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JAEA Reports

Ocean current data obtained by Acoustic Doppler Current Profiler across the Tsugaru Strait (Joint research)

Kawamura, Hideyuki; Hirose, Naoki*; Nakayama, Tomoharu*; Ito, Toshimichi

JAEA-Data/Code 2021-004, 34 Pages, 2021/05

JAEA-Data-Code-2021-004.pdf:3.72MB

The Japan Atomic Energy Agency measured the ocean current across the Tsugaru Strait using an Acoustic Doppler Current Profiler attached on a ferryboat from October 1999 to January 2008. The characteristics of the ocean current in the Tsugaru Strait must be understood for predicting oceanic dispersion of radioactive materials released from nuclear facilities around the strait. Furthermore, it is critical to elucidate the mechanism of the Tsugaru Warm Current from an oceanography viewpoint. The dataset obtained in this investigation consists of daily ocean current data files that record the components of the current speed in the east-west and north-south directions from the surface layer to the bottom layer. The dataset stores 2,211 daily ocean current data files, despite some data periods missing from October 1999 to January 2008. In this study, information on the dataset is described for users to analyze the dataset properly for their purposes. Section 1 provides the background and purpose of the ocean current measurement, Section 2 explains the methodology of measurement using an Acoustic Doppler Current Profiler, and Section 3 explains the record format of the daily ocean current data files and data acquisition rate and presents analysis results. Finally, Section 4 concludes this study.

JAEA Reports

Decommissioning activities and R&D of nuclear facilities in the second midterm plan

Terunuma, Akihiro; Mimura, Ryuji; Nagashima, Hisao; Aoyagi, Yoshitaka; Hirokawa, Katsunori*; Uta, Masato; Ishimori, Yuu; Kuwabara, Jun; Okamoto, Hisato; Kimura, Yasuhisa; et al.

JAEA-Review 2016-008, 98 Pages, 2016/07

JAEA-Review-2016-008.pdf:11.73MB

Japan Atomic Energy Agency formulated the plan to achieve the medium-term target in the period of April 2010 to March 2015(hereinafter referred to as "the second medium-term plan"). JAEA determined the plan for the business operations of each year (hereinafter referred to as "the year plan"). This report is that the Sector of Decommissioning and Radioactive Waste Management has summarized the results of the decommissioning technology development and decommissioning of nuclear facilities which were carried out in the second medium-term plan.

Journal Articles

ITER project; Status of procurement activities in domestic agency of Japan and application of HIP technology

Takatsu, Hideyuki; Enoeda, Mikio; Suzuki, Satoshi; Hirose, Takanori; Koizumi, Norikiyo; Takahashi, Koji

Proceedings of International Conference on Hot Isostatic Pressing (HIP '11), p.35 - 40, 2011/04

ITER is a mega-science fusion project, under an international collaboration of seven Members, to construct, operate, exploit and decommission a tokamak-type experimental reactor at Cadarache site with a mission to demonstrate the scientific and technological feasibility. The ITER Project started technical activities in 2007 and is now in a serious construction phase. Domestic Agencies of the seven member countries are in the process of manufacturing long lead-time components. Some of the ITER components apply HIP technology in manufacturing processes in view of a number of potential advantages. In this paper, examples and status of application of HIP technology by the Domestic Agency of Japan are overviewed.

Journal Articles

Numerical experiment for strontium-90 and cesium-137 in the Japan Sea

Kawamura, Hideyuki; Ito, Toshimichi; Kobayashi, Takuya; Otosaka, Shigeyoshi; Hirose, Naoki*; Togawa, Orihiko

Journal of Oceanography, 66(5), p.649 - 662, 2010/10

 Times Cited Count:2 Percentile:6.8(Oceanography)

A numerical experiment is performed to reproduce a distribution of concentrations of $$^{90}$$Sr and $$^{137}$$Cs and estimate their total amounts in the Japan Sea. The concentrations of $$^{90}$$Sr and $$^{137}$$Cs in the surface layer is in the range of 1.0-1.5 Bq/m$$^{3}$$ and 2.0-2.5 Bq/m$$^{3}$$. The concentrations in the intermediate and deep layer are higher than those observed in the northwestern Pacific Ocean, indicating active winter convection in the Japan Sea. The total amounts of $$^{90}$$Sr and $$^{137}$$Cs in the seawater is evaluated to be 1.34 PBq (1 PBq = 10$$^{15}$$ Bq) and 2.02 PBq, which demonstrates an estimation by observational data in the Japan Sea expeditions between 1997 and 2002 by Japan Atomic Energy Agency. The total amounts of $$^{90}$$Sr and $$^{137}$$Cs vary corresponding to deposition at the sea surface with the maximums of 4.86 PBq for $$^{90}$$Sr and 7.33 PBq for $$^{137}$$Cs in the mid-1960s.

Journal Articles

Simulation of concentrations of anthropogenic radionuclides in the Japan Sea

Kawamura, Hideyuki; Ito, Toshimichi; Kobayashi, Takuya; Otosaka, Shigeyoshi; Hirose, Naoki*; Togawa, Orihiko

Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 4 Pages, 2010/10

This study aims to demonstrate many findings in the Japan Sea expeditions by Japan Atomic Energy Agency between 1997 and 2002 making use of an ocean general circulation model. A numerical experiment is performed between 1945 and 2000 with deposition at the sea surface by global fallout as main source of anthropogenic radionuclides. The concentrations of $$^{90}$$Sr and $$^{137}$$Cs in the surface layer are approximately in the range of 1.0-1.5 Bq/m$$^{3}$$ and 2.0-2.5 Bq/m$$^{3}$$ and they exponentially decrease with depth from the sea surface to the sea bottom. Total amounts of $$^{90}$$Sr and $$^{137}$$Cs in the seawater of the Japan Sea are estimated to be about 1.34 PBq (1 PBq = 10$$^{15}$$ Bq) and 2.02 PBq in the numerical experiment, which demonstrates observational estimations in the Japan Sea expeditions. Time series of the total amounts show that they attain the maximums of 4.86 PBq for $$^{90}$$Sr and 7.33 PBq for $$^{137}$$Cs in 1964.

Journal Articles

Modeling of the branches of the Tsushima Warm Current in the eastern Japan Sea

Kawamura, Hideyuki; Ito, Toshimichi; Hirose, Naoki*; Takikawa, Tetsutaro*; Yoon, J.-H.*

Journal of Oceanography, 65(4), p.439 - 454, 2009/08

 Times Cited Count:4 Percentile:13.46(Oceanography)

This study aims at reproducing branches of the Tsushima Warm Current making use of an ocean general circulation model, which is important for movement of pollutants in the Japan Sea. The model was laterally exerted by volume transports measured by ADCP through the Tsushima Straits and the Tsugaru Strait. Sea level variation measured by coastal tide-stations as well as satellite altimeters is assimilated into the numerical model. It was demonstrated that an assimilation of sea level variation at the coastal tide-stations is useful to simulate oceanic condition in the nearshore region.

Journal Articles

Sequential forecasting of the surface and subsurface conditions in the Japan Sea

Hirose, Naoki*; Kawamura, Hideyuki; Lee, H. J.*; Yoon, J.-H.*

Journal of Oceanography, 63(3), p.467 - 481, 2007/06

 Times Cited Count:28 Percentile:54.65(Oceanography)

This study estimates and forecasts a realistic change of the Japan Sea by assimilating satellite measurements into an eddy-resolving circulation model. Suboptimal but feasible assimilation schemes of approximate filtering and nudging play essential roles in a system. The sequential updates of error covariance significantly outperforms the asymptotic covariance due to irregular sampling patterns from multiple altimeter satellites. The best estimate shows an average rms difference of 1.2 $$^{circ}$$C only to the radiometer data, and also explain about half of sea level variances measured by the microwave observation. It is demonstrated that a forecast persistency strongly depends on variable, depth, and location.

