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Oral presentation

Development of solidification techniques with minimised water content for secondary radioactive aqueous wastes in Fukushima, 5; Leaching rate of Sr$$^{2+}$$ and Cl$$^{-}$$

Irisawa, Keita; Taniguchi, Takumi; Namiki, Masahiro*; Garc$'i$a-Lodeiro, I.*; Osugi, Takeshi; Nakazawa, Osamu; Kinoshita, Hajime*

no journal, , 

no abstracts in English

Oral presentation

A Correction to the non-resonant process in the R-matrix analysis

Kunieda, Satoshi

no journal, , 

We propose a new method for the non-resonant process in the R-matrix theory, which is associated with additional background poles exclusive to the incident particles. This method is applied to the simultaneous analysis of the $$^6$$Li(p,p$$_0$$) $$^6$$Li, $$^6$$Li(p,$$alpha_0$$) $$^3$$He, $$^3$$He($$alpha$$,$$alpha_0$$) $$^3$$He and $$^3$$He($$alpha$$,p$$_0$$) $$^6$$Li reaction cross-sections. It is found that the present approach is necessary to obtain a reasonable description of all the measured data simultaneously. We also discuss the theoretical background for our recipe base on the physical aspects of the nuclear reactions.

Oral presentation

A Study on the safety of geological disposal of nitrate-containing waste, 2-1; The Exothermic measurement of the simulated waste and modeling heat flux

Mihara, Morihiro; Hara, Keiji*; Hasegawa, Kazutoshi*; Tochiyama, Osamu*; Adachi, Natsue*; Kirishima, Akira*

no journal, , 

no abstracts in English

Oral presentation

Numerical simulation of nitrate evolution in nitrate polluted groundwater using the model of nitrate evolution, 2

Abe, Toru*; Hirano, Fumio; Mihara, Morihiro; Honda, Akira

no journal, , 

no abstracts in English

Oral presentation

A Study on the safety of geological disposal of nitrate-containing waste, 2-2; Simulation study on the possibility of thermal reaction runaway after disposal

Nonaka, Kosuke*; Hirano, Fumio; Mihara, Morihiro; Hara, Keiji*; Tochiyama, Osamu*

no journal, , 

no abstracts in English

Oral presentation

International standardization of the education of cultures on nuclear safety and nuclear security

Hidaka, Akihide; Uesaka, Mitsuru*; Komatsuzaki, Tsuneo*; Takahashi, Makoto*; Okajima, Shigeaki; Uno, Masayoshi*

no journal, , 

no abstracts in English

Oral presentation

Development of nuclear transmutation methods for converting LLFP into stable or short-lived nuclides, 7; Neutron capture cross-section measurements of Cs and Se isotope nuclides

Nakamura, Shoji; Kimura, Atsushi; Hales, B. P.; Iwamoto, Osamu; Shibahara, Yuji*; Uehara, Akihiro*; Fujii, Toshiyuki*

no journal, , 

This presentation gives some progress about neutron capture cross section measurements of long-lived fission products, especially Cecium-135 under the ImPACT Project.

Oral presentation

The Results obtained from the 20 years of "Monju" plant data, 10-2; Effect of natural convection prevention plate in primary sodium pump

Morioka, Tatsuya; Hashidate, Ryuta; Sawazaki, Hiromasa; Kunogi, Kosuke

no journal, , 

Thermal natural convection occurred in Ar gas region between the inner and outer casing of the sodium pump in the past, which induces asymmetric circumferential temperature distribution on the casings. This thermal effect causes the contact of the pump shaft with the lower hydrostatic bearing, which places the bearing at risk for damage. To prevent this risk for Monju primary sodium pump, convection prevention plates are installed between the inner and outer casing of the pump. The soundness which in 2017 spring meeting, Monju plant data indicates the plates decrease the circumferential temperature difference, and then no contact arose between the pump shaft and the bearing. The circumferential temperature difference of the layer lower part is big compared with the layer upper part and the central part. We confirmed that difference in temperature among the measurement points of the lower gas layer was affected by the sodium vortex prevention plates.

Oral presentation

Development of nuclear transmutation methods for converting LLFP into stable or short-lived nuclides, 8; Neutron capture cross-section measurements of stable Se isotope nuclides as part of the ImPACT Project

Hales, B. P.; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu

no journal, , 

We have measured the neutron-capture cross-sections of various Se isotopes ($$^{74,76,77,78,80,82}$$Se) via neutron time-of-flight (nTOF) method, using J-PARC/MLF/ANNRI, up to the incident neutron energy range of 1.5 keV. We are currently considering measuring the long-lived fission product (LLFP) $$^{79}$$Se (half-life: 330,000 years), a component of nuclear waste, using J-PARC/MLF/ANNRI. It is thought to be very difficult to remove stable selenium isotopes from our $$^{79}$$Se sample. In order to increase the quality of the data in a $$^{79}$$Se measurement, data for stable selenium isotopes are necessary. In this presentation, we will presently mainly on our findings in regareds to $$^{78}$$.Se

Oral presentation

Characteristic evaluation for laser spectrochemistry using arcjet plasma

Kuwahara, Akira; Aiba, Yasuaki*; Nankawa, Takuya; Matsui, Makoto*

no journal, , 

no abstracts in English

Oral presentation

Discussion on the application of the fast neutron interrogation method to uranium wastes

Sakoda, Akihiro; Nakatsuka, Yoshiaki; Hata, Haruhi; Nakashima, Shinichi; Komeda, Masao; Ozu, Akira; Toh, Yosuke

no journal, , 

We have installed the waste assay system (JAWAS-N) in Ningyo-toge Environmental Engineering Center, JAEA. This system was developed based on the fast neutron interrogation method, which was one of the active neutron assay techniques. This presentation first describes the outline of mock-up tests and data analysis, and then illustrates the measured result of uranium contents in actual wastes. Since a part of the wastes was evaluated by the $$gamma$$-ray assay as well, the comparison of both results was made to discuss some issues that should be addressed.

