THE EUREX FLOWSHEET: PROCESSING OF IRRADIATED U-Al ALLOYS BY AMINE SOLVENT EXTRACTION
The possibility of using long chain tertiary amines as extracting agents in the recovery and decontamination of uranium from irradiated U-- Al alloys was investigated. Nitric acid dissolution of MTR type fuel elements yields a solution with a high Al/U molar ratio. Due to the salting but action of aluminum nitrate, uranium is easily extracted from the aqueous phase by a suitable tertiary amine-diluent system; fission products nitrates are much less extractable and good decontamination factors are attainable. Uranium partition coefficients and fission product decontamination factors are influenced by the concentration of nitric acid, aluminum nitrate, and uranyl nitrate. The chemical stability of the amine-diluent system in nitric acid and nitrates is excell ent in the experimental conditions of the flowsheet. High exposure rates result in a decreased Zr decontamination without causing retention of U in the organic phase: a suitable solvent clean up restores normal decontamination factors. The Eurex flowsheet is based on two separate extraction cycles: in both cycles the organic phase is 4 vol/% Alamine 336 in an aromatic hydrocarbon diluent. The salting out action in the second cycle is provided by adding aluminum nitrate to the scrub solution. The expected advantages of this flowsheet are connected with the higher selectivity of the amine solvent which permits higher decontamination factor and therefore a reduction of the number of extraction cycles. Savings in equipment, ancillary and analytical services, and hot cell space will lower both capital and operating costs. Based on the Eurex flowsheet a small size plant will be constructed to process MTR type fuel assemblies. (auth)
- Research Organization:
- Italy. Comitato Nazionale per l'Energia Nucleare
- NSA Number:
- NSA-17-023436
- OSTI ID:
- 4711025
- Report Number(s):
- RT/CHI(63)-3
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Italy
- Language:
- English
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