Study on investigation of microbial effects for geological disposal, 2 (Joint research)

Tochigi, Yoshikatsu; Yoshikawa, Hideki; Aoki, Kazuhiro; Yui, Mikazu; Asano, Takahiro*; Honjo, Hideko*; Haginuma, Masashi*; Kawakami, Yasushi*; Suzuki, Kazunori*

JAEA-Research 2008-025, 55 Pages, 2008/03

JAEA-Research-2008-025.pdf:8.55MB

Results of joint research on fiscal year 2006 between Japan Atomic Energy Agency (JAEA) and Institute of Research and Innovative (IRI) titled as "Study on investigation of microbial effects for geological disposal" are described in this report. The objective of this study is to develop a method for estimating microbial effects for barrier performance of geological disposal site. The modeling was performed to examine the effect on the change in groundwater chemistry (mainly by electron acceptors) by microbial metabolism as well as microbial activities. In order to use the data (chemical composition, biomass, etc.) in the MINT code, groundwater was collected from the drilled well prepared for chemical and microbial analyses of groundwater. The well was prepared in observation field near Horonobe Underground Research Center of JAEA in fiscal year 2006. Then, numerical modeling using collected data of groundwater with numerical modeling program code "MINT" considering microbial effects was carried out. The modeling was carried out to evaluate the microbial effect for stability of chemical and microbial composition of groundwater. As the result of the modeling, relatively low microbial effect for groundwater composition was observed in particular for the concentration of dissolved methane, methanogen, sulfur reducing bacteria (SRB) and sulfur ion. The result shows that low redox potential is stable in the well in spite of shallow depth.

Study on simulation of salt accumulation (Joint research)

Fujita, Tomoo; Yui, Mikazu; Suzuki, Hideaki*; Fujisaki, Kiyoshi; Sazarashi, Masami*

JAEA-Research 2007-017, 47 Pages, 2007/03

JAEA-Research-2007-017.pdf:9.27MB

This report describes the results of a joint research entitled "Study on Simulation of Salt Accumulation" which was conducted under the collaboration between the Institute of Research and Innovation and the Japan Atomic Energy Agency. In the experiments for salt accumulation, accumulation of and was observed near the heater surface. Based on the facts from experiments, we have made hypothesis for mechanism of salt accumulation, and developed the model for it. Then, we conducted numerical simulations for salt accumulation phenomena under the saturated condition using the geochemical code "PHREEQC". It became clear that salt accumulation behavior can be evaluated qualitatively from these simulations, but quantitative evaluation requires more realistic modeling. Moreover we evaluated salt accumulation phenomena by simulations using coupled thermo - hydro - mechanical and chemical model / code assuming the unsaturated and / or saturated condition. A series of simulations were conducted focusing on accumulation of gypsum, and the result showed that tendency of salt accumulation phenomena was in agreement with that of experiments, but the profile of distribution of accumulated gypsum was not in agreement. In conclusion, it became clear that more realistic boundary condition should be considered and problems on coupled model / code were identified for further study.

Reliability improvement of hydro-geochemical and hydrogeological model on geological environment in Horonobe Underground Research Laboratory project; Report on the 2005 FY research (Joint research)

Hama, Katsuhiro; Kunimaru, Takanori; Kurikami, Hiroshi; Sasamoto, Hiroshi; Takahashi, Yasuhiro*; Haginuma, Masashi*; Ishii, Tomoko*; Matsuo, Yuji*

JAEA-Research 2006-070, 93 Pages, 2006/09

JAEA-Research-2006-070.pdf:23.48MB
JAEA-Research-2006-070(errata).pdf:0.08MB

Japan Atomic Energy Agency and Institute of Research and Innovation have started collaborative study in order to enhance the reliability of technology for the geological disposal of High-level Radioactive Waste (HLW) since 2005 fiscal year. In this collaborative study, the analysis has carried out to estimate long-term evolution of groundwater chemistry and groundwater flow. The study items and results are summarized in this report. (1) Groundwater Chemistry. The following items have been carried out: 1. Multivariate analysis. 2. Estimation of distribution of groundwater chemistry. 3. Construction of geochemical model. (2) Groundwater Flow: 1. Construction of geological model. 2. Construction of hydrogeological model. 3. Groundwater flow analysis. The modeling work will be continued in 2006 fiscal year. The applicability of the modeling methodology will also be evaluated.

