Plutonium nitrate

Uranium—Plutonium Partitioning". The uranium and plutonium are separated in the partitioning column by reducing the plutonium to a less extractable valence state. The plutonium nitrate transfers back to the aqueous phase and the uranium remains with the organic. 

Uranium. The uranium product from the PUREX process is in the form of uranyl nitrate which must be converted to some other chemical depending on anticipated use. One route to MO fuel is to mix uranium and plutonium nitrates and perform a coprecipitation step. The precipitate is... 

Plutonium. The plutonium nitrate product must be converted to MO fuel if it is to be recycled to lightwater reactors. Whether from a plutonium nitrate solution or a mixed U/Pu nitrate solution, the plutonium is typically precipitated as the oxalate and subsequendy calcined to the oxide for return to the fuel cycle (33). 

The Los Alamos MPL can accept either plutonium nitrate solution or plutonium oxide as feed. If the feed is the nitrate solution, then the process steps are precipitation of... 

Precipitation Processes. Plutonium peroxide precipitation is used at Rocky Flats to convert the purified plutonium nitrate solution to a solid (14) the plutonium peroxide is then calcined to Pu02 and sent to the reduction step. The chemistry of the plutonium peroxide precipitation process is being studied, as well as alternative precipitation processes such as oxalate, carbonate, fluoride, and thermal denitration. The latter method shows the most promise for cost and waste reduction. 

Moody JC, Stradling GN, Britcher AR. 1994. Biokinetics of three industrial plutonium nitrate materials Implications for human exposure. Radiat Prot Dosim 53(1-4) 169-172. 

Okabayashi H. 1980. Differential movement of plutonium and americium in lungs of rats following the inhalation of submicron plutonium nitrate aerosol. J Radiat Res 21 111-117. 

Polythene bottles are not suitable for long-term storage of plutonium nitrate solutions as radiation-induced stress cracks appeared in the bases of several 10 1 bottles during 6 months storage. Short-term storage and improved venting are recommended. 

Fig. l.a. Plutonium nitrate in 0.01M HNO3 was passed through a 25 nm membrane, 50 jil of the resulting solution was added to rat serum (1.5 ml) which contained dimethylsulphoxide (75 ii ). The solution was eluted from Sephadex G-25 (0.9 x 60 cm) with 0.1M 2-amino-2-hydroxymethyl-propane-l,2-diol/lM NaCl, pH 8.0. b. The above procedure was repeated with rat serum adjusted to contain 0.01M rhodotorulic acid, added as a dimethylsulphoxide solution, 75 til... 

The ability of 2,3-dihydroxybenzoyl-N-glycine to form a stable complex with plutonium is demonstrated in Fig. 2. In the absence of 2,3-dihydroxybenzoyl-N-glycine plutonium nitrate hydrolyzed and could not be eluted from the column. In the presence of 2,3-dihydroxybenzoyl-N-glycine the plutonium recovery averaged 80%. 

Figure 3. Enrichment of trivalent actinides over Pu(IV) across biological membranes. The assimilation of Am-241 and Cm-244 from the rat GI tract is greater than for plutonium. When plutonium nitrate is inhaled by dogs, daughter Am-241 is preferentially transported to the liver, resulting in depletion in lung and lymph nodes.

The Purex process, ie, plutonium uranium reduction extraction, employs an organic phase consisting of 30 wt % TBP dissolved in a kerosene-type diluent. Purification and separation of U and Pu is achieved because of the extractability of U02+2 and Pu(IV) nitrates by TBP and the relative inextractability of Pu(III) and most fission product nitrates. Plutonium nitrate and U02(N03)2 are extracted into the organic phase by the formation of compounds, eg, Pu(N03)4 -2TBP. The plutonium is reduced to Pu(III) by treatment with ferrous sulfamate, hydrazine, or hydroxylamine and is transferred to the aqueous phase U remains in the organic phase. Further purification is achieved by oxidation of Pu(III) to Pu(IV) and re-extraction with TBP. The plutonium is transferred to an aqueous product. Plutonium recovery from the Purex process is ca 99.9 wt % (128). Decontamination factors are 106 — 10s (97,126,129). A flow sheet of the Purex process is shown in Figure 7. 

Impure uranyl nitrate 5. Uranium- plutonium partition 11 Impure plutonium nitrate, ... 

Since publication of this work, Japanese researchers have undertaken an effort to demonstrate the feasibility of direct dissolution of U02 from spent nuclear fuels by the TBP-HN03 complex in SC-C02.49 Ultimately, the project is directed at the extraction of both uranium and plutonium from mixed oxide fuels and from irradiated nuclear fuel. Ideally, soluble uranyl and plutonium nitrate complexes will form and dissolve in the C02 phase, leaving the FPs as unwanted solids. As in the conventional... 

Fig. 7-11. Effect of raindrop size and acidity on the retention of (a) plutonium-citrate and (b) plutonium-nitrate by Phaseolus vulgaris foliage (redrawn from Cataldo et at., 1981).

Figure 2. Integrated flowsheet used at the ALKEM plant for plutonium nitrate conversion combined with 241 Am separation and conversion...

Plutonium is subsequently stripped to an aqueous phase containing NH20H HN03 in the CC Column. In order to increase the plutonium concentration of the CC Column product, a portion of this stream (CAIS) is recycled to the CA Column after adjustment with HNO3. The remainder of the stream (CCP) is routed to the product concentrator. The resulting concentrated and purified plutonium nitrate solution is suitable feed to other processes for conversion to the desired product form (e.g., metal or plutonium dioxide). The remainder of the PRF solvent extraction system consists of a series of columns to wash the TBP-CCI4 solvent and prepare it for reuse. 

Redox [Reduction oxidation] A process for separating the components of used nuclear fuel by solvent extraction. It was the first such process to be used and was brought into operation at Hanford, WA, in 1951, but was superseded in 1954 by the Purex process. The key to the process was the alternate reduction and oxidation of the plutonium, hence the name. The solvent was Hexone (4-methyl-2-pentanone, methyl wobutyl ketone), so the process was also known as the Hexone process. The aqueous phase contained a high concentration of aluminum nitrate to salt out the uranium and plutonium nitrates into the organic phase. The presence of this aluminum nitrate in the wastes from the process, which made them bulky, was the main reason for the abandonment of the process. See also Butex. 

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