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Journal Articles

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 $"A$sp$"o$ Hard Rock Laboratory in Sweden

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

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

 Times Cited Count:0 Percentile:0.04(Environmental Sciences)

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 $"A$sp$"o$ 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.

Journal Articles

A Study on the propagation characteristics of surface waves in granite based on ultrasonic measurements

Kimoto, Kazushi*; Okano, Aoi*; Saito, Takayasu*; Sato, Tadanobu*; Matsui, Hiroya

Doboku Gakkai Rombunshu, A2 (Oyo Rikigaku) (Internet), 76(2), p.I_97 - I_108, 2020/00

AA2020-0209.pdf:2.72MB

This study investigates the propagation characteristics of surface wave traveling in a random heterogeneous medium. For this purpose, ultrasonic measurements are performed on a granite block as a typical randomly heterogeneous medium. In this measurement, a line-focus transducer is used to excite ultrasonic waves, whereas a laser Doppler vibrometer is used to pickup the ultrasonic motion on the surface of the granite block. The measured waveforms are analysed in the frequency domain to evaluate the travel-time for each measurement point based on the Fermat's principle. From the ensemble of travel-times, the probability distribution is established as a function of travel-distance. The uncertainty of the travel-time and its spatial evolution are then investigated using the standard deviation of the travel-time as a measure of the uncertainty. As a result, it was found that the uncertainty is approximately proportional to the mean travel-time divided by the square root travel-distance.

Journal Articles

Effects of fine-scale surface alterations on tracer retention in a fractured crystalline rock from the Grimsel Test Site

Tachi, Yukio; Ito, Tsuyoshi*; Akagi, Yosuke*; Sato, Hisao*; Martin, A. J.*

Water Resources Research, 54(11), p.9287 - 9305, 2018/11

 Times Cited Count:5 Percentile:38.47(Environmental Sciences)

Effects of fine-scale surface alterations on radionuclide migration in fractured crystalline rocks were investigated by a comprehensive approach coupling a series of laboratory tests, microscopic observations and modelling, using a single fractured granodiorite sample from the Grimsel Test Site, Switzerland. Laboratory tests including through-diffusion, batch sorption and flow-through tests using five tracers indicated that tracer retention was consistently in the sequence of HDO, Se, Cs, Ni, Eu, and as well as showing the existence of a diffusion-resistance layer near the fracture surface, cation excess and anion exclusion effects for diffusion. Microscale heterogeneities in structural properties around the fracture were clarified quantitatively by coupling X-ray CT and EPMA. A three layer model including weathered vermiculite, foliated mica and undisturbed matrix layers, and their properties such as porosity, sorption and diffusion parameters, could provide a reasonable interpretation for breakthrough curves and concentration distributions near fracture surface of all tracers, measured in flow-through tests.

Journal Articles

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.

JAEA Reports

DELIGHT-8; One dimensional fuel cell burnup analysis code for High Temperature Gas-cooled Reactor (HTGR) (Joint research)

Nojiri, Naoki; Fujimoto, Nozomu; Mori, Tomoaki; Obata, Hiroyuki*

JAERI-Data/Code 2004-012, 65 Pages, 2004/10

JAERI-Data-Code-2004-012.pdf:7.77MB

DELIGHT code is a fuel cell burnup analysis code which can produce the group constants necessary for High Temperature Gas-cooled Reactors (HTGR) core analyses. Collision probability method is used to the lattice calculation. The lattice calculation model is a cylinder type fuel or a ball type fuel of the HTGR. This code characterizes the burnup calculation considering the double heterogeneity caused by coated fuel particles of the HTGR fuel. DELIGHT code has updated its nuclear data library to the latest JENDL-3.3 data, and included new burnup chain models in order to calculate high burnup HTGR cores. The material regions of the periphery burnable poisons (BPs) were divided into details in order to improve calculation accuracy of the BP lattice calculation. This report presents the revised points of the DELIGHT-8 and can be used as user's manual.

