Presentation/Publication Type

Initialising ...

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

1
Calculation of radioactivity concentration of Cs-137 corresponded to the reference dose for the trench disposal facility according to the design condition
Sakai, Akihiro; Nakata, Hisakazu; Amazawa, Hiroya
JAEA-Technology 2017-030, 176 Pages, 2018/02
At present, the reuse method for the contaminated soil generated from the decontamination of radioactive materials caused by the accident of the Tokyo Electric Power Cooperation Fukushima Daiichi Nuclear Power Plant after intermediate storage is being discussed. The radioactivity concentration of contaminated soil with about 20 million cubic meters within total arising volume of the soil is less than 100 kBq/kg. Therefore, when it is assumed that contaminated soil was disposed of in the trench facility, exposure doses to public at the various exposure pathways resulting from Cs-134 and Cs-137 contained in the removal soil were calculated. From the dose calculation results, the radioactivity concentrations corresponded to reference doses that are assumed to be 0.01 mSv/y or 0.3 mSv/y were evaluated. Then, variation of the radioactivity concentrations was evaluated when the volume of disposal facility was increased taking into account variation of the volume of contaminated soil.
2
Study on characterisation of colloidal silica grout under condition of sea water
Toguri, Satohito*; Okihara, Mitsunobu*; Tsuji, Masakuni*; Nakashima, Hitoshi*; Sugiyama, Hirokazu*; Saito, Akira*; Sato, Toshinori; Aoyagi, Kazuhei; Masunaga, Kosuke
JAEA-Research 2017-013, 131 Pages, 2018/02
The discussions on scientifically promising site for the geological disposal has been made at the council of studying group on techniques for geological disposal of radioactive wastes, which is held by Resources and Energy Agency. From the aspect of ensuring safety during the transportation of disposal waste, the coastal area is discussed to be a more suitable area. This report shows the result of the first year of this project as following items; Study on the state-of-art technology and remain tasks; laboratory tests on characterization of colloidal silica grout under sea water; Study on the development of grouting technology (design and the evaluation method of influence on the rock mass).
3
Corrosion test of Fugen pressure tube (Zr-2.5wt%Nb alloy) under the sub-surface disposal environment, 2; Examination of long-term corrosion rate by 5 years keeping sample
Sugaya, Toshikatsu; Nakatani, Takayoshi; Sakai, Akihiro
JAEA-Technology 2017-032, 21 Pages, 2018/01
For the purpose of the setting of the rate of nuclide elution necessary to safety assessment, we planned the gas-accumulating type corrosion test on Zr-2.5wt%Nb alloy in order to obtain long-term corrosion rate under low temperature, low oxygen and alkaline conditions assuming the disposal environment. A corrosion rate over a testing period of 5 years is acquired with the aim to grasp a long-term corrosion rate behavior in this report. This corrosion rate is compared with the same data that was previously acquired over a testing period of 2 years. As a result, it is confirmed that an evaluation method that is proportional to the minus cubic root of corrosion time squared can be applicable to the corrosion rate behavior acquired this time over a testing period of 5 years, which is the same result in evaluating the corrosion rate behavior acquired over a testing period of 2 years.
4
Waste acceptance criteria for waste packages destined for near surface disposal containing radioactive waste from research, industrial and medical facilities; Study on a method that fills voidage in waste package with sandy soil
Nakata, Hisakazu; Hayashi, Hirokazu; Amazawa, Hiroya; Sakai, Akihiro
JAEA-Technology 2017-031, 41 Pages, 2018/01
JAEA plans to install disposal facilities for radioactive waste arising from research institutes. It must meet the technical standards specified in the relevant rule. One technical standard is that the disposal facilities shall be performance so as not to be left with the voids after the backfilling with soil. Additionally, the rule also requires this radioactive waste be enclosed in a container in which no harmful voids remain. In order to contribute to the development of a method that adapts the disposal facilities to these technical standards, JAEA adopts a waste conditioning artifice that aims for reducing a quantity of voidage in each waste container by a vibration filling method using sandy soil, providing with average void ratios inside the disposal facilities being adequately controlled. In this reports, filling property tests are conducted in the light of filling sand characteristics, types of metal waste and vibration conditions.
