Molecular geochemistry of radium; A key to understanding cation adsorption reaction on clay minerals

Yamaguchi, Akiko; Kurihara, Yuichi*; Nagata, Kojiro*; Tanaka, Kazuya; Higaki, Shogo*; Kobayashi, Toru; Tanida, Hajime; Ohara, Yoshiyuki*; Yokoyama, Keiichi; Yaita, Tsuyoshi; et al.

Journal of Colloid and Interface Science, 661, p.317 - 332, 2024/05

https://doi.org/10.1016/j.jcis.2024.01.120

no abstracts in English

Fe, Mn and U accumulations in naturally growing at the mill tailings pond; Iron plaque formation possibly related to root-endophytic bacteria producing siderophores

Nakamoto, Yukihiro*; Doyama, Kohei*; Haruma, Toshikatsu*; Lu, X.*; Tanaka, Kazuya; Kozai, Naofumi; Fukuyama, Kenjin; Fukushima, Shigeru; Ohara, Yoshiyuki; Yamaji, Keiko*

Minerals (Internet), 11(12), p.1337_1 - 1337_17, 2021/12

https://doi.org/10.3390/min11121337

Mine drainage is a vital water problem in the mining industry worldwide because of the heavy metal elements and low pH. Rhizofiltration using wetland plants is an appropriate method to remove heavy metals from the water via accumulation in the rhizosphere. is one of the candidate plants for this method because of metal accumulation, forming iron plaque around the roots. At the study site, which was the mill tailings pond in the Ningyo-toge uranium mine, has been naturally growing since 1998. The results showed that accumulated Fe, Mn, and U in the nodal roots without/with iron plaque compared with other plant tissues. Among the 837 bacterial colonies isolated from nodal roots, 88.6% showed siderophore production activities. Considering iron plaque formation around roots, we hypothesized that microbial siderophores might influence iron plaque formation because bacterial siderophores have catechol-like functional groups. The complex of catechol or other phenolics with Fe was precipitated due to the networks between Fe and phenolic derivatives. The experiment using bacterial products of root endophytes, such as spp. and spp., showed precipitation with Fe ions, and we confirmed that several spp. and spp. produced unidentified phenolic compounds. In conclusion, root-endophytic bacteria such as spp. and spp., isolated from metal-accumulating roots of , might influence iron plaque formation as the metal accumulation site. Iron plaque formation is related to tolerance in , and spp. and spp. might indirectly contribute to tolerance.

Changes in groundwater flow after remediation with capping for the Upstream of Mill Tailings Pond at Ningyo-toge Environmental Engineering Center

Nishida, Nobuho; Ohara, Yoshiyuki; Kawamoto, Tsutomu

Heisei-28-Nendo Zenkoku Kozan, Seirenjo Gemba Tantosha Kaigi Shigen/Shinzozai Koenshu, p.69 - 74, 2016/06

Japan Atomic Energy Agency Ningyo-toge Environmental Engineering Center, has been conducting environmental remediation of the Ningyo-toge mine and Togo mine, after decades of mine-related activities including uranium exploration, mining and test milling were terminated, with doing safety measure, under Mining Safety law. As the one, culvert installation and multi-layered capping were performed at Upstream of Yotsugi Mill Tailings Pond to inspect about stability of multi-layered capping with checking rainwater infiltration restraint and radon dissipation inhibiting effect, from FY 2011 to FY 2012. And it was presumed possibility of amount of underground water is increased, as result of fluctuation numerical analysis for Upstream of Yotsugi Mill Tailings Pond before and after the multi-layered capping, and the water level of bowling holes around the Pond and spring water which flows from lower place of the Pond. But a culvert possesses enough drainage function and groundwater does not rise to the multi-layered capping part. Therefore, it is considered that there isn't problem to the stability of the current state of the multi-layered capping, but we will continue the monitoring of the water level of the bowling hole around the Pond, and the spring water which flows from lower place of the Pond.

Application of support vector machine to rapid classification of uranium waste drums using low-resolution -ray spectra

Hata, Haruhi; Yokoyama, Kaoru; Ishimori, Yuu; Ohara, Yoshiyuki; Tanaka, Yoshio; Sugitsue, Noritake

Applied Radiation and Isotopes, 104, p.143 - 146, 2015/10

https://doi.org/10.1016/j.apradiso.2015.06.030

We investigated the feasibility of using support vector machine (SVM), a computer learning method, to classify uranium waste drums as natural uranium or reprocessed uranium based on their origins. The method was trained using 12 training datasets were used and tested on 955 datasets of -ray spectra obtained with NaI(Tl) scintillation detectors. The results showed that only 4 out of 955 test datasets were different from the original labels-one of them was mislabeled and the other three were misclassified by SVM. These findings suggest that SVM is an effective method to classify a large quantity of data within a short period of time. Consequently, SVM is a feasible method for supporting the scaling factor method and as a supplemental tool to check original labels.

