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JAEA Reports

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.

JAEA Reports

Study on equivalent continuum modeling with crack tensor on crystalline rock

Tanno, Takeo; Sato, Toshinori; Sanada, Hiroyuki; Hikima, Ryoichi; Matsui, Hiroya; Tada, Hiroyuki*; Goke, Mitsuo*; Kumasaka, Hiroo*; Ishii, Takashi*

JAEA-Research 2012-002, 86 Pages, 2012/03

JAEA-Research-2012-002.pdf:8.48MB

The Crack tensor model which is a kind of equivalent continuum model has been studied in rock mechanical investigation in the MIU. The fractured rock mass is modeled as the elastic continuum model with the crack tensor. In this study, crack tensor based on the geological observation in the MIU project was calculated, and REV (Representative Elementary Volume) in the shafts and research galleries was studied based on the relative error of the crack tensor. The correlation between the crack density, the trace length of crack and the trace of crack tensor and the rock mass classification was also studied.

JAEA Reports

Theoretical study of rock for estimating long-term behavior; FY2010 (Contract research)

Ichikawa, Yasuaki*; Tanno, Takeo; Hikima, Ryoichi; Sanada, Hiroyuki; Matsui, Hiroya; Sato, Toshinori

JAEA-Research 2012-003, 34 Pages, 2012/04

JAEA-Research-2012-003.pdf:3.33MB

A rock mass is a complex entity, including several classes of discontinuities and numerous heterogeneous and anisotropic minerals. From investigations of rock samples, we know that crystalline rock is a complex mix of minerals, grain boundaries and microcracks. Deformation and failure mechanisms may be more completely understood if we are able to correctly characterize the microscale composition and grain boundary properties. Amongst the rock-forming minerals, especially quartz and biotite in granite, numerous microcracks are developed. It is important to study coupled mechanical and chemical factors in crystalline rock for long-term behavior study. This report presents the results of the following FY2010 activities. (1) Explanation of nonlinear fracture mechanics, (2) Pressure dissolution experiments of using specimens of single quartz, (3) Theory study on the rate of quartz dissolution, (4) Homogenization theory for fractured rock

JAEA Reports

Study on hydrogeology on Mizunami Underground Research Laboratory Project; Hydrogeological modeling and groundwater flow simulation based on data of hydraulic and geochemical impacts during the construction of the MIU facilities; FY2008

Shimo, Michito*; Kumamoto, So*; Kosaka, Hiroshi; Onoe, Hironori; Saegusa, Hiromitsu; Mizuno, Takashi; Oyama, Takuya

JAEA-Research 2012-004, 126 Pages, 2012/04

JAEA-Research-2012-004.pdf:14.3MB

One of the goals of Mizunami Underground Research Laboratory (MIU) Project is to develop technical basis for investigation, analysis and evaluation technologies for understanding deep underground geological environment in various scales. Understanding groundwater flow system is one of the important issues in the project, and to achieve this purpose, technologies for a hydrogeological model and the groundwater flow simulation technique, have to be established. In this study, hydrogeological modeling and groundwater flow simulations have been carried out in order to predict hydraulic and geochemical impacts around the MIU Construction Site and inflow rate into the MIU facilities. As a result of this study, the significant hydrogeological structures could be estimated. The inflow rate into the MIU facilities and hydraulic and geochemical impacts with the MIU facilities construction could be predicted. The effect of pre-grouting to the MIU facilities could be also confirmed.

JAEA Reports

Experimental study on fundamental behavior of cavitation due to sub-surface vortex; Influences of fluid viscosity on occurrences of cavitation

Ezure, Toshiki; Miyake, Yasuhiro*; Tobita, Akira; Kimura, Nobuyuki; Kamide, Hideki

JAEA-Research 2012-005, 56 Pages, 2012/05

JAEA-Research-2012-005.pdf:10.06MB

In the design of JSFR, a two-loop cooling system and a compact reactor vessel are employed to achieve the economical improvement. However, these innovative designs lead to the increase of coolant velocity. As the results, strong vortices at the H/L intake may cause the cavitation (vortex cavitation). Therefore, the evaluation of occurrence behavior of vortex cavitation is the important issue for the structural integrity of reactor. In the present study, fundamental water experiments were performed in the cylindrical tank geometry. The water temperature was varied from 10$$^{circ}$$C to 80$$^{circ}$$C to clarify the influence of kinematic viscosity, $$nu$$. The occurrences behaviors of vortex cavitation were evaluated quantitatively by visualization measurement and image analysis. As the results, it was clarified that there was little dependence on $$nu$$ under the small $$nu$$ conditions, while it was relatively obvious under the large $$nu$$ conditions.

JAEA Reports

Research on diffusion behavior in oxide fuels (Joint research)

Sato, Isamu; Arima, Tatsumi*; Nishina, Masahiro*; Tanaka, Kosuke; Onose, Shoji; Idemitsu, Kazuya*

JAEA-Research 2012-006, 66 Pages, 2012/05

JAEA-Research-2012-006.pdf:13.55MB

As one of the important properties for fuel manufacturability and burning behavior, the diffusion behavior of actinides in oxide fuels was investigated by both the experimental and the molecular dynamics simulation (MD). Using diffusion couples consisted of an Am containing mixed oxide fuel and a UO$$_{2}$$ fuel, the diffusion tests were performed. The diffusion coefficients were estimated to be 10$$^{-12}$$m$$^{2}$$/s $$sim$$ 10$$^{-14}$$m$$^{2}$$/s. In addition, the difference between Pu and Am diffusion coefficients was vanishingly small. The temperature dependence of bulk diffusion coefficients of actinides in mixed oxide fuels could be evaluated by MD. An evaluation technique for the grain boundary diffusion could be established based on the coincidence site lattice theory. The practical diffusion coefficients were obtained by combining data from the experiments with those predicted from MD. The practical diffusion coefficients obtained was discussed for use of a fuel behavior analysis code.

