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Journal Articles

Japan Atomic Energy Agency; Contribution to the decommissioning of the Fukushima Daiichi Nuclear Power Station and the reconstruction of Fukushima Prefecture at the Naraha center for Remote Control technology development

Morimoto, Kyoichi; Ono, Takahiro; Kakutani, Satomi; Yoshida, Moeka; Suzuki, Soichiro

Journal of Robotics and Mechatronics, 36(1), p.125 - 133, 2024/02

The Naraha Center for Remote Control Technology Development was established for the purpose of developing and verifying remote control equipment for promoting the decommissioning of the Fukushima Daiichi Nuclear Power Station and the external use of this center was started in 2016. The mission of this center is to contribute to the decommissioning of the Fukushima Daiichi Nuclear Power Station and for the reconstruction of Fukushima Prefecture. In this review, we describe the equipment related to the full-scale mock-up test, the component test for a remote-control device and the virtual reality system in this center. In addition, the case examples for usage of these equipment are introduced.

Journal Articles

Development of performance evaluation method for nuclear emergency response robot

Yamada, Taichi; Watanabe, Kaho; Suzuki, Soichiro; Kawabata, Kuniaki

Automation Systems, 39(464), p.88 - 92, 2023/09

In Fukushima Daiichi Nuclear Power Station (FDNPS) emergency response and decommissioning, high radiation or unknown environments significantly restrict human workers' activity. Thus, a remotely controlled robot is essential to operate in such an environment instead of human workers. However, remote robot operation is not easy, and it is required to understand the robot's capability, that is, what/how the robot can do on the site. Therefore, robot evaluation method development is important for remote robot operation in disaster sites. We survey the required capabilities for a remotely controlled robot from the remote operation cases in FDNPS and develop test methods to evaluate the capabilities. This paper introduces the survey of FDNPS remote operation cases and the test method development.

Journal Articles

EBR-II MOX fuel characterization enabling ARES Phase I testing

Bess, J. D.*; Chipman, A. S.*; Pope, C. L.*; Jensen, C. B.*; Ozawa, Takayuki; Hirooka, Shun; Kato, Masato*

Nuclear Science and Engineering, 197(8), p.1845 - 1872, 2023/08

 Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)

Pretransient characterization was performed for the EBR-II MOX fuel pellets from the SPA-2/-2B Operational Reliability Testing collaboration between Japan and US. The continued collaboration will investigate the transient performance of these rods in TREAT at Idaho National Laboratory. The results will fill a gap in existing transient performance data for MOX as these rods have a peak burnup of ~134.4 GWd/t in the EBR-II. Fuel pellet properties were gathered from available resources and their irradiation and decay history evaluated. Further reactor physics calculations were performed to support the experiment design, reactor operations, and safety analyses necessary to enable the programmatic success. Of the three irradiated fuel pins, two will undergo transient testing, and all three will undergo post-irradiation examination.

Journal Articles

Development of performance evaluation method for nuclear emergency response robot

Yamada, Taichi; Watanabe, Kaho; Suzuki, Soichiro; Kawabata, Kuniaki

Keisoku To Seigyo, 62(5), p.268 - 271, 2023/05

In Fukushima Daiichi Nuclear Power Station (FDNPS) emergency response and decommissioning, high radiation or unknown environments significantly restrict human workers' activity. Thus, a remotely controlled robot is essential to operate in such an environment instead of human workers. However, remote robot operation is not easy, and it is required to understand the robot's capability, that is, what/how the robot can do on the site. Therefore, robot evaluation method development is important for remote robot operation in disaster sites. We survey the required capabilities for a remotely controlled robot from the remote operation cases in FDNPS and develop test methods to evaluate the capabilities. This paper introduces the survey of FDNPS remote operation cases and the test method development.

