Refine your search:     
Report No.
Search Results: Records 1-20 displayed on this page of 815

Presentation/Publication Type

Initialising ...


Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...


Initialising ...


Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Comparison of the therapeutic effects of [$$^{211}$$At]NaAt and [$$^{131}$$I]NaI in an NIS-expressing thyroid cancer mouse model

Watabe, Tadashi*; Liu, Y.*; Kaneda, Kazuko*; Sato, Tatsuhiko; Shirakami, Yoshifumi*; Oe, Kazuhiro*; Toyoshima, Atsushi*; Shimosegawa, Eku*; Wang, Y.*; Haba, Hiromitsu*; et al.

International Journal of Molecular Sciences (Internet), 23(16), p.9434_1 - 9434_11, 2022/08

 Times Cited Count:0

In this study, we compare the therapeutic effect between [$$^{211}$$At]NaAt and [$$^{131}$$I]NaI. In vitro analysis of double-stranded DNA break (DSB) and colony formation assay were performed using K1-NIS cells. [$$^{211}$$At]NaAt induced higher numbers of DSBs and had a reduced colony formation than [$$^{131}$$I]NaI. In K1-NIS mice, dose-dependent therapeutic effects were observed in both [$$^{211}$$At]NaAt and [$$^{131}$$I]NaI. The superior therapeutic effect of [$$^{211}$$At]NaAt suggests the promising clinical applicability of targeted alpha therapy using [$$^{211}$$At]NaAt in patients with differentiated thyroid cancer refractory to standard [$$^{131}$$I]NaI treatment.

Journal Articles

Parameter optimization for generating atmospheric boundary layers by using the locally mesh-refined lattice Boltzmann method

Onodera, Naoyuki; Idomura, Yasuhiro; Hasegawa, Yuta; Shimokawabe, Takashi*; Aoki, Takayuki*

Keisan Kogaku Koenkai Rombunshu (CD-ROM), 27, 4 Pages, 2022/06

We have developed a wind simulation code named CityLBM to realize wind digital twins. Mesoscale wind conditions are given as boundary conditions in CityLBM by using a nudging data assimilation method. It is found that conventional approaches with constant nudging coefficients fail to reproduce turbulent intensity in long time simulations, where atmospheric stability conditions change significantly. We propose a dynamic parameter optimization method for the nudging coefficient based on a particle filter. CityLBM was validated against plume dispersion experiments in the complex urban environment of Oklahoma City. The nudging coefficient was updated to reduce the error of the turbulent intensity between the simulation and the observation, and the atmospheric boundary layer was reproduced throughout the day.

Journal Articles

Performance measurement of an urban wind simulation code with the Locally Mesh-Refined Lattice Boltzmann Method over NVIDIA and AMD GPUs

Asahi, Yuichi; Onodera, Naoyuki; Hasegawa, Yuta; Shimokawabe, Takashi*; Shiba, Hayato*; Idomura, Yasuhiro

Keisan Kogaku Koenkai Rombunshu (CD-ROM), 27, 5 Pages, 2022/06

We have ported the GPU accelerated Lattice Boltzmann Method code "CityLBM" to AMD MI100 GPU. We present the performance of CityLBM achieved on NVIDIA P100, V100, A100 GPUs and AMDMI100 GPU. Using the host to host MPI communications, the performance on MI100 GPU is around 20% better than on V100 GPU. It has turned out that most of the kernels are successfully accelerated except for interpolation kernels for Adaptive Mesh Refinement (AMR) method.

Journal Articles

$$alpha$$-clustering in atomic nuclei from first principles with statistical learning and the Hoyle state character

Otsuka, Takaharu; Abe, Takashi*; Yoshida, Toru*; Tsunoda, Yusuke*; Shimizu, Noritaka*; Itagaki, Naoyuki*; Utsuno, Yutaka; Vary, J. P.*; Maris, P.*; Ueno, Hideki*

Nature Communications (Internet), 13(1), p.2234_1 - 2234_10, 2022/04

 Times Cited Count:0 Percentile:0.01(Multidisciplinary Sciences)

no abstracts in English

Journal Articles

A Storm-induced flood and associated nearshore dispersal of the river-derived suspended $$^{137}$$Cs

Uchiyama, Yusuke*; Tokunaga, Natsuki*; Azuma, Kohei*; Kamidaira, Yuki; Tsumune, Daisuke*; Iwasaki, Toshiki*; Yamada, Masatoshi*; Tateda, Yutaka*; Ishimaru, Takashi*; Ito, Yukari*; et al.