JAEA Reports

Studies on estimation of hydrogeological structure using self-potential monitoring around Mizunami Underground Research Laboratory (MIU)

Tokuyasu, Shingo; Matsuoka, Toshiyuki; Hodotsuka, Yasuyuki*

JAEA-Research 2012-007, 55 Pages, 2012/06

JAEA-Research-2012-007.pdf:35.8MB
JAEA-Research-2012-007-appendix(DVD-ROM).zip:951.94MB

During drilling the pilot boring in October 2008 before construction of -300 m Access/Research Gallery, groundwater inflow more than 1,000 L/min is induced, and original signals of SP monitoring are observed. First of all in this study, we thus assess the method of data processing to extract the applicable signal from SP monitoring, and the hydrogeological structure is estimated using the treated data. Secondly, the signals of SP monitoring observed between March and April in 2006 when pumping of groundwater from the shafts are applied to the same method of data processing mentioned above. In addition, the treated data is used to estimate the hydrogeological structures more in detail. Considering all results together, the applicability of SP monitoring for estimating the distributions of major water-conducting features and faults with low permeability is discussed. As the result of this study, we conclude that it is likely that the hydrogeological structures would be estimated using the SP monitoring.

JAEA Reports

Study on hydrogeology in the Mizunami Underground Research Laboratory Project; Hydrogeological investigation to evaluate hydraulic characteristic of main-shaft fault

Daimaru, Shuji; Onoe, Hironori; Takeuchi, Ryuji

JAEA-Research 2012-008, 70 Pages, 2012/06

JAEA-Research-2012-008.pdf:21.39MB
JAEA-Research-2012-008(errata).pdf:0.54MB

JAEA is performing the Mizunami Underground Research Laboratory (MIU) project. Currently, the project is under Phase II and Phase III. As part of Phase II, the borehole investigation (10MI22, 10MI23) was conducted at 100m Measurement Niche in -300m Access/Research Gallery in 2010. As a result of long-term pumping test, completely different pressures due to the pumping test were observed in monitoring boreholes on opposite sides of the Main-shaft fault. This observation indicates that the normal direction of the Main-shaft fault is low permeable. And, the Main-shaft fault acts as a flow barrier normal to the fault plane. As a result of hydraulic test, permeability of fracture zone with accompanying host rock zone was from 9.4E-7m/s to 3.8E-11m/s. And, this zone was classified as two sections, permeability of the section is same as the upper highly fractured domain (UHFD :1.0E-7m/s) and the section of its permeability is 4 order lower than UHFD.

JAEA Reports

Elution properties of cesium contained within irradiated fast neutron reactor fuel in water and diluted nitric acid solution

Nakahara, Masaumi; Kaji, Naoya; Nomura, Kazunori

JAEA-Research 2012-009, 15 Pages, 2012/06

JAEA-Research-2012-009.pdf:6.37MB

In terms of preventing the formation of Pu and Cs compound, Cs in the feed solution should decrease in the U crystallization process. In order to separate Cs contained within irradiated nuclear fuel, the immersion experiments were carried out with the pure water and diluted HNO$$_{3}$$ solution. The elusion ratio of Cs within the powdered fuel in the pure water and 0.1 mol/dm$$^{3}$$ HNO$$_{3}$$ solution after 67 h was 33.8 and 38.3%, respectively. The experimental results suggest a possible beneficial effect of Cs elusion by immersion of the powdered fuel in the pure water and diluted HNO$$_{3}$$ solution before the fuel dissolution process.

JAEA Reports

Research and development for treatment and disposal technologies of TRU waste; JFY 2010 annual report

Kamei, Gento; Honda, Akira; Oda, Chie; Hirano, Fumio; Ichige, Satoru; Kurimoto, Yoshitaka; Hoshino, Seiichi; Akagi, Yosuke; Sato, Nobuyuki; Takahashi, Kuniaki; et al.

JAEA-Research 2012-010, 80 Pages, 2012/06

JAEA-Research-2012-010.pdf:7.45MB

Based on Japanese governmental policy and general scheme, research and development of geological disposal technology for TRU waste has been proceeding to improve reliability of the safety assessment of the co-locational disposal of TRU waste and of HLW, to expand the basement of generic safety assessment, and to develop the alternative technology to cope with the broad geologic environment of Japan. Japan Atomic Energy Agency is dealing with the assignments in the governmental generic scheme. We report here the progress of the studies at the end of H22 (2010) Japanese fiscal year and their products during the last 5 years. These include (1) evaluation of long-term mechanical stability in the near-field including development of a creep mode of rock and analyses of mechanical behavior of TRU waste repository, (2) performance assessment of the disposal system including cementitious material alteration, bentonite and hostrock alteration with alkaline solution and nitrate effect, and (3) alternative technology development including decomposition of nitrate.

JAEA Reports

Study on dose assessment in surrounding environment of the Tono Mine associated with closure activity

Sasao, Eiji

JAEA-Research 2012-011, 147 Pages, 2012/07

JAEA-Research-2012-011.pdf:13.44MB

Dose assessment associated with closure activity of the Tono Mine has been performed. Localities for dose evaluation are selected at the Higashihoragawa and Hiyoshigawa. Evaluation scenarios are classified into the base and alternative scenarios. Parameters are set-up based on the existing data. But the range and uncertainty of parameters are considered in the alternative cases. Maximum exposure doses of the base and alternative scenarios are 0.08 mSv/year, and 0.09 mSv/year including direct and skyshine $$gamma$$ rays and exposure of exhalated radon at the Higashihoragawa. On the alternative cases, exposure doses are calculated as 0.05-0.14 mSv/year in the base and alternative scenarios. At the Hiyoshigawa, maximum exposure dose is less than 0.001 mSv/year for the base scenario, and 0.001 mSv/year for the alternative scenario. On the alternative cases, maximum exposure doses are less than 0.001 mSv/year for the base scenario and 0.0006-0.002 mSv/year for the alternative scenario.

JAEA Reports

Study on hydrogeology on the Mizunami Underground Research Laboratory Project; Groundwater flow and particle tracking simulation on site scale

Kosaka, Hiroshi; Saegusa, Hiromitsu; Kurihara, Arata*; Onoe, Hironori

JAEA-Research 2012-012, 100 Pages, 2012/07

JAEA-Research-2012-012.pdf:17.95MB

In this study, groundwater flow and particle tracking simulations using hydrogeological models have been carried out in order to evaluate the relationship between understanding of groundwater flow characteristics and the amount of information that is increased by the progress of investigations. The influences of difference of the method for interpretation of hydrogeology have been also evaluated. As a result, uncertainties of the groundwater flow characteristics were decreased by increasing the amount of information. It was also found that the distribution of large-scale discrete features and the heterogeneity of groundwater flow characteristics affect the groundwater flow characteristics. Furthermore, the method to identify the target of further investigation and to make plan for the investigation were proposed.