5
System management for aggregation of knowledge on marine geological survey in coastal areas
Takahashi, Tadao*; Sato, Toshinori; Masunaga, Kosuke
JAEA-Review 2017-030, 60 Pages, 2018/01
The amount of the information such as the data, models and analysis results related to geological environment has been enormous. It is believed that an appropriate organization of the information is useful for conducting geological environment survey work at the candidate sites of geological disposal. The Survey on Geological Disposal Technology projects commissioned by METI that started in FY2015 handles various information such as the data, models, analysis results, etc. of geological environment. In this project, in preparation for collection and compilation of the information on geological environment in coastal areas, we have made clear the current status of the existing systems including databases. At the same time, we have created measures for centralized information management for the purpose of organizing a huge amount of information as well as sharing the information and information management systems among the related organizations.
6
Mizunami Underground Research Laboratory Project annual report for fiscal year 2016
Ishibashi, Masayuki; Hama, Katsuhiro; Iwatsuki, Teruki; Matsui, Hiroya; Takeuchi, Ryuji; Nohara, Tsuyoshi; Onoe, Hironori; Ikeda, Koki; Mikake, Shinichiro; Iyatomi, Yosuke; et al.
JAEA-Review 2017-026, 72 Pages, 2018/01
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami, Gifu Prefecture, central Japan. On the occasion of the research program and management system revision of the entire JAEA organization in 2014, JAEA identified three important issues on the geoscientific research program: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technologies", based on the latest results of the synthesizing research and development (R&D). The R&D on three important issues have been carrying out on the MIU project. In this report, the current status of R&D activities and construction in 2016 is summarized.
7
Horonobe Underground Research Laboratory Project; Investigation report for the 2016 fiscal year
Hanamuro, Takahiro
JAEA-Review 2017-025, 100 Pages, 2018/01
The Horonobe Underground Research Laboratory Project is planned to extend over a period 20 years. The investigations will be conducted in three phases, namely "Phase 1: Surface-based investigations", "Phase 2: Construction Phase" (investigations during construction of the underground facilities) and "Phase 3: Operation phase" (research in the underground facilities). This report summarizes the results of the investigations for the 2016 fiscal year (2016/2017). The investigations, which are composed of "Geoscientific research" and "R&D on geological disposal technology", were carried out according to "Horonobe Underground Research Laboratory Project Investigation Program for the 2016 fiscal year".
8
The In-situ experiment for performance confirmation of engineered barrier system at Horonobe Underground Research Laboratory; Consideration of concrete-type plug composition
Nakayama, Masashi; Niunoya, Sumio*; Miura, Norihiko*; Takeda, Nobufumi*
JAEA-Research 2017-016, 62 Pages, 2018/01
The Horonobe URL Project has being pursued by JAEA to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formation at Horonobe, Hokkaido. The URL Project consists of 2 major research areas, "Geoscientific Research" and "Research and Development on Geological Disposal Technologies", and proceeds in 3 overlapping phases, over a period of around 20 years. Phase III (Investigations in the underground facilities) investigation was started in 2010 FY. The in-situ experiment for performance confirmation of engineered barrier system (EBS experiment) had started 2013 at GL-350 m gallery, and heating by electric heater in simulated overpack had started in January, 2015. One of objectives of the EBS experiment is acquiring data concerned with THMC coupled behavior. These data will be used in order to confirm the performance of engineered barrier system. This report shows consideration of concrete-type plug composition. The low alkaline cement developed by JAEA, called HFSC, was used for the plug. HFSC has used in construction test at the gallery as shotcrete in Horonobe URL.
