Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 208

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Oral presentation

Electrochemical study on the redox properties of humic substances from deep sedimentary groundwater

Saito, Takumi; Terashima, Motoki; Onuki, Toshihiko

no journal, , 

Redox properties of humic substances extracted from deep sedimentary groundwater was investigated by cyclic voltammetry and bulk electrolysis with a mediator organic molecule. Reversible current-potential curves were observed with the mediator, although electrode reaction of humic substances are slow in general. The redox capacities of various humic substances exhibited positive correlation with their aromaticity; those of deep groundwater humic substances were appreciably smaller than those of surface humic substances.

Oral presentation

Development of nuclear data processing system FRENDY, 2; Scattering cross section generation in the thermal energy range

Tada, Kenichi; Nagaya, Yasunobu

no journal, , 

JAEA has been developed the nuclear data processing system FRENDY (FRom Evaluated Nuclear Data librarY to any application). In this presentation, verification of scattering cross section generation in the thermal energy range is described.

Oral presentation

Design and development of a Pu NDA system using alternative He-3 neutron detectors using ceramic scintillator

Ozu, Akira; Kureta, Masatoshi; Kobayashi, Nozomi*; Takase, Misao*; Kurata, Noritaka*; Tobita, Hiroshi; Haruyama, Mitsuo; Nakamura, Tatsuya; Suzuki, Hiroyuki; Sakasai, Kaoru; et al.

no journal, , 

no abstracts in English

Oral presentation

Benchmark experiment on molybdenum with DT neutrons at JAEA/FNS

Ota, Masayuki; Kwon, Saerom; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara

no journal, , 

We perform a benchmark experiment with a Mo assembly and the DT neutron source at JAEA/FNS to validate recent nuclear data of Mo. A rectangular Mo assembly, the size of which is 253 mm $$times$$ 253 mm $$times$$ 354 mm, is covered with 51, 202 and 253 mm thick Li2O blocks around the front, side and back surfaces in order to eliminate background neutrons in the measuring points, respectively. The assembly is placed at a distance of 150 mm from the DT neutron source. Several dosimetry reaction rates and fission rates measured in the assembly are compared to those calculated with the Monte Carlo neutron transport code MCNP5-1.40 and the recent nuclear data libraries of ENDF/B-VII.1, JEFF-3.2 and JENDL-4.0 (FENDL-3.0). The ratios of the calculated reaction rates to the experimental ones generally decrease with the increasing distance from the front surface of the assembly. Reasons of the discrepancies are discussed in the presentation.

Oral presentation

A New benchmark experiment on copper with DT neutron source at JAEA/FNS

Kwon, Saerom; Ota, Masayuki; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara

no journal, , 

A benchmark experiment on copper with DT neutron source was performed 20 years ago at JAEA/FNS. However, the calculated results tended to underestimate the measured data related to lower energy neutrons below a few keV in the experiment, which suggested that the measured data might be affected by neutrons scattered in the concrete wall of the experiment room or other surroundings. Therefore, we have carried out an additional integral experiment on copper, where a copper assembly was covered with Li$$_{2}$$O blocks to reduce neutrons scattered in the concrete wall. We used the Monte Carlo neutron transport code, MCNP5-1.40 and the recent nuclear data libraries, ENDF/B-VII.1, JEFF-3.2, JENDL-4.0 and FENDL-3.0 (ENDF/B-VII.0) for the experiment analysis. JENDL/D-99 was used as dosimetry cross section data. The calculated reaction rates of the $$^{197}$$Au(n,$$gamma$$)$$^{198}$$Au reaction with all the nuclear data libraries still underestimate the measured data, although the underestimation was improved compared to the previous result with JENDL-4.0 in particular. We found out that the nuclear data of copper caused this underestimation problem.

Oral presentation

Reduction of uncertainties in reactor physics parameters of an accelerator-driven system by minor-actinide loaded experiments at J-PARC

Iwamoto, Hiroki; Nishihara, Kenji; Katano, Ryota*; Fujimoto, Atsushi*

no journal, , 

no abstracts in English

Oral presentation

Sensitivity study for the radionuclide inventory in the decommissioning of a light water reactor plant

Okumura, Keisuke; Hagura, Hiroyuki; Kojima, Kensuke; Yamamoto, Kento; Tanaka, Kenichi*

no journal, , 

A method of the activation sensitivity analysis was developed for the optimization of the inventory evaluation of radionuclides in the waste generated in the decommissioning of LWR plants. By applying the method to a BWR plant, we clarified the impurity nuclides in the structural materials and their nuclear reactions contributing the generation of about fifty radioactive nuclides important for the processing and disposal of radioactive wastes.

Oral presentation

Component-engineering development for glove-box dismantling

Watahiki, Masatoshi; Yanagawa, Chihiro; Kageyama, Ryoichi; Kuba, Meiji

no journal, , 

We reports the examination result about the applicability of a robot arm and the applicability of a new waste container as a component engineering for glove box dismantling.

Oral presentation

Dynamic recovery and recrystallization behavior caused by fatigue for sintered molybdenum

Nishi, Hiroshi; Enoeda, Mikio; Kawamura, Yoshinori

no journal, , 

Powder metallurgy molybdenum and tungsten received severe hot roll reduction after the sintering to reduce the internal defects such as voids. Hence these metals have high stored energy and show unstable microstructures. The molybdenum exhibits cyclic softening being caused dynamic recovery and recrystallization during high temperatures fatigue below its static recrystallization temperature. In this investigation, the observations of microstructures change during high temperatures fatigue are performed and compare to those of static recrystallization. Moreover, the apparent activation energy of the cyclic softening is evaluated to study the mechanisms of the dynamic recovery and recrystallization. The apparent activation energy of the cyclic softening is extremely lower than that of lattice diffusion of molybdenum and the activation energy of lattice diffusion is reduced during high temperatures fatigue.

Oral presentation

Material properties of weld joints of reduced activation ferritic/martensitic steel, F82H

Hirose, Takanori; Sakasegawa, Hideo; Nakajima, Motoki; Tanigawa, Hiroyasu

no journal, , 

Weld joints of a reduced activation ferritic/martensitic steel, F82H were prepared using Tungsten-Inert-Gas (TIG) and Electron Beam (EB) welding. Physical properties and mechanical properties of these weld joints were investigated in this work. Moreover, effects of Post Weld Heat Treatment (PWHT) was also investigated. After PWHT at 720 $$^{circ}$$C, most of physical properties of weld metal were very similar to those of F82H base metal. Coefficient of thermal expansion and thermal diffusivity of weld metal demonstrated 10% of degradation compared to the base metal. Although weld metal and heat affected zone heated above transformation temperature demonstrated hardening and embrittlement, PWHT above 750 $$^{circ}$$C successfully moderated the hardening without softening in the base metal.

Oral presentation

Effect of dissolved oxygen on corrosion properties of F82H in high temperature pressurized water

Nakajima, Motoki; Hirose, Takanori; Tanigawa, Hisashi; Kawamura, Yoshinori

no journal, , 

For blanket application, the structural material is required to be as thin as possible for tritium breeding. On the other hand, the pressure tightness is required to withstand 15 MPa of internal pressure. Therefore it is necessary to understand the corrosion mechanism in high temperature pressurized water. This work reports results of corrosion tests on a reduced activation ferritic/martensitic steel, F82H as a structural material for the blanket. Moreover, the effects of water flow and dissolved oxygen (DO) on corrosion properties were investigated using rotating disk specimen in autoclave. In previous study, it was reported that the weight loss by water flow becomes significant with lowering DO concentration. Based on the XRD and EPMA results, it seemed that the formation of Fe$$_{2}$$O$$_{3}$$ was effective for the suppression of weight loss. In this study, we discussed the relationship between stable oxide film and corrosion.

Oral presentation

Development of welding tool for remote maintenance of ITER blanket

Tanigawa, Hisashi; Ueno, Kenichi; Inoue, Ryuichi; Takeda, Nobukazu; Kakudate, Satoshi

no journal, , 

The shield blanket in ITER has an active cooling structure necessitating hydraulic connections to the cooling water manifold. To maintain or replace the blanket, welding the hydraulic connection by remote handling is necessary. Access for the welding is limited in a small hole in the first wall because of spatial constraints related to neutron and heat fluxes. A bore welding tool is required. Laser and TIG welding tools have been developed, and the welding conditions have been optimized for all position welding to horizontally located pipes. Additionally capability of re-welding between as-cut and new pipes has been confirmed. Based on the results, applicability of laser and TIG welding are comparatively assessed.

Oral presentation

An Analysis of dose distribution during the Fukushima Daiichi Nuclear Power Station accident based on atmospheric dispersion simulation

Terada, Hiroaki; Nagai, Haruyasu; Chino, Masamichi

no journal, , 

no abstracts in English

Oral presentation

Study of difference in reactor physics parameters of an accelerator-driven system between nuclear data libraries

Matsuyama, Daiki*; Iwamoto, Hiroki; Tagi, Kazuhiro*; Yudhitya, K.*; Uesaka, Mitsuru*; Fujiwara, Takeshi*

no journal, , 

no abstracts in English

Oral presentation

Development of three-dimensional reactor analysis code system for Accelerator-Driven System, ADS3D

Sugawara, Takanori; Hirai, Yasushi*; Nishihara, Kenji; Iwamoto, Hiroki; Sambuu, O.*; Ushio, Tadashi*

no journal, , 

To investigate an Accelerator-Driven System (ADS) with sub-criticality control mechanism such as control rods or burnable poison, the ADS3D code has been developed on MARBLE which is a next generation reactor analysis code system developed by JAEA. In the past neutronics calculation for the ADS, JAEA employed RZ calculation models to realize efficient investigations. However, it was very difficult to model sub-criticality control mechanisms in RZ calculation models. The ADS3D code system is available to calculate the transportation of protons and neutrons, the burn-up calculation and the fuel exchange in three-dimensional calculation models. It means this code system can treat ADS concepts with sub-criticality control mechanism and makes it possible to investigate a new concept of ADS.

