Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2022

Kokubun, Yuji; Nakada, Akira; Seya, Natsumi; Nagaoka, Mika; Koike, Yuko; Kubota, Tomohiro; Hirao, Moe; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; et al.

JAEA-Review 2023-052, 118 Pages, 2024/03

JAEA-Review-2023-052.pdf:3.67MB

Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2022. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Crystal structure of nesquehonite, MgCO 3H(D)O by neutron diffraction and effect of pH on structural formulas of nesquehonite

Yamamoto, Genichiro*; Kyono, Atsushi*; Abe, Jun*; Sano, Asami; Hattori, Takanori

Journal of Mineralogical and Petrological Sciences, 116(2), p.96 - 103, 2021/04

https://doi.org/10.2465/jmps.200117

Neutron diffraction, Raman spectroscopy, and thermal analysis were performed to investigate the composition, structure, and formation conditions of the magnesium carbonate hydrate nesquehonite. The time-of-flight neutron diffraction revealed the crystal structure of the monoclinic space group 2 with lattice parameters of =7.72100(12)=5.37518(7)=12.1430(3)=90.165(4), in which two deuterium atoms are coordinated to the O1, O2, and O6 atoms to form water molecules. The three water molecules in the structure suggests the structural formula of the nesquehonite should be MgCO 3HO rather than Mg(HCO)(OH) 2HO.

Dimension-reduced cross-section adjustment method based on minimum variance unbiased estimation

Yokoyama, Kenji; Yamamoto, Akio*; Kitada, Takanori*

Journal of Nuclear Science and Technology, 55(3), p.319 - 334, 2018/03

https://doi.org/10.1080/00223131.2017.1397563

A new formulation of the cross-section adjustment methodology with the dimensionality reduction technique has been derived. This new formulation is proposed as the dimension reduced cross-section adjustment method (DRCA). Since the derivation of DRCA is based on the minimum variance unbiased estimation (MVUE), an assumption of normal distribution is not required. The result of DRCA depends on a user-defined matrix that determines the dimension reduced feature subspace. We have examine three variations of DRCA, namely DRCA1, DRCA2, and DRCA3. Mathematical investigation and numerical verification have revealed that DRCA2 is equivalent to the currently widely used cross-section adjustment method. Moreover, DRCA3 is found to be identical to the cross-section adjustment method based on MVUE, which has been proposed in the previous study.

Study of annealing effect on crystal and local structures of doped zirconia using multi probe

Ito, Takanori*; Mori, Masashi*; Inukai, Manabu*; Nitani, Hiroaki*; Yamamoto, Takashi*; Miyanaga, Takashi*; Igawa, Naoki; Kitamura, Naoto*; Ishida, Naoya*; Idemoto, Yasushi*

Photon Factory News, 33(1), p.18 - 24, 2015/05

http://pfwww.kek.jp/publications/pfnews/33_1/saikin1.pdf

The effect of the annealing on the crystal and local structures of doped zirconia was investigated by multi-probe technique using synchrotron X-ray and neutron diffraction, and first principles calculation. It was revealed that the annealing process enhances the periodic distortion of some zirconia compounds by Rietveld/ maximum entropy methods applied to the SR-X-ray and neutron diffractions. In addition, the combined X-ray absorption spectroscopy and first-principles calculations results showed the ZrO polyhedra in zirconia were distorted by the annealing. Those results indicate that the degradation of oxide ionic conductivity by the annealing was related to the periodic distortion in zirconia.

Proceedings of the International Conference on Physics of Reactors (PHYSOR 2014); September 28-October 3, 2014, Kyoto, Japan

Suyama, Kenya; Sugawara, Takanori; Tada, Kenichi; Chiba, Go*; Yamamoto, Akio*

JAEA-Conf 2014-003, 76 Pages, 2015/03

JAEA-Conf-2014-003.pdf:5.13MB
JAEA-Conf-2014-003-appendix(CD-ROM).zip:360.78MB

Japan Atomic Energy Agency organized an international conference PHYSOR 2014 on the reactor physics which is one of basic researches in the nuclear engineering, in cooperation with Research Reactor Institute of Kyoto University. PHYSOR is the world's largest scale international conference in the reactor physics field. It originates in the conference held in Marseille, France in 1990, which originally had been organized in the United States as a Physics of Reactors Topical Meeting of the reactor physics division of the American Nuclear Society every two years. More than 500 papers had been submitted and finally 472 papers were presented in the conference after the paper review process. This report contains the presented papers, which the PHYSOR organizing committee has decided to publish in an official JAEA report with the permission by authors, except for several selected papers to be published in the Journal of Nuclear Science and Technology of the Atomic Energy Society of Japan.