JAEA Reports

Development of a standard data base for FBR core design, 14; Analyses of extensive FBR core characteristics based on JENDL-4.0

Sugino, Kazuteru; Ishikawa, Makoto; Numata, Kazuyuki*; Iwai, Takehiko*; Jin, Tomoyuki*; Nagaya, Yasunobu; Hazama, Taira; Chiba, Go*; Yokoyama, Kenji; Kugo, Teruhiko

JAEA-Research 2012-013, 411 Pages, 2012/07

JAEA-Research-2012-013.pdf:18.72MB
JAEA-Research-2012-013-appendix(CD-ROM).zip:75.82MB

Aiming at evaluating the core design prediction accuracy of fast reactors, various kinds of fast reactor core experiments/tests have been analyzed with the Japan's latest evaluated nuclear data library JENDL-4.0. Totally 643 characteristics of reactor physics experiments/tests and irradiation tests performed using the critical facilities: ZPPR, FCA, ZEBRA, BFS, MASURCA, ultra-small cores of LANL and power plants: SEFOR, Joyo, Monju were dealt. In analyses, a standard scheme/method for fast reactor cores was applied including detailed or precise calculations for best estimation. In addition, results of analyses were investigated from the viewpoints of uncertainties caused by experiment/test, analytical modeling and cross-section data in order to synthetically evaluate the consistency among different cores and characteristics. Further, by utilizing these evaluations, prediction accuracy of core characteristics were evaluated for fast power reactor cores that are under designing in the fast reactor cycle technology development (FaCT) project.

JAEA Reports

Experimental study on prevention of high cycle thermal fatigue in a compact reactor vessel of advanced sodium cooled reactor; Thermal striping phenomena at bottom of upper internal structure

Kobayashi, Jun; Kimura, Nobuyuki; Tobita, Akira; Kamide, Hideki

JAEA-Research 2012-014, 40 Pages, 2012/07

JAEA-Research-2012-014.pdf:7.8MB

As the temperatures difference between the control rod channels and the core fuel subassemblies is around 100 $$^{circ}$$C centigrade, temperature fluctuation due to the fluid mixing at the core outlet may cause high cycle thermal fatigue at the bottom of upper internal structure (UIS) in JSFR. Then, a water experiment was conducted using an 1/3 scale 60 $$^{circ}$$ sector model. As a result, thermal striping phenomena in the region between the fuel subassembly outlet and the bottom of the UIS were grasped. The modified geometry of the UIS bottom and the handling head of the primary CR channel was created so as to suppress the cold jets from the CR channels. The comparison of measured temperature fluctuations around the CR channels revealed that the modified geometry was effective to decrease the temperature fluctuation intensity and amplitude in the sensitive frequency band to the stress conversion.

JAEA Reports

Technical development to remove radionuclides from agricultural soils by plants (Joint research)

Yamada, Satoshi*; Sakoda, Akihiro; Ishimori, Yuu

JAEA-Research 2012-015, 32 Pages, 2012/07

JAEA-Research-2012-015.pdf:9.25MB

Tottori University and Japan Atomic Energy Agency started a joint study to develop an environmental remediation technique for agricultural soil. Nine plants were water-cultured and examined for screening. A few were selected as candidates for demonstrations in fields. Preselected plants were mainly halophytes. Easily cultivated and harvested plants without harmful effect on new agriculture were also considered. Seedings prepared were first grown for a certain term. Additive-free, $$^{133}$$Cs and $$^{88}$$Sr groups, which are both stable isotopes, were then made. Stems, leaves and roots were harvested, in principle, two weeks after the addition, to measure K, Ca, Mg, Sr and Cs concentrations in them. It was concluded that New Zealand spinach and ice plant were most adequate for removing contaminants from surface soil. The two accumulate Cs and Sr mostly in the shoots, are prostrate, and spread the roots shallowly. For valid application, growth-phase dependences of absorption and distribution, growth property and root distribution should be elucidated. Finally, the application study plan was developed based on screening test results.

JAEA Reports

Questionnaire survey on public risk perception of the wide area disposal of disaster waste generated after the Great East Japan Earthquake for residents in Okayama prefecture (Joint research)

Tanaka, Masaru*; Gofuku, Akio*; Ishizaka, Kaoru*; Sato, Kazuhiko; Nagahama, Yoji

JAEA-Research 2012-016, 23 Pages, 2012/07

JAEA-Research-2012-016.pdf:9.41MB

Japan Atomic Energy Agency, Okayama University, Tottori University of Environmental Studies and Research Institute of Solid Waste Management Engineering had been conducting a research on risk perception and confidence-building among stakeholders regarding environmental remediation of Uranium mine site and disposal of industrial waste. Cognitive structure of public on safety for wide area disposal of disaster waste which had been generated from Iwate and Miyagi prefectures after the Great East Japan Earthquake would be important from a view of our research. Therefore, a questionnaire survey on public risk perception of the disposal of disaster waste for residents in Okayama prefecture has been carried out. The results are; (1) 93% of respondents support the local government cooperation for the disposal, (2) 87% of respondents support the acceptance and the disposal in their home town, and (3) 70% of respondents were concerned about radioactive contamination caused by the disposal.

JAEA Reports

Study on thermalhydraulics of thermal striping phenomena; Evaluation of transfer characteristics of temperature fluctuation based on conjugated numerical simulation in triple-parallel jet geometry

Kimura, Nobuyuki; Kamide, Hideki; Nagasawa, Kazuyoshi*; Emonot, P.*

JAEA-Research 2012-017, 97 Pages, 2012/07

JAEA-Research-2012-017.pdf:12.12MB

A quantitative evaluation on thermal striping is of importance for reactor safety. In this study, sodium and water experiments of parallel triple jets configuration were performed. For these experiments, numerical simulations were carried out to evaluate the transfer characteristics of temperature fluctuation from fluid to structure. The analysis code, called Trio-U, used in the study has been developed at the CEA in France. In the simulations, the calculated time-averaged temperature distributions in fluid and structure were close to the experimental results in sodium and water. The power spectrum densities of temperature fluctuation in fluid and structure were also in good agreements between the experiments and calculations. Furthermore the calculated decay characteristics of temperature fluctuation from fluid to structure were in good agreements with the experimental results.