Verification of uranium 238 quantity calculated using waste assay systems

Yokoyama, Kaoru; Hata, Haruhi; Ohara, Yoshiyuki; Naganuma, Masaki; Sugitsue, Noritake

Radioisotopes, 63(12), p.559 - 566, 2014/12

https://doi.org/10.3769/radioisotopes.63.559

The amount of U in uranium-contaminated waste drums generated in the decommissioning of nuclear facilities is evaluated using ray measurement. We used the -ray measurement system made from CANBERRA: Qualitative and Quantitative (Q) Low Level Waste Assay Systems and measured the waste drum. This equipment assumes uniform distribution of the uranium radiation source. But, homogeneity is not checked with a real waste drum. Authors developed the new analysis technique which calculates the amount of uranium by correcting the influence of uneven distribution of the uranium radiation source. As a result of evaluating using the new analysis technique, the error which the radiation source uneven distribution in a drum gives to U quantitative value of this equipment has been evaluated.

Further study of measurement of performance of the NDA using Q2 system for uranium waste drum

Naganuma, Masaki; Ohara, Yoshiyuki; Miyamoto, Yasunori*; Murashita, Tatsuya*; Makita, Akinori*; Nohiro, Tetsuya*

JAEA-Technology 2014-012, 11 Pages, 2014/06

JAEA-Technology-2014-012.pdf:1.06MB

In Japan Atomic Energy Agency Ningyo-toge environmental engineering center, exploration for uranium and technical development of uranium refining, conversion and enrichment which are the front end of a nuclear fuel cycle have been performed since 1955. In 2002, we introduced Q2 low-level-waste drum measuring system which is a bulk measuring method of the passive ray. In 2007, OS2 analyzing operation system which was used in Q2, was replaced with windows system. This replacement improved the performance of the analysis of Q2. But quantified values of uranium obtained from win system did not correspond exactly to OS2 system. We considered whether the drum which was measured by OS2 system, was measured again by windows system. But it was difficult to measure these drum by win system. So in this study, we studied a calculation method for adjusting quantified values of uranium obtained by each system.

Measurement performance of the NDA using Q2 system for uranium waste drum

Ohara, Yoshiyuki; Naganuma, Masaki; Nohiro, Tetsuya*; Yoshida, Kimikazu*; Makita, Akinori*; Sakate, Mitsuo*; Irisawa, Takumi*; Murashita, Tatsuya*

JAEA-Technology 2012-048, 39 Pages, 2013/03

JAEA-Technology-2012-048.pdf:5.1MB

In Japan Atomic Energy Agency Ningyo-Toge Environmental Engineering Center, exploration for uranium and technical development of uranium refining, conversion and enrichment which are the front end of a nuclear fuel cycle have been performed since 1955. By these research and development, about 15000 radioactive waste (200 liter drum) has occurred by now. The analytical and measurement technique of the amount of uranium which are included in radioactive waste drum were very an inexperienced in those days. Therefore, measurement strict till 2002 was not able to be started. Such a situation as this, we introduced "Q2 low-level-waste drum measuring system" which is a bulk measuring method of the passive ray using a NaI scintillation detector in 2002. As a result, the total amount of uranium in a waste drum was estimated as about 20 tons.

Radioactive cesium behavior analysis in the refuse incineration plant, 1; An Introduction and a plan

Yokoyama, Kaoru; Sugitsue, Noritake; Ohara, Yoshiyuki; Takeda, Hiroshi*; Rong, D.*; Yanase, Shinichiro*; Kuwagi, Kenya*; Takami, Toshihiro*; Hyakutake, Toru*

no journal, , 

Some disaster wastes polluted with the radioactive cesium diffused in the accident of the Fukushima Daiichi Nuclear Power Plant are incinerated in the refuse incineration plant. It is thought that cesium is not emitted outside since cesium is coagulated to the refuse incineration ash and trapped by a bag filter or an electric dust collector. Therefore, we research concentration and particle size distribution of the refuse incineration ash. In this study, an introduction and a plan of study are reported.

Radioactive cesium behavior analysis in the refuse incineration plant, 3; Analysis of the state of cesium deposition to incinerated ash

Yokoyama, Kaoru; Sugitsue, Noritake; Ohara, Yoshiyuki; Takeda, Hiroshi*; Rong, D.*; Yanase, Shinichiro*; Kuwagi, Kenya*; Takami, Toshihiro*; Hyakutake, Toru*

no journal, , 

Some disaster wastes polluted with the radioactive cesium diffused in the accident of the Fukushima Daiichi Nuclear Power Plant are incinerated in the refuse incineration plant. It is thought that cesium is not emitted outside since cesium is coagulated to the refuse incineration ash and trapped by a bag filter or an electric dust collector. Therefore, we report the results of analysis of the cesium concentration and specific surface area of the ash, for the evaluation of the status of adherence to the incinerated ash of cesium.

Characterization for decommission of uranium handling facility, 3; Classification method based on the nuclide composition in Ningyo-Toge Environmental Engineering Center

Hata, Haruhi; Yokoyama, Kaoru; Tanaka, Yoshio; Ohara, Yoshiyuki; Sugitsue, Noritake

no journal, , 

For decommission of uranium handling facilities, it is important to characterize the details of the facilities, which are the distribution of nuclide, the existence of hazardous waste and so on. The report suggests classification method based on the nuclide composition by using principal component analysis.