Application of a Dual-Column Method to Selectively Extract and Purify Berkelium-249 from Other Actinides and Impurities

Technical Report · Sun Sep 01 04:00:00 EDT 2019

DOI:https://doi.org/10.2172/1675053· OSTI ID:1675053

Du, Miting ^[1]; Tan, Ryan ^[2]; Boll, Rose ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. Univ. of Pittsburgh, PA (United States). Swanson School of Engineering

The super heavy element (SHE) Tennessine (Ts, Element 117) was discovered in 2016 a collaboration of US and Russian scientists vis bombardment reaction of ²⁴⁹Bk + ⁴⁸Ca $$\rightarrow$$ ₁₁₇Ts, while the target element ²⁴⁹Bk (half-life 330d) was produced and provided by the Radiochemical Engineering Development Center (REDC), Oak Ridge National Laboratory (ORNL). The production of ²⁴⁹Bk at REDC, ORNL requires a multi-step chemical process of irradiated curium feedstock target to remove all fission product (FP) elements and to separate ²⁴⁹Bk from other actinide (An) elements (Am, Cm, Cf, Fm and Es), including: Caustic Dissolution, Acid Dissolution, Cleanex, two LiCl Anion Exchanges, LiOH Precipitation, Cation Exchange with AHIB, and with Bk Finishing as the final Bk purification step. The major product of this campaign is ²⁵²Cf, while ²⁴⁹Bk is one of important by-products. The current Cf campaign for recovery of c.a. 15 mg of ²⁴⁹Bk per campaign (not including the time for Finishing of Cf, Fm and Es) takes 6 or 7 months, including ~3 months spent on Bk Finishing. Bk Finishing includes two major processes: (1) BERKEX, operated inside a hot cell with two cycles of batch solvent extraction (SX) using di-2-ethylhexyl phosphoric acid (HDEHP) as the extractant for tetravalent ²⁴⁹Bk from an 8 $$M$$ HNO₃-0.3 $$M$$ NaBrO₃ solution; and (2) Cation Exchange (CX) with AHIB (α-Hydroxy isobutyric acid), operated inside a glove box laboratory. Entire Bk Finishing takes five SX, more than five column runs and several drying down processes for aqueous solutions including one from 500 mL to 1 mL for volume reduction. To shorten the Bk Finishing period and simplify the Bk purification operation steps, possibilities of using other resin columns were explored.Recent trials using columns of either $LN$ resin or $MP$-1 anion exchange resin adsorbing the tetravalent ²⁴⁹Bk⁴⁺ in 8 $$M$$ HNO₃-0.5 $$M$$ NaBrO₃, followed by eluting impurities (e.g. Ce⁴⁺,Cf³⁺) and stripping ²⁴⁹Bk resulted in a new Dual Column Method of selectively separating ²⁴⁹Bk from other trans-plutonium elements and fission product (FP) impurities. This new method is proposed to replace the current Bk Finishing and provide increased Bk purification effeciency and a shorter processing period of 4 to 5 months (less decay loss for higher ²⁴⁹Bk productivity). This TM Report discusses the trial experimental results, describes the dual column method with relevant chemistry issues and possibilities being used in further process steps ahead of the Bk Finishing.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1675053
• Report Number(s): ORNL/TM-2019/1138
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY