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JAEA Reports

Quantitative evaluation of long-term state changes of contaminated reinforced concrete considering the actual environments for rational disposal (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*

JAEA-Review 2021-047, 127 Pages, 2022/01

JAEA-Review-2021-047.pdf:5.57MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Quantitative evaluation of long-term state changes of contaminated reinforced concrete considering the actual environments for rational disposal" conducted in FY2020. The present study aims to construct a database for quantitative prediction of contaminated reinforced concrete inside the reactor building. In FY2020, in chapter 3.1, in order to obtain the data for the evaluation of mesoscale cracking behavior, the equipment for the making and the measurement of the test specimens were prepared, the evaluation method was confirmed, and preliminary experiments were carried out. And, for the prediction of cracking on the surface of thick concrete wall, the rigid-body spring network model associated with heat and moisture

Journal Articles

A Project focusing on the contamination mechanism of concrete after the accident at Fukushima Daiichi Nuclear Power Plant

Yamada, Kazuo*; Maruyama, Ippei*; Haga, Kazuko*; Igarashi, Go*; Aihara, Haruka; Tomita, Sayuri*; Kiran, R.*; Osawa, Norihisa*; Shibata, Atsuhiro; Shibuya, Kazutoshi*; et al.

Proceedings of International Waste Management Symposia 2021 (WM 2021) (CD-ROM), 10 Pages, 2021/03

Journal Articles

Study on chemisorption model of cesium hydroxide onto stainless steel type 304

Nakajima, Kunihisa; Nishioka, Shunichiro*; Suzuki, Eriko; Osaka, Masahiko

Mechanical Engineering Journal (Internet), 7(3), p.19-00564_1 - 19-00564_14, 2020/06

A large amount of cesium (Cs) chemisorbed onto stainless steel is predicted to be present especially in the upper region of reactor pressure vessel (RPV) during light water reactor severe accident (LWR SA) and a chemisorption model was developed for estimation of such amounts of Cs for stainless steel type 304 (SS304). However, this existing chemisorption model cannot accurately reproduce experimental results. Therefore, in this study, a modified Cs chemisorption model which accounts for silicon content in SS304 and concentration of cesium hydroxide (CsOH) in gaseous phases was constructed by combining penetration theory for gas-liquid mass transfer with chemical reaction and mass action law for CsOH decomposition at interface between gaseous and solid phases. As a result, it was found that the modified model was able to reproduce the experimental data more accurately than the existing model.

Journal Articles

Factors affecting the effectiveness of sheltering in reducing internal exposure

Hirouchi, Jun; Takahara, Shogo; Komagamine, Hiroshi*; Watanabe, Masatoshi*; Munakata, Masahiro

Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 11 Pages, 2017/11

no abstracts in English

Journal Articles

Identification of penetration path and deposition distribution of radionuclides in houses by experiments and numerical model

Hirouchi, Jun; Takahara, Shogo; Iijima, Masashi; Watanabe, Masatoshi; Munakata, Masahiro

Radiation Physics and Chemistry, 140, p.127 - 131, 2017/11

BB2016-0282.pdf:0.39MB

 Times Cited Count:2 Percentile:28.88(Chemistry, Physical)

Journal Articles

Influence of self-irradiation damage on the Pu-based superconductor PuCoGa$$_5$$ probed by muon spin rotation

Oishi, Kazuki; Ito, Takashi; Higemoto, Wataru; Heffner, R. H.

Journal of the Physical Society of Japan, 75(Suppl.), p.53 - 55, 2006/08

PuCoGa$$_5$$ has attracted much interest because it has a high transition temperature $$T_{rm c}$$ ($$simeq$$ 18 K) compared with other 115 systems. According to the previous $$mu$$SR results, temperature dependence of magnetic penetration depth $$lambda$$ in PuCoGa$$_5$$ shows $$T$$-linear behavior, suggesting that the superconducting order parameter of this material may be $$d$$-wave symmetry. In order to elucidate that point, we have measured the magnetic field dependence of $$lambda$$ in this sample by means of $$mu$$SR technique. At our poster presentation, we discuss the symmetry of superconducting order parameter in PuCoGa$$_5$$ in detail.

JAEA Reports

Rationalization and utilization of double-wall vacuum vessel for tokamak fusion facility

Nakahira, Masataka

JAERI-Research 2005-030, 182 Pages, 2005/09

JAERI-Research-2005-030.pdf:12.57MB

It is difficult for Vacuum Vessel (VV) of ITER to apply a non-destructive in-service inspection (ISI) and then new safety concept is needed. Present fabrication standards are not applicable to the VV, because the access is limited to the backside of closure weld of double wall. Fabrication tolerance of VV is $$pm$$5mm even the structure is huge as high as 10m. This accuracy requires a rational method on the estimation of welding deformation. In this report, an inherent safety feature of the tokamak is proved closing up a special characteristic of termination of fusion reaction due to tiny water leak. A rational concept not to require ISI without sacrificing safety is shown based on this result. A partial penetration T-welded joint is proposed to establish a rational fabrication method of double wall. Strength and susceptibility to crevice corrosion is evaluated for this joint and feasibility is confirmed. A rational method of estimation of welding deformation for large and complex structure is proposed and the efficiency is shown by comparing analysis experimental results of full-scale test.

