Recent Activities on R&D of Innovative Extractants and - PowerPoint PPT Presentation

The Tenth OECD/NEA Information Exchange Meeting on Actinide and Fission Product Partitioning & Transmutation Mito, Japan, October 8, 2008 Recent Activities on R&D of Innovative Extractants and Adsorbents for Partitioning of Minor Actinides at JAEA Takaumi Kimura, Yasuji Morita, Yoshikazu Koma Japan Atomic Energy Agency, Japan 1

Outline ・ Introduction - Recent activities on aqueous partitioning at JAEA ・ Recovery of An(III) with RE by solvent extraction - TRUEX process - DGA extraction poster III-15 ・ Separation of An(III) from RE by solvent extraction - SETFICS process - New extractants (PDA) poster III-23 ・ Application of chromatographic technology - Extraction chromatography - Tertiary pyridine resin poster III-12 2

Two Concepts of P&T • Homogeneous recycling with commercialized FR – MA-MOX fuel with aqueous reprocessing – MA-bearing metal fuel with pyrochemical reprocessing • Double-strata concept with accelerator driven system – MA-bearing nitride fuel with pyrochemical reprocessing Similar technologies can be used for MA/FP partitioning. Homogeneous recycling Double strata concept 3

Separation Steps on Aqueous Partitioning Partitioning process can be constructed by combining several separation steps. Dissolution e.g., DIAMEX, e.g., SANEX, TRUEX TALSPEAK U selective U-Np-Pu An(III)+RE An(III)/RE Am/Cm separation co-recovery separation separation separation U U, Pu, Np RE Am Cm Cs-Sr separation FP Cs, Sr 4

Recent Activities on Aqueous Partitioning The other methods & technologies NEXT Process* ・ Precipitation by pyrrolidone Crystallization U selective ・ Solvent extraction by TBP (modified PUREX) separation ・ Solvent extraction by N,N-dialkylamide ・ Solvent extraction N,N-dialkylamide U-Np-Pu Co-extraction by co-recovery TBP ・ TRUEX (Solvent extraction by CMPO) Extraction An(III)+RE ・ Solvent extraction by DGA-extractants chromatography separation ・ Solvent extraction by DIDPA (CMPO, TODGA) ・ SETFICS (Extraction by CMPO with DTPA) Extraction ・ TALSPEAK (Extraction by DIDPA with DTPA) chromatography An(III)/RE ・ Solvent extraction (TPEN, TPA, PDA, BTP etc.) (BTP, HDEHP) separation ・ Extraction chromatography (PDA) ・ Tertiary Pyridine Resin-HCl-MeOH － ・ Tertiary Pyridine Resin-HNO 3 -MeOH Am/Cm separation － ・ Novel inorganic adsorbent (cation exchanger) Cs-Sr ・ Extraction chromatography separation 5 *Fast reactor cycle technology development (FaCT) project

An(III)+RE Separation: TRUEX Process • TRUEX is a promising process for TRU recovery from acidic solutions including a raffinate from PUREX- type solvent extraction. • “Salt-free” reagents are utilized for stripping/back extraction of highly extractable U and Pu as well as washing solvent. • Flowsheet proposed Hydrazine oxalate was demonstrated by a Hydrazine carbonate counter-current test using a real raffinate from FR “Joyo” fuel. “Salt-free” TRUEX flowsheet 6

An(III)+RE Separation: DGA Extraction(1/2) 40 JAEA developed a novel extractant, N,N,N’,N’-tetraoctyldiglycolamide 3+ ] extracted to org. phase / mM 35 (TODGA) for the recovery of actinides. 30 - Strong extractability for An(III) and An(IV) from higher HNO 3 solution 25 20 -High solubility in n-dodecane TODGA(n=8) TDDGA(n=10) 15 - High stability for hydrolysis and TDdDGA(n=12) radiation Aq.：3 M HNO 3 10 Org.：0.1 M DGA/ [Nd n-dodecane H 2 5 R 1 C CH 2 O R 1 N C 0 C N 0 20 40 60 80 100 R 2 O O R 2 3+ ] in aq. phase/ mM Initial [Nd Modification of the alkyl groups Extraction capacity of TODGA 7 attached to amidic nitrogen atoms was improved about five times.

An(III)/RE Separation: SETFICS Process SETFICS: Solvent Extraction for Trivalent f-elements Intra-group Separation in CMPO-complexant System • Improved flowsheet of TRUEX for light lanthanides separation was developed. • An(III) is selectively stripped with DTPA and nitrate solution after TRUEX-like extraction–scrubbing. • Flowsheet was successfully demonstrated to separate La, Ce, Pr and Nd, ≥ 90% of Ln(III), from An(III). 8

An(III)/RE Separation: New Extractants(1/2) - N-type donor extractant for An(III)/RE separation N N N R N N R N N N N N N N N N N N N R R R=Propyl BTP TPEN TPA PPDT TPTC BTP Separation in acidic solution is difficult. Chemical stability is rather low. - NO-type hybrid donor extractant for An(III)/RE separation PDA NO-donor type extractant Pyridine dicarboxyamide (PDA) Eu N C N H 3 C C N CH 3 O O R 1 =Ph R 2 =CH 9 hard donor soft donor Electronic structure of PDA molecule 3 (calculated by Gaussian98)

Extraction Chromatography(1/2) ・ SiO 2 -P: porous SiO 2 covered by SDB polymer ・ Resin: extactants （ CMPO,TODGA,BTP,HDEHP,etc ） immobilized in SiO 2 -P Cross section of The CMPO/SiO 2 -P resin the porous SiO 2 Extraction chromatography is under development as an alternative for solvent extraction with expectation of cost and waste generation. Packed column can be Separation tests for simulated HLLW by CMPO/SiO 2 -P resin operated under high 10 (Column 10 mm φ x 50 mm h, Flow rate 0.76 m/h, Temp. 323K) pressure for fast elution.

Extraction Chromatography(2/2) After the separation of U, Pu, Np An(III) ＋ RE An(III) ＋ RE CMPO Cs,Sr Ｚｒ An(III) BTP C/C 0 (Am) C/C 0 (RE) RE Am,Cm Volume of Effluent (CV) BTP 2,6-bis(1,2,4-triazin-3yl)-pyridine Am/RE separation by nBu-BTP column Column ： 10 mm φ× 260 mmH; Flow rate ： 1 cm 3 /min; 25 ° C BTP has high selectivity for Y.-Z. Wei, et al., J. Alloys & Compounds, 374, 447 (2004) . An(III), but quite unstable and 11 high cost.

Conclusion - Solvent extraction and extraction chromatography have mainly been investigated for the partitioning of MA at JAEA. - The selection of the extractant is an essential point to achieve the selective separation of An(III) in both cases. - A large number of compounds have been synthesized and tested, but the definitive one is not found yet from the viewpoint of the engineering level. - The efforts to develop and improve the innovative extractants should be continued to achieve the partitioning process of MA, especially for the 12 separation of An(III) from RE.