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grade large tanksHayakawa, Masato; Shimoyama, Kazuhito; Miyakoshi, Hiroyuki; Suzuki, Shigeaki*
JAEA-Technology 2021-027, 33 Pages, 2022/01
JAEA-Technology-2021-027.pdf:3.64MB
At the Oarai Research and Development Institute of the Japan Atomic Energy Agency, experimental studies in various sodium environments are being conducted in connection with the research and development of sodium-cooled fast reactors such as the experimental fast reactor Joyo and the prototype fast reactor Monju. The dismantling of sodium test facilities and equipment that have achieved their purpose has been carried out sequentially, and a wealth of experience and technology has been accumulated. On the other hand, a large amount of metallic sodium used for research and testing is being reused for new testing facilities, and the large sodium tanks that contained the metallic sodium are being dismantled. In order to dismantle these tanks safely and efficiently, it is important to reduce the residual sodium inside the tanks (especially at the bottom) as much as possible before dismantling. Therefore, we have been working on the reduction of residual sodium at the bottom of several large sodium tanks of 100 m class. This report describes the technologies and experiences related to the reduction of residual sodium that have been carried out so far.
Sanada, Yukihisa; Takamura, Yoshihide; Urabe, Yoshimi; Tsuchida, Kiyofumi; Nishizawa, Yukiyasu; Yamada, Tsutomu; Sato, Yoshiharu; Hirayama, Hirokatsu; Nishihara, Katsuya; Imura, Mitsuo; et al.
JAEA-Research 2014-005, 67 Pages, 2014/05
JAEA-Research-2014-005.pdf:52.68MB
Distribution of radiocesium existing on the waterbed such as lake or pond was concerned about at the present that passed for two years by an accident. Here, the direct measurement technique of the radiocesium concentration (in-situ measurement technique) was developed. This method was used an plastic scintillation detector (p-Scanner). This detector carried out quick measurement of a large area. In addition, the count-rate of p-Scanner was converted to the radiocesium concentration (Ba/kg-wet) by comparative measurement of 
-ray spectrometer. We applied the technique to the agricultural pond in Fukushima and made a map of distribution of radiocesium concentration.
Takemoto, Noriyuki; Hori, Naohiko; Nakagawa, Shigeaki; Ishitsuka, Etsuo; Kaminaga, Masanori; Nurzhan, S.*; Takibayev. N.*; Aliyev, B.*; Suzuki, Masahide
Proceedings of International Conference of Young Scientists and Specialists; Current Issues on the Peaceful Use of Atomic Energy (Internet), p.17 - 27, 2012/06
The JMTR is expected to be a key infrastructure with related facilities to contribute the nuclear Human Resource Development (HRD) by a research and On-the-Job-Training (OJT) in order to support global expansion of nuclear power industry. The training program for Asian young researchers and engineers were started from JFY 2011 in JAEA, and 10 trainees from Kazakhstan and Thailand had studied in JFY 2011. In addition, the training course was newly established for domestic students and young engineers from JFY 2010 to JFY 2012, and 45 domestic students and engineers were studied in the course from JFY 2010 to JFY 2011.
Kitano, Akihiro; Nishi, Hiroshi; Suzuki, Takayuki; Okajima, Shigeaki; Kanemoto, Shigeru*
Proceedings of International Conference on Physics of Reactors; Advances in Reactor Physics; Linking Research, Industry, and Education (PHYSOR 2012) (CD-ROM), 14 Pages, 2012/04
The "Synthesis Method", a systematic and sophisticated method of sub-criticality measurement, is proposed in this work to ensure the safety margin before operation. The "Synthesis Method" is based on the modified source multiplication method (MSM) combined with the noise analysis method to measure the reference sub-criticality level for MSM. As a result of numerical simulation, it was suggested that a neutron detector located above the core center and three or more neutron detectors located above the radial blanket region enable the measurement of sub-criticality within 10% uncertainty from -0.5 to -2 and within 15% uncertainty for the deeper sub-criticality.
Matsumoto, Toshiyuki; Yoshida, Eiichi; Suzuki, Shigeaki*; Yasu, Tomohisa*
JAEA-Technology 2007-035, 35 Pages, 2007/03
JAEA-Technology-2007-035.pdf:23.9MB
In the future, a large amount of sodium (Na) containing radioactive wastes must be processed at the time of final shutdown/ decommissioning of FBR plant or radioactive sodium facilities in Japan. Therefore, its disposal technology should be established in consideration of economical efficiency, safety, etc. In the existing technology, since the method of processing sodium directly into radioactive waste is not established, conversion of sodium into chemically stable material can be considered. Then, basic experiments in which sodium was injected at 10 kg/h into solution of sodium hydroxide (NaOH) were conducted, with the improved Sodium Conversion Test Apparatus (SCOT). The conditions of NaOH solution were temperature of 100
C, and NaOH concentration of 45-50 wt%. Consequently, the injected sodium reacted completely in the NaOH solution, and NaOH temperature, NaOH concentration, etc. were controlled properly. It validated that the system of this apparatus was appropriate. Moreover, in case sodium is injected into NaOH solution, a nozzle blockades sometimes. Therefore, the methods to eliminate the cause of nozzle blockage were examined.
