Main findings, remaining uncertainties and lessons learned from the OECD/NEA BSAF Project

Pellegrini, M.*; Herranz, L.*; Sonnenkalb, M.*; Lind, T.*; Maruyama, Yu; Gauntt, R.*; Bixler, N.*; Morreale, A.*; Dolganov, K.*; Sevon, T.*; et al.

Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.1147 - 1162, 2019/08

Development of separation technology of transuranium elements and fission products by using new extractants and adsorbents; Development of separation technology of Cs and Sr (Contract research)

Hoshi, Harutaka; Kikuchi, Takahiro; Asakura, Toshihide; Morita, Yasuji; Kimura, Takaumi

JAEA-Research 2010-016, 70 Pages, 2010/07

JAEA-Research-2010-016.pdf:2.31MB

We have studied selective separation of Cs and Sr, which are included in high level liquid waste (HLLW) generated from reprocessing of spent nuclear fuel and are major heat generators, by using extractant impregnated adsorbents. Cs adsorbent using calix arane derivatives showed excellent selectivity for Cs. It also showed significant stability against -irradiation. Sr adsorbent using crown ether derivatives also showed high selectivity for Sr from nitric acid solution, except for Ba and Tc. Dynamic capacity decreased ca. 30% after -irradiation. Hot test using genuine HLLW stored in NUCEF was performed for separation of Cs and Sr through columns, respectively. Each Cs and Sr was separated from other typical fission product elements as well as the results obtained in preliminary experiments. Finally, Cs and Sr were separated according to a supposed separation scheme. Although some complexing agents were added in simulate HLLW, no negative effect was found.

Study on stability of CsSr solvent impregnated resin against irradiation

Hoshi, Harutaka; Kikuchi, Takahiro; Morita, Yasuji; Kimura, Takaumi

JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 24, 2009/12

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2009-041.pdf

Minimization of radioactive waste from reprocessing process of spent nuclear fuel is strongly desired. We develop an advanced technology for separation of heat generating elements (Cs and Sr) from high level waste to optimize radioactive waste by its characteristics. Some novel solvent impregnated resins (SIRs) were prepared and these SIRs indicated promising ability to separate Cs and Sr from other typical fission products dissolved in nitric acid solution. These adsorbents contacting with nitric acid solution were exposed to ray in a vial. After the irradiation, adsorbents were filtrated through a membrane filter. The adsorption capacity was examined by using irradiated adsorbents after drying. It is concluded that both SIRs maintained their high selectivity for Cs and Sr, respectively, after irradiation. Decreasing ratio of adsorption capacity by irradiation can be estimated from these results. It contributes significantly for conceptual design of separation plant.

A Hot test on minor actinides / lanthanides separation from HLLW using an R-BTP extraction resin

Wei, Y.*; Hoshi, Harutaka; Kumagai, Mikio*

Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10

To separate the long-lived minor actinides (MA=Am, Cm) from high level liquid waste, we have been studying an advanced separation process by extraction chromatography. The process consists of two separation columns packed with CMPO (octyl(phenyl)-N,N-diisobutylcarbamoyl-methyl phosphine oxide) extraction resin for elemental group separation and a soft-donor named R-BTP (2,6-bis-(5,6-dialkyl-1,2,4-triazine-3-yl)pyridine) extraction resin for the isolation of MA from lanthanides (Ln), respectively. In this work, a hot test for the separation of MA from MA containing effluent from the irradiated MOX-fuel treatment process was carried out using a column packed with R-BTP extraction resin. It was found that a complete separation between MA and Ln was achieved. In addition, small amounts of U and Pu remained in the MA-Ln effluent could be effectively recovered together with the MA. The test results indicate that the proposed MA separation process is essentially feasible.

Separation of minor actinides and lanthanides from nitric acid solution by R-BTP extraction resin

Hoshi, Harutaka*; Wei, Y.*; Kumagai, Mikio*; Asakura, Toshihide; Morita, Yasuji

Recent Advances in Actinide Science, p.596 - 598, 2006/06

Recently, extraction selectivity for trivalent minor actinides (MA = Am and Cm) over lanthanides (Ln) has been found in some extractants containing soft donor, such as S or N, ligands. Kolarik et al. reported that a new N-donor ligand 2,6-bis(5,6-dialkyl-1,2,4-triazine-3-yl)-pyridine (R-BTP) shows high selectivity for MA (III) over Ln(III) [1]. However, protonation of R-BTP results in its acidic hydrolysis in acidic medium. Stability in acidic solution was improved by substitution of long normal chain or branched chain [2]. In this work, separation of MA(III) and Ln(III) from nitric acid solution was studied by using novel R-BTP impregnated resin. Branched R-BTP resin had high affinity for Am from up to 4 M HNO solution and its distribution coefficient was over 10.

