Plutonium processing composite

Experiences with aqueous chemistry and behavior of the transuranium elements obtained in nuclear fuel reprocessing and plutonium processing are only of limited relevance for PWR primary coolants with the extremely low concentrations of these elements in a boric acid—LiOH solution of varying composition. The plutonium polymers which are formed in less acid and neutral solutions and which have been reported to show the highest plate-out potential (e. g. Wilkins and Wisbey,... 

Ground-Water Composition and Its Relationship to Plutonium Transport Processes... 

In summary, the solubility and sorption reactions of cobalt, strontium, neptunium, plutonium, and americium were found to be dependent on HLW compositions. Evidence revealed the formation in HLW of organic complexes of cobalt, strontium, and americium, and of hydroxide complexes of neptunium(V) and plutonium(V). Sorption reactions were dependent on radioelement complex formation and suspected waste/sediment reactions. These data can aid in assessing effects of future HLW processing operations as well as in judging the feasibility of continued storage of HLW in existing tanks. 

Cleveland, J. M. Reese, T. F. Nash, K. L. "Groundwater Composition and Its Relationship to Plutonium Transport Processes Amer. Chem. Soc. Fall Annual Mtg. Kansas City, Sept. 1982, Abstracts of Papers (NUCL 37). 

An initial experiment involving the treatment of small irradiated Pu/Al targets for the production of americium 243 and curium 244 was carried out in France in 1968 (2). The chemical process was based essentially on the use of a system comparable to the Talspeak system. After plutonium extraction by a 0.08 M trilaurylammonium nitrate solution in dodecane containing 3 vol % 2-octanol, the actinides (americium, curium) were coextracted with a fraction of the lanthanides by a 0.25 M HDEHP -dodecane solvent from an aqueous solution previously neutralized by A1(N0 ) x(0H)x and adjusted to 0.04 M DTPA. The actinides were selectively stripped by placing the organic phase in contact with an aqueous solution of the composition 3 M LiN0 -0.05 M DTPA. While this experiment achieved the recovery of 150 mg of americium 243 and 15 mg of curium 244 with good yields, the process presented a drawback due to the slow extraction of Al(III) which saturates the HDEHP. This process was therefore abandoned. 

In the molten salt extraction process, the variables that control the values of the americium and plutonium distribution coefficients are temperature, metal composition, salt composition, and total americium. To minimize the variables, the extractions are conducted at a fixed temperature of about 750°C. Slight changes of magnesium content in the metal have a negligible effect upon the value of the americium and plutonium distribution coefficients. The effect of americium concentration... 

Prior to beginning actual plant processing, it was necessary to flush all tanks and pipes extensively to avoid contamination of the plutonium and the americium with plutonium of a different isotopic composition or with fission products or other impurities. Processing began only after analyses of the flush solutions confirmed the product contamination would be acceptably low. 

The aqueous waste from the CA Column (CAW) contains virtually all of the americium present in the feed. Table I shows the typical composition of the CAW stream. The exact composition of the stream depends on the composition of the CAF which is highly variable in a plutonium scrap processing plant. The CAW stream is the feed to the americium recovery solvent extraction system. 

Plutonium peroxide was investigated by Hamaker and Koch, (0 Hopkins, (2) and Koshland, et al. (3) in the 19 0 s and Leary (h) in the early 1950 s. This work showed that the composition of the precipitate varied and often incorporated anions from the solution from which it was precipitated. These investigations, as well as other work (5), also showed that the peroxide precipitate exists in both hexagonal and cubic crystalline forms. Although both forms are compounds of Pu(lV), they have slightly different O /Pu ratios (6). The cubic form can be colloidal and therefore is less suitable for process application than the hexagonal form. The acidity of the solution has an effect on the... 

The Purex process will continue to be the main method for the reprocessing of nuclear reactor fuels. The inherent flexibility of this process allows for modifications needed to accomodate a large range of fuel compositions and product specifications. Among the several plutonium partitioning methods developed, those avoiding the introduction of extraneous metal ions... 