Oral presentation

Investigation on applicability of fast neutron direct interrogation method to fuel debris, 2; Basic design of non-destructive measurement system

Maeda, Makoto; Furutaka, Kazuyoshi; Kureta, Masatoshi; Ozu, Akira; Tobita, Hiroshi; Haruyama, Mitsuo; Komeda, Masao; Hattori, Kentaro

no journal, , 

We have developed the fast neutron direct interrogation, FNDI, method which measures the total amount of the fissile in fuel debris expected as promising nondestructive measurement technology. And we started examination about the possibility of whether to be applicable to measurement of the amount of fissile in the container which stored the fuel debris. In this report, the progress about the basic design of non-destructive measurement system which has been designed by using Monte Carlo code PHITS and newly developed visualization tools, and also the 4D visualization results of neutron diffusion characteristic in the system are reported.

Oral presentation

Investigation on applicability of fast neutron direct interrogation method to fuel debris, 1; Short term plan and interim report on parameter analysis

Kureta, Masatoshi; Maeda, Makoto; Ozu, Akira; Furutaka, Kazuyoshi; Tobita, Hiroshi; Haruyama, Mitsuo; Komeda, Masao; Hattori, Kentaro

no journal, , 

The plan about the material accountancy or measurement of fuel debris which occurs in a Fukushima Daiichi Nuclear Power Plant accident was not decided. It will be determined by the stakeholder in the future. We have developed the fast neutron direct interrogation, FNDI, method which measures the total amount of the fissile expected as promising nondestructive measurement technology. And we started examination about the possibility of whether to be applicable to measurement of the amount of fissile in the container which stored the fuel debris. We reports the short-term plan and the progress about the influence which composition of fuel debris has on the neutron measurement result by the FNDI method.

Oral presentation

Measurements of $$gamma$$-ray emission probabilities of $$^{237}$$Np and $$^{241}$$Am

Terada, Kazushi; Nakamura, Shoji; Kimura, Atsushi; Nakao, Taro; Iwamoto, Osamu; Harada, Hideo

no journal, , 

The research project entitled "Research and development for Accuracy Improvement of neutron nuclear date on Minor Actinides (AIMAC)" has been proceeded for the R&D of innovative nuclear systems and environmental load reduction from the disposal of nuclear waste. To obtain accurate cross section data, it is indispensable to determine the amount of MA sample accurately and non-destructively. However, the uncertainty concerning the amount of sample with high-precision by $$gamma$$-ray spectroscopy, accurate $$gamma$$-ray emission probabilities are necessary. Then, measurements of $$gamma$$-ray emission probabilities of $$^{237}$$Np and $$^{233}$$Pa have been performed. And the measurements of $$^{241}$$Am are under planning. This contribution presents the results.

Oral presentation

Development of automatic detection and measurement system for the Pu spot in the MOX fuel pellet

Hosogane, Tatsuya; Ishikawa, Fumitaka; Kageyama, Tomio; Kayano, Masashi; Kodaira, Satoshi*; Kurano, Mieko*

no journal, , 

For the safe design of MOX fuel,plutonium (Pu) spot analysis is an important control point,thus maximum diameter and Pu content of the Pu spot is defined as MOX fuel specification.Diameter and Pu content of the Pu spot has been analyzed by detecting Pu spot from pictures taken by alpha-autoradiography using commercial imaging analysis software and measure its diameter and content by hand work.because this method requires a lot of work,automatic detection and measurement system for the Pu spot diameter and Pu content was developed to save workload.

Oral presentation

Accuracy improvement of thermal-neutron capture cross-section for Np-237

Nakamura, Shoji; Terada, Kazushi; Kimura, Atsushi; Nakao, Taro; Iwamoto, Osamu; Harada, Hideo; Uehara, Akihiro*; Fujii, Toshiyuki*

no journal, , 

As a part of the AIMAC Project, our group have measured the cross sections for Minor Actinides by an activation method with research reactors. In this presentation, we will clear up the cause of discrepancies among reported data for Np-237 in terms of the $$gamma$$-ray emission probability, experimental method and so on.

208 (Records 1-20 displayed on this page)