JAEA Reports

Development of geological models in the Mizunami Underground Research Laboratory Project; Updating from "Shaft180 geological model" to "Stage300 geological model" in Phase 2

Ishibashi, Masayuki; Kurihara, Arata*; Matsuoka, Toshiyuki; Sasao, Eiji

JAEA-Research 2012-018, 48 Pages, 2012/07

JAEA-Research-2012-018.pdf:8.48MB
JAEA-Research-2012-018(errata).pdf:1.13MB
JAEA-Research-2012-018-appendix(CD-ROM).zip:13.81MB

This document presents about updating of geological models at the Phase 2 in the Mizunami underground research laboratory project. In the phase 2, the geological models has been updated four times (Shaft180 geological model, Pilot500 geological model, Sustage200 geological model, Stage300 geological model) based on geological mapping date and/or some borehole investigation data at the shafts and research galleries. These geological models represent distributions of lithofacies and/or geological structures based on each geological investigation. In order to evaluate relationship between understanding of geological environments and progress of investigations, to organize the history of geological models updating is important.

JAEA Reports

Rehabilitation experiment by phytoremediation using lawn grass

Fukushima Environmental Safety Center, Headquarters of Fukushima Partnership Operations; Ningyo-toge Environmental Engineering Center; Fuel Cycle Safety Research Unit, Nuclear Safety Research Center; Geological Isolation Research Unit, Geological Isolation Research and Development Directorate; Nuclear Cycle Backend Directorate

JAEA-Research 2012-019, 125 Pages, 2012/08

JAEA-Research-2012-019.pdf:12.81MB

Measures against environmental contamination by radioactive materials originated from the Fukushima nuclear accident (May, 2011), are being conducted in Fukushima and surrounding prefectures. Regarding to the measures, a phytoremediation experiment with several types of lawn grasses in a field scale have been carried out. Lawn grasses are generally characterized by shallow rizosphere, high density and root mat formation. Decontamination effectiveness of radioactive cesium by plant uptake and by sod removing was investigated. As a result, the range of decontamination factors by plant uptake was below than 1% because of low transfer rate form soil to plant. On the other hand, maximum decontamination factor by sod removing reached about 100%. Decontamination activities with various methods will be implemented according to the national decontamination policy and related plans in each municipality. The phytoremediation method with lawn grass would be applicable in limited circumstances.

JAEA Reports

Development of calculation system for decontamination effect, CDE

Satoh, Daiki; Kojima, Kensuke; Oizumi, Akito; Matsuda, Norihiro; Kugo, Teruhiko; Sakamoto, Yukio*; Endo, Akira; Okajima, Shigeaki

JAEA-Research 2012-020, 97 Pages, 2012/08

JAEA-Research-2012-020.pdf:7.32MB

A computer software, named CDE (Calculation system for Decontamination Effect), has been developed to support planning the decontamination. CDE calculates the dose rates before the decontamination by using a database of dose contributions by radioactive cesium. The decontamination factor is utilized in the prediction of the dose rates after the decontamination, and dose rate reduction factor is evaluated to express the decontamination effect. The results are visualized on the image of a target zone with color map. In this paper, the overview of the software and the dose calculation method are reported. The comparison with the calculation results by a three-dimensional radiation transport code PHITS is also presented. In addition, the source code of the dose calculation program and user's manual of CDE are attached as appendices.

JAEA Reports

Feasibility study of oxygen getter materials for FBR MOX fuel, 3; Evaluation for the titanium roll pellet method

Morihira, Masayuki

JAEA-Research 2012-021, 25 Pages, 2012/08

JAEA-Research-2012-021.pdf:9.24MB

Cladding inner corrosion is one of the life control factors of FBR MOX fuels. Because excess oxygen during fission brings the corrosion, oxygen getter option was proposed and a feasibility study has been conducted. In the previous study, an option was proposed to locate getter titanium in the lower end of the upper axial blanket region of a fuel element. Also the titanium roll pellet method was proposed to reduce the smear density of the getter titanium to absorb the swelling during the oxidation. In this study, producibility of titanium roll pellets and their oxidation behavior were evaluated.

JAEA Reports

Study for establishment of the methodology for hydrogeological modeling using hydraulic discrete fracture networks (Study on hydrogeology in crystalline fractured rock)

Ando, Kenichi*; Tanaka, Tatsuya*; Hashimoto, Shuji*; Saegusa, Hiromitsu; Onoe, Hironori

JAEA-Research 2012-022, 60 Pages, 2012/08

JAEA-Research-2012-022.pdf:8.51MB

In this study, water conducting features in Toki granite were defined by the interpretation and integration of geological and hydrogeological data obtained from the borehole investigation in the Phase I of the MIU Project and Regional Hydrogeological Study. Then, the hydrogeological model of Block scale was constructed using hydraulic discrete fracture networks, and equivalent hydraulic conductivities in Block scale were calculated. And, adequacy of equivalent hydraulic conductivities in Block scale was confirmed using result of hydraulic packer tests.

JAEA Reports

Study on applicability of low alkaline cement in Horonobe Underground Research Laboratory Project; In-situ experiment at 250m gallery

Nakayama, Masashi; Sawada, Sumiyuki; Sato, Haruo; Sugita, Yutaka

JAEA-Research 2012-023, 65 Pages, 2012/08

JAEA-Research-2012-023.pdf:13.17MB

In Japan, any high-level radioactive waste repository is to be constructed at over 300m depth below surface. Tunnel support is used for safety during the construction and operation, and shotcrete and concrete lining are used as the tunnel support. Concrete is a composite material comprised of aggregate, cement and various additives. Low alkaline cement has been developed for the long term stability of the barrier systems whose performance could be negatively affected by highly alkaline conditions arising due to cement used in a repository. Japan Atomic Energy Agency (JAEA) has developed a low alkaline cement, named as HFSC (Highly fly-ash contained silicafume cement), containing over 60wt% of silica-fume (SF) and coal ash (FA). JAEA is presently constructing an underground research laboratory (URL) at Horonobe for research and development in the geosciences and repository engineering technology. HFSC was used experimentally as the shotcrete material in construction of part of the 140m deep gallery in Horonobe URL in 2010. The objective of this experiment was to assess the performance of HFSC shotcrete in terms of mechanics, workability, durability, and so on. HFSC used in this experiment is composed of 40wt% OPC (Ordinary Portland Cement), 20wt% SF, and 40wt% FA. This composition was determined based on mechanical testing of various mixes of the above components. Because of the low OPC content, the strength of HFSC tends to be lower than that of OPC in normal concrete. The total length of tunnel constructed using HFSC shotcrete is about 53m. The workability of HFSC shotcrete was confirmed by this experimental construction. In this report, we present detailed results of the ${it in-situ}$ construction test.

