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Miyamoto, Yutaka; Suzuki, Daisuke; Tomita, Ryohei; Tomita, Jumpei; Yasuda, Kenichiro
Isotope News, (786), p.22 - 25, 2023/04
no abstracts in English
Tomita, Ryohei; Tomita, Jumpei; Yomogida, Takumi; Suzuki, Daisuke; Yasuda, Kenichiro; Esaka, Fumitaka; Miyamoto, Yutaka
KEK Proceedings 2022-2, p.108 - 113, 2022/11
Automated Particle Measurement (APM) is the first measurement of environmental sample for safeguard purpose. APM tells us the number of particles in sample, their enrichment and their location. Precision and accuracy of APM is easily affected by particle condition. We have investigated how influential baking temperature in sample preparation are for uranium secondary ion quantity, uranium hydride generation and particle crystallinity. Our experimental results showed that baking temperature of 800C reduced uranium secondary ion quantity to 33% compared with baking at 350C. Uranium hydride generation ratio of the sample baked at 850C was also 4 times higher than the sample baked at 350C. Baking at 850C raised only crystallinity of uranium particles. Baking sample at too high temperature caused less uranium secondary ion generation and much more uranium hydride generation. It made precision and accuracy of APM worse. In our experiment, baking at 350C is suitable for uranium particles in the safeguards sample.
Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka
KEK Proceedings 2022-2, p.154 - 158, 2022/11
Precise determination of minor U isotopes (U and U) of particles from the safeguard environmental samples is powerful method for detecting the undeclared nuclear activities. In this study, preparation method of U particle was examined to utilize for the minor U isotope determination. The porous silica particles were used as the particle matrix and lutetium was mixed to the impregnation solution as U impregnation indicator for the particle picking. The result of the Scanning Electron Microscope indicated that the contacting the solution with Si particles overnight gently could produce the impregnated particles effectively rather than the mixing them with PFA stick.
Tomita, Jumpei; Ozawa, Mayumi; Ohara, Yoshiyuki; Miyamoto, Yutaka
KEK Proceedings 2021-2, p.130 - 134, 2021/12
no abstracts in English
Tomita, Ryohei; Tomita, Jumpei; Yomogida, Takumi; Suzuki, Daisuke; Yasuda, Kenichiro; Esaka, Fumitaka; Miyamoto, Yutaka
KEK Proceedings 2021-2, p.146 - 150, 2021/12
no abstracts in English
Suzuki, Daisuke; Tomita, Ryohei; Tomita, Jumpei; Esaka, Fumitaka; Yasuda, Kenichiro; Miyamoto, Yutaka
Journal of Radioanalytical and Nuclear Chemistry, 328(1), p.103 - 111, 2021/04
Times Cited Count:3 Percentile:47.54(Chemistry, Analytical)An analytical technique was developed to determine the age of uranium particles for safeguards. After the chemical separation of uranium and thorium, the Th/U ratio was measured using single-collector inductively coupled plasma mass spectrometry and a U-based reference material comprising a certain amount of Th as a progeny nuclide of U. The results allowed us to determine the purification age of two certified materials, i.e., U-850 and U-100, which was in good agreement with the reference purification age (61 y). Moreover, the age of a single U-850 particle was determined with a difference of -28 to 2 years from the reference date.
Sonoda, Tetsu*; Wada, Michiharu*; Tomita, Hideki*; Sakamoto, Chika*; Takatsuka, Takaaki*; Furukawa, Takeshi*; Iimura, Hideki; Ito, Yuta*; Kubo, Toshiyuki*; Matsuo, Yukari*; et al.
Nuclear Instruments and Methods in Physics Research B, 295, p.1 - 10, 2013/01
Times Cited Count:20 Percentile:83.94(Instruments & Instrumentation)no abstracts in English
Tomita, Yutaka; Morihira, Masayuki; Tamaki, Yoshihisa*; Nishimura, Kazuhisa*; Shoji, Shuichi*; Kihara, Yoshiyuki; Kase, Takeshi; Koizumi, Tsutomu
JAEA-Research 2006-088, 95 Pages, 2007/01
JAEA has developed sphere-pac fuels in the feasibility study on commercialized FBR cycle systems as one of the candidates for low decontamination TRU fuels. Optimization of the fabrication condition for coarse spheres, development of an improved external gelation process, and examination of peculiar problems for the low decontamination fuel were carried out in Phase II. The results are shown as follows. (1) Fabrication condition of coarse spheres was optimized. (2) Feasibility of the improved external gelation process was confirmed. (3) Rare earth elements did not bring any problem for the characteristic of spheres and fabrication condition. (4) Radiation resistant data of the feed solution was acquired. Results of tests show the feasibility of the external gelation process for the low decontamination TRU fuel microsphere fabrication.
Tomita, Yutaka; Morihira, Masayuki; Kihara, Yoshiyuki; Tamaki, Yoshihisa*
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 4 Pages, 2005/10
High economic competitiveness and low environmental impact are required for advanced FBR cycle systems. Sphere-pac fuel has been considered as promising fuel systems, due to its inherent advantage in remote operation, dustfree fuel fabrication process and cost reduction. Japan Nuclear Cycle Development Institute (JNC) has been investigated the external gelation process for sphere-pac fuel. In this report, the result of the sphere fabrication test by the external gelation process is reported.
