Annual Report 2009/2010 - JUWEL - Forschungszentrum Jülich

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5.5. 1-cycle SANEX process development studies and lab-scale demonstrations for the direct recovery of trivalent actinides from PUREX raffinate A. Wilden, M. Sypula, C. Schreinemachers, J. Assenmacher, S. Gülland, G. Modolo Corresponding author: a.wilden@fz-juelich.de Abstract The direct selective extraction of trivalent actinides from a simulated PUREX raffinate solution (1-cycle SANEX) was studied using a mixture of CyMe 4 BTBP and TODGA. The solvent showed a high selectivity for trivalent actinides with a high lanthanide separation factor. However the co-extraction of some fission products, such as Cu, Ni, Zr, Mo, Pd, Ag and Cd was observed. The extraction of Zr and Mo could be suppressed using oxalic acid but the use of the well-known Pd complexant HEDTA was unsuccessful. During screening experiments with different amino acids, the sulphur-bearing amino acid L-cysteine showed good complexation of Pd and prevented its extraction into the organic phase without influencing the extraction of trivalent actinides. The development of a process-like batch extraction series and a continuous counter-current test using a single centrifuge contactor showed very promising results in view of further optimizing the process. A strategy for a single-cycle process is proposed within this paper. Introduction The development of new and innovative processes for the processing of spent nuclear fuel solutions is a very intensively studied topic in nuclear research all over the world [1, 2]. As the liquid aqueous waste solution from reprocessing contains approx. 40 different elements in concentrations ranging from a few milligrams up to several grams per litre, the selective separation of trivalent actinides from this multi-element solution is one of the most challenging problems. The separation of the trivalent actinides from the lanthanides is a particularly difficult step, as the two groups of f-elements have very similar chemical properties. In Europe, the DIAMEX-SANEX (DIAMide EXtraction - Selective ActiNide EXtraction) partitioning process is one of the most promising strategies to be converted from lab scale to industrial scale. The first step of this process (DIAMEX) uses a diamide extractant to coextract lanthanides and minor actinides from the highly acidic PUREX (Plutonium-Uranium Recovery by EXtraction) raffinate [3, 4]. In the subsequent step (SANEX), the trivalent actinides are separated from the lanthanides e.g. by the highly selective CyMe 4 BTBP extractant [5, 6]. A drawback of such a process design is the need for two separate processes using two different ligands. Within the current European project ACSEPT (Actinide reCycling by SEParation and Transmutation), a new process design is envisaged, the socalled “innovative-SANEX” concept. In this strategy, the trivalent actinides and lanthanides are co-extracted in a DIAMEX-type process. Then, the loaded solvent is subjected to several stripping steps. The first one concerns selectively stripping the trivalent actinides with selective water-soluble ligands followed by the subsequent stripping of trivalent lanthanides [7]. 57
A more challenging route studied within this paper is the direct actinide (III) separation from the PUREX raffinate using a mixture of CyMe 4 BTBP and TODGA (structures shown in Fig. 37) as extractants, the so-called 1-cycle SANEX process. A single process directly using the PUREX raffinate would reduce the number of cycles, thus saving the DIAMEX process, making the complete advanced reprocessing process more economical and easier. O O C 8 H 17 N O N C 8 H 17 C 8 H 17 C 8 H 17 N N N N N N N N TODGA N,N,N',N'-tetraoctyldiglycolamide Fig. 37: Structures of TODGA, CyMe4BTBP and HEDTA. CyMe 4 BTBP 6,6'-Bis ( 5,5,8,8-tetramethyl- 5,6,7,8-tetrahydrobenzo [ 1,2,4] -triazin-3- yl) - [2,2'] -bipy ridine HO O OH N N O O OH OH HEDTA N- ( 2-Hydroxyethyl) -ethylendiamin- N,N',N'-triacetic acid Geist et al. have shown the CyMe 4 BTBP molecule to be a very selective extractant for the separation of actinides from lanthanides [8]. Magnusson et al. demonstrated the performance of CyMe 4 BTBP in a hot SANEX test using 0.25 mol/L of the malonamide DMDOHEMA as phase transfer reagent [5]. The use of a phase transfer reagent is necessary owing to the slow kinetics of the CyMe 4 BTBP-molecule which can be significantly improved by the use of DMDOHEMA. Modolo et al. recently proposed that 0.25 mol/L DMDOHEMA can be substituted with 0.005 mol/L TODGA [9]. This system shows comparably good extraction properties and kinetic behaviour compared to DMDOHEMA, and the performance of the system was demonstrated in a spiked test. Both experiments used a DIAMEX raffinate solution containing actinides and lanthanides as a SANEX feed solution for the experiments. After a 20-stage counter-current process, an