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Journal Articles

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Journal Articles

Science from the initial operation of HRC

Ito, Shinichi*; Yokoo, Tetsuya*; Masuda, Takatsugu*; Yoshizawa, Hideki*; Soda, Minoru*; Ikeda, Yoichi*; Ibuka, Soshi*; Kawana, Daichi*; Sato, Taku*; Nambu, Yusuke*; et al.

JPS Conference Proceedings (Internet), 8, p.034001_1 - 034001_6, 2015/09

Journal Articles

Analysis of tungsten transport in JT-60U plasmas

Shimizu, Yusuke*; Fujita, Takaaki*; Arimoto, Hideki*; Nakano, Tomohide; Hoshino, Kazuo; Hayashi, Nobuhiko

Plasma and Fusion Research (Internet), 10(Sp.2), p.3403062_1 - 3403062_4, 2015/07

Journal Articles

Selector-valve failed fuel detection and location system for Japan Sodium-cooled Fast Reactor

Aizawa, Kosuke; Fujita, Kaoru; Kamide, Hideki; Kasahara, Naoto*

Nuclear Technology, 189(2), p.111 - 121, 2015/02

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

Selector-valve mechanism is adopted in the design of JSFR for its failed-fuel detection and location (FFDL) system. JSFR has only two FFDL units for 562 core fuel subassemblies to reduce construction cost by decreasing the reactor vessel diameter. Consequently, one SV-FFDL unit must handle about 300 subassemblies. In addition, JSFR adopts an upper internal structure (UIS) with a slit above the core. Sampling performance for the subassemblies under the UIS slit has been evaluated to be lower than those under the normal UIS position in the previous water experiments and numerical simulation. In this paper, the outline of FFDL system is shown, which can be applied to so large number of fuel subassemblies in a compact reactor vessel. Detection capability of the FFDL system was studied to achieve the design conditions. Operation modes and procedure of the FFDL system also investigated.

Journal Articles

Detection capability and operation patterns of a selector-valve failed-fuel detection and location system for large sodium-cooled reactors

Aizawa, Kosuke; Fujita, Kaoru; Kamide, Hideki; Kasahara, Naoto

Proceedings of 2011 International Congress on Advances in Nuclear Power Plants (ICAPP '11) (CD-ROM), p.605 - 613, 2011/05

A conceptual design study of an advanced large-sized (1,500 MWe class) sodium-cooled fast reactor, JSFR, is in progress in the FaCT project in Japan. JSFR has adopted a selector-valve mechanism for a failed-fuel detection and location (FFDL) system. The selector-valve FFDL system identifies a failed fuel subassembly by sampling sodium from each fuel subassembly outlet and detecting fission product gas or delayed neutron precursors of fission products. One of the technologies which JSFR has adopted is an upper internal structure (UIS) with a radial slit. Because sampling nozzles cannot be set in the UIS slit, several sampling nozzles are installed around the slit so as to sample sodium from the failed fuel subassemblies under the UIS slit. In this study, a signal and noise detected by the delayed neutron detector have been calculated. On the basis of these results, appropriate operation patterns of the selector-valve FFDL system for JSFR have been constructed.

Journal Articles

Development of failed fuel detection and location system in sodium-cooled large reactors; Sampling method of failed fuels under the slit

Aizawa, Kosuke; Fujita, Kaoru; Kamide, Hideki; Kasahara, Naoto

Nihon Kikai Gakkai Rombunshu, B, 77(776), p.982 - 986, 2011/04

A conceptual design study of Japan Sodium-cooled Fast Reactor (JSFR) is in progress as an issue of the "Fast Reactor Cycle Technology Development (FaCT)" project in Japan. JSFR adopts a Selector-Valve mechanism for a failed fuel detection and location (FFDL) system. The Selector-Valve FFDL system identifies failed fuel subassemblies by sampling sodium from each fuel subassembly outlet and detecting fission product. One of the JSFR design features is employing an upper internal structure (UIS) with a radial slit, in which an arm of fuel handling machine can move and access the fuel assemblies under the UIS. Thus, JSFR cannot place sampling nozzles right above the fuel subassemblies located under the slit. In this study, appropriate sampling method for indentifying under-slit failed fuel subassemblies has been developed by water experiments.