9
Visualization of fractures in an Excavation Damaged Zone in the Horonobe Underground Research Laboratory (Joint research)
Aoyagi, Kazuhei; Chen, Y.*; Sakurai, Akitaka; Ishii, Eiichi; Ishida, Tsuyoshi*
JAEA-Research 2017-014, 49 Pages, 2018/01
In this research, we performed the resin injection experiment at the 350 m gallery of the Horonobe Underground Research Laboratory in order to identify the three dimensional distribution of fractures induced around the gallery owing to excavation. To this end, the low viscosity resin mixed with a fluorescent substance was developed and applied to the in situ resin injection experiment. As a result, the resin was successfully penetrated into the fractures around the gallery without disturbing their situation and then fixed within them. After the experiment, the rock cores around the injection borehole were drilled for the observation. The observation under ultraviolet light revealed that the extent of the development of fractures was about 0.9 m into the borehole wall. In addition, the aperture of the fractures distributed within 0.3 m from the gallery wall was ranged 1 to 2 mm, and that distributed from 0.3 to 0.9 m was less than 1 mm. On the other hand, in the borehole televiewer (BTV) survey, only one fracture within 0.2 m from the wall could be detected owing to the resolution of the survey system. Thus, it is expected that the BTV survey underestimate the extent of the development of fractures.
10
Development of in situ stress estimation method based on the measured convergence and geological observations
Kamemura, Katsumi*; Aoyagi, Kazuhei; Nago, Makito*; Sugawara, Kentaro*
Dai-45-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.43 - 48, 2018/01
In situ stress state is very important for the design of deep underground facility of high-level radioactive waste disposal repository. This study establishes a practical and effective method for estimating in situ stress state based on the measured convergence and detailed geological observations during gallery excavation. The convergence was measured in various directions of the loop gallery at 350m depth of the Horonobe URL; this allows determination of the stress state corresponding to the rock mass behavior in 120m $$times$$ 200m area. In situ stress state estimated by the back analysis considering existing faults and fractures showed a good agreement with that of estimated from hydraulic fracturing method.
11
Study on analysis methodology of AE signal wave at great depth excavation
Niunoya, Sumio*; Hata, Koji*; Uyama, Masao*; Aoyagi, Kazuhei; Wakasugi, Keiichiro
Dai-45-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.226 - 231, 2018/01
The objective of this research is to investigate the long-term hydro-mechanical behavior of rock mass around the shaft in the Horonobe Underground Research Laboratory (URL). The long-term monitoring has been carried out by optical AE sensors, optical water pressure sensors, and optical temperature sensors below 350m depth of the shaft in the Horonobe URL. From the first analytical results, it was too hard to discriminate the uncleared AE wave by using the resonant characteristic. Thus, at this time, we tried to reanalysis by using the half width of spectrum, we could discriminate it correctly as AE from the breaking of rock.
12
An Evaluation of the long-term stagnancy of porewater in the neogene sedimentary rocks in northern Japan
Nakata, Kotaro*; Hasegawa, Takuma*; Oyama, Takahiro*; Ishii, Eiichi; Miyakawa, Kazuya; Sasamoto, Hiroshi
Geofluids, 2018, p.7823195_1 - 7823195_21, 2018/01
A groundwater scenario is one of the scenario for safety assessment of geological disposal of high-level radioactive waste. In the safety assessment for groundwater scenario, the slow groundwater flow for a long-term should be an important factor. In the present study, study on stability of groundwater in the Koetoi and Wakkanai formations of Neogene marine based sedimentary rock at the Horonobe area, Hokkaido was performed by investigating the isotopes of chlorine and helium, and the stable isotopes of water. As the results, the stability of groundwater in deeper part of the Wakkanai formation was suggested due to no direct evidence of meteoric water intrusion during the uplift since ca. 1 Ma. Contrary, the groundwater both in the Koetoi formation and the upper Wakkanai formation would be unstable because the meteoric water intrusion was suggested by paleohydrogeological condition and the results of groundwater dating. Likely the Horonobe area, the accurate dating of groundwater would be difficult due to the complex effects of upward and mixing water derived from diagenesis in the thick sediment formation. However, a comparative procedure using both the results of groundwater dating and paleohydrogeological information would be useful for general evaluation of groundwater flow conditions for the long-term (i.e., check the possibility for long-term stability of groundwater).