Journal Articles

Monte Carlo analysis of HTTR with the MVP statistical geometry model

Mori, Takamasa; Okumura, Keisuke; Nagaya, Yasunobu; Ando, Hiroei

Transactions of the American Nuclear Society, 83, p.283 - 284, 2000/00

no abstracts in English

JAEA Reports

Preliminary analyses for HTTR's start-up physics tests by Monte Carlo code MVP

Nojiri, Naoki; Nakano, Masaaki; Ando, Hiroei; Fujimoto, Nozomu; Takeuchi, Mitsuo; Fujisaki, Shingo; Yamashita, Kiyonobu

JAERI-Tech 98-032, 59 Pages, 1998/08

JAERI-Tech-98-032.pdf:2.48MB

no abstracts in English

Journal Articles

Preparation for the 2nd edition of nuclear criticality safety handbook

; Nomura, Yasushi

Nihon Genshiryoku Gakkai-Shi, 39(10), p.832 - 841, 1997/00

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Neutronics integral experiments of lithium-oxide fusion blanket with heterogeneous configurations using deuterium-tritium neutrons

Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; ; ; Kosako, Kazuaki*; Maekawa, Hiroshi; Nakakawa, Masayuki; Mori, Takamasa; Nakamura, Tomoo; et al.

Fusion Technology, 28(1), p.216 - 235, 1995/08

no abstracts in English

JAEA Reports

Pre-analyses of SS316 and SS316/Water bulk shielding experiments

Konno, Chikara; Maekawa, Fujio; *; Kosako, Kazuaki*; Ikeda, Yujiro; Oyama, Yukio; Maekawa, Hiroshi

JAERI-Tech 94-019, 43 Pages, 1994/10

JAERI-Tech-94-019.pdf:1.64MB

no abstracts in English

Journal Articles

Evaluation of local power distribution with fine-mesh core model for High Temperature Engineering Test Reactor(HTTR)

Murata, Isao; Yamashita, Kiyonobu; Maruyama, So; Shindo, Ryuichi; Fujimoto, Nozomu; Sudo, Yukio; Nakata, Tetsuo*

Journal of Nuclear Science and Technology, 31(1), p.62 - 72, 1994/01

 Times Cited Count:3 Percentile:36.42(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Phase IIC experiments of the USDOE/JAERI collaborative program on fusion blanket neutronics; Experiments and analysis of heterogeneous fusion blankets, Volume II: Analysis

Nakakawa, Masayuki; Kosako, Kazuaki*; Mori, Takamasa; Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; Yamaguchi, Seiya*; Tsuda, Koichi*; Maekawa, Hiroshi; *; et al.

JAERI-M 92-183, 106 Pages, 1992/12

JAERI-M-92-183.pdf:2.6MB

no abstracts in English

JAEA Reports

Phase IIC experiments of the JAERI/USDOE collaborative program on fusion blanket neutronics; Experiments and analysis of the heterogeneous fusion blankets, Volume I: Experimental results

Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; Yamaguchi, Seiya*; Tsuda, Koichi*; Maekawa, Hiroshi; *; Kosako, Kazuaki*; Nakakawa, Masayuki; Mori, Takamasa; et al.

JAERI-M 92-182, 151 Pages, 1992/12

JAERI-M-92-182.pdf:4.31MB

no abstracts in English

JAEA Reports

Effects of UO$$_{2}$$ fuel grain size on reactivity; Continuous energy Monte Carlo calculations

Sakurai, Y.*; Okuno, Hiroshi; Naito, Yoshitaka

JAERI-M 91-137, 35 Pages, 1991/09

JAERI-M-91-137.pdf:0.88MB

no abstracts in English

Journal Articles

Measured characteristics of Be multi-layered and coolant channel blankets; Phase IIC experiments of the JAERI/USDOE collaborative program on fusion neutronics

Oyama, Yukio; ; ; Konno, Chikara; Ikeda, Yujiro; Maekawa, Hiroshi; Nakamura, Tomoo; K.Porges*; E.Bennett*

Fusion Technology, 19(3), p.1955 - 1960, 1991/05

no abstracts in English

Journal Articles

Evaluation of local power distribution with fine-mesh core model for the HTTR

Murata, Isao; Yamashita, Kiyonobu; Maruyama, So; Shindo, Ryuichi; Fujimoto, Nozomu; Sudo, Yukio; Nakata, Tetsuo*

Proc. of the 1st JSME/ASME Joint Int. Conf. on Nuclear Engineering,Vol. 1, p.413 - 418, 1991/00

no abstracts in English

JAEA Reports

DELIGHT-7; One dimensional fuel cell burnup analysis code for High Temperature Gas-Cooled Reactors (HTGR)

Shindo, Ryuichi; Yamashita, Kiyonobu; Murata, Isao

JAERI-M 90-048, 225 Pages, 1990/03

JAERI-M-90-048.pdf:5.06MB

no abstracts in English

JAEA Reports

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