Suematsu, Hisayuki*; Sato, Soma*; Nakayama, Tadachika*; Suzuki, Tatsuya*; Niihara, Koichi*; Nanko, Makoto*; Tsuchiya, Kunihiko
Journal of Asian Ceramic Societies (Internet), 8(4), p.1154 - 1161, 2020/12
Pulsed electric current sintering of molybdenum trioxide (MoO) was carried out by one- and two-step pressuring methods for fabrication of irradiation target using production of Mo and Tc nuclear medicine. At 550C by the two-step pressurizing method, a relative density of 93.1% was obtained while, by the one-step pressurization method, the relative density was 76.9%. Direct sample temperature measurements were conducted by inserting a thermocouple in a punch. By the two-step pressurizing method, the sample temperature was higher than that by the one-step pressurizing method even almost the same die temperature. From voltage and current waveforms, it was thought that the conductivity of the sample increased by the two-step pressurizing method to increase the sample temperature and the relative density. The two-step pressurization method enables us to prepare dense targets at a low temperature from recycled and coarse-grained Mo enriched MoO powder.
Sun, X. H.*; Wang, H.*; Otsu, Hideaki*; Sakurai, Hiroyoshi*; Ahn, D. S.*; Aikawa, Masayuki*; Fukuda, Naoki*; Isobe, Tadaaki*; Kawakami, Shunsuke*; Koyama, Shumpei*; et al.
Physical Review C, 101(6), p.064623_1 - 064623_12, 2020/06
The spallation and fragmentation reactions of Xe induced by proton, deuteron and carbon at 168 MeV/nucleon were studied at RIKEN Radioactive Isotope Beam Factory via the inverse kinematics technique. The cross sections of the lighter products are larger in the carbon-induced reactions due to the higher total kinetic energy of carbon. The energy dependence was investigated by comparing the newly obtained data with previous results obtained at higher reaction energies. The experimental data were compared with the results of SPACS, EPAX, PHITS and DEURACS calculations. These data serve as benchmarks for the model calculations.
Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.
Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07
Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.
Fujii, Kotaro*; Yashima, Masatomo*; Hibino, Keisuke*; Shiraiwa, Masahiro*; Fukuda, Koichiro*; Nakayama, Susumu*; Ishizawa, Nobuo*; Hanashima, Takayasu*; Ohara, Takashi
Journal of Materials Chemistry A, 6(23), p.10835 - 10846, 2018/06
Kim, J.*; Yamanaka, Satoru*; Nakajima, Akira*; Kato, Takanori*; Kim, Y.*; Fukuda, Tatsuo; Yoshii, Kenji; Nishihata, Yasuo; Baba, Masaaki*; Takeda, Masatoshi*; et al.
Ferroelectrics, 512(1), p.92 - 99, 2017/08
Yamanaka, Satoru*; Kim, J.*; Nakajima, Akira*; Kato, Takanori*; Kim, Y.*; Fukuda, Tatsuo; Yoshii, Kenji; Nishihata, Yasuo; Baba, Masaaki*; Yamada, Noboru*; et al.
Advanced Sustainable Systems (Internet), 1(3-4), p.1600020_1 - 1600020_6, 2017/04
no abstracts in English
Hama, Katsuhiro; Sasao, Eiji; Iwatsuki, Teruki; Onoe, Hironori; Sato, Toshinori; Fujita, Tomo; Sasamoto, Hiroshi; Matsuoka, Toshiyuki; Takeda, Masaki; Aoyagi, Kazuhei; et al.
JAEA-Review 2016-014, 274 Pages, 2016/08
We synthesized the research results from the Mizunami/Horonobe Underground Research Laboratories (URLs) and geo-stability projects in the second midterm research phase. This report can be used as a technical basis for the Nuclear Waste Management Organization of Japan/Regulator at each decision point from siting to beginning of disposal (Principal Investigation to Detailed Investigation Phase).