JAEA Reports

Annual report for research on geosphere stability for long-term isolation of radioactive waste in fiscal years 2011

Asamori, Koichi; Niwa, Masakazu; Hanamuro, Takahiro; Yamada, Kunimi; Kusano, Tomohiro; Makuuchi, Ayumu; Takatori, Ryoichi; Kokubu, Yoko; Matsubara, Akihiro; Ishimaru, Tsuneari; et al.

JAEA-Research 2012-024, 132 Pages, 2012/09

JAEA-Research-2012-024.pdf:15.68MB

This annual report documents the progress of R&D in the 2nd fiscal year during the JAEA 2nd Midterm Plan (FY 2010 - 2014) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planed framework is structured into the following categories: (1) development and systematization of investigation techniques for selecting suitable sites in geosphere stability, (2) development, application and verification of prediction models for evaluating the changes of geological environment in thermal, hydraulic, mechanical and geochemical conditions for a long period of time, and (3) development of new dating techniques for providing information about geologic history and the timing of geologic events. In this paper, the current status of R&D activities with previous scientific and technological progress is summarized.

JAEA Reports

Studies about strength recovery and generalized relaxation behavior of rock, 5

Sanada, Masanori; Kishi, Hirokazu*; Sugita, Yutaka; Hayashi, Katsuhiko*; Takebe, Atsuji*; Okubo, Seisuke*

JAEA-Research 2012-025, 130 Pages, 2012/09

JAEA-Research-2012-025.pdf:4.12MB

In this study, strength recovery, generalized stress relaxation and two tensile strength tests were carried out using shale sampled in the Wakkanai-formation. As the results, by using the value of a suitable constant with the constitutive equation showing strength recovery, it was showed that change of the axial stress in a compacting test could be expressed. About the generalized relaxation, it examined by the air dried and the saturated condition. Visco-elastic behavior was more remarkable in saturated condition than the air dried. Moreover, when the loading rate up to the starting point of the generalized relaxation test was large, the influence on visco-elastic behavior was remarkable. About tensile characteristics, a splitting tensile strength test and a uniaxial tensile strength test were carried out. About splitting tensile strength, it turned out that the influence of the loading direction on a bedding plane is great.

JAEA Reports

Thermal-hydraulic analysis of boiling event of reprocessed liquid wastes with MELCOR code

Yoshida, Kazuo; Ishikawa, Jun

JAEA-Research 2012-026, 25 Pages, 2012/09

JAEA-Research-2012-026.pdf:1.74MB

Boiling events of reprocessed liquid wastes are postulated to be occurred caused by the loss of cooling function persisting over a long period of time at a fuel reprocessing plant. Some amounts of radioactive materials could be released from facilities caused by vapor flow from a boiling liquid waste storage tank. Thermal-hydraulic behaviors in compartments of facility building are essential to be analyzed for assessing amount of released radioactive materials. MELCOR, which has been developed for severe accident analysis of nuclear reactors, has been applied in this study. Functional features of Control Functions and Time-Specified Volumes in MELCOR have been used to model key phenomena such as, boiling at higher temperature than water boiling point, vaporization of nitric acid and generation of non-condensable gases due to denitrating reaction. Results of analysis demonstrate applicability of MELCOR to those events.

JAEA Reports

Alpha-ray irradiation damage on diverse rubber materials applied to glove box for plutonium treatment

Saito, Kosuke; Nogami, Yoshitaka; Kodato, Kazuo; Matsuyama, Kazutomi; Endo, Hideo

JAEA-Research 2012-027, 118 Pages, 2012/09

JAEA-Research-2012-027.pdf:21.12MB

This report is compilation of 4 years tests and experiments of simulated alpha-ray irradiation on diverse materials for glove box application at Plutonium Fuel Development Center, Tokai, JAEA. Specimens prepared from the materials are irradiated with $$^{4}$$He$$^{2+}$$ ion beam whose kinetic energy was 5 MeV and sent to exterior observation, optical microscopy and tensile tests. Experiments revealed ion-irradiation generally makes tens of micrometers of deteriorated layer which is hardened and discolored on the surface of the specimens. According to dose, tensile properties such as tensile strength and elongation at break decrease generally. Tensile strength decrease is expected to ascribe to stress concentration on cracks of irradiation-damaged surface and rupture. Lead-contained glove, which is ordinarily used on highly $$gamma$$-radiative environments, saturates the decrease of its tensile strength around fluence of 1.4e+14 cm$$^{-2}$$. In addition, deterioration was accelerated for tension-loaded material and the saturation is around 4.6e+13 cm$$^{-2}$$ for 100%-extended specimens. The candidates of alternative new materials are two kinds of developed chlorosulfonated polyethylene (CSM) and conductive rubber, which were experimented and tested in like manner. From the results and inherent properties of these materials, one kind of CSM and conductive rubber are relatively promising. Gloves used at low-dose environments and vinyl chloride applied for glove ports were also experimented and tested, and quantitative data were which are useful for life-elongation measure obtained. The irradiation tests on this report are unprecedented ones with low-energy ion, and the obtained quantitative data of material properties and deterioration are scientifically rare and important.

JAEA Reports

Reverse Vertical Seismic Profiling using vibration during the construction of underground facility

Matsuoka, Toshiyuki; Hodotsuka, Yasuyuki*; Yamada, Nobuto

JAEA-Research 2012-028, 70 Pages, 2012/11

JAEA-Research-2012-028.pdf:19.33MB

Reverse Vertical Seismic Profiling (R-VSP) using vibration during the construction of underground facility has been carried out at the MIU construction site to develop the technique that estimate the 3-dimensional geological structure. In this report, we apply plural data processing/analysis methods (VSP-CDP transform, VSP migration, IP transform and seismic interferometory) to observed vibration data (blasting data, drilling vibration data and construction noise data), and discuses the applicability of the R-VSP. In this study, geological structures such as unconformities between sedimentary rocks and granite, and steep faults were extracted using applied prual data processing/analysis methods. We conclude that it is likely that the R-VSP using various vibration data and prual data processing/analysis, can apply to estimate the 3-dimensional geological structure.