actinide product fraction containing >99.9% of the actinides with less than 0.1% lanthanides was obtained. Despite these very successful tests, the question arose as to whether it would be possible to directly and selectively extract the actinides from a PUREX raffinate solution leaving the lanthanides and the other fission products in the aqueous phase. Results and discussion Batch extraction studies in 2 mL glass vials were carried out with a synthetic PUREX raffinate solution. An organic phase consisting of 0.015 mol/L CyMe 4 BTBP and 0.005 mol/L TODGA diluted in a mixture of TPH and 1-octanol (40/60 v/v) was used as solvent. The composition of the synthetic PUREX raffinate solution and the corresponding distribution ratios of the elements for the extraction without adding any complexants are given in Tab. 7 (see column 3). 58
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Mitglied Mitglied der der Helmholtz
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Forschungszentrum Jülich GmbH Inst
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TABLE OF CONTENTS 1 Preface .......
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6.2.2 Doctoral Thesis .............
Page 11 and 12: state of NRW. The collaborative pro
Page 13 and 14: 2 Institute’s Profile Due to the
Page 15 and 16: 2.2. Organization chart Reactor Saf
Page 17 and 18: 3 Key Research Topics 3.1. Long Ter
Page 19 and 20: actinide co-conversion into polyact
Page 21 and 22: Fig. 7: Non-destructive analytical
Page 23 and 24: Fig. 9: Thermal treatment of an AVR
Page 25 and 26: 3.8. Product Quality Control of Rad
Page 27 and 28: 3.8.2 Product Quality Control of Lo
Page 29 and 30: The advantage of working at low vac
Page 31 and 32: NdPO 4 powder sample, directly rece
Page 33 and 34: 4.5. Non-destructive assay testing
Page 35 and 36: 5 Scientific and Technical Reports
Page 37 and 38: Results and Discussion The irradiat
Page 39 and 40: work will focus on the identificati
Page 41 and 42: Different solvents (iso-propanol an
Page 43 and 44: e & j) Aggregates of aluminium oxid
Page 45 and 46: Experimental details The corrosion
Page 47 and 48: Intensity [CPS] 500 400 300 200 100
Page 49 and 50: Fig. 24: Left: High resolution TEM
Page 51 and 52: a) MD model [10] b) Derived Lesukit
Page 53 and 54: 5.4. Minor actinide(III) recovery f
Page 55 and 56: Extensive extraction studies were p
Page 57 and 58: of the extraction properties of the
Page 59 and 60: Cm(III) together with the lanthanid
Page 61: using a mixture of CyMe4BTBP and TO
Page 65 and 66: These preliminary results show that
Page 67 and 68: The 1-cycle SANEX process is intend
Page 69 and 70: Continuous counter-current tests us
Page 71 and 72: Conclusion In this work, it was sho
Page 73 and 74: shaken by a vortex mixer for 15 min
Page 75 and 76: 100 100 Distribution ratio 10 1 0.1
Page 77 and 78: Tab. 15: The distribution ratios of
Page 79 and 80: 5.7. Synthesis and thermal treatmen
Page 81 and 82: Acid-Deficient Uranyl-Nitrate via d
Page 83 and 84: Optical investigation showed a noti
Page 85 and 86: TG /% 100 98 96 94 92 90 88 86 84 8
Page 87 and 88: Radiolysis in the aqueous solutions
Page 89 and 90: is about 4% while the one of the rh
Page 91 and 92: Fig. 59: Compressibility curve for
Page 93 and 94: Conclusion and outlook Monazite-typ
Page 95 and 96: Fig. 63: Description of the unit ce
Page 97 and 98: agents for the synthesis of neodymi
Page 99 and 100: 100 TG 785°C Exo DSC 0,2 0,0 90 -0
Page 101 and 102: After synthesis the product was cen
Page 103 and 104: process of monazite and additional
Page 105 and 106: Tab. 18: Lattice parameters determi
Page 107 and 108: Conclusions For Sm 1-x Ce x PO 4 mo
Page 109 and 110: 5.11. Raman Spectra of Synthetic Ra
Page 111 and 112: The numerical values of all measure
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knowledge, these special relationsh
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Fig. 80: Raman spectra of LaPO 4 ir
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5.12. MC simulation of thermal neut
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content was replaced by hydrogen. C
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constant for hydrogen concentration
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with a 0 1 -183.88 ± 8.55 and a 2
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5.13. An Improved Method for the no
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2 2 2 d0 R ds d0 dw la( )
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The relative uncertainty for the ac
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In the drum, 4 ‘hot spots’ for
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activity of Cs-137 is much more und
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gamma-ray detector approximated by
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shown in Fig. 96. In both cases the