Journal Articles

Designing test methods for running capabilities of ground robots for nuclear disaster response

Kawabata, Kuniaki; Yamada, Taichi; Shirasaki, Norihito; Ishiyama, Hiroki

Proceedings of IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM 2019) (USB Flash Drive), p.559 - 564, 2019/07

Journal Articles

Potential for remote controllable systematization of the method of testing reinforced concrete using guided-wave on rebar

Furusawa, Akinori; Nishimura, Akihiko; Takenaka, Yusuke; Muramatsu, Toshiharu

Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 4 Pages, 2019/05

The aim of this work presented here is to demonstrate the potential of our method for remote controllable systematization, of testing reinforced concrete based on ultrasonic guided-wave on rebar. In order to investigate how the deteriorated phenomena has the effects on the ultrasonic guided-wave propagating on the rebar, following experiments are conducted. Test pieces used for the experiments are made of bare steel rod and cylindrically pored mortar to be representing the actual reinforced concrete. Irradiating the end face of the rod with nanosecond pulsed laser makes the ultrasonic guided-wave induced, at the other end face, the guided wave signal is measured with ultrasonic receiver. One test piece is with no damage and the other is deteriorated test piece. The deterioration is made by electrolytic corroded method. The guided-wave signal from the deteriorated test piece is measured with respect to each energization time, the change in the waveform is investigated. Analyzing the results from the experiments above, it is found that the deterioration of rebar has remarkable effects on the guided-wave signal. The signal from test piece with no damage has strong peak at both specific frequency and lower region, on the other hand, signals from deteriorated test piece has only at the specific frequency depending on the diameter of the steel rod. Finally, discussion concerning with the experimental results and future perspective for remote controllable systematization of our method is carried out.

JAEA Reports

Annual report for FY2016 on the activities of Naraha Center for Remote Control Technology Development (April 1, 2016 - March 31, 2017)

Naraha Center for Remote Control Technology Development, Fukushima Research Insitute

JAEA-Review 2018-014, 52 Pages, 2018/12

JAEA-Review-2018-014.pdf:5.62MB

The Naraha Remote Technology Development Center (Naraha Center) consists of a mock-up test building and a research management building, and various test facilities necessary for the decommissioning work after the accident of TEPCO Fukushima Daiichi Nuclear Power Station are installed. Using these test facilities, a wide range of users, such as companies engaged in decommissioning work, research and development institutions, educational institutions, etc., can efficiently develop robots through characterization and performance evaluation of remote-controlled robots. Furthermore, it is possible to make various uses such as exhibitions that many companies have met together, experts' meetings on decommissioning. This report summarizes the activities of the Naraha Center such as development of remote control technologies, maintenance and training of remote control equipment for emergency response, use of component test areas, and so on in FY2016.

Journal Articles

Application of phosphate modified CAC for incorporation of simulated secondary aqueous wastes in Fukushima Daiichi NPP, 1; Characterization of solidified cementitious systems with reduced water content

Garcia-Lodeiro, I.*; Lebon, R.*; Machoney, D.*; Zhang, B.*; Irisawa, Keita; Taniguchi, Takumi; Namiki, Masahiro*; Osugi, Takeshi; Meguro, Yoshihiro; Kinoshita, Hajime*

Proceedings of 3rd International Symposium on Cement-based Materials for Nuclear Wastes (NUWCEM 2018) (USB Flash Drive), 4 Pages, 2018/11

JAEA Reports

Mock-up test of the modified STACY (Performance check of water feed and drain system)

Seki, Masakazu; Maekawa, Tomoyuki; Izawa, Kazuhiko; Sono, Hiroki

JAEA-Technology 2017-038, 52 Pages, 2018/03

JAEA-Technology-2017-038.pdf:4.6MB

The Japan Atomic Energy Agency is conducting a reactor modification project of the Static Experiment Critical Facility (STACY). In the modification, STACY is to be converted from a thermal reactor using solution fuel into that using fuel rods and light water moderator. Reactivity of the modified STACY core is controlled by the water level fed in the core tank as well as the present STACY. In order to verify the basic design of the water feed and drain system of the modified STACY, we constructed a mockup test apparatus with almost the same structure and specifications as the modified STACY. In the mockup test, performance checks were pursued regarding limitation of maximum flow of water feeding, adjustment of the flow rate of water feeding, stop of water feeding and others. This report describes the outline and results of the mock-up test of the water feed and drain system of the modified STACY.