Tomita, Yutaka; Shigetome, Yoshiaki; Kihara, Yoshiyuki
Saikuru Kiko Giho, (24), p.1 - 10, 2004/00
JNC has carried out the joint research project with PSI in Switzerland and NRG in Netherlands.In this project, three types of fuel segments (sphere-pac segments, vipac segments and pellet segments) were fabricated by PSI. They have been irradiated under same irradiation condition to compare their performances in the High Flux Reactor. This report describes the fabrication of sphere-pac segments and vipac segments for irradiation tests.
Nakahara, Masaumi; Tomita, Yutaka; Nomura, Kazunori; Washiya, Tadahiro
no journal, ,
Concerning the purification technology of UNH crystallization, cesium plutonium nitrate was obtained and was estimated by colorimetry, XRD, TG data. These experiments show cesium plutonium nitrate product increases with nitric acid concentration in the solution. This complex of XRD patterns was almost agreed with CsU(NO) of that. When CsPu(NO) is heated for short periods, no change occurs up to 100 degrees C, after plutonium is oxidized to CsPuO(NO) above 245 degrees C. This observed mass loss step for TG curve of cesium plutonium nitrate was about 10%.
Kaji, Naoya; Nakahara, Masaumi; Nakamura, Kazuhito; Shibata, Atsuhiro; Tomita, Yutaka; Washiya, Tadahiro; Kitajima, Takafumi; Koizumi, Tsutomu
no journal, ,
Solubility obtained from the latest crystallization tests using irradiated fuel and the tests implemented before using U or Pu/U are compared with the data showed by Hart. Based on the result, availability of the data to estimate crystallization ratio is considered.
Hinai, Hiroshi; Tomita, Yutaka; Nomura, Kazunori; Oyama, Koichi; Kitajima, Takafumi; Koizumi, Tsutomu
no journal, ,
no abstracts in English
Akahane, Yutaka; Tomita, Hitoshi*; Ogawa, Kanade; Nishioka, Hajime*; Yamakawa, Koichi
no journal, ,
Spectral phases of interacting (signal, idler, pump) pulses on optical-parametric amplification process were measured, aimed for compensating higher order dispersion on compressed idler pulses by phase modulation on pump pulses in optical-parametric chirped-pulse amplification. An wide-time-range spectral-shearing interferometry developed very recently was applied to these phase measurement, which is capable for measuring picosecond chirped pulses unsuitable for SPIDER phase measurement formerly. In the measurement, some variations of spectral dispersions on idler pulses caused by phase modulation on pump pulses were observed, which enables us to control spectral dispersions of idler pulse by manipulating spectral phases of pump pulses.
Akahane, Yutaka; Ogawa, Kanade; Tomita, Hitoshi*; Nishioka, Hajime*; Yamakawa, Koichi
no journal, ,
We have proposed and demonstrated a novel chirped-pulse amplification (CPA) scheme which idler pulses in optical-parametric chirped-pulse amplification have been compressed with an identical positive dispersive media as signal pulse stretcher. With this idler compression scheme simple, robust and efficient CPA laser can be realized for industrial applications. In the demonstration experiment, sub-100 fs compressed idler pulses successfully obtained.
Kumata, Masahiro; Tomita, Yutaka
no journal, ,
A big earthquake occured in the eastern Japan on March 11, 2011. Operation and maintenance activities just after the big earthquake in RN38, Takasaki, Japan would be presented.
Akahane, Yutaka; Tomita, Hitoshi*; Ogawa, Kanade; Nishioka, Hajime*; Yamakawa, Koichi
no journal, ,
For generation of intense few-cycle laser pulse with our idler pulse compression scheme, we have now been studying residual high-order dispersion compensation of idler pulses with pump phase modulation. The pump pulse has a narrow bandwidth with respect to signal or idler pulses, which you can easily control the pump phase by spatial light modulator or other conventional devices. And once a proper phase modulation is fixed, you can apply the modulation by some robust device such as such fiber Bragg grating or volume Bragg grating in practical use. From the first phase measurement of OPA interacting pulses, we have found that the sign of the 3rd order dispersion of the idler pulse have been inverted from the signal one and the sign of 4th order have not been inverted, which had not been expected from theory without considering the effect from pump phase modulation.
Tomita, Yutaka; Kumata, Masahiro; Wakabayashi, Shuji; Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo
no journal, ,
Esaka, Fumitaka; Yomogida, Takumi; Tomita, Ryohei; Miyamoto, Yutaka
no journal, ,
Chemical state analysis is important to elucidate the origin of particles and its effect on the environment. However, the analysis is difficult because the amounts of elements in individual particles are considerably small. In the present study, electron backscatter diffraction (EBSD) is applied to the chemical state analysis of individual uranium particles. As a result, uranium particles with diameters of 1m were able to be measured and clear electron backscatter patterns were observed. In addition, the patterns of UO particles were distinguished from those of UO particles.
Tomita, Ryohei; Esaka, Fumitaka; Miyamoto, Yutaka
no journal, ,
In the previous study, we developed a combination method of particle manipulation and secondary ion mass spectrometry (SIMS) for removing the interferences from other elements in other particles. Since the particles were selected randomly and manipulated, it caused the problem not to cover the range of U/U isotope ratio in the sample. In this study, we improved the procedure of analyzing uranium isotope ratios in individual particles by SIMS to cover the range of U/U in the sample.