JAEA Reports

Study of cable ageing mechanism for nuclear power plant (Contract research)

Seguchi, Tadao*; Tamura, Kiyotoshi*; Watashi, Katsumi; Suzuki, Masahide; Shimada, Akihiko; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito; Oshima, Takeshi; Kudo, Hisaaki*

JAEA-Research 2012-029, 158 Pages, 2012/12

JAEA-Research-2012-029.pdf:9.4MB

The degradation mechanisms of ethylene-propylene rubber (EPR), crosslinked polyethylene (XLPE), polyvinylchloride (PVC), and silicone rubber (SiR) as the cable insulation materials were investigated for the cable ageing research of the nuclear power plant. The materials as same insulations for the practical cable (practical formulation) and as the model formulation containing specific additive were selected. They were exposed to the accelerated radiation and thermal environments. The mechanical properties, the crosslinking and chain scission, and the distribution of antioxidant and of oxidative products were measured and analyzed.

JAEA Reports

Study on separation of platinum-group metals by using laser-induced particle formation

Saeki, Morihisa; Esaka, Fumitaka; Taguchi, Tomitsugu; Oba, Hironori

JAEA-Research 2012-030, 16 Pages, 2012/11

JAEA-Research-2012-030.pdf:2.76MB

We proposed separation technique of platinum-group metals (PGMs) from a solution of high-level radioactive waste by using laser-induced particle formation, and performed its proof-of-principle experiment. The simulated solution of high-level radioactive liquid wastes (HLLW) was prepared by dissolving palladium (Pd), rhodium (Rh), ruthenium (Ru) and neodymium (Nd) into distilled water. The Nd metal was added as representative of lanthanide and minor actinide. After 40-min irradiation of a mixture of the simulated solution of HLLW and ethanol (v/v = 1/1) with a UV laser (266 nm, 20 mJ), the Pd, Rh and Ru metals were separated from the Nd ion as particle with sub-micron size. The PGM particles were recovered by filtration and centrifugation. Analysis of ion concentration in the sample solution by ICP-AES suggested that the Pd, Rh and Ru metals were recovered with efficiency of 100%, 94-99%, 65-69%, while the Nd ion was completely kept in the sample solution.

JAEA Reports

Development of separation process for Mo by extraction with di-2-ethylhexylphosphoric acid

Morita, Yasuji; Yamagishi, Isao; Tsubata, Yasuhiro; Matsumura, Kazumi; Sakurai, Koji*; Iijima, Takahiko

JAEA-Research 2012-031, 39 Pages, 2012/11

JAEA-Research-2012-031.pdf:4.87MB
JAEA-Research-2012-031(errata).pdf:0.14MB

Solvent extraction process with di-2-ethylhexylphosphoric acid has been developed for the purpose of Mo separation from high-level radioactive liquid wastes (HLLW). Mo has very low solubility in borosilicate glasses and makes so-called yellow phase when it contained beyond the solubility. After extraction and back-extraction data of Mo and other fission products were obtained by batch extraction tests, continuous extraction tests with simulated HLLW were performed using mixer-settler twice. At the second test, reduction of Y extraction yield and increase of Mo and Zr back-extraction yield were obtained compared with the results of the first tests, but those values should be still improved. Process simulation technique was developed using simulation code named PARC-MA, and the optimized process condition was obtained by the simulation.

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage; Progress report on NUMO-JAEA collaborative research in FY2011 (Joint research)

Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Hayano, Akira; Mitsui, Seiichiro; Taniguchi, Naoki; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.

JAEA-Research 2012-032, 298 Pages, 2012/09

JAEA-Research-2012-032.pdf:33.68MB

JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation phase. The topics and the conducted research are follows; (1) Study on selection of host rock: in terms of hydraulic properties, items for assessing rock property, and assessment methodology of groundwater travel time has been organized with interaction from site investigation. (2) Study on development of scenario: the existing approach has been embodied, in addition, the phenomenological understanding regarding dissolution of and nuclide release from vitrified waste, corrosion of the overpack, long-term performance of the buffer are summarized. (3) Study on setting nuclide migration parameters: the approach for parameter setting has been improved for sorption and diffusion coefficient of buffer/rock, and applied and tested for parameter setting of key radionuclides. (4) Study on ensuring quality of knowledge: framework for ensuring quality of knowledge has been studied and examined aimed at the likely disposal facility condition.

JAEA Reports

Numerical calculation of axisymmetric fluid-liquid interfaces by polar coordinate system and examples associated with U-Pu co-conversion technology

Hosoma, Takashi

JAEA-Research 2012-033, 66 Pages, 2013/01

JAEA-Research-2012-033.pdf:13.1MB

An exquisite shape of gas-liquid interface, that is a bubble/drop/liquid bridge, is the result of continuous pressure balance along vertical axis between the pressure due to difference of density and the pressure due to surface tension and curvature of interface. However, there have been surprisingly a little papers arguing the accurate shape, curvatures and volume. Regarding the research and development of U-Pu co-conversion technology, some phenomena were well understood by obtaining the accurate shape and/or volume. A numerical solving method by polar coordinate system with a switched-origin algorithm applicable to the shape that includes multiple tangential planes both in horizontal and in vertical was derived through such experiences, although static physical conditions and axisymmetrical property are assumed. The real interface shape is actualized or selected as a part of the calculated curve, which depends on physical conditions. A bubble at the tip of dip-tube used for density/level measurement, a bubble nucleates in the cylindrical shape of liquid heated by microwave and an estimated liquid bridge in the granule after co-conversion were described as actual examples. Interfaces between water and air under normal temperature and atmospheric pressure were described as numerical examples for systematic investigation. Contact angle, internal/external pressure difference, volume, surface energy and wavelength of periodically deforming shape are physical conditions actualizing the calculation.

JAEA Reports

Corrosion and low-cycle fatigue behavior of FBR structural materials in sodium contaminated by oxygen

Yoshida, Eiichi; Kato, Shoichi; Furukawa, Tomohiro

JAEA-Research 2012-034, 68 Pages, 2013/01

JAEA-Research-2012-034.pdf:11.75MB

Oxygen concentration in sodium is the important factor for the corrosion of FBR structural materials. In this study, the experiments have been done to clarify the effect of sodium contaminated by oxygen on corrosion and low cycle fatigue strength of the materials. The materials for use of the experiments were FBR Grade type 316 SS (316FR) and Mod. 9Cr-1Mo steel. The corrosion test has been performed in sodium containing of 1, 10$$^{3}$$ and 10$$^{4}$$ ppm of initial oxygen at 650$$^{circ}$$C for 500 hours. The fatigue test has been done for the post-immersed steels at 650$$^{circ}$$C in air.