Matsumoto, Toshiyuki; Yoshida, Eiichi; Suzuki, Shigeaki*; Yasu, Tomohisa*
JAEA-Research 2007-038, 32 Pages, 2007/03
JAEA-Research-2007-038.pdf:5.06MB
Decommissioning of a sodium cooled fast reactor or an experimental facility which used radioactive sodium will bring a lot of radioactive sodium. However, technology to deal with such the radioactive sodium and decommission is not well established in Japan. Then, basic experimental study has been carried out in order to find and estimate an economic and safety process of the radioactive sodium decommission. There were some examples in overseas to convert the sodium into sodium hydroxide via sodium-water reaction. This method was examined by a basic sodium conversion test apparatus. In the experiment, liquid metal sodium was injected into the sodium hydroxide. Influences of temperature and concentration of the sodium hydroxide were investigated. Nitrogen gas was injected into the sodium hydroxide as atomizing gas in order to protect the sodium injection nozzle and also to mix the sodium. Then the gas flow rate was also varied to see the desired effects. Injected sodium temperature and mass flow rate were fixed at 200C and 10kg/h, respectively. The atomizing gas flow rate, the temperature and concentration of the sodium hydroxide were varied in ranges of 60-100 l/min, 70-100C and 40-60wt%, respectively. The influences of these parameters on the sodium conversion reaction were evaluated. The experiments showed that increase of the atomizing gas resulted in stable injection of the sodium and also larger reaction area. The temperature of the sodium hydroxide had small influences on the reaction, however, the sodium injection nozzle tended to choke up when the temperature was less than 70C. The lower concentration resulted in larger temperature fluctuation and also enlarged the reaction area. Unstable reaction, for example, sudden increase of reaction rate due to excess sodium, was not found under the conditions above listed ranges and stable sodium conversion was confirmed.
Iwamura, Takamichi; Okubo, Tsutomu; Akie, Hiroshi; Kugo, Teruhiko; Yonomoto, Taisuke; Kureta, Masatoshi; Ishikawa, Nobuyuki; Nagaya, Yasunobu; Araya, Fumimasa; Okajima, Shigeaki; et al.
JAERI-Research 2004-008, 383 Pages, 2004/06
JAERI-Research-2004-008.pdf:21.49MB
The present report contains the achievement of "Research and Development on Reduced-Moderation Light Water Reactor with Passive Safety Features", which was performed by Japan Atomic Energy Research Institute (JAERI), Hitachi Ltd., Japan Atomic Power Company and Tokyo Institute of Technology in FY2000-2002 as the innovative and viable nuclear energy technology (IVNET) development project operated by the Institute of Applied Energy (IAE). In the present project, the reduced-moderation water reactor (RMWR) has been developed to ensure sustainable energy supply and to solve the recent problems of nuclear power and nuclear fuel cycle, such as economical competitiveness, effective use of plutonium and reduction of spent fuel storage. The RMWR can attain the favorable characteristics such as high burnup, long operation cycle, multiple recycling of plutonium (Pu) and effective utilization of uranium resources based on accumulated LWR technologies.
