Evaluation of change of LSD spikes by long-term storage

Shibano, Koya; Abe, Katsuo; Tsukasa, Kazuo*; Hosogane, Tatsuya; Kayano, Masashi; Sumi, Mika; Fujiwara, Hideki*; Yamaguchi, Kazuya*; Motoki, Chika*

Dai-41-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2020/11

Large-sized dried spikes, called LSD spike, are used as reference material for accountancy analysis for Plutonium and Uranium by Isotope Dilution Mass Spectrometry. LSD spikes preparation is performed each steps as followed (1) Preparing Plutonium and Uranium mix solution, (2) Aliquoting mix solution to vials, and (3) Drying. J-MOX have planned prepared in-house LSD spike and utilized it for accountancy analysis. If LSD spikes are stored for long term, dried material peel off from bottom of vial and it may affect analytical results. In this study, LSD spikes, which have composition suitable for accountancy analysis in J-MOX, had been stored for about 2 years, then long-term stability of LSD spikes had been evaluated.

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2017

Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Yamada, Ryohei; Yoshii, Hideki*; Hiyama, Yoshinori*; Otani, Kazunori*; et al.

JAEA-Review 2018-028, 120 Pages, 2019/02

JAEA-Review-2018-028.pdf:2.69MB

Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2017. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Japan - IAEA Joint Nuclear Energy Management School 2016

Yamaguchi, Mika; Hidaka, Akihide; Ikuta, Yuko; Murakami, Kenta*; Tomita, Akira*; Hirose, Hiroya*; Watanebe, Masanori*; Ueda, Kinichi*; Namaizawa, Ken*; Onose, Takatoshi*; et al.

JAEA-Review 2017-002, 60 Pages, 2017/03

JAEA-Review-2017-002.pdf:9.41MB

Since 2010, IAEA has held the NEM School to develop future leaders who plan and manage nuclear energy utilization in their county. Since 2012, JAEA together with Japan Nuclear HRD Network, University of Tokyo, Japan Atomic Industrial Forum and JAIF International Cooperation Center have cohosted the school in Japan in cooperation with IAEA. Since then, the school has been held in Japan every year. In 2006, Japanese nuclear technology and experience, such as lessons learned from the Fukushima Daiichi Nuclear Power Plant accident, were provided to offer a unique opportunity for the participants to learn about particular cases in Japan. Through the school, we contributed to the internationalization of Japanese young nuclear professionals, development of nuclear human resource of other countries including nuclear newcomers, and enhanced cooperative relationship with IAEA. Additionally, collaborative relationship within the network was strengthened by organizing the school in Japan.

Aiming for leading parsons development in Nuclear Field; Japan-IAEA Joint Nuclear Energy Management School

Yamaguchi, Mika

Nihon Genshiryoku Gakkai-Shi ATOMO, 58(12), P. 759, 2016/12

https://doi.org/10.3327/jaesjb.58.12_759

The Japan Nuclear Human Resource Development Network, the Japan Atomic Energy Agency, the University of Tokyo, and the Japan Atomic Industrial Forum, JAIF International Cooperation Center and Wakasa Wan Energy Research Center had held the "Japan-IAEA Joint Nuclear Energy Management school 2016" to develop future leaders who plan and manage nuclear energy utilization in cooperation with IAEA from July 11 to 27, 2016 in Japan. Through the school, we contributed to the internationalization of Japanese young nuclear professionals, development of nuclear human resource of other countries including nuclear newcomers, and enhanced cooperative relationship between IAEA and Japan.

Mathematical Modeling of Radioactive Contaminants in the Fukushima Environment

Kitamura, Akihiro; Kurikami, Hiroshi; Yamaguchi, Masaaki; Oda, Yoshihiro; Saito, Tatsuo; Kato, Tomoko; Niizato, Tadafumi; Iijima, Kazuki; Sato, Haruo; Yui, Mikazu; et al.

Nuclear Science and Engineering, 179(1), p.104 - 118, 2015/01

https://doi.org/10.13182/NSE13-89

The prediction of the distribution and fate of radioactive materials eventually deposited at surface in the Fukushima area is one of the main objectives and expected to be achieved in an efficient manner. In order to make such prediction, a number of mathematical models of radioactive contaminants, with particular attention on cesium, on the land and in rivers, lakes, and estuaries in the Fukushima area are developed. Simulation results are examined with the field investigations simultaneously implemented. The basic studies of the adsorption/absorption mechanism of cesium and soils have been performed to shed light on estimating distribution coefficient between dissolved contaminant and particulate contaminant.

Comparative study on annual Cs discharge rates after the Fukushima Dai-ichi Nuclear Power Plant accident from two distinct watershed simulation models

Kitamura, Akihiro; Imaizumi, Yoshitaka*; Yamaguchi, Masaaki; Yui, Mikazu; Suzuki, Noriyuki*; Hayashi, Seiji*

Kankyo Hoshano Josen Gakkai-Shi, 2(3), p.185 - 192, 2014/09

Annual discharge rates of radioactive cesium through selected rivers due to the Fukushima Dai-ichi Nuclear Power Plant accident were simulated by two different watershed models. One is the Soil and Cesium Transport, SACT, model which was developed by Japan Atomic Energy Agency and the other one is the Grid-Catchment Integrated Modeling System, G-CIEMS, which was developed by National Institute of Environmental Studies. We choose the Abukuma, the Ukedo, and the Niida rivers for the present study. Comparative results showed that while components and assumptions adopted in two models differ, both methods predicted the same order of magnitude estimates.