Separation of trivalent actinides from lanthanides by using R-BTP resins and stability of R-BTP resin

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

Journal of Alloys and Compounds, 408-412, p.1274 - 1277, 2006/02

https://doi.org/10.1016/j.jallcom.2005.04.128

For the development of advanced aqueous reprocessing system, it is one of the most important subjects to separate minor trivalent actinides (MA = Am and Cm). Recently, extraction selectivity for MA(III) over Ln(III) 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). The novel silica-based extraction resins were prepared by impregnating some R-BTP molecules into a macroreticular styrene-divinylbenzene copolymer which is immobilized in porous silica particles with a mean diameter of 50 m. Separation of simulated high level liquid waste solution containing Ln(III) and trace amount of Am(III) was studied. Am(III) was mutually separated from Ln(III) through a packed column with R-BTP impregnating resin, very high decontamination factor ( 10) for Am, and all the elements were recovered quantitatively.

Study of Cs Recovery by Extraction Chromatography (2)

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

JNC TJ8400 2005-011, 20 Pages, 2005/02

JNC-TJ8400-2005-011.pdf:0.86MB

In order to apply CalixR14 extractant to extraction chromatography for Cs separation, basic characteristics of CalixR14 adsorbent were studied. CalixR14 impregnated resin and CalixR14 + TBP impregnated resin were prepared. CalixR14 extractant showed no adsorption for Cs by liquid-liquid extraction and CalixR14 impregnated resin also showed no adsorption for Cs. Therefore, it is concluded that CalixR14 itself has no affinity for Cs. On the other hand, Cs was adsorbed onto CalixR14-TBP impregnated resin from a concentrated nitric acid solution. The distribution coefficients of Cs were more than 10 cm/g from 2 to 6 M nitric acid. While Rb showed week adsorption, Na, K, Sr and La showed no adsorption and separation factor was over 199. A slight amount of CalixR14 and TBP was leaked from impregnated resin into the aqueous phase. Separation from simulated liquid waste was carried out by using a column packed with CalixR14-TBP adsorbent. Na, K, Sr and La were not adsorbed onto the column, however, Cs and Rb were adsorbed onto the column. Cs and Rb were eluted from the column by water. Cs and Rb were quantitatively recovered.

Experimental Study on a Novel Cation Exchanger (3)

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

JNC TJ8420 2004-001, 23 Pages, 2004/02

JNC-TJ8420-2004-001.pdf:1.01MB

The separation behavior of rare earth in simulated high-level liquid waste was examined by using a cation exchanger, which is synthesized by embedding a macroreticular resin containing sulfonic acid group as exchanger site in porous silica particles.

Experimental Study on Extraction Chromatography Using CMPO Adsorbent (3)

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

JNC TJ8410 2004-008, 27 Pages, 2003/12

JNC-TJ8410-2004-008.pdf:0.68MB

In order to investigate the possibility to realize an engineering system of extraction chromatographyusing CMPO adsorbent, experiments on CMPO leak and process flowsheet were carried out.

Experimental Study on a Novel Cation Exchanger (2)

Kuraoka, Etsushu*; Arai, Tsuyoshi*; Zhang, A.*

JNC TJ8420 2003-003, 25 Pages, 2003/02

JNC-TJ8420-2003-003.pdf:1.19MB

In order to study the applicability of the separation of Am, Cm and rare earths from each other by cation exchange technology, a novel silica-based cation exchanger (SiSCR) with sulfonic acid group as exchange site has been synthesized. Its thermo-decomposition property and the performance of adsorption, elution and separation for some rare earths were investigated.

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.

None

Kuraoka, Etsushu*; Arai, Tsuyoshi*

JNC TJ8420 2002-003, 35 Pages, 2002/03

JNC-TJ8420-2002-003.pdf:0.59MB

no abstracts in English