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Recent progress in fission product separation; Progres recents de la separation des produits de fission

Abstract

Successful experiments have been done on the method described at Geneva in 1958. The process has been considerably improved: 1 - Initially, the caesium phospho tungstate precipitate was leached barium hydroxide in the centrifuge and this was followed by a distillation of ammonia in a concentrator. The barium hydroxide was then eliminated by carbonate precipitation and centrifugation. It has been proved that the ammonia distillation could be replaced by its evaporation during centrifugation, thus eliminating the need of a concentrator. It was then possible to carry out the carbonation on the solide-liquid mixture produced by the baryte water leaching. 2 - In applying the above process to the treatment of solutions derived from uranium molybdenum fuels, concentrating is to be recommended in order to hold the molybdenum in solution by complexing it with phosphoric acid. This complexing process provides a suspension of zirconium phosphate and ammonium phospho tungstate. These are separated by passing into a basic medium which precipitates the zirconium oxide, then turning back to an acid medium; the end of the treatment remains unchanged. 3 - Studies carried out in several countries on the exchange properties of hetero-polyacid salts have always met with difficulties as a result of  More>>
Authors:
Raggenbass, A [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-2640
Resource Relation:
Other Information: 5 refs
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; CESIUM 137; FISSION PRODUCTS; RARE EARTHS; SEPARATION PROCESSES; STRONTIUM 90
OSTI ID:
20668334
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR05R2640107035
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
16 pages
Announcement Date:
Dec 14, 2005

Citation Formats

Raggenbass, A. Recent progress in fission product separation; Progres recents de la separation des produits de fission. France: N. p., 1964. Web.
Raggenbass, A. Recent progress in fission product separation; Progres recents de la separation des produits de fission. France.
Raggenbass, A. 1964. "Recent progress in fission product separation; Progres recents de la separation des produits de fission." France.
@misc{etde_20668334,
title = {Recent progress in fission product separation; Progres recents de la separation des produits de fission}
author = {Raggenbass, A}
abstractNote = {Successful experiments have been done on the method described at Geneva in 1958. The process has been considerably improved: 1 - Initially, the caesium phospho tungstate precipitate was leached barium hydroxide in the centrifuge and this was followed by a distillation of ammonia in a concentrator. The barium hydroxide was then eliminated by carbonate precipitation and centrifugation. It has been proved that the ammonia distillation could be replaced by its evaporation during centrifugation, thus eliminating the need of a concentrator. It was then possible to carry out the carbonation on the solide-liquid mixture produced by the baryte water leaching. 2 - In applying the above process to the treatment of solutions derived from uranium molybdenum fuels, concentrating is to be recommended in order to hold the molybdenum in solution by complexing it with phosphoric acid. This complexing process provides a suspension of zirconium phosphate and ammonium phospho tungstate. These are separated by passing into a basic medium which precipitates the zirconium oxide, then turning back to an acid medium; the end of the treatment remains unchanged. 3 - Studies carried out in several countries on the exchange properties of hetero-polyacid salts have always met with difficulties as a result of the poor mechanical properties of these substances. This difficulty has been overcome by wrapping the ammonium phospho tungstate in a zirconium phosphate matrix. The exchanger obtained possesses: satisfactory mechanical properties, - a capacity of 0.1 milli equivalent per gram in concentrated nitric acid solution. It can be eluted and regenerated by a solution of an ammonium salt. The procedure for recovery of these various fission products is briefly the following: extraction of rare earths by di-2-ethyl hexyl phosphoric acid into dodecane at pH 2, the chemical impurities being complexed by citric acid, extraction of most of the magnesium at pH 4 by the same solvents the solvent being saturated with magnesium in order to avoid as far as possible the extraction of strontium, extraction of strontium at pH 4. (author) [French] La methode decrite a Geneve en 1958 a ete experimentee avec succes. Des ameliorations importantes ont ete apportees a ce procede: 1 - Initialement, la precipitation phosphotungstique du cesium etait suivie d'une reprise a la baryte en centrifugeuse et d'une distillation de l'ammoniac dans un concentrateur. Ensuite, l'hydroxyde de baryum etait elimine par precipitation carbonique et centrifugation. 1 - Il a ete prouve que la distillation de l'ammoniac pouvait etre remplacee par une evaporation au cours de la centrifugation, ce qui supprime le concentrateur. Il a ensuite ete possible d'effectuer la carbonatation sur le melange solide-liquide provenant de l'attaque a la baryte. 2 - Pour appliquer le precedent procede au traitement des solutions provenant des combustibles uranium-molybdene, nous avons recommande une concentration qui maintient en solution le molybdene par complexation par l'acide phosphorique. Cette complexation fournit une suspension de phosphate de zirconium et de phosphotungstate d'ammonium. Ils sont separes en repassant en milieu basique qui fait precipiter la zircone, puis en revenant en milieu acide, la suite du traitement restant le meme. 3 - Les etudes sur les proprietes d'echange des sels d'hetero-polyacides poursuivies dans plusieurs pays ont toujours rencontre l'ecueil des mauvaises qualites mecaniques de ces produits. Cette difficulte a ete surmontee en emprisonnant le phosphotungstate d'ammonium dans une matrice en phosphate de zirconium. L'echangeur obtenu possede: - des proprietes mecaniques satisfaisantes - une capacite de 0,1 milliequivalent par gramme en milieu acide nitrique concentre. II est eluable et regenerable par une solution d'un sel d'ammonium. Le schema de recuperation de ces differents produits de fission est succinctement le suivant: - extraction des terres rares par l'acide di-2-ethyl hexyl phosphorique-dodecane a pH 2, les impuretes chimiques etant complexees par l'acide citrique. - extraction de la majeure partie du magnesium a pH 4 par le meme solvant, le solvant travaillant a saturation de magnesium pour eviter au maximum l'extraction du strontium. - extraction du strontium a pH 4. (auteur)}
place = {France}
year = {1964}
month = {Jul}
}