JAEA Reports

Corrosion behavior of austenitic and ferritic/martensitic steels in oxygen-saturated liquid Pb-Bi eutectic at 450$$^{circ}$$C and 550$$^{circ}$$C

Kurata, Yuji; Futakawa, Masatoshi; Saito, Shigeru

JAERI-Research 2005-002, 37 Pages, 2005/02

JAERI-Research-2005-002.pdf:20.04MB

Static corrosion tests of various austenitic and ferritic/martensitic steels were conducted in oxygen-saturated liquid Pb-Bi at 450$$^{circ}$$C and 550$$^{circ}$$C for 3000h to study the effects of temperature and alloying elements on corrosion behavior. Oxidation, grain boundary corrosion, dissolution and penetration were observed. The corrosion depth decreases at 450$$^{circ}$$C with increasing Cr content in steels regardless of ferritic/martensitic or austenitic steels. Appreciable dissolution of Ni and Cr does not occur in the three austenitic steels at 450$$^{circ}$$C. The corrosion depth of ferritic/martensitic steels also decreases at 550$$^{circ}$$C with increasing Cr content whereas the corrosion depth of austenitic steels, JPCA and 316ss becomes larger due to ferritization caused by dissolution of Ni at 550$$^{circ}$$C than that of ferritic/martensitic steels. An austenitic stainless steel containing about 5%Si exhibits fine corrosion resistance at 550$$^{circ}$$C because the protective Si oxide film is formed and prevents dissolution of Ni and Cr.

Journal Articles

Irradiation and penetration tests of boron-doped low activation concrete using 2.45 MeV and 14 MeV neutron sources

Morioka, Atsuhiko; Sato, Satoshi; Kinno, Masaharu*; Sakasai, Akira; Hori, Junichi*; Ochiai, Kentaro; Yamauchi, Michinori*; Nishitani, Takeo; Kaminaga, Atsushi; Masaki, Kei; et al.

Journal of Nuclear Materials, 329-333(2), p.1619 - 1623, 2004/08

 Times Cited Count:7 Percentile:46.83(Materials Science, Multidisciplinary)

The neutron penetration and the activation characteristics of the boron-doped low activation concrete were investigated for irradiation of 2.45 and 14 MeV neutrons. The shielding property of the 2 wt% boron-doped low activation concrete is superior to that of the 1 wt% boron for the thermal neutron, on the contrary to the no clear difference for the fast neutron. The total activity detected in the boron-doped low activation concrete was about one hundredth of that in the geostandard sample at more than 30 days cooling time. The total activity of the boron-doped concrete by major nuclei does not depend on the boron density for the 14 MeV neutron irradiation.

JAEA Reports

Evaluation of susceptibility on crevice corrosion for ITER vacuum vessel

Nakahira, Masataka

JAERI-Tech 2003-083, 79 Pages, 2003/11

JAERI-Tech-2003-083.pdf:10.29MB

The ITER Vacuum Vessel has a double-walled structure and cooling water is filled in between inner and outer shells. It is planned to apply T-welded joints with partial penetration at the connection between outer shell and rib. The length and gap of non-penetrated part are controlled and limited to less than 5mm and 0.5mm respectively. Although it can be considered to be low susceptibility, crevice corrosion can possibly occur, because the water is stagnant in the crevice and impurities will condense. In this report, the corrosion-crevice repassivation potential, E$$_{R,CREV}$$, was experimentally measured under the several density of NaCl solution, and compared to the steady-state corrosion potential in the pertinent environment, to evaluate the susceptibility. Simulated conditions are normal operating condition with water temperature of 150$$^{circ}$$C, baking operation with water temperature of 200$$^{circ}$$C and impurity condense by cyclic wet and dry condition.

Journal Articles

Technical code issues of ITER vacuum vessel and their resolutions

Nakahira, Masataka

Journal of Nuclear Science and Technology, 40(9), p.687 - 694, 2003/09

 Times Cited Count:3 Percentile:26.72(Nuclear Science & Technology)

The ITER vacuum vessel is a double-walled torus with large-sized quadrilateral ports and is required to provide a quite high degree of vacuum for deutrium - tritium fusion reaction. The vacuum vessel is required to install after assembled with toroidal field coils. From a radiological safety aspect, the vacuum vessel is functioned as a physical barrier to enclose radioactive materials. Therefore, construction of the vacuum vessel needs application of newly developed technologies on design, fabrication and examination. The technologies include design approach by finite element analysis, and partial penetration T welded joints to join ribs to outer shell. Several issues have to be resolved for applying those technologies to the vacuum vessel. This paper describes several newly developed technologies and key issues for applying to the vacuum vessel and then their resolutions.

