Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 35

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

Journal Articles

Demonstration of a neutron resonance transmission analysis system using a laser-driven neutron source

Hironaka, Kota; Ito, Fumiaki*; Lee, J.; Koizumi, Mitsuo; Takahashi, Tone; Suzuki, Satoshi*; Yogo, Akifumi*; Arikawa, Yasunobu*; Abe, Yuki*

Dai-42-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2021/11

Neutron resonance transmission analysis (NRTA) is a method for non-destructive measurement of nuclear material by using a time-of-flight (TOF) technique with a pulsed neutron source. For NRTA system to carry out the short-distance TOF measurements with high resolutions, a short-pulsed neutron source is required. Laser-driven neutron sources (LDNSs) is very suitable as such a neutron source because of its short pulse width. Moreover, the compactness of the laser system is also expected due to the remarkable development of laser technology in recent years. In the present study, we have developed a technology for applying LDNS to the NRTA system and conducted the demonstration experiment using the LFEX laser at Osaka University to investigate the feasibility of the system. In this experiment, we successfully observed the neutron resonance peaks of indium and silver samples.

Journal Articles

Morphological reproductive characteristics of testes and fertilization capacity of cryopreserved sperm after the Fukushima accident in raccoon (${it Procyon lotor}$)

Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.

Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03

We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.

Journal Articles

Deep microbial life in high-quality granitic groundwater from geochemically and geographically distinct underground boreholes

Ino, Kohei*; Konno, Yuta*; Kozuka, Mariko*; Hirota, Akinari*; Togo, Yoko*; Fukuda, Akari*; Komatsu, Daisuke*; Tsunogai, Urumu*; Tanabe, Akifumi*; Yamamoto, Satoshi*; et al.

Environmental Microbiology Reports (Internet), 8(2), p.285 - 294, 2016/04

 Times Cited Count:18 Percentile:67.66(Environmental Sciences)

To understand the subsurface biosphere, borehole investigation was conducted for 300-m deep granitic rocks at the Mizunami underground research laboratory, Japan. The initial biomass was the highest with the flourish of aerobic H$$_{2}$$-oxidizing Hydrogenophaga spp., whereas an uncultivated lineage of the phylum Nitrospirae became predominant after three years with decreasing biomass. The common occurrence of many species of Nitrospirae and Chlorobi phyla at the geographically distinct sites and the exclusive detection of their phylogenetically related environmental sequences from deep groundwaters and terrestrial hot springs, suggest that these bacteria are indigenous and potentially adapted to the deep terrestrial subsurface.

JAEA Reports

Characteristics of OSL dosimeter as individual monitoring for external radiation

Suzuki, Akifumi; Suzuki, Takehiko; Takahashi, Masa; Nakata, Toru; Murayama, Takashi; Tsunoda, Masahiko

JAEA-Technology 2014-049, 19 Pages, 2015/03

JAEA-Technology-2014-049.pdf:9.12MB

Optically Stimulated Luminescence, OSL, dosimeters have been used as individual dosimeters for external radiation in Nuclear Science Research Institute and so on since October, 2014 as successor of the RPL glass dosimeters. Characteristics of the OSL dosimeters such as dose linearity, energy response, angular dependence, fading characteristics and responses at mixed irradiation fields were examined prior to the start of use. As a result, it was found that the OSL dosimeters met the performances that the national standard (JIS Z 4339) determined. The characteristics of OSL dosimeters were comparable with those of the RPL glass dosimeters. In conclusion, it was confirmed the OSL dosimeters had sufficient performances for the practical use on individual monitoring. This report shows the testing methods and the results for the characteristics of OSL dosimeters.

Journal Articles

Application of the small OSL elements to the ring type dosemeter

Miyauchi, Hideaki; Yoshitomi, Hiroshi; Sato, Yoshitaka; Takahashi, Fumiaki; Tachibana, Haruo; Kobayashi, Ikuo*; Suzuki, Akifumi*

Nihon Hoshasen Anzen Kanri Gakkai-Shi, 12(1), p.41 - 45, 2013/07

In the Japan Atomic Energy Agency (JAEA), exposures to fingertips can be significant in radiological decontamination at the facilities with mixture fields of beta and $$gamma$$ (X) rays. The radiation doses to fingertips have been measured by ring type dosemeters equipped with thermoluminescence dosemeters (TLD) in JAEA. We applied small Optically Stimulated Luminescence (OSL) elements to the ring type dosemeter, which has the advantages in the use for long term and repeating in dose measurements comparing to the TLDs. In this report, we introduce the outline and the dose evaluation method of the new ring type dosimeter which we applied.