JAEA Reports

Experiment on evaluation of confinement capability of fuel cycle facility under combustion of combustible materials (Contract research)

Abe, Hitoshi; Tashiro, Shinsuke; Watanabe, Koji; Uchiyama, Gunzo

JAEA-Research 2012-035, 26 Pages, 2013/01

JAEA-Research-2012-035.pdf:1.94MB

To contribute on confirmation of safety of fuel cycle facilities, an evaluation method for soundness of confinement capability of the facilities under fire accident has been investigated. Organic extraction solvents, zinc stearate, which is added into MOX powder in MOX fuel preparation process, and typical lubricating oil were considered to be examination objects as the representative combustible materials in the facilities. Combustion property data, such as mass loss rate and soot release fraction, of them and clogging property data of HEPA filter with combustion of the organic extraction solvents were measured. As the results, it was found that soot release fraction from burning 30%TBP/70%dodecane was larger than that of the other materials including dodecane and very rapid rise of differential pressure of HEPA filter, which has not been reported, would be induced in the last stage of combustion of 30%TBP/70%dodecane. Furthermore, it was confirmed that zinc stearate, of which combustibility has not been considered, burned continuously in the condition which was heated from outside.

JAEA Reports

Development of geological structure modeling technology based on regional tectonic process (Joint research)

Tagami, Masahiko*; Yamada, Yasuhiro*; Yamashita, Yoshihiko*; Miyakawa, Ayumu*; Matsuoka, Toshifumi*; Xue, Z.*; Tsuji, Takeshi*; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Amano, Kenji; et al.

JAEA-Research 2012-036, 110 Pages, 2013/02

JAEA-Research-2012-036.pdf:44.93MB

Northeast strike faults developed in and around the Mizunami Underground Research Laboratory (MIU) control groundwater flow. These faults were possibly formed as a part of pull-apart structure by the right lateral movement of the Tsukiyoshi fault distributed in the north of MIU site. But the formational mechanism of these faults is still uncertain. In this joint research, the analog experiment and the numerical simulation were used to restore the geological structures around MIU site. The paleo-stress analysis were exposed an ancient deformation mechanism, and the formation timing was presumed in the regional tectonics. The results are adopted for the design of the analog experiment and the numerical simulation. The results of obtained analog experiment and numerical simulation are verified three-dimensionally, and then compared to the current geological structure model. Then the geological structure in the uninvestigated area is estimated.

JAEA Reports

Study on geology on the Mizunami Underground Research Laboratory Project; Geology and geological structure from the surface to G.L. -300m

Kuboshima, Koji; Ishibashi, Masayuki; Sasao, Eiji; Tsuruta, Tadahiko; Tagami, Masahiko*; Yuguchi, Takashi

JAEA-Research 2012-037, 78 Pages, 2013/03

JAEA-Research-2012-037.pdf:235.85MB

The MIU (Mizunami Underground Research Laboratory) Project has three overlapping phases, Surface-based investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). Currently, the project is under Phase II and Phase III. One of Phase II goals is set up to develop and revise models of the geological environment using the investigation results obtained during excavation, and to determine and assess changes in the geological environment in response to excavation. This report aims compiling results of study on geology and geological structure from the surface to G.L. -300m in the Phase II and provides the fundamental information on the geology and geological structure for future study. The compiling results of this report reflected basic data are utilized in the updating of the geological models in the Phase II.

JAEA Reports

Method development to evaluate retardation effects of nuclide migration in the near-field host rock

Hayano, Akira; Sawada, Atsushi

JAEA-Research 2012-038, 32 Pages, 2013/02

JAEA-Research-2012-038.pdf:3.66MB

The purpose of this study is to contribute to methodology development for evaluating retardation effects of nuclide transport in near-field host rock to flexibly respond to the uncertainty of SDMs. Initially, the methodology for evaluating retardation effects of nuclide transport quantitatively in near-field host rock was developed. Then, the nuclide transport analysis using the data obtained at the surface-based investigation phase of Mizunami underground laboratory project was carried out in order to show the example of application for the methodology. Finally, the impact on results of evaluation caused by the uncertainty of SDMs was considered, and feedback to the investigation of geological environment was given from the result of the analysis of this study.

JAEA Reports

Development of evaluation method for the effect of reducing equivalent doses to the thyroid by implementing iodine thyroid blocking

Kimura, Masanori; Takahara, Shogo; Homma, Toshimitsu

JAEA-Research 2012-039, 24 Pages, 2013/02

JAEA-Research-2012-039.pdf:1.91MB

To consider the method of implementing urgent protective actions in a nuclear accident appropriately, the authors have been assessing the effects of reducing doses by taking such actions using a Level 3 Probabilistic Safety Assessment (PSA) code, the OSCAAR, developed by the JAEA. Iodine thyroid blocking is an effective urgent protective action to reduce the equivalent doses to the thyroid due to inhalation of radioactive iodine. However, the timing of the administration of stable iodine is important to maximize the effectiveness for thyroidal blocking. Therefore, the careful consideration should be given to the most effective way of iodine thyroid blocking when preparing off-site emergency plans. In the present study, the authors introduced a metabolic model of iodine into the OSCAAR for evaluating the effect of the administration of stable iodine for reducing equivalent doses to the thyroid depending on the its timing. Then, examined the effectiveness of iodine thyroid blocking combined with sheltering or evacuation in the containment bypass scenario with large radioactive release to the environment.