Initial experiments were performed to verify and demonstrate the feasibility of the electrolytic reduction method with uranium, followed by experiments with a mixture of uranium and plutonium. Experiments were conducted batchwise in a small electrolytic cell. Basic parameters, such as concentration of solutes and type of holding agents (in the aqueous phase) for removal of any nitrite which would reoxidize the reduced heavy metal, electrode material and geometry, off-gas composition and type of diaphragm, were also determined. These data were valuable in the conceptual design of the first continuously operating column for the electrolytic reduction process. 

Aqueous Process. In 1967-68, a hot reprocessing test had been conducted using the spent fuel (ca. 600 MWD/T) from JRR-3 (Japan Research Reactor-3) (6). About 200 g of purified plutonium was recovered by a modified PUREX process from aluminum-claded uranium fuels of natural isotopic composition. 

The scraps which arise during the fabrication of plutonium-containing nuclear fuels are collected and stored for some time before they are processed to recover the plutonium. Due to the decay of Pu-241, considerable amounts of Am-241 may build up in the stored material. At the Alkem company, plutonium is recovered from the scrap by anion exchange the americium which is not sorbed on the resin is collected in the combined effluents from the loading and wash steps. The effluents are concentrated by evaporation besides americium, the concentrated effluents contain major amounts of uranium, plutonium, corrosion products, and residues from chemical reagents. A typical composition is given below ... 

Plutonium in this feed solution is removed by an anion exchange column process. The anion exchange resin is Dowex 1-X4, 50 to 80 mesh nitrate form, obtained from Bio-Rad Laboratories. Ferrous sulfamate is added to the solution to eliminate hexavalent plutonium, and the feed is passed through the column. The ion column effluent (ICE) contains the americium and impurities. Residual americium and impurities are washed from the column with 7M HNO3 anc t 1e was s combined with the ICE this is the feed to the bidentate process. A typical composition in g/1 is Am, 0.15 Pu, 8.2 x 10 3, Al,... 

Fuel composition may change from uranium to plutonium, and cladding from aluminum to zirconium to stainless steel. In some cases blankets, moderators, and coolants must be processed, and these will introduce thorium, beryllium, NaK, and bismuth to the chemical process. These changes in materials will present new chemical and corrosion problems in waste treatment processes and waste storage procedures. 

In Fig. 10.28 it is assumed that assemblies from the core and radial blanket are reprocessed in the proportion in which they are discharged from the reactor. The average composition of feed to the reprocessing plant then is 10 w/o plutonium, 3.56 w/o flssion products, and 86.44 w/o uranium. The 5000 kg of fuel processed per day is associated with 6858 kg of stainless steel and an indeterminate amount of metMlic sodium that coats exterior surfaces of the assembly and possibly has penetrated imperfections in some of the fuel rods. Sodium is used as... 

Figure 10.29 shows the principal steps in applying the Purex process to irradiated LMFBR fuel, step 7 of Fig. 10.28. The flow scheme and the compositions and locations of solvent, scrubbing, and stripping streams have been taken from the process flow sheet of a 1978 Oak Ridge report [Oil] describing a planned experimental reprocessing facility designed for 0.5 MT of uranium-plutonium fuel or 0.2 MT of uranium-plutonium-thoiium fuel per day. As that report gave process flow rates only for the uranium-plutonium-thorium fuel. Fig. 10.29 does not give flow rates for the uranium-plutonium fuel of present interest. This flow sheet shows the codecontamination step, in which flssion products are separated from uranium and plutonium the partitioning step, which produces an aqueous stream of partially decontaminated...

As an example. Table 8 presents data characteiizing a denaturation process (isotope composition changing) of weapons grade plutonium in BN-800 (reactor-burner) and WWER-1000 reactors. 

Table 3 equilibrium plutonium composition in the multi-recycling process in a CAPRA... 

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