Journal Articles

Release behavior of Cs and its chemical form during late phase of Fukushima Daiichi Nuclear Power Plant accident

Hidaka, Akihide; Yokoyama, Hiroya

Proceedings of Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia 2017 (AWC 2017) (USB Flash Drive), p.29 - 42, 2017/09

no abstracts in English

Journal Articles

Design of test methods for remotely operated robots utilized for decommissioning tasks

Kawabata, Kuniaki; Tanifuji, Yuta; Mori, Fumiaki; Shirasaki, Norihito

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 4 Pages, 2017/04

This paper describes to develop test methods for evaluation of remotely operated robots and operator proficiency for nuclear emergency response and decommissioning tasks. We summarized representative robot's behaviors in the actual operations by the time analysis approach. We also examined environmental factors from the view point of the operation efficiency. Based on these examinations, we currently design some modules of the field for testing remotely operated machines. The approach and progress of the test method development are reported.

Journal Articles

Altitude control performance improvement via preview controller for unmanned airplane for radiation monitoring system

Sato, Masayuki*; Muraoka, Koji*; Hozumi, Koki*; Sanada, Yukihisa; Yamada, Tsutomu*; Torii, Tatsuo

Nihon Koku Uchu Gakkai Rombunshu (Internet), 65(2), p.54 - 63, 2017/02

This paper is concerned with the design problem of preview altitude controller for Unmanned Airplane for Radiation Monitoring System (UARMS) to improve its control performance. UARMS has been developed for radiation monitoring around Fukushima Daiichi Nuclear Power Plant which spread radiation contaminant due to the huge tsunamis caused by the Great East Japan Earthquake. The monitoring area contains flat as well as mountain areas. The basic flight controller has been confirmed to have satisfactory performance with respect to altitude holding; however, the control performance for variable altitude commands is not sufficient for practical use in mountain areas. We therefore design preview altitude controller with only proportional gains by considering the practicality and the strong requirement of safety for UARMS. Control performance of the designed preview controller was evaluated by flight tests conducted around Fukushima Sky Park.

Journal Articles

Contributions to the decommissioning of Fukushima Daiichi Nuclear Power Station by JAEA Naraha Remote Technology Development Center

Daido, Hiroyuki; Kawatsuma, Shinji; Kojima, Hisayuki; Ishihara, Masahiro; Nakayama, Shinichi

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 8 Pages, 2017/00

JAEA Reports

Results and progress of fundamental research on fission product chemistry; Progress report in 2015

Osaka, Masahiko; Miwa, Shuhei; Nakajima, Kunihisa; Di Lemma, F. G.*; Suzuki, Chikashi; Miyahara, Naoya; Kobata, Masaaki; Okane, Tetsuo; Suzuki, Eriko

JAEA-Review 2016-026, 32 Pages, 2016/12

JAEA-Review-2016-026.pdf:6.18MB

A fundamental research program on fission product (FP) chemistry has started since 2012 for the purpose of establishment of a FP chemistry database in each region of LWR under severe accident and improvement of FP chemical models based on the database. Research outputs are reflected as fundamental knowledge to both the research and development of decommissioning of Fukushima Daiichi Nuclear Power Station (1F) and enhancement of LWR safety. Four research items have thus been established considering the specific issues of 1F and the priority in the source term research area, as follows: effects of boron (B) release kinetics and thermal-hydraulic conditions on FP behavior, cesium (Cs) chemisorption and reactions with structural materials, enlargement of a thermodynamic and thermophysical properties database for FP compounds and development of experimental and analytical techniques for the reproduction of FP behavior and for direct measurement methods of chemical form of FP compounds. In this report, the research results and progress for the year 2015 are described. The main accomplishment was the installation of a reproductive test facility for FP release and transport behavior. Moreover, basic knowledge about the Cs chemisorption behavior was also obtained. In addition to the four research items, a further research item is being considered for deeper interpretation of FP behavior by the analysis of samples outside of the 1F units.

