Radioactive particles from a range of past nuclear events; Challenges posed by highly varied structure and composition

Johansen, M. P.*; Child, D. P.*; Collins, R.*; Cook, M.*; Davis, J.*; Hotchkis, M. A. C.*; Howard, D. L.*; Howell, N.*; Ikeda, Atsushi; Young, E.*

Science of the Total Environment, 842, p.156755_1 - 156755_11, 2022/10

https://doi.org/10.1016/j.scitotenv.2022.156755

Phase-field mobility for crystal growth rates in undercooled silicates, SiO and GeO liquids

Kawaguchi, Munemichi; Uno, Masayoshi*

Journal of Crystal Growth, 585, p.126590_1 - 126590_7, 2022/05

https://doi.org/10.1016/j.jcrysgro.2022.126590

Phase-field mobility, , and crystal growth rates in crystallization of 11 oxides or mixed oxides in undercooled silicates, SiO and GeO liquids were calculated with a simple phase-field model (PFM), and material dependence of the was discussed. Ratios between experimental crystal growth rates and the PFM simulation with were confirmed to be proportional to a power of on the solid/liquid interface process during the crystal growth in a log-log plot. We determined that parameters, and , of the were to mJs and to , which were unique for the materials. It was confirmed that our PFM simulation with the determined reproduced quantitively the experimental crystal growth rates. The has a proportional relationship with the diffusion coefficient of a cation molar mass average per unit an oxygen molar mass at in a log-log graph. The depends on the sum of the cation molar mass per the oxygen molar mass, , in a compound. In , the decreases with the cation molar mass increasing. The assumed cause is that the B represents the degree of the temperature dependence of the . Since the cation molar mass is proportional to an inertial resistance of the cation transfer, the decreases with inverse of the cation molar mass. In crystallization of the silicates of heavy cation in , the saturates at approximately 0.67, which leads to .

Development of stable solidification technique of ALPS sediment wastes by apatite ceramics (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*

JAEA-Review 2021-077, 217 Pages, 2022/03

JAEA-Review-2021-077.pdf:12.34MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Development of stable solidification technique of ALPS sediment wastes by apatite ceramics" conducted in FY2020. The present study aims to establish an apatite solidification process of radioactive sediment wastes, which were generated from the ALPS process manipulating the large amount of contaminated water from Fukushima Daiichi Nuclear Power Station. In FY2020, the synthetic scheme and elemental composition were updated to precipitation method to accept the actual ALPS sediment wastes in engineering scale. The synthesis of apatite or phosphate wastes and their molding conditions were surveyed, and the relations among elemental compositions, structures and chemical properties were clarified.

Data comparison of measurement of carbon isotope standards between JAEA-AMS-TONO and JAEA-AMS-MUTSU

Kokubu, Yoko; Matsubara, Akihiro; Fujita, Natsuko; Kuwabara, Jun; Kinoshita, Naoki

JAEA-Technology 2021-028, 33 Pages, 2022/02

JAEA-Technology-2021-028.pdf:2.18MB

Japan Atomic Energy Agency (JAEA) has two facilities of accelerator mass spectrometry, JAEA-AMS-TONO and JAEA-AMS-MUTSU at Tono Geoscience Center and Aomori Research and Development Center, respectively. In this report, characteristics of each facility and results of standard samples in the inner-comparison test of carbon isotope measurement will be described. Both facilities have been used for research by not only JAEA's staff but also researchers who belong to universities and other institutes on the shared use program of JAEA facilities. Recently, researchers trend to use both facilities with the expansion of demand for the carbon isotope measurement by using the accelerator mass spectrometer (AMS). However, each facility has a spectrometer made by a different manufacturer and equipped with different mechanical components. There is a difference in each ability to the carbon isotope measurement such as background level. This is, for example, due to different ion injection system adapted at each spectrometer. Further, each facility uses a different analytical method adjusted to each main research field. When a researcher uses both facilities, the researcher understands more about the characteristics and need to make a suitable choice of a facility for samples and the analytical method. The report presents a detailed information of characteristics of the spectrometer, sample preparation method and analytical method, and of ability of the measurement based on the inner-comparison test.

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.