Oral presentation

Investigation of platinum group compounds generated in the vitrification process, 1; Synthetic experiments of ruthenium, rhodium, and glass frit

Nagai, Takayuki; Kobayashi, Hidekazu; Okamoto, Yoshihiro; Shiwaku, Hideaki; Akiyama, Daisuke*; Sato, Nobuaki*

no journal, , 

no abstracts in English

Oral presentation

Evaluation of preconditioned Chebyshev basis CG solver for multiphase CFD code JUPITER

Mayumi, Akie; Idomura, Yasuhiro; Ina, Takuya; Yamada, Susumu; Imamura, Toshiyuki*

no journal, , 

Improvement of convergence property is an issue in applying the Communication-Avoiding CG (CA-CG) method to the Poisson solver in the JUPITER code, which analyzes a multi-phase thermal-hydraulic problem. In this work, we implemented the Chebyshev basis CG (CBCG) method and evaluated its convergence property in real problems. As a result, the CBCG method greatly improved robustness of the convergence property and succeeded in reducing collective communication to 2/3 compared with the CA-CG method.

Oral presentation

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 5; Viscosity measurement of 5mass% B$$_{4}$$C-SS eutectic molten material

Nishi, Tsuyoshi*; Ota, Hiromichi*; Yamano, Hidemasa

no journal, , 

It is necessary to obtain viscosity data of eutectic molten material of boron carbide (B$$_{4}$$C) and stainless steel (SS) for severe accident analyses. In this study, the viscosity measurement has been initiated for the 5mass% B$$_{4}$$C-SS eutectic molten material by using a rotational viscometer.

Oral presentation

Study on eutectic melting behavior of control rod materials in core disruptive accidents of sodium-cooled fast reactors, 4; Emissivity, heat capacity and thermal conductivity of 5mass%B$$_{4}$$C-SS eutectic molten material

Higashi, Hideo*; Fukuyama, Hiroyuki*; Yamano, Hidemasa

no journal, , 

To develop thermophysical property model to simulate eutectic reaction behavior of B$$_{4}$$C as control rod material and stainless steel (SS) in core disruptive accident of sodium-cooled fast reactor, this paper reports measurement results of density and surface tension of 5mass%B$$_{4}$$C-SS melt by droplet oscillation method and laser imaging density measurement method with very high temperature physical property measurement system (PROSPECT).

Oral presentation

Evaluation of re-evaporation behavior of Cs adsorption compound by HAXPES

Kobata, Masaaki; Okane, Tetsuo; Nakajima, Kunihisa; Suzuki, Eriko; Kobayashi, Keisuke*; Osaka, Masahiko

no journal, , 

To Evaluate of re-evaporation behavior of Cs-Si-Fe-O compound formed by Cs chemisorption on the stainless steel under severe accident, HAXPES analysis was performed on the re-heated samples under various atmospheres. As a result, it was found that the re-heated samples under a reducing atmosphere, were changed to a Cs-Si-O compound with Fe desorption.

Oral presentation

Reduction and resource recycling of high-level radioactive wastes through nuclear transmutation; From viewpoint of reprocessing and recycling, 1; Separation and recovery of LLFP from high-level liquid wastes

Sasaki, Yuji; Morita, Keisuke; Suzuki, Shinichi; Shiwaku, Hideaki; Ito, Keisuke; Takahashi, Yuya*; Kaneko, Masaaki*; Asano, Kazuhito*

no journal, , 

no abstracts in English

Oral presentation

Cs chemical reaction with stainless steel under a LWR severe accident, 1; Effect of temperature and atmosphere on Cs chemisorbed amounts

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

no journal, , 

In order to clarify the behaviour of Cs chemisorption onto stainless steel under various LWR severe accident conditions, simulated Cs chemisorption tests, the parameters were temperature and atmosphere, were performed. As a results, it was observed that Cs chemisorbed amounts and Cs revaporization behaviour from Cs chemisorbed compounds were different between the atmosphere containing H$$_{2}$$O or not. It means that Cs chemisorption behaviour is greatly affected by not only temperature but also atmosphere.

Oral presentation

Fault reactivation experiment and frictional properties of Mont Terri Rock Laboratory, Switzerland

Aoki, Kazuhiro; Seshimo, Kazuyoshi; Nussbaum, C.*; Guglielmi, Y.*; Shimamoto, Toshihiko*; Sakai, Toru*; Kametaka, Masao*; Ma, S.*; Yao, L.*

no journal, , 

In order to contribute to the Fault Slip experiment, JAEA has performed friction experiment of borehole cores of the measured interval using a rotary-shear low to high-velocity friction apparatus at Institute of Geology, China Earthquake Administration. Friction experiments were done either dry with room humidity or with 30wt% of H$$_{2}$$O, at a normal stress of 1.4 and 4.0 MPa and at low to intermediate slip rates ranging 0.21 microns/s to 2.1mm/s. Cylindrical specimens of Ti-Al-V alloy with 40 mm in diameter were used as rotary and stationary pistons and the alloy pistons exhibit similar behaviors as host rock specimens.

279 (Records 1-20 displayed on this page)