Journal Articles

A Rapid evaluation method of the heat removed by a VCS before rise-to-power tests

Takamatsu, Kuniyoshi

Journal of Thermal Science, 24(3), p.295 - 301, 2015/06

 Times Cited Count:2 Percentile:10.19(Thermodynamics)

Before rise-to-power tests, the actual measured value of heat released from the Reactor Pressure Vessel (RPV) or removed by the Vessel Cooling System (VCS) cannot be obtained. It is difficult for operators to evaluate the reactor outlet coolant temperature supplied from the High Temperature Engineering Test Reactor (HTTR) before rise-to-power tests. Therefore, when the actual measured value of heat released from the RPV or removed by the VCS are changed during rise-to-power tests, operators need to evaluate quickly, within a few minutes, the heat removed by the VCS and the reactor outlet coolant temperature of 30 (MW), at the 100% of the reactor power, before the temperature achieves to 967 ($$^{circ}$$C) which is the maximum temperature limit generating the reactor scram. In this paper, a rapid evaluation method for use by operators is presented.

Journal Articles

Heat exchanger performance in main cooling system on high temperature test operation at High Temperature Gas-Cooled Reactor 'HTTR'

Tochio, Daisuke; Nakagawa, Shigeaki; Furusawa, Takayuki*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(2), p.147 - 155, 2005/06

High Temperature Engineering Test Reactor (HTTR) of high temperature gas-cooled reactor at JAERI achieved the reactor outlet coolant temperature of 950$$^{circ}$$C for the first time in the world at Apr. 19, 2004. To remove of generated heat at reactor core and to hold reactor inlet coolant temperature as specified temperature, heat exchangers in HTTR main cooling system should have designed heat exchange performance. In this report, heat exchanger performance is evaluated based on measurement data in high temperature test operation. And it is confirmed the adequacy of heat exchanger designing method by comparison of evaluated value with designed value.

JAEA Reports

Proposal for evaluation methods of reactor outlet coolant temperature in HTGRs

Takamatsu, Kuniyoshi; Nakagawa, Shigeaki

JAERI-Tech 2005-030, 21 Pages, 2005/05

JAERI-Tech-2005-030.pdf:1.06MB

The High Temperature engineering Test Reactor (HTTR) is a graphite moderated and gas cooled reactor with the thermal power of 30MW and the reactor outlet coolant temperature of 850$$^{circ}$$C/950$$^{circ}$$C. Rise-to-power test in the HTTR was performed from March 31th to May 1st in 2004 as phase 5 test up to 30MW in the high temperature test operation mode. It was confirmed that the thermal reactor power and the reactor outlet coolant temperature reached to 30MW and 950$$^{circ}$$C respectively on April 19th. Achievement of the reactor outlet coolant temperature of 950$$^{circ}$$C is the first time in Japan as well as the world. This report describes proposal for evaluation methods of reactor outlet coolant temperature in the HTGRs through the HTTR operation experiments. The equation is derived from relationships among PRM reading values, reactor outlet coolant temperature, reactor thermal power and heat removal by VCS. The deliberation processes in this study will be applicable to the research and developments of HTGRs in the future.

JAEA Reports

Radiation monitoring data of the HTTR rise-to-power test; Results up to 30MW operation on the high-temperature test operation mode

Ashikagaya, Yoshinobu; Kawasaki, Tomokatsu; Yoshino, Toshiaki; Ishida, Keiichi

JAERI-Tech 2005-010, 81 Pages, 2005/03

JAERI-Tech-2005-010.pdf:16.65MB

no abstracts in English

Journal Articles

Rise-to-power test result of core outlet coolant tamperature of 950 $$^{circ}$$C in HTTR

Iyoku, Tatsuo; Nakagawa, Shigeaki; Takamatsu, Kuniyoshi

UTNL-R-0446, p.14_1 - 14_9, 2005/03

no abstracts in English

Journal Articles

High temperature gas-cooled reactor

Tachibana, Yukio

Genshiryoku Nenkan 2005-Nen Ban, p.279 - 287, 2005/00

no abstracts in English

78 (Records 1-20 displayed on this page)