Journal Articles

Operation and management of STACY experiment using Pseudo-FPs-doped fuel

Izawa, Kazuhiko; Seki, Masakazu; Hirose, Hideyuki; Kaminaga, Jota; Aoyama, Yasuo; Yoshida, Hiroshi; Sono, Hiroki; Ogawa, Kazuhiko; Sakuraba, Koichi

UTNL-R-0453, p.9_1 - 9_10, 2006/03

no abstracts in English

Journal Articles

Oil spill simulation in the Japan Sea

Kawamura, Hideyuki; Kobayashi, Takuya; Hirose, Naoki*; Ito, Toshimichi; Togawa, Orihiko

WIT Transactions on Ecology and the Environment, Vol.88, p.273 - 278, 2006/00

An assessment system of marine environment in the Japan Sea is being constructed in the Japan Atomic Energy Agency. It is composed of an ocean general circulation model (RIAMOM), a particle random-walk model (SEA-GEARN) and a radiation dose assessment model (COLDOS). This study aims to confirm a validity of the assessment system by reproducing a movement of spilled oil at an incident of Russian tanker Nakhodka, in January 1997. Realistic reproduction of ocean conditions is a significant factor for accurate simulations of the movement of spilled oil. In this study, one of data assimilation techniques, an approximate Kalman filter, was introduced by combining RIAMOM with sea level measurements of satellite data. The assimilated results were in good agreement with observed oceanic phenomena both qualitatively and quantitatively. Using the calculated ocean currents, simulations of behaviour of spilled oil was performed with SEA-GEARN. The tanker was ruptured in a storm about 100 km north of the Oki Islands in Shimane Prefecture, Japan, on January 2, 1997. Most of oil spread over off Hyogo, Kyoto, Fukui and Ishikawa Prefecture, meanwhile a part of it reached a coast of Niigata Prefecture detouring around Noto Peninsula by January 21, 1997. The most important feature in these regions is considered to be a branch of the Tsushima Warm Current (TWC). Owing to a variability of TWC, ocean eddy activities and a sea surface wind, the spilled oil dispersed widely in space. On the other hand, the strong northeastward component of TWC was likely to drive the spilled oil to Niigata Prefecture. A number of experiments with different parameters and situations showed that the assimilated daily ocean currents with wind drift gave the best effect on simulation for the movement of spilled oil.

Journal Articles

Comparison of thermal neutron distributions within shield materials obtained by experiments, SN and Monte Carlo code calculations

Asano, Yoshihiro; Sugita, Takeshi*; Suzaki,Takenori; Hirose, Hideyuki

Radiation Protection Dosimetry, 116(1-4), p.284 - 289, 2005/12

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

no abstracts in English

Journal Articles

Benchmark experiments of thermal neutron and capture $$gamma$$-ray distributions in concrete using $$^{252}$$Cf

Asano, Yoshihiro; Sugita, Takeshi*; Hirose, Hideyuki; Suzaki,Takenori

Nuclear Science and Engineering, 151(2), p.251 - 259, 2005/10

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

no abstracts in English

Journal Articles

MCD study on materials without magnetic order

Miyahara, Tsuneaki*; Ishii, Hiroyoshi*; Takayama, Yasuhiro*; Hirose, Masaaki*; Maruyama, Kenichi*; Obu, Kenji*; Shinoda, Motoki*; Muro, Takayuki*; Saito, Yuji; Matsuda, Tatsuma*; et al.

Journal of the Physical Society of Japan, 70(10), p.2977 - 2981, 2001/10

 Times Cited Count:6 Percentile:42.89(Physics, Multidisciplinary)

no abstracts in English

JAEA Reports

Annual report of STACY operation in FY. 2000; Experiments on neutron-interacting systems with two slab-shaped core tanks and 10% enriched uranyl nitrate solution, 2 (Contract research)

Onodera, Seiji; Hirose, Hideyuki; Izawa, Kazuhiko; Tanino, Shuichi; Kaminaga, Jota*; Sakuraba, Koichi; Miyauchi, Masakatsu; Tonoike, Kotaro; Miyoshi, Yoshinori; Yanagisawa, Hiroshi; et al.