Science of the Total Environment, 816, p.151573_1 - 151573_13, 2022/04

 Times Cited Count:2 Percentile:89.24(Environmental Sciences)

no abstracts in English

Journal Articles

Development of reacting jet evaluation model based on engineering approaches with particle method for improvement of LEAP-III code

Kosaka, Wataru; Uchibori, Akihiro; Takata, Takashi; Yanagisawa, Hideki*; Watanabe, Akira*; Jang, S.*

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 11 Pages, 2022/03

For the safety assessment of a steam generator (SG) in a sodium-cooled fast reactor, the analysis code LEAP-III can evaluate the water leak rate during the long-term event progress including the tube failure propagation triggered by an occurrence of a small water leak in a failed heat transfer tube in SG. The LEAP-III has the advantage in completing the calculation with low computational cost since it consists of semi-empirical formulae and one-dimensional equations of conservation. However, an evaluation model of temperature distribution by the reacting jet provides wider high temperature region than the experimental data. As a result, LEAP-III shows excessive conservativeness in some case. A Lagrangian particle method code based on engineering approaches has been developed in order to improve this model to get more realistic temperature distribution. In this method, the jet behavior and chemical reaction are simulated using Newton's equation of motion with several engineering approximations instead of solving multi-dimension multiphase thermal hydraulic equations with sodium-water reaction. In this study, interparticle interaction force model was added, and also the chemical reaction and gas-liquid heat transfer evaluation models were improved. We conducted a test analysis, and compared the results by this particle method with the ones by SERAPHIM, that is a mechanistic analysis code for multi-dimensional multiphase flow considering compressibility and sodium-water reaction. Through this test analysis, it confirmed that this particle method has the basic capability to get a realistic temperature distribution with low computational cost, and also to predict tube failure occurrence by coupled with LEAP-III.

Journal Articles

Unstructured-mesh simulation of sodium-water reaction in tube bundle system by SERAPHIM code

Uchibori, Akihiro; Shiina, Yoshimi*; Watanabe, Akira*; Takata, Takashi*

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 12 Pages, 2022/03

An unstructured mesh-based analysis method has been integrated into the sodium-water reaction analysis code, SERAPHIM, in our recent studies. In this study, numerical analysis of an experiment on sodium-water reaction in a tube bundle domain was performed to investigate the effect of the unstructured mesh. The unrealistic behavior appeared in the coarse structured mesh was improved by the unstructured mesh. The numerical result in the case of the unstructured mesh reproduced the peak value of the temperature in the reacting flow.

Journal Articles

Variation in formation and migration of self-interstitial atom clusters in electron irradiated copper with material purity and specimen preparation method

Sato, Yuki*; Abe, Yosuke; Okubo, Kenji*; Tanioka, Takashi*

Philosophical Magazine, 102(12), p.1152 - 1172, 2022/00

 Times Cited Count:0 Percentile:0.01(Materials Science, Multidisciplinary)

Using in situ observation with high-voltage electron microscope, one-dimensional (1D) migration of self-interstitial atom (SIA) clusters under electron irradiation at 300 K was surveyed for copper materials of five nominal purities and TEM specimens prepared with three methods. In standard (STD) specimens that were prepared through cold rolling and annealing in the vacuum, formation and 1D migration of SIA clusters did not depend much on the nominal purity. In non-annealed (NA) specimens, prepared from high purity materials through mechanical processing and electropolishing, defect structure was coarser than in STD specimens. Results of bulk annealing (BA) specimens showed that annealing of as-received block material had minor effects. Above results were discussed based on the hypothesis that impurity atoms existing in as-received materials and those induced by annealing act as traps for SIA clusters.

Journal Articles

Ground-state properties of light $$4n$$ self-conjugate nuclei in ${it ab initio}$ no-core Monte Carlo shell model calculations with nonlocal $$NN$$ interactions

Abe, Takashi*; Maris, P.*; Otsuka, Takaharu*; Shimizu, Noritaka*; Utsuno, Yutaka; Vary, J. P.*

Physical Review C, 104(5), p.054315_1 - 054315_22, 2021/11

 Times Cited Count:5 Percentile:88.76(Physics, Nuclear)

no abstracts in English

JAEA Reports

Study on the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute (FY2020)

Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi; Miyakoshi, Hiroyuki; Takamatsu, Misao; Sakamoto, Naoki; Isozaki, Ryosuke; Onishi, Takashi; et al.

JAEA-Review 2021-020, 42 Pages, 2021/10


The disposal of radioactive waste from the research facility need to calculate from the radioactivity concentration that based on variously nuclear fuels and materials. In Japan Atomic Energy Agency Oarai Research and Development Institute, the study on considering disposal is being advanced among the facilities which generate radioactive waste as well as the facilities which process radioactive waste. This report summarizes a study result in FY2020 about the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute.