Hama, Katsuhiro; Mizuno, Takashi; Sasao, Eiji; Iwatsuki, Teruki; Saegusa, Hiromitsu; Sato, Toshinori; Fujita, Tomo; Sasamoto, Hiroshi; Matsuoka, Toshiyuki; Yokota, Hideharu; et al.
JAEA-Research 2015-007, 269 Pages, 2015/08
We have synthesised the research results from Mizunami/Horonobe URLs and geo-stability projects in the second mid-term research phase. It could be used as technical bases for NUMO/Regulator in each decision point from sitting to beginning of disposal (Principal Investigation to Detailed Investigation Phase). High quality construction techniques and field investigation methods have been developed and implemented and these will be directly applicable to the National Disposal Program (along with general assessments of hazardous natural events and processes). It will be crucial to acquire technical knowledge on decisions of partial backfilling and final closure by actual field experiments in Mizunami/Horonobe URLs as main themes for the next phases.
Kim, Y.*; Kim, J.*; Yamanaka, Satoru*; Nakajima, Akira*; Ogawa, Takashi*; Serizawa, Takeshi*; Tanaka, Hirohisa*; Baba, Masaaki*; Fukuda, Tatsuo; Yoshii, Kenji; et al.
Advanced Energy Materials, 5(13), p.1401942_1 - 1401942_6, 2015/07
An innovative electro-thermodynamic cycle based on temporal temperature variations using pyroelectric effect has been presented. Practical energy is successfully generated in both synchrotron X-ray diffraction measurements under controlled conditions and real engine dynamometer experiments. The main generating origin is revealed as a combination of a crystal structure change and dipole change phenomenon corresponds to the temperature variation. In particular, the electric field induced 180 domain switching extremely improves generating power, and the true energy breakeven with temperature variation is firstly achieved.
Emi, Naoya*; Hamabata, Ryosuke*; Nakayama, Daisuke*; Miki, Toshihiro*; Koyama, Takehide*; Ueda, Koichi*; Mito, Takeshi*; Kohori, Yo*; Matsumoto, Yuji*; Haga, Yoshinori; et al.
Journal of the Physical Society of Japan, 84(6), p.063702_1 - 063702_4, 2015/06
Nakayama, Shigeru*; Kawaguchi, Koichi; Segawa, Tomomi; Yamada, Yoshikazu
Proceedings of 19th International Symposium on Artificial Life and Robotics (AROB 2014) (CD-ROM), p.246 - 249, 2014/01
In the nuclear fuel fabrication process, moisture content is very important parameter because of criticality safety control. Considering future commercial nuclear fuel fabrication plant, rapid and durable moisture sensor is required. We have developed an open-ended semi-coaxial microwave sensor to measure moisture involved in a substance. This sensor has no semiconductor tips, so it can be used in strong radiation field. In this paper, we carry out a preliminary experiment for measuring moisture of MOX(UO+PuO) in granulation process, in which water is added as a binder. In our preliminary experiment, to simulate granulated MOX powder, granulated tungsten trioxide powder, which has similar dielectric constant to MOX and has voids to hold water inside, was used. The principle of microwave measurement of moisture is as follows. When the tungsten trioxide contained in a pyrex beaker is placed at the open end of the cavity, the resonant frequency is shifted by a variation in the end of capacitance which results from the difference in the dielectric constant of tungsten trioxide from that of air. Furthermore, the peak value of the resonance curve is attenuated by the absorption of microwave in the tungsten trioxide. Therefore, the moisture content of tungsten trioxide can be estimated by measuring either the frequency shift or attenuation. They are measured using a tracking generator and a spectrum analyzer. In our presentation, we will show the experimental results in detail.
Nakatsuka, Noboru; Hatanaka, Koichiro; Sato, Haruo; Sugita, Yutaka; Nakayama, Masashi; Asano, Hidekazu*; Saito, Masahiko*; Suyama, Yasuhiro*; Hayashi, Hidero*; Honda, Yuko*; et al.