A Scaling approach for retention properties of crystalline rock; Case study of the in-situ long-term sorption and diffusion experiment (LTDE-SD) at the sp Hard Rock Laboratory in Sweden

Tachi, Yukio; Ito, Tsuyoshi*; Gylling, B.*

Water Resources Research, 57(11), 20 Pages, 2021/11

https://doi.org/10.1029/2020WR029335

This paper focuses on the scaling approach for sorption and diffusion parameters from laboratory to in-situ conditions using the dataset of LTDE-SD experiment performed at the sp HRL. The near-surface heterogeneities at both fracture surface and rock matrix could be evaluated by conceptual model with high porosity and diffusivity, and sorption capacity, and their gradual change at the near-surface zones. The modelling results for non-sorbing Cl-36 and weak-sorbing Na-22 could validate the model concept and the parameter estimation of porosity and diffusivity, by considering the disturbed zone of 5 mm thickness with gradual parameter changes. The De values of these cationic and anionic tracers showed typical cation excess and anion exclusion effects. The modelling results for high sorbing tracers (Cs-137, Ra-226, Ni-63 and Np-237) with different sorption mechanism could confirm the validity of the scaling approaches of Kd values as a function of particle size and their relation to the near-surface disturbances.

Implications of the (3985) and (4000) as two different states

Meng, L.*; Wang, B.*; Wang, G.-J.*; Zhu, S.-L.*

Science Bulletin, 66(20), p.2065 - 2071, 2021/10

https://doi.org/10.1016/j.scib.2021.06.026

Two recently found tetraquark resonances (3985) and (4000) are studied in a solvable nonrelativistic effective field theory. We include the possible violations of heavy quark spin symmetry and SU(3) flavor symmetry in a comprehensive approach. Our results show that the decay rates can be used to judge whether these resonances can be different states or not.

Study on the radioactivity evaluation method of biological shielding concrete of JPDR for near surface disposal

Kochiyama, Mami; Okada, Shota; Sakai, Akihiro

JAEA-Technology 2021-010, 61 Pages, 2021/07

JAEA-Technology-2021-010.pdf:3.56MB
JAEA-Technology-2021-010(errata).pdf:0.75MB

It is necessary to evaluate the radioactivity inventory in wastes in order to dispose of radioactive wastes generated from dismantling nuclear reactor in the shallow ground. In this report, we examined radioactivity evaluation method for near surface disposal about biological shield concrete near the core generated from the dismantling of JPDR. We calculated radioactive concentration of the target biological concrete using the DORT code and the ORIGEN-S code, and we estimated radioactivity concentration Di (Bq/t). For DORT calculation, the cross-section library created from the MATXSLIB-J40 file from JENDL-4.0 was used, and for ORIGEN-S, the attached library of SCALE6.0 was used. As a result of comparing the calculation results of the radioactivity concentration with the past measured values in the radial direction and the vertical direction, we found that the trends were generally the same. We calculated radioactive concentration of the target biological concrete Di (Bq/t), and we compared with the estimated Ci (Bq/t) equivalent to the dose criteria of trench disposal calculated for 140 nuclides. As a result we inferred that the except for about 2% of target waste could be disposed of in the trench disposal facility. We also preselected important nuclides for trench disposal based on the ratios (Di/Ci) for each nuclide, H-3, C-14, Cl-36, Ca-41, Co-60, Sr-90, Eu-152 and Cs-137 were selected as important nuclides.

Fission gas release from irradiated mixed-oxide fuel pellet during simulated reactivity-initiated accident conditions; Results of BZ-3 and BZ-4 tests

Kakiuchi, Kazuo; Udagawa, Yutaka; Amaya, Masaki

Annals of Nuclear Energy, 155, p.108171_1 - 108171_11, 2021/06

https://doi.org/10.1016/j.anucene.2021.108171

Development of stable solidification technique of ALPS sediment wastes by apatite ceramics (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*

JAEA-Review 2020-060, 116 Pages, 2021/02

JAEA-Review-2020-060.pdf:16.98MB

JAEA/CLADS had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project in FY2019. Among the adopted proposals in FY2019, this report summarizes the research results of the "Development of Stable Solidification Technique of ALPS Sediment Wastes by Apatite Ceramics" conducted in FY2019.