Development of the ERIX process for reprocessing spent FBR-MOX fuel; A Study on minor actinides separation process

Hoshi, Harutaka*; Wei, Y.*; Kumagai, Mikio*; Asakura, Toshihide; Morita, Yasuji

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10

For the development of nuclear fuel cycle, it is one of the most important tasks to improve reprocessing more economically and efficiently. Especially, to establish the Fast Breeder Reactor (FBR) cycle system for the future, it is strongly desirable to develop a new reprocessing which uses more compact equipments and produces less radioactive wastes compared to the present PUREX process. For this purpose, we have proposed a novel aqueous reprocessing system named ERIX Process to treat spent FBR-MOX fuels. This process consists of (1) Pd removal by selective adsorption using a specific anion exchanger; (2) electrolytic reduction for the valence adjustment of the major actinides including U, Pu, Np and some fission products (FP) such as Tc and Ru; (3) anion exchange separation for the recovery of U, Pu and Np using a new type of anion exchanger, AR-01; and (4) selective separation of long-lived minor actinides (MA = Am and Cm) by extraction chromatography. In this work, MA separation process was studied.

Electrolytic reduction of Tc(VII) in nitric acid solution using glassy carbon electrode

Hoshi, Harutaka*; Wei, Y.*; Kumagai, Mikio*; Asakura, Toshihide; Morita, Yasuji

Journal of Radioanalytical and Nuclear Chemistry, 262(3), p.601 - 605, 2005/01

https://doi.org/10.1007/s10967-005-0482-6

Electroreduction of Tc(VII) in nitric acid solution using grassy carbon electrode was studied. The electroreduction was conducted at a constant potential -300 mV (vs. Ag/AgCl) with a potentiostat. It was found that difference of the Tc concentration in the solutions before and after the electrolysis was negligibly small. This means that there were almost no TcO or Tc deposited on the carbon fiber electrode during the electroreduction. Absorption spectra and distribution coefficients obtained by ion-exchange analysis indicated that Tc(VII) was reduced to Tc(IV).

Experimental Study on the Basic Characteristics of TODGA Adsorbent

Hoshi, Harutaka*; Zhang, A.*; Kuraoka, Etsushu*; Yamaguchi, Hiromi*

JNC TJ8410 2004-001, 26 Pages, 2004/02

JNC-TJ8410-2004-001.pdf:1.16MB

In order to apply the extraction chromatography for trivalent actinides (Am and Cm) recovery process from high level liquid waste, the basic characteristics of TODGA adsorbent were experimentally studied.

Preparation of novel silica-based R-BTP extraction-resins and their application to trivalent actinides and lanthanides separation

Wei, Y.*; Hoshi, Harutaka*; Kumagai, Mikio*; Asakura, Toshihide; Uchiyama, Gunzo*

Journal of Nuclear Science and Technology, 39(Suppl.3), p.761 - 764, 2002/11

http://www.tandfonline.com/doi/abs/10.1080/00223131.2002.10875578

To separate long-lived minor actinides and specific fission products such as Zr and Mo from nitrate acidic high-level liquid waste, we studied an advanced partitioning process by extraction chromatography using minimal organic solvent and compact equipment. In this work, we synthesized several new type of nitrogen donor ligands, 2,6-bi-(5,6-dialkyl-1,2,4-triazine-3-yl)-pyridine (R-BTP) with different alkyl groups and prepared novel silica-based extraction-resins by impregnating these ligands into the SiO-P support with a diameter of 50 m. The adsorption performance of Am and Ln (III) from nitrate solution was investigated. It was found that the adsorption behavior depends strongly on the alkyl group in R-BTP. Bu-BTP/SiO-P and Hex-BTP/SiO-P showed high absorbability and selectivity for Am (III) over Ln (III). The separation factor is about 10 for Am/Ce and near 10 for Am/Eu-Gd, respectively. Effective Am (III) separation form Ln (III) by extraction chromatography using R-BTP/SiO-P extraction-resins is expected.

Elemental groups separation for high-level waste partitioning using a novel silica-based CMPO extraction-resin

Hoshi, Harutaka*; Wei, Y.*; Kumagai, Mikio*; Asakura, Toshihide; Uchiyama, Gunzo*

Journal of Nuclear Science and Technology, 39(Suppl.3), p.874 - 877, 2002/11

http://www.tandfonline.com/doi/abs/10.1080/00223131.2002.10875608

To facilitate the management of high-level liquid waste (HLLW) and minimize its long-term radiological risk in geologic disposal, we have proposed an advanced partitioning process by extraction chromatography using a minimal organic solvent and compact equipment to separate long-lived minor actinides (MA) and specific fission products (FP) such as Zr and Mo from nitrate acidic HLLW solution. Novel silica-based extraction-resin for elemental groups separation was prepared by impregnating CMPO (octyl(phenyl)-N, N-diisobutylcarbamoylmethylphosphine oxide) into a macro-reticular styrene-divinylbenzene copolymer immobilized in porous silica particles with a diameter of 50 m (SiO-P). Separation experiments for simulated HLLW solutions containing a trace amount of Am (III) and macro amounts of typical FP elements were carried out by column chromatography. It was found that the elements in the simulated HLLW were successfully separated to the following three groups: Cs-Sr-Rh-Ru, Pd-Ln-Am and Zr-Mo.