Journal Articles

AMR-Net: Convolutional neural networks for multi-resolution steady flow prediction

Asahi, Yuichi; Hatayama, Sora*; Shimokawabe, Takashi*; Onodera, Naoyuki; Hasegawa, Yuta; Idomura, Yasuhiro

Proceedings of 2021 IEEE International Conference on Cluster Computing (IEEE Cluster 2021) (Internet), p.686 - 691, 2021/10

 Times Cited Count:0 Percentile:0.01

We develop a convolutional neural network model to predict the multi-resolution steady flow. Based on the state-of-the-art image-to-image translation model pix2pixHD, our model can predict the high resolution flow field from the set of patched signed distance functions. By patching the high resolution data, the memory requirements in our model is suppressed compared to pix2pixHD.

Journal Articles

Soil microbial community responding to moderately elevated nitrogen deposition in a Japanese cool temperate forest surrounded by fertilized grasslands

Nagano, Hirohiko; Nakayama, Masataka*; Katata, Genki*; Fukushima, Keitaro*; Yamaguchi, Takashi*; Watanabe, Makoto*; Kondo, Toshiaki*; Atarashi-Andoh, Mariko; Kubota, Tomohiro*; Tateno, Ryunosuke*; et al.

Soil Science and Plant Nutrition, 67(5), p.606 - 616, 2021/10

 Times Cited Count:0 Percentile:0.01(Plant Sciences)

We analyzed the relationships between nitrogen deposition (deposition of nitrate and ammonium ions) and soil microbial properties in a cool temperate forest surrounded by normally fertilized pasture grasslands in northern Japan. The aim of the present study was to gain the primary information on soil microbial response to moderately elevated nitrogen deposition ($$<$$ 10 kg N ha$$^{-1}$$ y$$^{-1}$$). We established three experimental plots in the forest edge adjacent to grasslands and other three plots in the forest interior at least 700 m away from the grasslands. During May to November 2018, nitrogen deposition in each plot was measured. In August 2018, litter and soil (0-5 cm depth) samples were collected from all plots to measure net nitrogen mineralization and nitrification rates as indicators of microbial activity, and microbial biomass carbon and nitrogen and various gene abundances (i.e. bacterial 16S rRNA, fungal ITS, bacterial amoA, and archaeal amoA genes) as indicators of microbial abundance and structure. Nitrogen deposition in the forest edge was 1.4-fold greater than that in the forest interior, even while the maximum deposition was 3.7 kg N ha$$^{-1}$$. Nitrogen deposition was significantly correlated to the net nitrogen mineralization and nitrification rates and the 16S rRNA and bacterial amoA gene abundances. Microbial community structures were different between litter and soil samples but were similar between the forest edge and interior. Significant correlations of nitrogen deposition to the soil carbon to nitrogen ratio, and the nitrate and ammonium contents were also observed. Thus, our results show that moderately elevated nitrogen deposition in nitrogen-limited forest edges can stimulate microbial activities and abundances in soils.

JAEA Reports

Carrying-out of whole nuclear fuel materials in Plutonium Research Building No.1

Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.

JAEA-Technology 2021-001, 144 Pages, 2021/08


Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.

Journal Articles

Droplet entrainment by high-speed gas jet into a liquid pool

Sugimoto, Taro*; Kaneko, Akiko*; Abe, Yutaka*; Uchibori, Akihiro; Kurihara, Akikazu; Takata, Takashi; Ohshima, Hiroyuki

Nuclear Engineering and Design, 380, p.111306_1 - 111306_11, 2021/08

 Times Cited Count:2 Percentile:66.2(Nuclear Science & Technology)

Liquid droplet entrainment by a high-speed gas jet is a key phenomenon for evaluation of sodium-water reaction. In this study, a visualization experiment for liquid droplet entrainment by an air jet in a water pool by using frame-straddling method was carried for development of an entrainment model in a sodium-water reaction analysis code. This experiment successfully provided clear images that captured generation and movement of droplets. Droplet diameter and moving speed were obtained at different locations and gas jet velocities from image processing. The measured data contributes phenomena elucidation and model development.

Journal Articles

Droplet-entrainment phenomena affected by interfacial behavior of a high-speed gas jet into a liquid pool

Saito, Masafumi*; Kaneko, Akiko*; Abe, Yutaka*; Uchibori, Akihiro; Kurihara, Akikazu; Takata, Takashi*; Ohshima, Hiroyuki

Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 7 Pages, 2021/08

In order to provide the data for validation and improvement of the sodium-water reaction analysis code, a visualization experiment on liquid droplet entrainment in a high-pressure air jet submerged in a water pool was conducted. Diameter and velocity of entrained liquid droplets were successfully measured. The effect of a nozzle shape was elucidated.