Engineering scale development test of MOX fuel fabrication technology to establish commercialized fast reactor fuel, 1; The O/M ratio preparation tests of sintered pellets

Takato, Kiyoto; Murakami, Tatsutoshi; Suzuki, Kiichi; Shibanuma, Kimikazu; Hatanaka, Nobuhiro; Yamaguchi, Bungo; Tobita, Yoshimasa; Shinozaki, Masaru; Iimura, Naoto; Okita, Takatoshi; et al.

JAEA-Technology 2013-026, 42 Pages, 2013/10

JAEA-Technology-2013-026.pdf:3.17MB

In order to cope with making a commercial fast reactor fuel burn-up higher, oxygen-to-metal (O/M) ratio in the fuel specification is designed to 1.95. As the test for the fabrication of such low O/M ratio pellets, two kinds of O/M ratio preparation tests of different reduction mechanism were done. In the first test, we evaluated the technology to prepare the O/M ratio low by annealing the sintered pellets in production scale. In addition, we know from past experience that O/M ratio of the sintered pellets can be reduced by residual carbon when the de-waxed pellets with high carbon content are sintered. Thus, in another test, the green pellets containing a large amount of organic additives were sintered and we evaluated the technology to produce the low O/M ratio sintered pellets by the reduction due to residual carbon. From the first test results, we found a tendency that the higher annealing temperature or the longer annealing time resulted in the lower O/M ratio. However, the amount of O/M ratio reduction was small and it is estimated that a substantial annealing time is necessary to prepare the O/M ratio to 1.95. It is considered that reducing O/M ratio by annealing was difficult because atmosphere gas containing oxygen released from pellets remained and the O/M ratio was changed to the value equilibrated with the gas having high oxygen potential. From another test results, it was confirmed that O/M ratio was reduced by the reduction due to residual carbon. We found that it was important to manage an oxygen potential of atmosphere gas in a sintering furnace low to reduce the O/M ratio effectively.

The International Atomic Energy Agency Nuclear Energy Management School 2012

Ohgama, Kazuya; Ando, Yoko; Yamaguchi, Mika; Ikuta, Yuko; Shinohara, Nobuo; Murakami, Hiroyuki; Yamashita, Kiyonobu; Uesaka, Mitsuru*; Demachi, Kazuyuki*; Komiyama, Ryoichi*; et al.

JAEA-Review 2013-004, 76 Pages, 2013/05

JAEA-Review-2013-004.pdf:13.53MB

JAEA together with the Japan Nuclear Human Resource Development Network (JN-HRD Net), the University of Tokyo (UT) and the Japan Atomic Industrial Forum (JAIF) cohosted the IAEA-Nuclear Energy Management School in Tokai Village, aiming that Japan will be the center of nuclear HRD in the Asian region. In the school, not only lectures by IAEA experts, but also lectures by Japanese experts and technical visits were included for foreign participants. The school contributed to the internationalization of Japanese young professionals, development of nuclear human resource of other countries, and enhancement of cooperation between IAEA and Japan. Additionally, collaborative relationship within JN-HRD Net was strengthened by the school. In this report, findings obtained during the preparatory work and the school period are reported for future international nuclear HRD activities in Japan.

Review of the studies on the effect of ionizing radiation for redox front migration in HLW repository

Yamaguchi, Makoto; Yui, Mikazu

JAEA-Review 2008-050, 61 Pages, 2009/01

JAEA-Review-2008-050.pdf:3.67MB

Studies on the effect of ionizing radiation for redox front migration in HLW repository were reviewed. The concept of the redox front by groundwater radiolysis around HLW was proposed by Neretnieks in 1982, and it was employed in the performance assessment of spent fuel disposal system executed by Swedish regulatory organization (SKI) in early 90s. With very conservative assumption that all the radiolytic oxidants diffuse into engineered barrier, the redox front reached the bedrock after several hundred years after canister failure, which increased the dose rate of redox-sensitive radioactive elements. However, dissolution tests of spent fuels under various redox conditions indicated that dissolved hydrogen strongly suppress the oxidative dissolution of UO matrix and redox front migration by radiolytic oxidants has not been mentioned in performance assessments since late 90s.

Measurement plan and observational construction program on drift excavation at the Horonobe Underground Research Laboratory Project

Yamazaki, Masanao; Yamaguchi, Takehiro; Funaki, Hironori; Fujikawa, Daisuke; Tsusaka, Kimikazu

JAEA-Research 2008-068, 45 Pages, 2008/09

JAEA-Research-2008-068.pdf:3.76MB

This report summarizes the measurement plan during construction of the underground facility based on the design in advance and the observational construction program for feedback measurements data into design and construction on subsequent steps. This report also describes about design and construction management program for contractor of underground facilities.