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Pegase: safety studies - experimental study of burn-out risks in transient operation; Pegase: etude de surete - etude experimentale des risques de burn out en regime transitoire

Abstract

An experiment out-of-pile experimental set up is proposed simulating the breakage of a pipe supplying the core of the reactor Pegase. The two fast phenomena, depressurization of the vessel and flow reversal, are reproduced. The aluminium heating channel has the same shape as that of the reactor channel but has twice the heat capacity. The starting conditions are V= 4.50 and 6 m/sec., T{sub E} = 50 and 60 degrees C and P{sub E} = 4 bars. The results show that the critical flux PHI{sub C} varies with the flow-rate from 45 to 60 W/cm{sup 2} in the case where there is no power reduction. For fluxes of 90 W/cm{sup 2} the results lead to the conclusion that the hot channel attains a state of burn-out after 0.1 sec. and that its temperature reaches 500 C in 0.8 sec. The hydrodynamic conditions in the channels after the accident involve periodic expulsion (0.2 to 0.5 sec.), characteristic of boiling at low pressure. A study of the steady state flow redistribution through a by-pass has given flux redistribution PHI{sub R} of 190 W/cm{sup 2} for a flow rate of 4.5 m/sec. at 50 and of 175 W/cm{sup 2} at 60 C. These  More>>
Authors:
Vernier, P [1] 
  1. Commissariat a l'Energie Atomique, Grenoble (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1968
Product Type:
Technical Report
Report Number:
CEA-R-3477
Resource Relation:
Other Information: PBD: 1968
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; BURNOUT; FUEL ELEMENTS; HEAT FLUX; HEAT TRANSFER; PEGASE REACTOR; PIPES; REACTOR ACCIDENTS; RISK ASSESSMENT; SAFETY ANALYSIS; SIMULATION
OSTI ID:
20547169
Research Organizations:
CEA Grenoble, 38 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR04R3477002776
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
[87] pages
Announcement Date:
Feb 01, 2005

Citation Formats

Vernier, P. Pegase: safety studies - experimental study of burn-out risks in transient operation; Pegase: etude de surete - etude experimentale des risques de burn out en regime transitoire. France: N. p., 1968. Web.
Vernier, P. Pegase: safety studies - experimental study of burn-out risks in transient operation; Pegase: etude de surete - etude experimentale des risques de burn out en regime transitoire. France.
Vernier, P. 1968. "Pegase: safety studies - experimental study of burn-out risks in transient operation; Pegase: etude de surete - etude experimentale des risques de burn out en regime transitoire." France.
@misc{etde_20547169,
title = {Pegase: safety studies - experimental study of burn-out risks in transient operation; Pegase: etude de surete - etude experimentale des risques de burn out en regime transitoire}
author = {Vernier, P}
abstractNote = {An experiment out-of-pile experimental set up is proposed simulating the breakage of a pipe supplying the core of the reactor Pegase. The two fast phenomena, depressurization of the vessel and flow reversal, are reproduced. The aluminium heating channel has the same shape as that of the reactor channel but has twice the heat capacity. The starting conditions are V= 4.50 and 6 m/sec., T{sub E} = 50 and 60 degrees C and P{sub E} = 4 bars. The results show that the critical flux PHI{sub C} varies with the flow-rate from 45 to 60 W/cm{sup 2} in the case where there is no power reduction. For fluxes of 90 W/cm{sup 2} the results lead to the conclusion that the hot channel attains a state of burn-out after 0.1 sec. and that its temperature reaches 500 C in 0.8 sec. The hydrodynamic conditions in the channels after the accident involve periodic expulsion (0.2 to 0.5 sec.), characteristic of boiling at low pressure. A study of the steady state flow redistribution through a by-pass has given flux redistribution PHI{sub R} of 190 W/cm{sup 2} for a flow rate of 4.5 m/sec. at 50 and of 175 W/cm{sup 2} at 60 C. These values increase which has to be made between the critical flux PHI{sub C} during the periodic expulsion conditions and the flux redistribution PHI{sub R} during the steady state, has been shown. (author) [French] On propose un schema experimental hors pile d'une rupture du tuyau alimentant le coeur du reacteur PEGASE. On reproduit les phenomenes rapides de depressurisation du caisson et d'inversion du debit dans le coeur. Le canal chauffant en aluminium a la meme geometrie que le canal du reacteur, mais une capacite calorifique double. Les conditions initiales sont V= 4.5 et 6 m/s, T{sub E} = 50 et 60 C et P{sub E} = 4 bars. Les resultats montrent que le flux critique PHI{sub C} evolue avec la vitesse de 45 a 60 60 W/cm{sup 2} dans le cas ou il n'y a pas reduction de puissance. Pour des flux de 90 W/cm{sup 2} l'interpretation des resultats permet de conclure que le canal chaud se met en etat de calefaction au bout de 0.1 s et que sa temperature atteint 500 C en 0.8 s. Les regimes hydrodynamiques rencontres dans les canaux apres l'accident sont des regimes d'expulsion periodiques de periodes courtes 0.2 a 0.5 s, caracteristiques de l'ebullition a basse pression. L'etude en regime permanent de la redistribution de debit dans un by-pass a donne des flux PHI{sub R} de redistribution de 190 W/cm{sup 2} pour une vitesse de 4.5 m/s a 50 C et de 175 W/cm{sup 2} a 60 C. Ces valeurs sont a majorer de 25 pour cent pour une vitesse de 6 m/s. On a montre la distinction a faire entre flux critique PHI{sub C} en regime periodique d'expulsion et flux de redistribution PHI{sub R} en regime permanent. (auteur)}
place = {France}
year = {1968}
month = {Jul}
}