JAEA Reports

Horonobe Underground Research Laboratory Project; Synthesis of phase I investigation 2001 - 2005, Volume "Geological disposal research"

Fujita, Tomoo; Taniguchi, Naoki; Matsui, Hiroya; Tanai, Kenji; Maekawa, Keisuke; Sawada, Atsushi; Makino, Hitoshi; Sasamoto, Hiroshi; Yoshikawa, Hideki; Shibata, Masahiro; et al.

JAEA-Research 2011-001, 193 Pages, 2011/03

JAEA-Research-2011-001.pdf:5.23MB

This report summarizes the progress of research and development on geological disposal during the surface-based investigation phase (2001-2005) in the Horonobe Underground Research Laboratory project, of which aims are to apply the design methods of geological disposal and mass transport analysis to actual geological conditions obtained from the surface-based investigations in the Horonobe Underground Research Laboratory project as an example of actual geological environment.

Journal Articles

Development of failed fuel detection and location system in sodium-cooled large reactor; Sampling method of failed fuels under the slit

Aizawa, Kosuke; Fujita, Kaoru; Kamide, Hideki; Kasahara, Naoto

Dai-15-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.229 - 230, 2010/06

A conceptual design study of Japan Sodium-cooled Fast Reactor (JSFR) is in progress as an issue of the "Fast Reactor Cycle Technology Development (FaCT)" project in Japan. JSFR adopts a selector-valve mechanism for the Failed Fuel Detection and Location (FFDL) system. The selector-valve FFDL system identifies failed fuel subassemblies by sampling sodium from each fuel subassembly outlet and detecting fission product. One of the JSFR design features is employing an Upper Internal Structure (UIS) with a radial slit, in which an arm of fuel handling machine can move and access the fuel assemblies under the UIS. Thus, JSFR cannot place sampling nozzles right above the fuel subassemblies located under the slit. In this study, the sampling method for identifying under-slit failed fuel subassemblies has been demonstrated by water experiments.

JAEA Reports

Evaluation method of pH elevation due to reaction between hydrates of ordinary Portland cement and saline groundwater

Masuda, Kenta; Oda, Chie; Nakanishi, Hiroshi*; Sasaki, Ryoichi*; Takase, Toshio*; Akagi, Yosuke*; Fujita, Hideki*; Negishi, Kumi*; Honda, Akira

JAEA-Research 2008-104, 194 Pages, 2009/03

JAEA-Research-2008-104.pdf:9.43MB

Saline groundwater contains high concentrations of chloride ions, which possibly elevate the pH of cement pore water by reacting with hydrogarnet and producing Friedel's salt. Calcium aluminate hydrates and portlandite, which can be found in hydrated ordinary Portland cement (OPC), were immersed in a sodium chloride solution, which had concentrations similar to those found in seawater.

Journal Articles

Modeling of pH elevation due to the reaction of saline groundwater with hydrated ordinary Portland cement phases

Honda, Akira; Masuda, Kenta; Nakanishi, Hiroshi*; Fujita, Hideki*; Negishi, Kumi*

Materials Research Society Symposium Proceedings, Vol.1124, p.365 - 372, 2009/00

Journal Articles

The Influence of nitrate on dissolution behavior of cement hydrates

Fujita, Hideki*; Negishi, Kumi*; Osawa, Tsutomu*; Honda, Akira

Semento, Konkurito Rombunshu, (61), p.262 - 269, 2008/02

The influence of sodium nitrate on dissolution of cement hydrates was investigated by flow through experiment. Dissolution of portlandite was accelerated in NaNO$$_{3}$$ solution of 1 mol dm$$^{-3}$$ than in ion exchanged water. The acceleration of portlandite dissolution attributed to impact of ionic strength on the activities of aqueous species, because Ca concentration in 1 mol kg$$^{-1}$$ NaNO$$_{3}$$ solution equilibrated with portlandite was estimated to be 1.5 times as high as that in pure water. After flow through experiment, compressive strength fell down and porosity was higher than blank test using pure water. However low permeabilities were contradictory kept during NaNO$$_{3}$$ solution flowing. Dense existence of Na was possible to cause the low permeability during NaNO$$_{3}$$ solution flowing.

Journal Articles

Evaluation of residual behavior of organic admixture in pore water from hardened cement pastes

Fujita, Hideki*; Haga, Kazuko*; Shibata, Masahito*; Mihara, Morihiro

Semento, Konkurito Rombunshu, (61), p.65 - 71, 2008/02

The elution behavior of polycarboxylate type superplasticizer from hardened cement pastes were examined by analysis of organic matter in the pore water and curing water. A small quantity of superplasticizer was eluted and a large quantity remained in the solid. Only lower molecular weight matter was detected in the pore water, and decomposition of polymer under high alkalinity environment or selective elution of small molecule were suggested. Though there was the assumption that the effect of primary organic matter in cement like grinding aid was canceled by blank test, the assumption may need to be reconsidered.

JAEA Reports

Development and management of the knowledge base for the geological disposal technology; Annual report 2006

Umeda, Koji; Oi, Takao; Osawa, Hideaki; Oyama, Takuya; Oda, Chie; Kamei, Gento; Kuji, Masayoshi*; Kurosawa, Hideki; Kobayashi, Yasushi; Sasaki, Yasuo; et al.

JAEA-Review 2007-050, 82 Pages, 2007/12

JAEA-Review-2007-050.pdf:28.56MB

This report shows the annual report which shows the summarized results and topic outline of each project on geological disposal technology in the fiscal year of 2006.

JAEA Reports

Horonobe Underground Research Laboratory project synthesis of phase I investigation 2001-2005 volume "Geological Disposal Research"

Fujita, Tomoo; Taniguchi, Naoki; Matsui, Hiroya; Tanai, Kenji; Nishimura, Mayuka; Kobayashi, Yasushi; Hiramoto, Masayuki; Maekawa, Keisuke; Sawada, Atsushi; Makino, Hitoshi; et al.

JAEA-Research 2007-045, 140 Pages, 2007/03

JAEA-Research-2007-045-1.pdf:38.33MB
JAEA-Research-2007-045-2.pdf:44.62MB

This report summarizes the progress of research and development on geological disposal during the surface-based investigation phase (2001-2005) in the Horonobe Underground Research Laboratory project (HOR), of which aims are to apply the design methods of geological disposal and mass transport analysis to actual geological environments and derive future subjects based on the results. The design methods of geological disposal were reviewed based on the recent knowledge and the advertences were identified. Then the parameters for virtual design of engineered barrier system, backfill deposition hole and tunnel were set up based on actual geological conditions obtained from the surface-based investigations in HOR as an example of actual geological environment. The conceptual structure from site investigation and evaluation to mass transport analysis was represented as a work flow at first. Then following this work flow a series of procedures for mass transport analysis were carried out based on actual geological conditions obtained from the surface-based investigations in HOR to illustrate the functioning of the work flow and the applicability of this methodology. Consequently, knowledge that will help follow-up or future execution and planning activities was obtained.

JAEA Reports

The DH-15 Borehole Investigations in the Regional Hydrogeological Study Project

Tsuruta, Tadahiko; Fujita, Yuji; Abumi, Kensho; Mie, Hideki; Fujishiro, Hideyuki

JNC TN7400 2005-025, 82 Pages, 2005/08

JNC-TN7400-2005-025.pdf:8.63MB

The DH-15 borehole investigations were carried out to develop and apply a variety of geoscientific techniques for the geological and hydrogeological characterization of water conducting features and the rock mass. The main investigations performed were : Measurement of geochemical parameters of the drilling fluid and the return water, Coring, core logging and photographing of core, Borehole television observation, Geophysical logging, Fluid logging, Multi-offset VSP survey, Hydraulic tests, Measurement of geochemical parameters of the pumping water, and Installation of a long-term groundwater monitoring system. This report describes the results of the DH-15 borehole investigations with respect to the above results.

JAEA Reports

The Evaluation of Solidifying Performance of Heavy Metal Waste Using Cementitious Materials (2)