Journal Articles

Shielding experiments and analyses on proton accelerator facility at TIARA

Nakashima, Hiroshi; Sakamoto, Yukio*; Tanaka, Shunichi; Tanaka, Susumu; Baba, Mamoru*; Nakamura, Takashi*; Hirayama, Hideo*; Shin, Kazuo*; JAERI-Universities Collaboration Working Group for Accelerator Shielding Study

Proceedings of 6th International Meeting on Nuclear Applications of Accelerator Technology (AccApp '03), p.959 - 968, 2003/00

In order to validate shielding design methods on proton accelerator facilities, a series of shielding experiments in several tens of MeV energy region were carried out at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) of Japan Atomic Energy Research Institute (JAERI). The experiments include thick target neutron yield (TTY) measurements by charged particles, deep penetration experiments on concrete, steel and polyethylene shields using p-Li monoenergetic neutron source and radiation streaming experiment at a labyrinth of TIARA using p-Cu white neutron source. These experimental results are compared with calculation results with some high-energy particle transport codes such as MCNPX and NMTC/JAERI. The TTY measurements were analyzed by a code developed by Shin with a moving source model, and the streaming experiment was also analyzed by the DUCT-III code based on Shin's equation. This paper reviews the experimental results and the analyses on the results.

Journal Articles

Main features of ITER vacuum vessel and approach to code application

Nakahira, Masataka; Takeda, Nobukazu; Hada, Kazuhiko; Tada, Eisuke; Miya, Kenzo*; Asada, Yasuhide*

Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 7 Pages, 2002/04

The special features of Vacuum Vessel (VV) of International Thermonuclear Experimental Reactor (ITER) are complicated structure and electromagnetic load. The VV is torus shaped, double-walled structure with ribs. The electromagnetic force is not uniform. Thus the rules for axisymmetric structures and loading are not effective for ITER VV. The double ミwalled structure requires one-sided welding joints with no possibility of access from the other side. Every joints between outer wall and rib and field joints are this type. The joint between outer wall and rib is special T-joint with partial penetration. To cover these special issues on ITER VV, a new code is under development. Supporting R&Ds are planned to be material tests to obtain joint efficiency and fatigue reduction factor, UT sensitivity tests, sensitivity tests on crevice corrosion and examination-free welding for application to field joints. This paper describes the special features of ITER VV from code stand point, concept of new code and R&Ds to apply the new code to ITER VV.

JAEA Reports

High temperature corrosion of iron-base and nickel-base alloys for hydrogen production apparatus by thermochemical method in H$$_{2}$$O+SO$$_{3}$$ atmosphere

Kurata, Yuji; Suzuki, Tomio; Shimizu, Saburo

JAERI-Research 2000-011, p.56 - 0, 2000/03

JAERI-Research-2000-011.pdf:14.24MB

no abstracts in English

Journal Articles

A Simple model of supersonic molecular beam injection

Song, X. M.*; Sugie, Tatsuo; Yoshino, Ryuji

Purazuma, Kaku Yugo Gakkai-Shi, 76(3), p.282 - 287, 2000/03

no abstracts in English

Journal Articles

A Factorization of LET effects of ion induced photostimulated luminescence

Abe, Ken*; Saito, Kiwamu*; To, Kentaro; Kojima, Takuji; Sakai, Takuro

JAERI-Review 99-025, TIARA Annual Report 1998, p.103 - 105, 1999/10

no abstracts in English

JAEA Reports

JAEA Reports

Development of integrated containment and surveillance system for fast critical facility FCA; Portal and penetration monitors

Mukaiyama, Takehiko; Ogawa, Hironobu; *

JAERI-Research 98-001, 76 Pages, 1998/01

JAERI-Research-98-001.pdf:2.97MB

no abstracts in English

Journal Articles

Penetration of isothermal plunging jet into denser liquid

H.Park*; ; Moriyama, Kiyofumi; Maruyama, Yu; Y.Yang*; A.R.Antariksawan*; Sugimoto, Jun; *

Proc. of 4th KSME-JSME Fluids Engineering Conf., p.581 - 584, 1998/00

no abstracts in English

Journal Articles

Time dependency of HEPA filter performance during loading with liquid particles

; ; Ikezawa, Yoshio

Hoken Butsuri, 32(2), p.185 - 191, 1997/00

no abstracts in English

40 (Records 1-20 displayed on this page)