JAEA Reports

Characteristic of tritium release from Li$$_{2}$$TiO$$_{3}$$ under D-T neutron irradiation

Edao, Yuki; Kawamura, Yoshinori; Ochiai, Kentaro; Hoshino, Tsuyoshi; Takakura, Kosuke; Ota, Masayuki; Iwai, Yasunori; Yamanishi, Toshihiko; Konno, Chikara

JAEA-Research 2012-040, 15 Pages, 2013/02

JAEA-Research-2012-040.pdf:1.8MB

Tritium generation and recovery studies on Li$$_{2}$$TiO$$_{3}$$ as a solid breeding material under neutron irradiation carried out in the Fusion Neutron Source (FNS) facility. A capsule with Li$$_{2}$$TiO$$_{3}$$ packed bed was put in a system which simulated an actual blanket system which built in beryllium blocks and lithium titanate ones. Estimated values of the amount of tritium generation by a numerical calculation agreed closely with experimental values. The capsule was heated up to 300$$^{circ}$$C, and helium, helium with water vapor, hydrogen or hydrogen/water vapor were selected as purge gas. In the case of purge by helium added water vapor, the ratio of HTO to total tritium release was 98%. In helium with hydrogen/water vapor purge, the ratio of HTO to total tritium release was 80%, which was confirmed that HTO released by isotope exchange reaction between water vapor and tritium. In helium with hydrogen purge, the ratio of HT to total tritium release was 60$$sim$$70%, which was shown that HT released by isotope exchange reaction between hydrogen gas and tritium. HTO released by water generation reaction between hydrogen in purge gas and oxygen in Li$$_{2}$$TiO$$_{3}$$ although water vapor was not added in purge gas. The ratio of HTO release seemed to be small under the deoxidized condition of the Li$$_{2}$$TiO$$_{3}$$ surface. Tritium release behavior in the Li$$_{2}$$TiO$$_{3}$$ depended on the composition of purge gas, and its chemical form was affected by the surface conditions of Li$$_{2}$$TiO$$_{3}$$.

JAEA Reports

Fuel and core design studies on metal fuel sodium-cooled fast reactor (4), (5) and (6); Joint research report for JFY2009 - 2012

Uematsu, Mari Mariannu; Sugino, Kazuteru; Kawashima, Katsuyuki; Okano, Yasushi; Yamaji, Akifumi; Naganuma, Masayuki; Oki, Shigeo; Okubo, Tsutomu; Ota, Hirokazu*; Ogata, Takanari*; et al.

JAEA-Research 2012-041, 126 Pages, 2013/02

JAEA-Research-2012-041.pdf:16.49MB

The characteristics of sodium-cooled metal fuel core compared to MOX fuel core are given by its higher heavy metal density and superior neutron economy. By taking advantage of these characteristics and allowing flexibility in metal fuel specification and core design conditions as sodium void reactivity and bundle pressure drop, core design with high burnup, high breeding ratio and low fuel inventory features will be achievable. On ground of the major achievements in metal fuels utilization as driver fuels in sodium fast reactors in U.S., the metal fuel core concept is selected as a possible alternative of MOX fuel core concept in FaCT project. This report describes the following items as a result of the joint study on "Reactor core and fuel design of metal fuel core of sodium-cooled fast reactor" conducted by JAEA and CRIEPI during 4 years from fiscal year 2009 to 2012.

JAEA Reports

Choice evaluation of power supply composition using the mapping method of the long-term energy demand-and-supply scenario

Tatematsu, Kenji

JAEA-Research 2012-042, 45 Pages, 2013/03

JAEA-Research-2012-042.pdf:2.47MB

Long-term energy demand-and-supply were analyzed for our country using the MARKAL model, supposing six kinds of energy demand-and-supply scenarios where different installed capacity of nuclear power generation and the emission standard of carbon-dioxide were employed. It was shown that even when nuclear power generation was not used, the carbon-dioxide emissions in the whole country and a power generation sector are reducible by 37% and 47% in 2050 from the 1990 level, respectively. However, when nuclear power generation was phase-out and renewable energy and natural gas were substituted, it was found that an average power generating cost was higher than the case where use of nuclear or coal was continued, 3.7 yen/kWh or more. Moreover, in the case where immediate cessation of the nuclear power generation was carried out, it was also shown that a current average power generating cost rose by 4.4 yen/kWh. In order to evaluate and visualize the influence of power supply composition change on both the average power generating cost and the carbon-dioxide emissions, a new mapping method was proposed where diversity of an energy source, the carbon-dioxide emissions, and the average power generating cost were used as indexes. Based on the result of model analysis, when nuclear power generation was substituted with renewable energy, natural gas, or coal, oligopoly of an energy source was shown to increase sharply by abolition of nuclear power generation. These results showed that by continuing use of the nuclear power generation with a fixed scale, less carbon-dioxide emissions, avoiding oligopolization of an energy source and suppressing the steep rise of an average power generating cost were possible.

JAEA Reports

Study of hydrogeology in the Mizunami Underground Research Laboratory Project; Hydrogeological modeling and groundwater flow simulation based on data of hydraulic and geochemical impacts during the construction of the MIU facilities; FY 2009

Shimo, Michito*; Kumamoto, So*; Tsuyuguchi, Koji; Onoe, Hironori; Saegusa, Hiromitsu; Mizuno, Takashi; Oyama, Takuya

JAEA-Research 2012-043, 98 Pages, 2013/03

JAEA-Research-2012-043.pdf:26.71MB

One of the goals of the Mizunami Underground Research Laboratory (MIU) Project is to develop technical basis for investigation, analysis and evaluation technologies for understanding the deep underground geological environment in various scales. Understanding groundwater flow system is one of the important issues in the project, and to achieve this purpose, technologies for hydrogeological model and groundwater flow simulation technique, have to be established. As a result of this study, the significant hydrogeological structures around the MIU Construction Site were estimated. The inflow rate into the MIU facilities and hydraulic and geochemical impacts around the MIU Construction Site caused by the MIU facilities construction were predicted. The effect of pre-grouting to the MIU facilities was also confirmed.

JAEA Reports

Kd setting approaches for Horonobe mudstone systems; Applications of TSMs and semi-quantitative estimation procedures

Ochs, M.*; Tachi, Yukio; Trudel, D.*; Suyama, Tadahiro*

JAEA-Research 2012-044, 130 Pages, 2013/03

JAEA-Research-2012-044.pdf:3.61MB

JAEA has developed the setting approaches of sorption parameter (Kd) for site-specific conditions, to derive reliable parameter for performance assessment (PA) of geological disposal. These approaches include any transferring procedures from experimental conditions to PA conditions through expert judgments, semi-quantitative estimation procedures and thermodynamic sorption models (TSMs). The present report focused on illustrating a range of example calculations regarding the derivation of Kd values and their uncertainties based on semi-quantitative estimation procedures and TSMs. The Kd values of four key radionuclides, Cs, Ni, Am and Th were derived for Horonobe mudstone systems. These Kd-setting exercises allowed to estimate the magnitude of sorption under the site-specific conditions, and to identify some critical gaps in the existing data and process understanding. The possibilities of extending such approaches to further rock types including granitic rocks were also discussed.

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