JAEA Reports

FEMAXI-6 code verifications for predicting FLWR MOX fuel rod behaviors

Yamaji, Akifumi; Suzuki, Motoe; Okubo, Tsutomu

JAEA-Research 2010-029, 54 Pages, 2010/09

JAEA-Research-2010-029.pdf:3.07MB

This study has evaluated uncertainties in FEMAXI-6 calculations and clarified key models and parameters for predicting LWR MOX fuel rod behavior. Irradiation data obtained from the Halden reactor experiments (IFA-597.4 rod-10, rod-11, and IFA-514 rod-1) were used. The maximum discharge burnup was about 40 GWd/tMOX (IFA-514 rod-1). The results showed that uncertainties in fission gas release calculations were particularly high, and contributions of pellet relocation, densification and swelling models on pellet temperature were also evaluated. The basic fission gas release mechanism of MOX fuels should be the same as that of UO$$_{2}$$ fuels, but the parameters in the model need to be revised for MOX fuels. More experimental data are needed. However, frequent reactor shutdowns and restarts may cause pellet relocation changes which need to be considered in the evaluations.

Journal Articles

Toward integrated laser-driven ion accelerator systems at the Photo-Medical Research Center in Japan

Bolton, P.; Hori, Toshihiko; Kiriyama, Hiromitsu; Mori, Michiaki; Sakaki, Hironao; Sutherland, K.*; Suzuki, Masayuki; Wu, J.*; Yogo, Akifumi

Nuclear Instruments and Methods in Physics Research A, 620(1), p.71 - 75, 2010/08

 Times Cited Count:10 Percentile:60.62(Instruments & Instrumentation)

Journal Articles

FEMAXI-6 code verification with MOX fuels irradiated in Halden reactor

Yamaji, Akifumi; Suzuki, Motoe; Okubo, Tsutomu

Journal of Nuclear Science and Technology, 46(12), p.1152 - 1161, 2009/12

 Times Cited Count:5 Percentile:32.89(Nuclear Science & Technology)

The advanced reactor concept of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) has been proposed and being studied to achieve effective and flexible utilization of the uranium and plutonium resources based on the well-developed light water reactor (LWR) technology. In order to design and evaluate the FLWR fuel rod behavior, the uncertainties in the FEMAXI-6 calculations and the key models and parameters for predicting LWR MOX fuel rod behavior need to be evaluated. In this study, the Test-Fuel-Data-Base (TFDB) obtained from the Halden reactor experiments (IFA-597.4 rod-10, rod-11, and IFA-514 rod-1) were used for the evaluations. The maximum discharge burnup was about 40 GWd/tMOX.

Journal Articles

Application of laser-accelerated protons to the demonstration of DNA double-strand breaks in human cancer cells

Yogo, Akifumi; Sato, Katsutoshi; Nishikino, Masaharu; Mori, Michiaki; Teshima, Teruki*; Numasaki, Hodaka*; Murakami, Masao*; Demizu, Yusuke*; Akagi, Takashi*; Nagayama, Shinichi*; et al.

Applied Physics Letters, 94(18), p.181502_1 - 181502_3, 2009/05

 Times Cited Count:95 Percentile:94.5(Physics, Applied)

Journal Articles

Evaluation of uncertainties in FEMAXI-6 calculations for predicting MOX fuel behavior in FLWR design

Yamaji, Akifumi; Suzuki, Motoe; Okubo, Tsutomu

Proceedings of 2009 International Congress on Advances in Nuclear Power Plants (ICAPP '09) (CD-ROM), p.9092_1 - 9092_9, 2009/05

