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Takahashi, Naoki; Suzuki, Soju; Saito, Hiroto; Ueno, Takashi; Abe, Sadayoshi; Yamanaka, Atsushi; Tanigawa, Masafumi; Nakamura, Daishi; Sasaki, Shunichi; Mine, Tadaharu
Nihon Genshiryoku Gakkai Homu Peji (Internet), 20 Pages, 2017/05
no abstracts in English
Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.
Nihon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00
no abstracts in English
Sasaki, Satoru; Suzuki, Soju; Nakano, Junichi; Takamatsu, Misao; Matoba, Ichiyo*; Nakano, Makoto*; Oketani, Koichiro*; Natsume, Tomohiro*
Genshiryoku eye, 57(2), p.66 - 75, 2011/02
no abstracts in English
Maeda, Shigetaka; Sekine, Takashi; Aoyama, Takafumi; Suzuki, Soju
Reactor Dosimetry State of the Art 2008, p.607 - 615, 2009/00
The experimental fast reactor Joyo is the first sodium-cooled fast reactor in Japan. One of the primary missions of it is to perform irradiation tests of fuel and structural materials to support the development of fast reactors. The MK-III high performance core upgrade to enhance the irradiation testing capabilities was completed in 2003. In order to expand Joyo's capabilities for innovative irradiation testing applications, neutron spectrum tailoring, lower irradiation temperature, sample movable devices and fast neutron beam holes are being considered. By this program, the latent core performance is sufficiently drawn. It accurately responds to existing irradiation needs and aims at further various irradiations.
Suzuki, Soju
Gijutsushi, 20(9), p.16 - 19, 2008/09
In view of the long-term energy security, the global warming prevention, the recent rapid rise of oil price etc., the time of Nuclear Power Renaissance has just come worldwide and the FBR is spotlighted again as a perspective technology leading the Renaissance. The Japan's approach to the commercialization of FBR is described briefly in this paper.
Ito, Kazumoto; Suzuki, Soju
Nihon Genshiryoku Gakkai-Shi ATOMO, 50(1), p.44 - 49, 2008/01
no abstracts in English
Aoyama, Takafumi; Sekine, Takashi; Maeda, Shigetaka; Yoshida, Akihiro; Maeda, Yukimoto; Suzuki, Soju; Takeda, Toshikazu*
Nuclear Engineering and Design, 237(4), p.353 - 368, 2007/02
Times Cited Count:17 Percentile:72.91(Nuclear Science & Technology)Many changes were made in the recent upgrade of the experimental fast reactor JOYO to the MK-III design. The core changes which were made to achieve a fourfold increase in irradiation capacity include the introduction of a second enrichment zone, an increase in core radius and a decrease in core height. Performance tests done at low power, during the rise to power, and at full power, which focus on the neutronics characteristics, are presented. These tests include the nuclear instrumentation system response, the approach to criticality and excess reactivity evaluation, control rod worth calibration, isothermal temperature coefficient evaluation, the calibration of the nuclear instrumentation system with reactor thermal power, and the burn-up reactivity coefficient evaluation. The measurements and comparisons with calculated predictions are shown. The design predictions are consistent with the performance test results, and all technical safety specifications are satisfied. The JOYO MK-III core will provide enhanced irradiation testing capability, as well as serve as a test bed for improving fast reactor operation, performance and safety. Through the performance test evaluation, the core characteristics of a small size sodium cooled fast reactor with a hard neutron spectrum are clarified.
Aoyama, Takafumi; Sekine, Takashi; Nakai, Satoru; Suzuki, Soju
Proceedings of 15th Pacific Basin Nuclear Conference (PBNC-15) (CD-ROM), 6 Pages, 2006/10
The experimental fast reactor JOYO is the first liquid sodium fast reactor in Japan. The purpose of constructing JOYO was to obtain technical information about liquid metal fast breeder reactors (LMFBR). In addition to providing operating experience, many kinds of irradiation tests have been conducted for the development of fuels and materials under the conditions of higher fast neutron flux and temperature than those in LWRs. JOYO has been operated successfully since its criticality was first achieved in 1977 without any serious problem, and this operation demonstrated the safety and reliability of the sodium cooled fast reactor. Continual facility improvements have been punctuated by major enhancements, the latest of which is MK-III. Compared to MK-II, MK-III has a four times larger irradiation capability, improved irradiation test vehicles and improved irradiation characterization. The applications of this enhanced capability include testing fuels and safety features for future FBRs, exploring use of fast reactors for transmutation of radioactive waste, and developing advanced materials for fusion power. In light of the shutdown of several fast reactors around the world, the ability to make such major contributions to reactor development takes on even greater significance. Irradiation tests, steady-state and safety related operations of JOYO are also expected to promote the development of JAEA's prototype FBR, Monju.
Aoyama, Takafumi; Maeda, Shigetaka; Maeda, Yukimoto; Suzuki, Soju
Journal of Nuclear and Radiochemical Sciences, 6(3), p.279 - 282, 2005/12
The present study examines the potential for the demonstration of fission product transmutation in the experimental fast reactor JOYO at JNC's Oarai Engineering Center. The possibility of creating a highly-efficient transmutation irradiation field by loading neutron moderating subassemblies in the reflector region of JOYO was examined in a series of scoping calculations. A cluster of reflector subassemblies was replaced with beryllium or zirconium hydride (ZrH1.65) moderated subassemblies. These moderated subassemblies surrounded one central test subassembly that would contain Tc or
I target material. The
Tc transmutation rate was 16.2% using ZrH
and 13.9% using beryllium as moderator. As a result of this study, basic characteristics of LLFP transmutation in JOYO using relevant moderator materials were investigated and the future feasibility was shown.