13
A Proposed method to estimate in situ dissolved gas concentrations in gas-saturated groundwater
Tamamura, Shuji*; Miyakawa, Kazuya; Aramaki, Noritaka*; Igarashi, Toshifumi*; Kaneko, Katsuhiko*
Groundwater, 56(1), p.118 - 130, 2018/01
Groundwater saturated with gas forms bubble under atmospheric pressure, bothering most authorized methods to determine in-situ dissolved gas concentrations. To circumvent this problem, a simple theory to quantify effect of $rm bubble formation on in-situ dissolved gas concentration was developed: Pressure ({it P$_{i},rm original $}$ [bar]) of a gas component "${it i}$" (e.g., CH$$_{4}$$, CO$$_{2}$$ and H$$_{2}$$) in equilibrium with in-situ dissolved concentration (${it C $_{i},rm original $}$ [mol L $$^{-1}$$]) was related to partial pressure of the $rm bubble ({it P $_{i},rm bubble $}$ [bar]) emerged from groundwater in the form: ${it P$_{i},rm original $}$ = ${it P $_{i},rm bubble $}$ + $$Delta$$ ${it P}$ (k${it i}$' ${it P $_{i},rm bubble $}$/($$Sigma$$ ${it j}$k${it j}$' ${it P $_{ j },rm bubble $}$)), where $$Delta$$ ${it P}$ [bar] is groundwater pressure difference before and after the $rm bubble formation, and j refers to all gas components in the system including "{it i.}$" The k${it $_{i}$}$' and k${it $_{j}$}$' corresponds to the Henry's constant [bar L mol$$^{-1}$$] of ${it i}$ (k${it $_{i}$}$) and ${it j}$ (k${it $_{j}$}$), respectively, except for k$$_{CO2}$$', which is pH-dependent function. Dissolved CH$$_{4}$$ concentrations were successfully estimated by the model within the error of $$pm$$ 4.0% from the direct measurements by the sealed sampler method. Similar TIC concentration in the groundwater before and after the rm bubble formation was consistent with the model prediction. The wide application of the model is suggested without selecting sampling locations.
14
Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment
Ino, Kohei*; Hernsdorf, A. W.*; Konno, Yuta*; Kozuka, Mariko*; Yanagawa, Katsunori*; Kato, Shingo*; Sunamura, Michinari*; Hirota, Akinari*; Togo, Yoko*; Ito, Kazumasa*; et al.
ISME Journal, 12(1), p.31 - 47, 2018/01
In this study, we found the dominance ofanaerobic methane-oxidizing archaea in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock.
15
Onsite chelate resin solid-phase extraction of rare earth elements in natural water samples; Its implication for studying past redox changes by inorganic geochemistry
Watanabe, Takahiro; Kokubu, Yoko; Murakami, Hiroaki; Iwatsuki, Teruki
Limnology, 19(1), p.21 - 30, 2018/01
Rare earth element (REE) patterns in natural water and geological samples provides information on changes in past environmental conditions, such as redox changes and material cycles; however, quantitative analysis of REEs in these samples is complicated because of relative low content and mass interference from barium oxide in the inductively coupled plasma mass spectrometry (ICP-MS) analyses. In this study, we adopted onsite solid-phase extraction and preconcentration methods for REEs using an iminobisacetic acid-ethylenediaminetriacetic acid chelate resin for the analyses. Standard reference materials, natural ground water, and spring water samples were used for the evaluation of these methods. The REE patterns in the natural water samples were in good agreement with those obtained using previous methods. Therefore, it was deduced that onsite solid-phase extraction using chelate resin is a rapid and simple preparation technique for REE analyses.
16
Research plan on geosphere stability for long-term isolation of radioactive waste; Scientific programme for fiscal year 2017
Ishimaru, Tsuneari; Ogata, Nobuhisa; Shimada, Akiomi; Kokubu, Yoko; Asamori, Koichi; Niwa, Masakazu; Watanabe, Takahiro; Saiga, Atsushi; Sueoka, Shigeru; Yokoyama, Tatsunori; et al.