Fujita, Hideki*; Harasawa, Shuichi*

JNC TJ8410 2005-005, 103 Pages, 2005/02

JNC-TJ8410-2005-005.pdf:0.75MB

Some of radioactive waste generated from JNC's facilities contain the poisonous substances such as lead and mercury. In order to establish an appropriate method of the treatment of these heavy metals, solidification performance was evaluated using cementitious materials. The results are summarized below:1. The test of stabilization process of mercuryThe conversion process from mercury to the powdery mercury sulfide(red) was examined. It was confirmed that the conversion was possible using the liquid phase reaction at 80$$^{circ}$$C by the addition of sulfur powder with the NaOH solution. 2. The fabrication and evaluation of solidified wastes (1) solidification test of the lead wasteAs for the elution ratio of lead, it had obtained the better result (0.06 mg/L) at the case of solidification of sulfide lead 30mass% packed in the total solidified waste by using Highly Fly-ash contained Silicafume Cement (HFSC) than standard value(0.3mg/L) at Regulations of Waste Management and Public Cleansing Law. Additionally, it was confirmed the using admixture of the inorganic reducing agent such as the Iron (II) chloride tetrahydrate deceased the elution ratio of lead to the under limit of measurement (0.01 mg/L) at the case of solidification of sulfide lead 30 mass% packed in the total solidified waste by using Low Alkalinity Cement contained calcium sulpho-aluminate (LAC). (2)solidification test of the mercury waste Four types of solidified waste were fabricated with different binder. It was confirmed one-axis compressive strength for all solidified waste to pass the technical standards 15kg/cm2 (1.5 Mpa) for homogeneously solidified waste as the Low-level Radioactive Waste Disposal Center in Aomori Prefecture, and the elution ratio of mercury, it had obtained the result for all solidified waste to pass the standard value (0.005 mg/L) at Regulations of Waste Management and Public Cleansing Law.

JAEA Reports

The Evaluation of Solidifying Performance of Heavy Metal Waste using Cementitious Materials

Takei, Akihiko*; Fujita, Hideki*; Harasawa, Shuichi*

JNC TJ8410 2004-007, 108 Pages, 2004/02

JNC-TJ8410-2004-007.pdf:3.03MB

In order to establish an appropriate method of the treatment of these heavy metals such as lead, cadmium and mercury, solidification performance was evaluated using cementitious materials. In this report, the solidification performance of lead, which accounts for relatively high ratio in total wastes, was evaluated.

JAEA Reports

Study on the Alteration of Hydrogeological and Mechanical Properties of the Cementitious Material (III); Summary Report

Takei, Akihiko*; Fujita, Hideki*; Harasawa, Shuichi*

JNC TJ8400 2004-025, 79 Pages, 2004/02

JNC-TJ8400-2004-025.pdf:5.79MB

We experimentally investigated the influence of several phenomena at the disposal environment, to evaluate the long-term alteration of cementitious material. The results are shown below. (1)Hardened cement paste specimens were altered and characterized after artificial seawater permeation. The calcium dissolution was accelerated, and secondary minerals containing magnesium were deposited. The permeability became one to three orders of magnitude smaller than data from specimens altered by deionized water permeation. It was estimated that secondary mineral formations reduced the permeability. These results meant that seawater and pure water differ remarkably from each other in influence to alteration of cementitious material. (2)Two type mixture proportions concrete, two type mixture proportions mortar and a cement paste under same W/C ratio 55% were characterized, to apply the accumulated data of paste to concrete or mortar. Compressive strength of paste was lower than that of concrete and mortar. It was contrary to the previous report. The behavior of Young's modulus and Poisson's ratio could be explained well using amount of aggregate. The data of permeability meant that boundary between aggregate and cement paste didn't become path of water flow, and that aggregate disturbed permeation. (3)Self-sealing property of cracked specimen of cementitious material were investigated by the water permeation test using sodium bicarbonate solution. The permeability decreased in two orders of magnitude, and possibility of sealing was suggested. By the morphology, the deposits in the cracks might be portlandite and C-S-H, and be not calcium carbonate. (4)Alteration of characteristics of cementitious material in sodium-nitrate and ammonia solution was evaluated by the water permeation test. Alteration degree of the nitrate and ammonia solution case showed similar trend to that of the sodium nitrate solution case. This result meant that ammonia solution would not ...

JAEA Reports

Study on the Alteration of Hydrogeological and Mechanical Properties of the Cementitious Material (III)

Takei, Akihiko*; Fujita, Hideki*; Harasawa, Shuichi*

JNC TJ8400 2004-024, 184 Pages, 2004/02

JNC-TJ8400-2004-024.pdf:10.86MB

A study on the alteration of hydrogeological and mechanical prorperties of the cementitious material.

JAEA Reports

Study on the Alteration of Hydrogeological and Mechanical Properties of the Cementitious Material II

Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*; Hibiya, Keisuke*; Yokozeki, Kosuke*; Watanabe, Kenzo*

JNC TJ8400 2003-047, 120 Pages, 2003/02

JNC-TJ8400-2003-047.pdf:4.46MB

We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or immersing as the fundamental data.

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