JAEA-Research 2013-026, 57 Pages, 2013/11
JAEA and RWMC concluded the letter of cooperation agreement on the research and development of radioactive waste disposal in April, 2005, and have been carrying out the collaboration work described above based on the agreement. JAEA have been carrying out the Horonobe URL Project which is intended for a sedimentary rock in the Horonobe town, Hokkaido, since 2001. In the project, geoscientific research and research and development on geological disposal technology are being promoted. Meanwhile, the government (the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry) has been promoting construction of equipments for the full-scale demonstration of engineered barrier system and operation technology for high-level radioactive waste (HLW) disposal since 2008, to enhance public's understanding to the geological disposal of HLW, using underground facility, etc. RWMC received an order of the project in fiscal year 2010 continuing since fiscal year 2008. Since topics in this project are included in the Horonobe URL Project, JAEA carried out this project as collaboration work continuing in FY 2008. This report summarizes the results of engineering technology carried out in this collaboration work in fiscal year 2010. In fiscal year 2010, part of the equipments for emplacement of buffer material was produced and a house for the equipments and apparatus was opened in the adjoining land of Public Information House of JAEA Horonobe.
Nakatsuka, Noboru; Hatanaka, Koichiro; Sato, Haruo; Sugita, Yutaka; Nakayama, Masashi; Miyahara, Shigenori; Asano, Hidekazu*; Saito, Masahiko*; Suyama, Yasuhiro*; Hayashi, Hidero*; et al.
JAEA-Research 2010-060, 50 Pages, 2011/02
Japan Atomic Energy Agency (JAEA) and Radioactive Waste Management Funding and Research Center (RWMC) concluded the letter of cooperation agreement on the research and development of radioactive waste disposal in April, 2005, and have been carrying out the collaboration work described above based on the agreement. JAEA have been carrying out the Horonobe Underground Research Laboratory (URL) Project which is intended for sedimentary rock in the Horonobe town, Hokkaido, since 2001. In the project, geoscientific research and research and development on geological disposal technology are being promoted. Meanwhile, the government (the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry) has been promoting construction of equipments for the full-scale demonstration of engineered barrier system and operation technology for high-level radioactive waste (HLW) disposal since 2008, to enhance publics understanding to the geological disposal of HLW, using underground facility, etc. RWMC received an order of the project in fiscal year 2009 (2009/2010) continuing in fiscal year 2008 (2008/2009). Since topics in this project are included in the Horonobe URL Project, JAEA carried out this project as collaboration work continuing in fiscal year 2008. This report summarizes the results of engineering technology carried out in this collaboration work in fiscal year 2009. In fiscal year 2009, a part of the equipments for equipment of buffer material and visualization test apparatus for water penetration in buffer material were produced and house for the equipments and apparatus was constructed.
Hatanaka, Koichiro; Nakayama, Masashi
Konkurito Tekuno, 29(2), p.36 - 44, 2010/02
no abstracts in English
Nakatsuka, Noboru; Hatanaka, Koichiro; Sato, Haruo; Sugita, Yutaka; Nakayama, Masashi; Miyahara, Shigenori; Asano, Hidekazu*; Saito, Masahiko*; Suyama, Yasuhiro*; Hayashi, Hidero*; et al.
JAEA-Research 2009-044, 53 Pages, 2010/01
Japan Atomic Energy Agency (JAEA) and Radioactive Waste Management Funding and Research Center (RWMC) effect an agreement about research and development of high level radioactive waste (HLW) disposal and carried out research and technological development about geological disposal technology. JAEA has been carried out the Horonobe Underground Research Laboratory (URL) Project which is intended for sedimentary rock and the Project includes geoscientific research and geological disposal technology. RWMC carried out an investigation about full-scale demonstration of engineered barrier system (EBS) and operation technology for HLW disposal, under the contract with the Natural Resources and Energy Agency, Ministry of Economy, the Trade and Industry. The investigation aims to obtain the citizens' understanding of the geological disposal. This work includes the full-scale demonstration of operation technology in the Horonobe URL. This joint research is about engineering technology concerned with the work. In 2008 fiscal year (2008/2009), the master plan of the work was made, and a part of the device for transportation of engineered barrier was made, and it has begun the exhibition of full-scale bentonite block and overpack.