The concept of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) has been proposed and being studied at JAEA to achieve effective and flexible utilization of the uranium and plutonium resources based on the well-developed LWR technology. FLWR is a BWR type concept and it is planned to be introduced by two stages. In the first stage, the MOX fuels are irradiated in a similar condition to that of the current BWR but with a harder neutron spectrum. The core average discharge burnup is about 45 GWd/tHM. In the second stage, the neutron spectrum is further hardened to achieve a multiple recycling of plutonium with higher burnups. In order to design and evaluate the integrities of FLWR fuel rods, the uncertainties in FEMAXI-6 calculations and models for predicting LWR MOX fuel behavior need to be evaluated. As an introduction to the evaluation process, the Test-Fuel-Data-Base (TFDB) obtained from the Halden reactor experiments (IFA-514) were used for the evaluations. The maximum discharge burnup was about 40 GWd/tMOX. Based on the present investigation, the following models were found to be particularly important. Namely the FGR, pellet densification, swelling, and relocation models. These models of FEMAXI-6 have been developed and the parameters have been optimized based on the past UO$$_{2}$$ irradiation test data. For predicting MOX fuel behavior, the FGR model has a relatively large uncertainty and causes a large uncertainty in the FGR calculations. On the other hand, the uncertainties in the other models are within the range expected by the property variations of typical UO$$_{2}$$ fuels. Hence, the densification, swelling, and the relocation models of FEMAXI-6 can be applied to MOX fuel analyses provided the corresponding MOX property variations are taken into account in the input parameters of these models.

Journal Articles

Stream discharge of metals and rare earth elements in rainfall events in a forested catchment

Matsunaga, Takeshi; Tsuzuki, Katsunori; Yanase, Nobuyuki; Hanzawa, Yukiko; Naganawa, Hirochika; Inoue, Takanobu*; Yamada, Toshiro*; Miyata, Akifumi*

Proceedings of International Symposium on Environmental Modeling and Radioecology, p.243 - 246, 2007/03

The aim of this work is to obtain a fundamental scheme of stream discharge of inorganic toxic materials derived from Characteristics of the stream discharge of metallic elements were investigated in two forested catchments in the Oda River and the Ijira River watersheds. Precipitations, stream water and soil water samples were collected in raining events and were analyzed for inorganic elements, dissolved organic carbon and isotopic abundance of deuterium. Results revealed an accelerated discharge of specific metals of Cu, Sb and Cr and all the studied REE in dissolved form. This feature was commonly found in the two catchments. The specific metals are strongly suspected to be of anthropogenic origin. An analysis of hydrological discharge, using chemical and isotopic tracers, suggested that the increased discharge of the metals originate from their deposits on the ground surface and/or instantaneous resuspension of stream sediment. Contrary, REE discharge was tightly coupled with that of dissolved humic substances.

Journal Articles

Rationalization of the fuel integrity and transient criteria for the super LWR

Yamaji, Akifumi*; Oka, Yoshiaki*; Ishiwatari, Yuki*; Liu, J.*; Koshizuka, Seiichi*; Suzuki, Motoe

Proceedings of 2005 International Congress on Advances in Nuclear Power Plants (ICAPP '05) (CD-ROM), 7 Pages, 2005/05

Ensuring the fuel integrities is one of the most fundamental parts in the High Temperature Supercritical-Pressure Light Water Reactor. Most abnormal transient events of SCLWR-H last for a short period of time and the fuel rods are replaced after being irradiated in the core. In this study, the fuel integrity criteria are rationalized based on the fact that the fuel rod mechanical failures can be represented by the strain of the fuel rod cladding. A new fuel rod is designed with a Stainless Steel cladding. It is internally pressurized to reduce the stress on the cladding and also to increase the gap conductance between the pellet and the cladding. The fuel integrities both at normal operation and abnormal transient conditions are evaluated using the fuel analysis code FEMAXI-6 of JAERI.

JAEA Reports

Characteristics of OSL dosimeters

Suzuki, Akifumi*; Ito, Masashi

JAERI-Tech 2000-089, 30 Pages, 2001/02

JAERI-Tech-2000-089.pdf:1.81MB

no abstracts in English

Oral presentation

Analysis of nitrogen transport to a stream using distributed runoff model

Tsuzuki, Katsunori; Matsunaga, Takeshi; Inoue, Takanobu*; Miyata, Akifumi*; Yamada, Toshiro*

no journal, , 

no abstracts in English

Oral presentation

Evaluation of uncertainties in FEMAXI-6 calculations with MOX fuels irradiated in Halden reactor