Tomiyama, Shingo*; Matsuo, Shigeaki*; Matsunaga, Kinuko*; Suzuki, Mihoko*
JNC TJ7420 2005-054, 295 Pages, 2004/02
JNC-TJ7420-2005-054.pdf:17.76MB
None
Nabeshima, Kunihiko; Tuerkcan, E.*; Suzudo, Tomoaki; Nakagawa, Shigeaki; Inoue, K.*; Oono, Tomio*; *; Suzuki, Katsuo
Proc. of Human-Computer Interaction International'99, 2, p.1187 - 1191, 1999/00
no abstracts in English
Shimazaki, Junya; Suzuki, Katsuo; Nabeshima, Kunihiko; ; Nakagawa, Shigeaki; Shinohara, Yoshikuni
JAERI-M 89-223, 55 Pages, 1990/01
no abstracts in English
Kunitomi, Kazuhiko; Nakagawa, Shigeaki; Suzuki, Katsuo; Wada, Hozumi*; Hirano, Mitsumasa
JAERI-M 89-001, 34 Pages, 1989/02
no abstracts in English
Matsumoto, Toshiyuki; Yoshida, Eiichi; Suzuki, Shigeaki*; Yasu, Tomohisa*
no journal, ,
no abstracts in English
Nishi, Hiroshi; Kitano, Akihiro; Suzuki, Takayuki; Okajima, Shigeaki
no journal, ,
A simulation calculation study has been carried out on the relationship between the control rod insertion patterns and the neutron detector responses under sub-critical state, assuming a measurement of the core reactivity change by the modified source multiplication (MSM) method. Location-dependent characteristics of the neutron detectors were analyzed based on the results of the simulation calculations. A sensitivity analysis on the fuel composition burn-up change to the neutron detector responses was performed at the same time, and the major sensitive macroscopic cross-sections were identified. It is important to take into account the actual burn-up reactivity change of the actual reactor in order to reduce the effect of the uncertainty, induced by the fuel composition burn-up change, on the modification factor for MSM. It was concluded that the adjustment of these major macroscopic cross-sections will be effective and practical for this purpose.
Kitano, Akihiro; Nishi, Hiroshi; Suzuki, Takayuki; Okajima, Shigeaki; Kanemoto, Shigeru*
no journal, ,
A study on the basic algorithm and application to actual reactors of the synthesis method, which combines the reactor noise analysis and modified source multiplication (MSM) method, has been conducted based on numerical simulation calculations, in order to establish a concept of the sub-critical reactivity measurement system. Required performances of the sub-criticality measurement algorithm for the reactor noise analysis was studied, assuming the reference sub-criticality measurement by noise analysis for MSM. As a result it was found out that the accuracy of the measurement will be dominated by the neutron detector efficiency and the improvement of the accuracy will be expected by using lower frequency amplitude data for the break (corner) frequency method. A numerical simulation was performed for actual reactors based on these results, and the dual-detector method was identified to be effective, which can avoid the influence of higher-order effect.
Okajima, Shigeaki; Nishi, Hiroshi; Yamane, Yoshihiro*; Kanemoto, Shigeru*; Yamane, Tsuyoshi; Mori, Takamasa; Kitamura, Yasunori; Fukushima, Masahiro; Kitano, Akihiro; Ando, Masaki; et al.
no journal, ,
The program was planned and has been carried out to develop of the reactivity feedback effect measurement techniques under sub-critical condition in the start-up experiment for fast reactors. The program includes the demonstration of the developed technique in fast critical assembly (FCA) and the proposal of the appropriate measurement system based on the results. The background and the purposes of the program and the outline of development subjects are presented.
samples in a uranium fueled coreSuzuki, Motomu*; Yamamoto, Toru*; Ando, Yoshihira*; Nakajima, Tetsuo*; Ando, Masaki; Kugo, Teruhiko; Okajima, Shigeaki
no journal, ,
To obtain experimental data to evaluate calculation accuracy for the Doppler effect in MOX fueled LWR, a series of experiment has been carried out at FCA with the use of uranium and plutonium samples. Parametric survey calculations as for the modeling, nuclear data library and calculation method were carried out for the experiments in the uranium core using uranium samples. The effect of those parameters for the calculation of the Doppler effect was obtained.
Okajima, Shigeaki; Nishi, Hiroshi; Kanemoto, Shigeru*; Yamane, Yoshihiro*; Fukushima, Masahiro; Kitamura, Yasunori; Kitano, Akihiro; Suzuki, Takayuki; Ando, Masaki; Yamane, Tsuyoshi
no journal, ,
no abstracts in English
Kitano, Akihiro; Nishi, Hiroshi; Suzuki, Takayuki; Okajima, Shigeaki; Kanemoto, Shigeru*
no journal, ,
no abstracts in English
Nishi, Hiroshi; Kitano, Akihiro; Suzuki, Takayuki; Okajima, Shigeaki
no journal, ,
no abstracts in English
Shimoyama, Kazuhito; Hayakawa, Masato; Suzuki, Shigeaki*; Miyakoshi, Hiroyuki; Ara, Kuniaki
no journal, ,
We are conducting dismantling inspection of large-scale sodium component that we have been using in sodium environment for a long time. It was found from the operation history etc. that the sodium compound adhesion behavior on the inner surface of each device exposed to the sodium environment for several decades from the start of use affects sodium purity. In dismantling large sodium equipment, it is important to reduce the residual sodium in the equipment as much as possible, and proposing to carry out high temperature refining operation effective for removal of these attached impurities at the end of plant operation.