JAERI-Tech 2001-057, 54 Pages, 2001/09

JAERI-Tech-2001-057.pdf:4.28MB

no abstracts in English

JAEA Reports

Annual report of STACY operation in FY.1999; Experiments on two unit neutron-interacting system with slab-shaped core tanks and 10% enriched uranyl nitrate solutions, 1 (Contract research)

Onodera, Seiji; Sono, Hiroki; Hirose, Hideyuki; Tanino, Shuichi; Kaminaga, Jota*; Myomae, Tomoki*; Murakami, Kiyonobu; Sakuraba, Koichi; Miyauchi, Masakatsu; Tonoike, Kotaro; et al.

JAERI-Tech 2000-059, 46 Pages, 2000/11

JAERI-Tech-2000-059.pdf:2.86MB

no abstracts in English

JAEA Reports

Annual report of STACY operation in F.Y. 1998, 2; 800mm-diameter cylindrical core$$cdot$$10% enriched uranyl nitrate solution (Contract research)

Onodera, Seiji; Sono, Hiroki; Hirose, Hideyuki; Tanino, Shuichi; Nagasawa, Makoto*; Murakami, Kiyonobu; Sakuraba, Koichi; Miyauchi, Masakatsu; Yamane, Yuichi; Ono, Akio

JAERI-Tech 2000-013, p.57 - 0, 2000/03

JAERI-Tech-2000-013.pdf:2.43MB

no abstracts in English

JAEA Reports

Annual report of STACY operation in F.Y. 1998, 1; 280mm thickness slab core$$cdot$$10% enriched uranyl nitrate solution (Contract research)

Onodera, Seiji; Sono, Hiroki; Hirose, Hideyuki; Tanino, Shuichi; Nagasawa, Makoto*; Murakami, Kiyonobu; Sakuraba, Koichi; Miyauchi, Masakatsu; Kikuchi, Tsukasa; Ono, Akio

JAERI-Tech 99-084, p.54 - 0, 1999/12

JAERI-Tech-99-084.pdf:2.7MB

no abstracts in English

JAEA Reports

Construction of STACY(Static Experiment Critical Facility)

Murakami, Kiyonobu; ; Hirose, Hideyuki; ; *; *; Sakuraba, Koichi; ; ; *; et al.

JAERI-Tech 98-033, 70 Pages, 1998/08

JAERI-Tech-98-033.pdf:2.25MB

no abstracts in English

JAEA Reports

Annual report of STACY operation in F.Y. 1997; 280mm thickness slab core・10% enriched uranyl nitrate solution (Contract research)

; ; Hirose, Hideyuki; *; *; Murakami, Kiyonobu; Takahashi, Tsukasa; Sakuraba, Koichi; Miyauchi, Masakatsu; ; et al.

JAERI-Tech 98-023, 66 Pages, 1998/06

JAERI-Tech-98-023.pdf:2.89MB

no abstracts in English

JAEA Reports

Improvement of fuel sampling device for STACY and TRACY

Hirose, Hideyuki; Sakuraba, Koichi; ; ; *; *; ; ; ; Miyauchi, Masakatsu; et al.

JAERI-Tech 98-015, 52 Pages, 1998/05

JAERI-Tech-98-015.pdf:1.68MB

no abstracts in English

Journal Articles

Simplified method to estimate the criticality of uranyl nitrate solutions

; Miyoshi, Yoshinori; ; ; Hirose, Hideyuki

Transactions of the American Nuclear Society, 79, p.179 - 180, 1998/00

no abstracts in English

40 (Records 1-20 displayed on this page)