Formation of Precipitate in High-Level Liquid Waste from Nuclear Fuel Reprocessing

SummaryImprovement of the nuclear fuel reprocessing involves separating the minor actinides (Am(III) and Cm(III)) from the fission products. In the French strategy, the first step consists in the separation of the trivalent actinides and lanthanides from high-level liquid waste, for which malonamides RR´NCO(CHR´´)CONRR´ are promising ligands. These molecules have been optimized for reprocessing but still require basic chemical studies to describe the complexation mechanisms at a molecular scale. This paper discusses a thermodynamic and structural study of a Ln(III)-malonamide complex formed with the hydrosoluble tetraethylmalonamide ligand (TEMA=(C

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Studies on hydrolysis and radiolysis of N,N,N′,N′-tetraoctyl-3-oxapentane-1,5-diamide

Radiochimica Acta ◽

10.1524/ract.2002.90.3_2002.161 ◽

2002 ◽

Vol 90 (3) ◽

Cited By ~ 106

Author(s):

Y. Sugo ◽

Y. Sasaki ◽

S. Tachimori

Keyword(s):

Gamma Irradiation ◽

Room Temperature ◽

Degradation Products ◽

Liquid Waste ◽

Amide Bond ◽

Radioactive Liquid Waste ◽

Ether Bond ◽

Nuclear Fuel Reprocessing ◽

High Level ◽

Fuel Reprocessing

SummaryHydrolytic and radiolytic stabilities of a promising extractant, N,N,N′,N′-tetraoctyl-3-oxapentane-1,5-diamide (TODGA), for actinides in high-level radioactive liquid waste from nuclear fuel reprocessing were investigated in air at room temperature. Hydrolysis by nitric acid was not observed, whereas radiolysis by gamma irradiation was notably observed. The radiolysis study showed that an amide-bond, an ether-bond, and a bond adjacent to the ether-bond tended to be broken by gamma irradiation, and dioctylamine and various N,N-dioctylmonoamides were identified as the main degradation products by GC/MS and NMR analyses. The

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Vitrification of HLW Produced by Uranium/Molybdenum Fuel Reprocessing in COGEMA’s Cold Crucible Melter

9th ASME International Conference on Radioactive Waste Management and Environmental Remediation: Volumes 1, 2, and 3 ◽

10.1115/icem2003-4594 ◽

2003 ◽

Cited By ~ 7

Author(s):

R. Do Quang ◽

V. Petitjean ◽

F. Hollebecque ◽

O. Pinet ◽

T. Flament ◽

...

Keyword(s):

Atomic Energy Commission ◽

Liquid Waste ◽

Glass Layer ◽

Cold Crucible ◽

High Level Liquid Waste ◽

Process Waste ◽

Glass Formulation ◽

High Level ◽

Fuel Reprocessing ◽

High Frequency Induction

The performance of the vitrification process currently used in the La Hague commercial reprocessing plants has been continuously improved during more than ten years of operation. In parallel COGEMA (industrial Operator), the French Atomic Energy Commission (CEA) and SGN (respectively COGEMA’s R&D provider and Engineering) have developed the cold crucible melter vitrification technology to obtain greater operating flexibility, increased plant availability and further reduction of secondary waste generated during operations. The cold crucible is a compact water-cooled melter in which the radioactive waste and the glass additives are melted by direct high frequency induction. The cooling of the melter produces a soldified glass layer that protects the melter’s inner wall from corrosion. Because the heat is transferred directly to the melt, high operating temperatures can be achieved with no impact on the melter itself. COGEMA plans to implement the cold crucible technology to vitrify high level liquid waste from reprocessed spent U-Mo-Sn-Al fuel (used in gas cooled reactor). The cold crucible was selected for the vitrification of this particularly hard-to-process waste stream because it could not be reasonably processed in the standard hot induction melters currently used at the La Hague vitrification facilities: the waste has a high molybdenum content which makes it very corrosive and also requires a special high temperature glass formulation to obtain sufficiently high waste loading factors (12% in molybednum). A special glass formulation has been developed by the CEA and has been qualified through lab and pilot testing to meet standard waste acceptance criteria for final disposal of the U-Mo waste. The process and the associated technologies have been also being qualified on a full-scale prototype at the CEA pilot facility in Marcoule. Engineering study has been integrated in parallel in order to take into account that the Cold Crucible should be installed remotely in one of the R7 vitrification cell. This paper will present the results obtained in the framework of these qualification programs.

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Production of Synroc Ceramics from Titanate Gel Microspheres

MRS Proceedings ◽

10.1557/proc-333-305 ◽

1993 ◽

Vol 333 ◽

Author(s):

Erden Sizgek ◽

J.R. Bartlett ◽

J.L. Woolfrey ◽

E.R. Vance

Keyword(s):

Spray Drying ◽

Nuclear Fuel ◽

High Level Waste ◽

Nuclear Fuel Reprocessing ◽

Controlled Porosity ◽

High Level ◽

Precursor Powders ◽

Fuel Reprocessing ◽

Titanate Ceramic

Synroc is a multi-component titanate ceramic, designed to immobilise High Level Waste (HLW) from nuclear fuel reprocessing plants [1]. Synroc precursor powders have been previously produced by various methods, such as oxide and alkoxide-hydrolysis routes [2]. However, various technological aspects of HLW processing make the use of free-flowing, dustfree, highly sinterable precursor powders desirable. Such powders have been produced by spray-drying colloidal precursors, yielding microspherical particles with controlled porosity.

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