Aoyama, Takafumi; Maeda, Shigetaka; Maeda, Yukimoto; Suzuki, Soju
Journal of Nuclear and Radiochemical Sciences, 6(3), p.279 - 282, 2005/12
no abstracts in English
Suzuki, Soju
Nihon Kikai Gakkai Doryoku Enerugi Shisutemu Bumon Nyusu Reta, (31), p.3 - 6, 2005/10
ACROSS (Accurately Controlled Routinely Operated Signal System) is a method to investigate any change of physical state in the Earth's interior using accurately controlled seismic ans/or electromagnetic sources. We preliminary obtained Pg, Sg, and possible plate boundary reflected PxP phase using one-moth long stacking data up to nearly 70 km distance. The seismic reflection experiment across the central Japan revealed the strong PxP reflection phase from 30-40 km deep of the Philippine Sea Plate boundary around the Tokai Region, Japan (Iidaka et al., 2003). The same seismic exploration line crossed the area where many active faults distribute. One of the big issues for revealing the loading process for active faults is to examine the process in the lower crust around active faults. To examine the seismic exploration records obtained by Iidaka et al. (2003), we noticed the presence of strong phases, which can be explained as PxP reflection from the plane at 20 km deep around the Atera fault, which is one of the most active faults in Japan. The phases are identified by a number of explosions on the survey line from north to south of this region. One of high possibilities for the 20 km reflector is the detachment in the lower crust. The high velocity contrast can explain such PxP reflection phase. We evaluated the possibility to observe such phase by the ACROSS transmission from the present source located in Toki city and may conclude to be able to observe such phase and its temporal change, if the seismometers are placed 50-100 km distance north of this region. We also generated synthetic seismograms to confirm the detection. In addition to seismic ACROSS, electrometric ACROSS method may identify the strong-reflection source and its temporal change using resistively analysis around the Tokai Region, Japan. This approach can give high possibility to watch the change of physical state beneath the active faults and it may contribute for the earthquake forecasting.
; Ito, Hideaki; Odo, Toshihiro; Suzuki, Soju
FNCA Genshiryoku Anzen Bunka Wakushoppu, 0 Pages, 2004/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Hara, Hiroshi; Nagata, Takashi; Aoyama, Takafumi; Suzuki, Soju; Nagata, Takashi
Proceedings of 14th Pacific Basin Nuclear Conference (PBNC-14), 0 Pages, 2004/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
; Maeda, Yukimoto; Suzuki, Soju; Hara, Hiroshi
Russian Forum for Sci. and Tech. FAST NEUTRON REAC, 0 Pages, 2003/00
The experimental fast reactor JOYO attained its initial criticality in 1977 with the MK-I breeder core. In 1982, JOYO was modified to the MK-II irradiation core and finished its operation in 2000. Throughout the successful operation of MK-I and MK-II core, the net operation time has exceeded 60,000 hours, and experience on the operation, maintenance and core/fuel management of a fast reactor plant has been accumulated. Furthermore the MK-III modification program is underway to improve the irradiation capability of JOYO. When the MK-III core is started, it will support irradiation tests in feasibility studies for fast reactor and related fuel cycle research and development in Japan.
Sumino, Kozo; Ichige, Satoshi; Fukami, Akihiro*; Maeda, Yukimoto; Suzuki, Soju
PNC TN9430 98-008, 40 Pages, 1998/09
The Raman Distributed Temperature Sensor (RDTS) based on the Raman Scattering Phenomena in the optical fiber is a system, which can easily measure the accurate temperature distribution. In order to evaluate the applicability of RDTS for FBR plant instrumentation, a temperature distribution measurement using RDTS was performed in the primary cooling system of JOYO. By using two optical fiber sensors, which were installed spirally around the primary piping, the temperature distribution on the primary piping was measured from the 30th through the 32nd duty cycle. In addition, the same test was carried out in the secondary cooling system of JOYO in order to test the measurement data from the primary cooling system. The main results were as follows; (1) The temperature data in the primary cooling system was acquired over 180EFPDs of operation at JOYO (accumulated dose : 3 10
R). (2) The chracteristics of FTR in the high dose rate nuclear plant environment was confirmed. (3) The radiation induced temperature errors were calibrated succesfully by using thermocouple readings. The accuracy of the temperature after calibration was approximately
3
C. (4) It was confirmed that diffent fiber and insulator settings on the piping cause temperature changes.
Torimaru, Tadahiko; Yoshida, Akihiro; Nagasaki, Hideaki*; Suzuki, Soju
PNC TN9410 98-034, 31 Pages, 1998/03
Decay heat measurement system for the JOYO spent fuels was developed to obtain the decay heat data of the fuel assemblies as a non-destructive examination method. Since then, decay heat of the JOYO Mk-II fuels, which were cooled for more than 70 days, was measured in the spent fuel storage pond. The measurement of the short term cooled spent fuels, which were discharged without cooling in the reactor vessel, was performed in order to obtain the higher decay heat of the spent fuels. The burn-up of the measured fuels was about 60GWd/t, and the shortest cooling time was 24 days. The experimental data were compared with calculated values of ORIGEN2 using new libraries based on latest nuclear data library "JENDL-3.2". The main results are as follows; (1) The measured decay heat at 24 days after the reactor shut down was approximately 1.250.3 kW. (2) The ratio between calculated and experimental values, C/E, was approximately 0.9 and indicated a cool down time dependence. (3) The heat generated by
Pu and
Am, which amount to 1% of initial composition of fresh fuel, reached 7 - 19% of decay heat at 24-160 days after the reactor shut down.
Maeda, Yukimoto; Suzuki, Soju; Hara, Hiroshi
ENC'98 Transactions, p.21 - 30, 1998/00
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