Nakayama, Masashi; Iriya, Keishiro*; Fujishima, Atsushi; Mihara, Morihiro; Hatanaka, Koichiro; Kurihara, Yuji*; Yui, Mikazu
Materials Research Society Symposium Proceedings, Vol.932, p.159 - 166, 2006/00
Cementitious material is one of candidates of engineered barriers in TRU and HLW repositories. However, since ordinary Portland cement may rises pH of pore water due to its high alkalinity, bentnite and rock which contact with cementitious barriers as a mulch barrier system may deteriorate for a long term by its high pH. Low alkalinity cement with high pozzolanic material content are developed in order to reduce such hyper alkaline deterioration. This paper shows that pH of pore water of this cement is about 11, and that it can be applied for actual structures as self compacting concrete and shotcrete.
Sugimoto, Masayoshi; Imai, Tsuyoshi; Okumura, Yoshikazu; Nakayama, Koichi*; Suzuki, Shohei*; Saigusa, Mikio*
Journal of Nuclear Materials, 307-311(Part2), p.1691 - 1695, 2002/12
International Fusion Materials Irradiation Facility (IFMIF) is an accelerator-based intense neutron source for fusion reactor materials development. Each one of the two accelerator modules needs to have a capability to provide the 40MeV/125mA deuteron beam continuously. Although the technology to produce the 7MeV/100mA proton beam is already verified using 350 MHz linac in the past, an engineering study using a prototype is necessary to verify the performance of IFMIF 175 MHz deuteron linac, and Engineering Validation Phase (EVP) is planned for this purpose. Some critical design parameters, like final and transition energies of linacs or RF source characteristics, are needed to be optimised for the prototype. As it is also important to verify the essential component technology, e.g. ion source, RFQ beam matching, rf system components, etc., the present status and expected results of such undergoing verification tests are described. An integrated concept of prototype accelerator is shown as a Japanese proposal for EVP to provide for the international discussion.
Kano, Shigeki; Nakayama, Koichi; Koakutsu, Toru; *; *; *
PNC TN941 81-183, 115 Pages, 1981/09
The wear mark was observed between fuel cladding tube and adjacent wrapping wire in the fuelassembly irradiated at the "JOYO" MK-I core. It is necessitated that the formation mechanism, formation condition in the core and the effect of wear mark on the integrity of fuel cladding tube are clarified. The out-of-core sodium test was conducted at the Sodium Tachnology Section, O-arai Engineering Center, PNC, to estimate the load condition in the core and grasp the growth of wear mark. The test conditions were as follows: sodium temperature of 550C, cold trap temparatures of 120C and 150C, contact loads of 59 - 885g, sliding frequency of 1 Hz and sliding cycles of 10, 10 and 10. The test results obtained are as follows. (1)The wear depth linearly increases with increasing load and logarithm of sliding cycle, respectively. The growth of wear mark changes from initial wear to steady state wear. (2)The contact load between fuel cladding tube and wrapping wire in "JOYO" MK-I core is estimated as lower than 250g by the analysis using the test results, wear depth values, obtained at the present test. (3)The higher the contact load, the smoother the morphology of wear mark surface was. The increase of hardness was observed on the sliding surface, but the compositional and crystalline structure change and the crack caused by fatigue were not observed. (4)The sliding resistance between fuel cladding tube and wrapping wire incrementally increases with sliding and, there after, it is apt to be constant at ca. 510 sliding cycles. (5)There is not significant difference in the wear depth and the sliding reststance, respectively, between at cold trap temperatures of 120C and 150C. (6)The estimation of the growth of wear mark until the JOYO MK-I No.6 cycle by the present test results shows that the growth of wear depth is slight even after No.6 cycle.
