Neptunium Valence Chemistry in Anion Exchange Processing

Kyser, Edward A.

doi:10.2172/890227

Cited by 6 publications

(28 citation statements)

References 6 publications

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“…Also, note the appearance of characteristic Np 5+ peaks at 615 and 980 nm in low HNO 3 . While relatively small, the 615 nm Np 5+ peak has been used in past work to identify the presence of Np 5+ in 8 M HNO 3 (9). In the current study, a small amount of Np 5+ was observed during the loading step of Cr263 * .…”

Section: +mentioning

confidence: 52%

“…These samples were routinely analyzed by alpha PHA and gamma scan analyses to determine the activity from . They also ob- Figure 7 shows Np 4+ spectra in both low and high HNO 3 compared with reference Np 5+ spectra (9). Note that the major Np 4+ peak at 960 nm at low acid is shifted to 980 nm in 8 M HNO 3 .…”

Section: +mentioning

confidence: 89%

“…Resin Pretreatment: Like the earlier Np work (9,10,12,18), no resin pretreatment was performed to eliminate the low temperature exotherm. All resin that was tested came from the same 1998 manufacturer's lot (#80302MA) that was purchased by SRNL for Pu flowsheet work.…”

Section: Column Studiesmentioning

confidence: 99%

“…In a later study, Kyser (10) developed a modified flowsheet to accomplish a nominal 30 percent 238 Pu removal via reductive washing (sometimes referred to as partition). Based on previous work of Kyser (9) and also Burney (11), reductive wash conditions were proposed and tested. The recommended approach was to wash with 6 BVs of 6.4 M HNO 3 Pu removal is not significant to the effect of oxalate on the loading of Np onto the resin for the current study.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Oxalate on the Recycle of Neptunium Filtrate Solution by Anion Exchange

Kyser¹

2004

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Section: +mentioning

confidence: 52%

Section: +mentioning

confidence: 89%

Section: Column Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Oxalate on the Recycle of Neptunium Filtrate Solution by Anion Exchange

Kyser¹

2004

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“…Samples from this lot of resin had been previously used for the various ion exchange flowsheet studies for the Np project 9,10,11,12 . A sample of nitrate-form resin was filtered and air dried for to obtain a sample of dry resin that could be added by weight to the digestion experiments.…”

Section: Equipmentmentioning

confidence: 99%

Validation for the Permanganate Digestion of Reillex HPQ Anion Resin

Kyser¹

2009

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SummaryThe flowsheet for the digestion of Reillex™ HPQ was validated both under the traditional alkaline conditions and under strongly acidic conditions. Due to difficulty in performing a pH adjustment in the large tank where this flowsheet must be performed, the recommended digestion conditions were changed from pH 8-10 to 8 M HNO 3 . Thus, no pH adjustment of the solution is required prior to performing the permanganate addition and digestion and the need to sample the digestion tank to confirm appropriate pH range for digestion may be avoided. Neutralization of the acidic digestion solution will be performed after completion of the resin digestion cycle. The amount of permanganate required for this type of resin (Reillex™ HPQ) was increased from 1 kg/L resin to 4 kg/L resin to reduce the amount of residual resin solids to a minimal amount (<5%). The length of digestion time at 70 C remains unchanged at 15 hours. These parameters are not optimized but are expected to be adequate for the conditions. The flowsheet generates a significant amount of fine manganese dioxide (MnO 2 ) solids (1.71 kg/L resin) and involves the generation of a significant liquid volume due to the low solubility of permanganate. However, since only two batches of resin (40 L each) are expected to be digested, the total waste generated is limited.

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Conceptual Design for the Pilot-Scale Plutonium Oxide Processing Unit in the Radiochemical Processing Laboratory

Lumetta¹,

Meier²,

Tingey³

et al. 2014

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This report describes a conceptual design for a pilot-scale capability to produce plutonium oxide for use as exercise and reference materials, and for use in identifying and validating nuclear forensics signatures associated with plutonium production. This capability is referred to as the Pilot-scale Plutonium oxide Processing Unit (P3U), and it will be located in the Radiochemical Processing Laboratory at the Pacific Northwest National Laboratory. The key unit operations are described, including plutonium dioxide (PuO 2 ) dissolution, purification of the Pu by ion exchange, precipitation, and conversion to oxide by calcination. v SummaryThe National Technical Nuclear Forensics Center (NTNFC) has funded Pacific Northwest National Laboratory (PNNL) to establish a pilot-scale (up to 200 g Pu per batch) capability to produce plutonium oxide for use as exercise and reference materials, and for use in identifying and validating nuclear forensics signatures associated with plutonium production. This capability is referred to as the Pilot-scale Plutonium oxide Processing Unit, abbreviated as "P3U." The P3U will be established in Room 604 in the Radiochemical Processing Laboratory (RPL).The key unit operations for producing plutonium dioxide (PuO 2 ) are as follows. Plutonium will be received in the RPL in oxide form. The as-received oxide will be dissolved in nitric acid media. The resulting solution will be subjected to ion exchange to remove impurities from the Pu stream, and then the Pu will be precipitated in the form of a salt (e.g., oxalate, peroxide, hydroxide, or fluoride). This Pu salt will be converted back to PuO 2 by heating (calcining). In order to make this capability a useful tool for identifying and validating nuclear forensics signatures, the system will be designed to be flexible, allowing variations in the different process parameters (e.g., temperature, manner of reagent addition, type of precipitating agent, etc.). This report conceptually describes the P3U to be established at PNNL. The key features include  Plutonium oxide will be received and placed in a glovebox in RPL/Room 604. The PuO 2 will be dissolved in nitric acid media. Hydrofluoric acid will be added to aid in dissolution of the oxide. The dissolved Pu solution will be clarified by filtration and will then be purified by anion exchange using Reillex HPQ ® anion exchange resin. Although the design allows for a variety of Pu precipitation steps, the conceptual design is based on Pu(III) oxalate precipitation. The purified Pu solution is adjusted to the +3 oxidation state with ascorbic acid, then is treated with oxalic acid to precipitate Pu 2 (C 2 O 4 ) 3 •10H 2 O. The Pu(III) oxalate will be calcined in a muffle furnace to convert it to PuO 2 . The PuO 2 product will be packaged and distributed as directed by the NTNFC.Functional descriptions are provided for each unit operation, and the various requirements for these operations are identified in this report.vii

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Neptunium Valence Chemistry in Anion Exchange Processing

Cited by 6 publications

References 6 publications

Effect of Oxalate on the Recycle of Neptunium Filtrate Solution by Anion Exchange

Effect of Oxalate on the Recycle of Neptunium Filtrate Solution by Anion Exchange

Validation for the Permanganate Digestion of Reillex HPQ Anion Resin

Conceptual Design for the Pilot-Scale Plutonium Oxide Processing Unit in the Radiochemical Processing Laboratory

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