Journal Articles

Real-time tracer dispersion simulations in Oklahoma City using the locally mesh-refined lattice Boltzmann method

Onodera, Naoyuki; Idomura, Yasuhiro; Hasegawa, Yuta; Nakayama, Hiromasa; Shimokawabe, Takashi*; Aoki, Takayuki*

Boundary-Layer Meteorology, 179(2), p.187 - 208, 2021/05

 Times Cited Count:5 Percentile:79.69(Meteorology & Atmospheric Sciences)

A plume dispersion simulation code named CityLBM enables a real time simulation for several km by applying adaptive mesh refinement (AMR) method on GPU supercomputers. We assess plume dispersion problems in the complex urban environment of Oklahoma City (JU2003). Realistic mesoscale wind boundary conditions of JU2003 produced by a Weather Research and Forecasting Model (WRF), building structures, and a plant canopy model are introduced to CityLBM. Ensemble calculations are performed to reduce turbulence uncertainties. The statistics of the plume dispersion field, mean and max concentrations show that ensemble calculations improve the accuracy of the estimation, and the ensemble-averaged concentration values in the simulations over 4 km areas with 2-m resolution satisfied factor 2 agreements for 70% of 24 target measurement points and periods in JU2003.

Journal Articles

Acceleration of locally mesh allocated Poisson solver using mixed precision

Onodera, Naoyuki; Idomura, Yasuhiro; Hasegawa, Yuta; Shimokawabe, Takashi*; Aoki, Takayuki*

Keisan Kogaku Koenkai Rombunshu (CD-ROM), 26, 3 Pages, 2021/05

We develop a mixed-precision preconditioner for the pressure Poisson equation in a two-phase flow CFD code JUPITER-AMR. The multi-grid (MG) preconditioner is constructed based on the geometric MG method with a three- stage V-cycle, and a cache-reuse SOR (CR-SOR) method at each stage. The numerical experiments are conducted for two-phase flows in a fuel bundle of a nuclear reactor. The MG-CG solver in single-precision shows the same convergence histories as double-precision, which is about 75% of the computational time in double-precision. In the strong scaling test, the MG-CG solver in single-precision is accelerated by 1.88 times between 32 and 96 GPUs.

Journal Articles

Multi-resolution steady flow prediction with convolutional neural networks

Asahi, Yuichi; Hatayama, Sora*; Shimokawabe, Takashi*; Onodera, Naoyuki; Hasegawa, Yuta; Idomura, Yasuhiro

Keisan Kogaku Koenkai Rombunshu (CD-ROM), 26, 4 Pages, 2021/05

We develop a convolutional neural network model to predict the multi-resolution steady flow. Based on the state-of-the-art image-to-image translation model Pix2PixHD, our model can predict the high resolution flow field from the signed distance function. By patching the high resolution data, the memory requirements in our model is suppressed compared to Pix2PixHD.

JAEA Reports

Development of fireproof sheet on glove box panels

Kawasaki, Kohei; Shinada, Kenta; Okamoto, Naritoshi; Kageyama, Tomio; Eda, Takashi; Okazaki, Hiro; Suzuki, Hiromichi; Yamamoto, Kazuya; Otabe, Jun

JAEA-Technology 2020-025, 80 Pages, 2021/03


Plutonium Fuel Production Facility was built in 1988 for the purpose of mainly producing MOX fuel of the prototype fast breeder reactor MONJU, and large glove boxes were installed for handling unsealed nuclear fuel material remotely. The panels of these glove boxes are made of acrylic, except for those installed after December 2013. For fires inside the glove box, automatic fire extinguishing systems using halides have been introduced since the beginning of construction, but for fires outside the glove box, there have been issues with direct measures for acrylic. Therefore, we have developed a fireproof sheet that mitigates the effect of fire outside the glove box on the panels as much as possible. As a result, fire-retardant sheets have been selected and attached to the glove box panels. We conducted a flammability test of the acrylic plate attached with these fireproof sheets and a usage environment influence test of fireproof sheets, and obtained good results. In addition, we set up a working group in the Plutonium Fuel Development Center in view of reducing external exposure during the work of attaching fireproof sheets, in which we discussed and examined the work procedure, and summarized it in the basic procedure manual.

Journal Articles

Visualization of the boron distribution in core material melting and relocation specimen by neutron energy resolving method

Abe, Yuta; Tsuchikawa, Yusuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Oishi, Yuji*; Kamiyama, Takashi*; Nagae, Yuji; Sato, Ikken

JPS Conference Proceedings (Internet), 33, p.011075_1 - 011075_6, 2021/03

815 (Records 1-20 displayed on this page)