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econstruction than the old calculat
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Neutron capture cross sections and
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Outlook The evaluated data will be
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from carbon-based HTR fuel elements
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Fig. 102: 3D volume reconstructions
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dislocate the 14 C atom from its pr
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It can be seen that nearly all trit
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Acknowledgement The authors like to
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development by investigations of ga
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Fig. 109: The left picture shows th
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[2] A European Roadmap for Developi
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from airborne SWIR Full Spectrum Im
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Fig. 113: Visualization of the vege
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number of training samples up to 19
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Acknowledgements The work presented
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three approaches has severe drawbac
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neighbours from the list of merge c
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it gives a difference in segmentati
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[6] I. Niemeyer, F. Bachmann, A. Jo
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Monitoring 3 cooperated intensively
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facilities and other treaty related
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parameters of the SAR system, such
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The MGD products used in the study
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Fig. 134 contains the result for th
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[2] H. Maître (ed.), Processing of
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Preparatory Committee to allocate t
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unconditional security assurances f
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safeguards was also requested. Deci
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[16] United Nations Security Counci
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5.24. Development and Application o
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Hardware layer The hardware layer i
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So in most applications the scale u
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The ENDF-B/V and ENDF-B/VI librarie
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5.26. Product control of waste prod
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Polysiloxane which has been investi
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acceptance requirements [3]. In the
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Fig. 145: List of description and d
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6.1. Courses taught at universities
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Umwelt / Energy & Environment 2010;
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6.5. Institute Seminar The IEK-6 or
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6.5.3 Invited talks 2009 30.04.2009
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21.09.2010 Dr. N. Evans: The Chemis
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8 Selected R&D projects 8.1. EU pro
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K. Aymanns: Nominated as deputy re
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Bukaemskiy A.A., Barrier D., Modolo
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11.2. Publications 2009 11.2.1 Jour
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Rezniczek, A.; Richter, B.; Jussofi
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Daniels, H.: Co-conversion of actin
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11.3. Publications 2010 11.3.1 Jour
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Sypula, M.; Wilden, A.; Schreinemac
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(Partitioning) - Stabilitätsunters
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Modolo, G.; Bosbach, D.; Geist, A.;
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12 How to reach us Postal Address F
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By train: Take the train from Aache
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Schriften des Forschungszentrums J
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