCIDENTS; RELIABILITY; SAFETY ENGINEERING
OSTI ID:
20668346
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR05R2652107047
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
25 pages
Announcement Date:
Dec 14, 2005

Citation Formats

Debrie, G, Lavie, J, and Planque, M. Part 1: The detection of criticality accidents in the Commissariat a l'Energie Atomique. Part 2: The Burst Slug Detection; 1. partie: la detection des accidents de criticite au Commissariat a l'Energie Atomique. 2. partie.: la detection des ruptures de gaines. France: N. p., 1964. Web.
Debrie, G, Lavie, J, & Planque, M. Part 1: The detection of criticality accidents in the Commissariat a l'Energie Atomique. Part 2: The Burst Slug Detection; 1. partie: la detection des accidents de criticite au Commissariat a l'Energie Atomique. 2. partie.: la detection des ruptures de gaines. France.
Debrie, G, Lavie, J, and Planque, M. 1964. "Part 1: The detection of criticality accidents in the Commissariat a l'Energie Atomique. Part 2: The Burst Slug Detection; 1. partie: la detection des accidents de criticite au Commissariat a l'Energie Atomique. 2. partie.: la detection des ruptures de gaines." France.
@misc{etde_20668346,
title = {Part 1: The detection of criticality accidents in the Commissariat a l'Energie Atomique. Part 2: The Burst Slug Detection; 1. partie: la detection des accidents de criticite au Commissariat a l'Energie Atomique. 2. partie.: la detection des ruptures de gaines}
author = {Debrie, G, Lavie, J, and Planque, M}
abstractNote = {In all installations where fissionable materials are handled in quantities virtually greater than the critical mass, there exists permanent risk of accidental nuclear excursion entailing a serious irradiation hazard to the personnel, in spite of all the precautions that might be taken. Immediate detection followed by rapid evacuation greatly limits the risks of irradiation due to the fission products or to the sustained nuclear reaction. The necessity for a suitable equipment for the detection of accidents of criticality is imposed by the fact that the physical phenomena accompanying a nuclear, excursion are insufficient to follow the alarm, and may lead to confusion. Taking into account the accidents which have occurred and the role expected from a detector, we choose a dose integration device for the detecting probe proper, and a system based on the coincidence of several information to trigger the alarm. At the demand of the Commission des Masses Critiques, the minimal physical and electronic features required to obtain a very reliable system with minimal risk of false alarm has been established. These features are described in some detail. The equipment constructed at the Commissariat a l'Energie Atomique on the basis of these recommendations has been tested systematically under actual conditions of nuclear excursions at the Health Physics Research Reactor of the National Laboratory at Oak Ridge. These tests have served to determine two types of detection probes which will be described: a photomultiplier and a semiconductor probe. Finally the authors present an example of a complete unit for the detection of criticality accidents in an installation for the processing of fissile material. B - The evolution of the installations for burst slug detection (BSD) in french reactors. The main part of the effort in the field of the Burst Slug Detection has been orientated on the large gas-cooled reactors where the problem of bursts slugs is associated with the economics of the plant. The techniques developed during this programme can be subsequently adapted to easily solve problems of detection in other types of reactor. The main characteristics of the evolution of the various installations constructed or under construction is reflected in the continuous progress towards greater automation and the use of detectors working under higher and higher temperatures and pressures. Succeeding to the reactor G3 whose BSD installation was already highly automatic, the EDF reactors at Chinon use digital computers especially meant for BSD data processing. In the planned reactor EL 4, the BSD measurements will be processed with all the other control measurements in a centralized computer unit. The progressive pressure increase of the cooling gas (15 bars in G3, 25 bars in the Chinon reactors, 60 bars in EL 4) has required the development of electric precipitations able to separate and measure the fission products in the carbonic gas at temperatures reaching 300 C and under pressures as high as 60 bars. In spite of the severe conditions of utilisation, the various devices developed offer all the guarantees of safety and long life expectancy required for their use on BSD installations. (authors) [French] Dans toute installation ou est manipulee de la matiere fissile en quantite potentiellement superieure a la masse critique, existe, quelles que soient les precautions prises, un risque permanent d'excursion nucleaire accidentelle, pouvant entrainer une irradiation grave du personnel. La detection immediate suivie d'une evacuation rapide limite considerablement les risques d'irradiation dus aux produits de fission ou a la reaction nucleaire elle-meme si elle se poursuit. Les phenomenes physiques qui accompagnent une excursion nucleaire, demeurant insuffisants pour suivre l'alarme et pouvant preter a confusion, la necessite d'un appareillage approprie de la detection des accidents de criticite s'impose donc. Compte-tenu des caracteristiques des accidents survenus et du role attendu d'un detecteur, le choix s'est porte sur un dispositif a integration de dose en ce qui concerne la sonde de detection proprement dite et sur un principe de la coincidence de plusieurs informations pour le declenchement de l'alarme. Les caracteristiques physiques et electroniques minimales d'un materiel garantissant un fonctionnement sur et limitant au maximum le risque de fausses alarmes etablies a la demande de la Sous-Commission des Masses Critiques sont exposees avec quelques details. Les materiels realises sur ces bases au Commissariat a l'Energie Atomique ont fait l'objet d'essais systematiques dans des conditions reelles d'excursion nucleaire aupres du Health Physics Research Reactor du Laboratoire National d'Oak Ridge. Ces essais ont permis de retenir deux principes de sondes de detection qui seront decrites: sonde a photomultiplicateur fonctionnant en courant et sonde a semi-conducteur. Enfin les auteurs presentent un exemple concret de realisation d'un equipement complet de detecteur des accidents de criticite dans une installation traitant de la matiere fissile. B - L'evolution des installations de detection des ruptures de gaines (DRG) dans les piles francaises. La majorite des efforts dans le domaine de la detection des ruptures de gaine a porte ces dernieres annees sur les grands reacteurs refroidis par gaz, ou le probleme des ruptures de gaine est lie a la rentabilite de la centrale. Une adaptation des techniques mises au point a cette occasion permet ensuite de resoudre facilement les problemes de detection pour les autres types de reacteurs. L'essentiel de l'evolution des diverses installations realisees ou en cours de realisation s'est traduit par une progression constante vers une plus grande automaticite et par l'utilisation de detecteurs fonctionnant sous des temperatures et des pressions de plus en plus elevees. Apres la pile G 3 qui possedait deja une installation tres automatique, on a vu apparaitre pour les piles de l'EDF a Chinon l'utilisation de calculateurs numeriques, affectes specialement a la DRG. Pour la pile EL 4 en projet, les mesures de DRG seront traitees, avec toutes les autres mesures du controle de la pile, dans une unite de calcul centralisee. L'augmentation progressive de la pression du gaz caloporteur (15 bars dans G3, 25 bars dans les piles de la Centrale de Chinon, 60 bars dans EL 4) a necessite la mise au point de detecteurs a collection electrique pouvant separer et mesurer les produits de fission presents dans le gaz carbonique, a des temperatures allant jusqu'a 300 C et sous des pressions atteignant 60 bars. Malgre les conditions severes d'utilisation, les divers appareillages mis au point offrent toutes les garanties de securite et de longevite requises pour leur utilisation sur les installations de DRG. (auteurs)}
place = {France}
year = {1964}
month = {Jul}
}