JAEA-Review 2017-022, 45 Pages, 2017/12
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency, in fiscal year 2017. The objectives and contents in fiscal year 2017 are described in detail based on the outline of 7 years plan (fiscal years 2015-2021). Background of this research is clarified with the necessity and the significance for site investigation and safety assessment, and the past progress in this report. In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
17
Modal analysis using scanning X-ray analytical microscope and image processing and analyzing softwares
Ueki, Tadamasa; Niwa, Masakazu
Chishitsugaku Zasshi, 123(12), p.1061 - 1066, 2017/12
Conventional point counting method for modal analysis is time-consuming, and often affected by measurer's skill and subjective view on the determination of minerals. We introduce the alternate method using scanning X-ray analytical microscope and image processing and analyzing softwares. This method is simple and not affected by measurer's skill and subjective view. By using this method for thin sections or polished slabs of granitic rocks, we provided clear images showing mineral distributions and obtained objective data of modal compositions efficiently and quickly.
18
Thermochronologic studies on the formation of the Japanese Alps
Sueoka, Shigeru
Fisshon, Torakku Nyusureta, (30), p.4 - 6, 2017/12
熱年代等の手法を用いた山地の隆起・削剥史の検討事例として、南アルプス北部地域と北アルプス黒部地域の事例を紹介する。南アルプス北部地域では、フィッション・トラック年代や(U-Th)/He年代が山地東方に向かって系統的に若返る傾向が見られた。Thermo-kinematicモデルで検討したところ、これらの年代パターンは、白州-鳳凰山断層の活動によって再現可能であり、本地域は主にこれらの断層運動によって隆起していることが示唆された。北アルプス黒部地域では、新第三紀から第四紀の若い花崗岩が多数分布するため、従来の熱年代学的手法では隆起・削剥史の復元が困難であった。そのため、国内外の研究者との共同プロジェクトにより、新たに2種類のアプローチを用いて隆起・削剥史の復元を試みた。
19
Report on 41st Annual Meeting of Fission Track Research Group in Japan
Sueoka, Shigeru
Fisshon, Torakku Nyusureta, (30), p.30 - 32, 2017/12
第41回フィッション・トラック研究会が、2017年3月1日から3月3日にかけて、奈良県明日香村祝戸荘にて開催された。本研究会は、ESR応用計測研究会及びルミネッセンス年代測定研究会と合同で行われ、48名の参加者により、31件の発表が行われた。また、3月2日には、第41回フィッション・トラック研究会総会も行われ、今後のフィッション・トラック研究会の体制や運営方法などについて議論された。
20
Elucidating uplift/denudation history of the NE Japan Arc by using low-temperature thermochronology
Fukuda, Shoma*; Sueoka, Shigeru; Hasebe, Noriko*; Tamura, Akihiro*; Arai, Shoji*; Tagami, Takahiro*
Fisshon, Torakku Nyusureta, (30), p.7 - 10, 2017/12
東北日本弧の100万年スケールの地殻変動像把握のために、阿武隈山地、奥羽脊梁山脈、朝日山地にて、アパタイトフィッション・トラック(AFT)解析を実施した。前弧側の阿武隈山地では79.5-66.0Maの古いAFT年代が得られ、熱履歴解析の結果や先行データと合わせて、本地域は白亜紀後期以降は比較的安定な削剥環境だったことが推定された。対照的に、奥羽脊梁山脈では29.8-5.5Ma、背弧側の朝日山地では21.0-17.6Maの若いAFT年代が得られた。熱履歴解析の結果や既報のアパタイト(U-Th)/He年代と合わせると、最近数Maの山地形成に伴う急冷を反映していると解釈できる。脊梁山脈と背弧側の一部では、日本海拡大より古い年代も得られたが、これらの解釈に関しては、今後の追加分析が望まれる。