Hasegawa, Naruo; *; Kano, Shigeki; Nakayama, Koichi; Nakasuji, Takashi; Koakutsu, Toru
PNC TN941 80-127, 124 Pages, 1980/08
It is an important subject to clarify the tribological behaviors of structural materials applied for contacting and/or sliding parts of "MONJU" components and take a measure to meet the design condition. From this point of view, a series of parameter tests are conducted on stellite No.6, Colmonoy No.5, Inconel 718 and LC-1C selected by the screening tests, and SUS 316, SUS 304 and 2.25Cr-1Mo steel as main structural materials for "MONJU". Among parameters, the effect of oxygen content in sodium on tribological behaviors is one of disputed points. As the cold trap temperature of "MONJU" primary system is intended to decrease from 140C (or 145C) to 120C, the authors started the tests whose parameter is cold trap temperature. This report describes the test results obtained partially. The test items and test conditions are as follows: I. Corrosion Test Sodium temperature : 600C, Exposure time : 2,000 hr. Cold trap temperature : 120C II. Friction Test Sodium temperature : 600C, Exposure time : 2,000 hr., Contact stress : 0.3kg/mm. Cold trap temperature : 120C III. Self-Welding Test Sodium temperature : 450 700C, Dwell time : 200 hr., Contact stress : 4 kg/mm , cold trap temperature : 120 C Comparison of as-received material with pre-exposed material. Estimation of self-weldability by tension breakaway. Main results obtained are as follows: I. Corrosion Test (1)Corrosion behavior did not indicate apparent difference between cold trap temperature of 120C and 140C. (2)Stellite No.6 showed an increase in weight and other materials tested showed a reduction in weight. II. Friction Test (Stellite No.6/itself and LC-1C/itself) (1)Kinetic friction coefficients did not show apparent difference between cold trap temperature of 120C and 140C. (2)Kinetic friction coefficients did not depend on sodium exposure time. III. ...
Kano, Shigeki; Hasegawa, Naruo; Nakayama, Koichi; Koakutsu, Toru; *; Nakasuji, Takashi
PNC TN941 79-144, 47 Pages, 1979/08
It is requested to obtain the self-welding characteristics in sodium on the contacting materials of "MONJU" components. By tension breakaway method, the tests were up to date conducted on many kinds of materials in sodium which was not cold-trapped and was purified by the cold trap temperature of 190C or 145C. These results were used for material screening. The present study relates to the dwell temperature dependence of 200 hrs. self-welding characteristics on the selected hard facing materials and main structural materials of "MONJU" in 450 700C sodium purified by the cold trap temperature of 140C or 145C. The main results obtained are as follows. (1)The breakaway stress shows the apparent dwell temperature dependence. (2)The combinations of SUS 304/itself and SUS 316/itself self-weld above 500C and the breakaway stress increases linearly with the dwell temperature. (3)Ferritic steels exhibit the higher breakaway stress than austenitic stainless steels. (4)The combination of LC-1C/itself does not easily self-weld even at 700C. The combinations of Stellite No.6/itself, Colmonoy No.5/itself and Inconel 718/itself self-weld at 700C and do not self-weld at 600C. Only Colmonov No.5 breakaways at the inside as well as the self-welded interface. (5)Only Colmonoy No.5 shows the apparent corroded surface among the test materials after exposure to 700C sodium for 200 hrs. LC-1C exhibits flaking partially from the substratum. It is because the coating layer (0.2 mm thick) was too thick and there were the problems of the grid blast method on substratum surface and the manufacturing method on coating edge.