Developing the soil moisture sensor using optical fiber technique (Joint research)

Komatsu, Mitsuru*; Nishigaki, Makoto*; Seno, Shoji*; Hirata, Yoichi*; Takenobu, Kazuyoshi*; Tagishi, Hirotaka*; Kunimaru, Takanori; Maekawa, Keisuke; Yamamoto, Yoichi; Toida, Masaru*; et al.

JAEA-Research 2012-001, 77 Pages, 2012/09

JAEA-Research-2012-001.pdf:4.85MB

This research focused on methods of estimating the amounts of groundwater recharge, which are normally required as upper boundary conditions in groundwater flow analyses, based on measurements of infiltrating water in the ground, to systematize the methods and establish systems which are stable and measurable on site over a long time. Regarding developing measurement systems, fiber-optic strain measurement methods that enable multiple-point and long-distance measurement were used for measuring three quantities: suction pressure, soil moisture and volumetric water content rate obtained by applying water absorption swelling material, and each measurement was discussed. The results showed that the fiber-optic soil aquameter has two types of practical application: one for measuring suction pressure (Type I), and the other for measuring volumetric water content rate obtained by applying water absorption swelling material (Type III). Furthermore, by using measurement instruments in actual fields, the validity of the two methods for estimating the rainfall infiltration capacities of shallow-layer soils, that is, estimating the capacities either directly by measurements of soil water or from unsaturated hydraulic conductivities, was confirmed.

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2010

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Ueno, Takashi; Tokuyasu, Shingo; Daimaru, Shuji; Takeuchi, Ryuji; et al.

JAEA-Review 2012-020, 178 Pages, 2012/06

JAEA-Review-2012-020.pdf:33.16MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II. And Phase III started in 2010 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2010, as a part of the Phase II based on the MIU Master Plan updated in 2002.

Mizunami Underground Research Laboratory Project, Plan for fiscal year 2011

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Takeuchi, Ryuji; Saegusa, Hiromitsu; Mizuno, Takashi; Sato, Toshinori; Ogata, Nobuhisa; et al.

JAEA-Review 2011-027, 30 Pages, 2011/08

JAEA-Review-2011-027.pdf:4.18MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). Geoscientific research and the MIU project is planned in three overlapping phases; Surface-based Investigation Phase (Phase1), Construction Phase (Phase2) and Operation Phase (Phase3). Currently, the project is under the Construction Phase, and the Operation Phase. This document introduces the research and development activities planned for 2011 fiscal year plan based on the MIU Master Plan updated in 2010, Investigation Plan, Construction Plan and Research Collaboration Plan, etc.

Groundwater/porewater hydrochemistry at Horonobe URL; Data freeze II; Preliminary data quality evaluation for boreholes HDB-1 to 8

Kunimaru, Takanori; Ota, Kunio; Alexander, W. R.*; Yamamoto, Hajime*

JAEA-Research 2011-010, 52 Pages, 2011/06

JAEA-Research-2011-010.pdf:2.29MB

Work has been currently ongoing to establish an appropriate quality management system (QMS), which is applicable to all aspects of the site characterisation process, in the Horonobe Underground Research Laboratory project. A quality assurance (QA) audit of hydrochemical datasets for JAEA's deep boreholes HDB-1 to HDB-8 was carried out, along similar lines to that of the previous study for boreholes HDB-9 to HDB-11, by applying both the groundwater QA methodology employed in the recent site assessments in Sweden and a porewater QA regime proposed in this study. The results of the QA audit indicated that data were classified into low QA categories because mainly of a lack of relevant information, such as the records of groundwater sampling, which are necessary for more fully assessing the data quality. As such, a formalised field manual for hydrochemical sampling was developed. In addition, work to further improve the site characterisation QMS progressed.

Groundwater/porewater hydrochemistry at Horonobe URL: Data Freeze I; Preliminary data quality evaluation for boreholes HDB-9, 10 and 11

Kunimaru, Takanori; Ota, Kunio; Alexander, W. R.*; Yamamoto, Hajime*

JAEA-Research 2010-035, 109 Pages, 2010/11

JAEA-Research-2010-035.pdf:2.53MB

A quality management system (QMS) will save on effort by reducing errors and the requirement to re-sample and re-analysis and eventually lead to ensuring the reliability of the investigation results. In the Horonobe Underground Research Laboratory project, work has been ongoing to develop an appropriate QMS which is applicable to surface-based investigations. A quality assurance (QA) audit of hydrochemical datasets for boreholes HDB-9 - 11 has been carried out by applying both the groundwater QA methodology employed in the recent site assessments in Sweden and the porewater QA regime newly proposed for assigning the QA categories. This QA audit exercise indicates that the HDB-9 - 11 hydrochemical data are classified into lower categories because mainly of contamination of waters by drilling fluids, poor time-series data coverage and oxidation of core materials and also clarifies areas where additional information/work would be required to the ongoing programme.