Yamaji, Akifumi; Suzuki, Motoe; Okubo, Tsutomu

no journal, , 

FEMAXI-6 is considered to be a powerful tool for developing an advanced LWR concept that utilizes MOX fuel rods, such as FLWR. In order to use this code, verifications with LWR MOX fuel irradiation data is necessary. In this study, the MOX fuel test data obtained from Halden reactor is used to verify FEMAXI-6. Up to about 40 GWd/t, the pellet temperature calculations through the gap conduction calculations are important to predict the fuel rod behavior. Especially, the FGR, pellet relocation, densification, and swelling are influential. These models in FEMAXI-6 have been developed based on UO$$_{2}$$ irradiation experience. However, the results show that these models can also be applied to LWR MOX fuel analysis except the FGR model.

Oral presentation

Peta watt class laser in Japan

Kiriyama, Hiromitsu; Nagashima, Keisuke; Ochi, Yoshihiro; Mori, Michiaki; Tanaka, Momoko; Sasao, Fumitaka; Kosuge, Atsushi; Okada, Hajime; Kondo, Kiminori; Sagisaka, Akito; et al.

no journal, , 

We have developed a femtosecond high intensity laser system, which combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric chirped-pulse amplification (OPCPA) techniques, that produces more than 30 J broadband output energy, indicating the potential for achieving peak powers in excess of 500 TW. With a cleaned high-energy seeded OPCPA preamplifier as a front-end in the system, for the final compressed pulse we found that the temporal contrast in this system exceeds 10$$^{10}$$ on the sub-nanosecond timescale before the main femtosecond pulse. Using diffractive optical elements for beam homogenization of 100-J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with near-perfect top-hat intensity distributions.

Oral presentation

Feasibility of OSL dosimeter for environmental $$gamma$$-ray monitoring

Okura, Takehisa; Oishi, Tetsuya; Miyauchi, Hideaki; Yoshitomi, Hiroshi; Tachibana, Haruo; Higashi, Daisuke; Suzuki, Akifumi*; Kobayashi, Ikuo*

no journal, , 

no abstracts in English

Oral presentation

OSL dosimetry in radiation control; For extremity dose monitoring

Yoshitomi, Hiroshi; Miyauchi, Hideaki; Sato, Yoshitaka; Nojima, Shun; Tachibana, Haruo; Suzuki, Takashi; Takahashi, Fumiaki; Kobayashi, Ikuo*; Suzuki, Akifumi*

no journal, , 

no abstracts in English

Oral presentation

High-spatiotemporal-quality high-intensity laser system

Kiriyama, Hiromitsu; Mori, Michiaki; Shimomura, Takuya; Nakai, Yoshiki*; Tanoue, Manabu*; Sasao, Hajime*; Kondo, Shuji; Kanazawa, Shuhei; Ochi, Yoshihiro; Tanaka, Momoko; et al.

no journal, , 

We report on a femtosecond high-intensity OPCPA/Ti:sapphire hybrid laser system that produces more than 30 J broadband output energy, indicating the potential for achieving petawatt-class peak powers. High temporal-contrast of 10$$^{-10}$$ to 10$$^{-11}$$ has been obtained with a near-perfect flat-topped spatial-profile of filling factor $$sim$$80%. We also present a compact, high-intensity OPCPA/Yb:YAG hybrid laser system that generates $$sim$$100 mJ output energy with a temporal contrast of better than 10$$^{-8}$$ and good spatial beam quality.

Oral presentation

Application of the small OSL elements to the ring type dosemeter

Miyauchi, Hideaki; Yoshitomi, Hiroshi; Takahashi, Fumiaki; Tachibana, Haruo; Suzuki, Akifumi; Sato, Yoshitaka*; Kobayashi, Ikuo*

no journal, , 

In the Japan Atomic Energy Agency (JAEA), exposures to fingertips can be significant in radiological decontamination at the facilities with mixture fields of beta and $$gamma$$ (X) rays. The radiation doses to fingertips have been measured by ring type dosemeters equipped with thermoluminescence dosemeters (TLD) in JAEA. We applied small Optically Stimulated Luminescence (OSL) elements to the ring type dosemeter, which has the advantages in the use for long term and repeating in dose measurements comparing to the TLDs. The ring type dosemeter using OSL elements have started operating from 2012.

35 (Records 1-20 displayed on this page)