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JAEA Reports

Completion of waste removal work from the hot cell of Operation Testing Laboratory in Tokai Reprocessing Plant

Goto, Yuichi; Suzuki, Yoshimasa; Horigome, Kazushi; Miyamoto, Toshihiko*; Usui, Masato*; Mori, Eito*; Kuno, Takehiko

JAEA-Technology 2022-005, 42 Pages, 2022/07

JAEA-Technology-2022-005.pdf:4.48MB

Radioactive wastes were generated and stored in the hot cell of Operation Testing Laboratory of Tokai Reprocessing Plant due to the experiments related to the reprocessing technology development from 1974 to 2014. Waste removal work was strengthened by the shift work in the past, however another wastes were generated by the equipment dismantling. From 2006, an improved waste removal method was established by using bag-out technique and wastes were taken from the glove-box connected to the hot cell. The removal period, estimated from the conventional method using Cask No. 10, was reduced from 14 to 5 years. From 2016, upgrade of worker's awareness including related departments was performed by various software and hardware improvements. Also, the worker's skills were improved and equipment in Cask No.10 was checked for preventive maintenance. The prevention measures for past troubles were discussed with Radiation Control Department. In addition, transportation schedule including safety operation with Transportation Department and Waste Receiving Department was optimized to maintain the waste removal cycle. The removal period was reduced from 5 to 3 years by the above efforts. Finally, the work was completed in March 2020.

Journal Articles

In-house texture measurement using a compact neutron source

Xu, P. G.; Ikeda, Yoshimasa*; Hakoyama, Tomoyuki*; Takamura, Masato*; Otake, Yoshie*; Suzuki, Hiroshi

Journal of Applied Crystallography, 53(2), p.444 - 454, 2020/04

AA2019-0242.pdf:2.9MB

 Times Cited Count:7 Percentile:66.23(Chemistry, Multidisciplinary)

Journal Articles

Convergence behavior in line profile analysis using convolutional multiple whole-profile software

Kumagai, Masayoshi*; Uchida, Tomohiro*; Murasawa, Kodai*; Takamura, Masato*; Ikeda, Yoshimasa*; Suzuki, Hiroshi; Otake, Yoshie*; Hama, Takayuki*; Suzuki, Shinsuke*

Materials Research Proceedings, Vol.6, p.57 - 62, 2018/10

 Times Cited Count:0 Percentile:0.18

Journal Articles

Determination approach of dislocation density and crystallite size using a convolutional multiple whole profile software

Murasawa, Kodai*; Takamura, Masato*; Kumagai, Masayoshi*; Ikeda, Yoshimasa*; Suzuki, Hiroshi; Otake, Yoshie*; Hama, Takayuki*; Suzuki, Shinsuke*

Materials Transactions, 59(7), p.1135 - 1141, 2018/07

 Times Cited Count:7 Percentile:37.12(Materials Science, Multidisciplinary)

Journal Articles

Development of on-site measurement technique of retained austenite volume fraction by compact neutron source RANS

Ikeda, Yoshimasa*; Takamura, Masato*; Hakoyama, Tomoyuki*; Otake, Yoshie*; Kumagai, Masayoshi*; Suzuki, Hiroshi

Tetsu To Hagane, 104(3), p.138 - 144, 2018/03

 Times Cited Count:4 Percentile:22.98(Metallurgy & Metallurgical Engineering)

Neutron engineering diffraction is a powerful technique which provides the information of the micro structure of steels in bulk-average, while X-ray diffraction or Electron backscatter diffraction can provide information only from the surface layer. However, such measurement using neutron diffraction is typically performed in a large facility such as a reactor and a synchrotron, while a compact neutron source has never been used for this purpose. Authors have recently developed a neutron diffractometer installed in Riken Accelerator driven compact Neutron Source (RANS) and succeeded in the measurement of texture evolution of a steel sheet. In this study, we made an attempt to measure the volume fraction of retained austenite by RANS. Background noise was carefully eliminated in order to detect as many diffraction peaks as possible with low flux neutrons. The volume fraction was estimated by Rietveld analysis. The accuracy of the measurement result was discussed by comparing with those obtained by a large neutron facility (J-PARC TAKUMI). The volume fraction obtained by RANS with reasonable measurement time, i.e. 30 to 300 min, showed only 1 to 2 % discrepancies with those obtained in J-PARC. These comparisons suggest that neutron diffraction by RANS is capable of quantitative analysis of the volume fraction of crystal phases, showing the possibility of practical use of an in-house compact neutron source in the industry.

Journal Articles

Design and application of greenhouse on the maintenance of analytical machineries in Tokai Reprocessing Plant

Suzuki, Yoshimasa; Tanaka, Naoki; Goto, Yuichi; Inada, Satoshi; Kuno, Takehiko

Nihon Hozen Gakkai Dai-14-Kai Gakujutsu Koenkai Yoshishu, p.385 - 389, 2017/08

Greenhouse is used in order to prevent diffusion of radioactive materials on the maintenance of machineries and decomposition of the analytical equipment such as glove box in Tokai Reprocessing Plant (TRP). The specifications of the greenhouse change depending on a risk of the radiation exposure, operation and environment. Design and application of original greenhouses in the analytical laboratory of TRP is summarized.

JAEA Reports

Report on analytical activities in potentially hazardous materials mitigation measures at the Plutonium Conversion Development Facility; 2014.4 $$sim$$ 2015.12

Horigome, Kazushi; Suzuki, Hisanori; Suzuki, Yoshimasa; Ishibashi, Atsushi; Taguchi, Shigeo; Inada, Satoshi; Kuno, Takehiko; Surugaya, Naoki

JAEA-Technology 2016-026, 21 Pages, 2016/12

JAEA-Technology-2016-026.pdf:1.14MB

In order to mitigate potential hazards of storage plutonium in solution such as hydrogen generation, conversion of plutonium solution into MOX powder has been carried out since 2014 in the Plutonium Conversion Development Facility. With respect to the samples taken from the conversion process, about 3500 items of plutonium/uranium solutions and MOX powders have been analyzed for the operation control in the related analytical laboratories at the Tokai Reprocessing Plant. This paper describes the reports on analytical activities and related maintenance works in the analytical laboratories conducted from April 2014 to December 2015.

Journal Articles

Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

Ikeda, Yoshimasa*; Taketani, Atsushi*; Takamura, Masato*; Sunaga, Hideyuki*; Kumagai, Masayoshi*; Oba, Yojiro*; Otake, Yoshie*; Suzuki, Hiroshi

Nuclear Instruments and Methods in Physics Research A, 833, p.61 - 67, 2016/10

 Times Cited Count:37 Percentile:96.72(Instruments & Instrumentation)

A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by the large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 minutes. The minimum resolution of the 110 reflection for RANS is approximately 2.5 % at 8 $$mu$$s of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 $$mu$$s, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenite phase was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS was proved to be capable for neutron engineering diffraction aiming for the easy access measurement of the texture and the amount of retained austenite.

Journal Articles

Texture evaluation in ductile fracture process by neutron diffraction measurement

Sunaga, Hideyuki*; Takamura, Masato*; Ikeda, Yoshimasa*; Otake, Yoshie*; Hama, Takayuki*; Kumagai, Masayoshi*; Suzuki, Hiroshi; Suzuki, Shinsuke*

Journal of Physics; Conference Series, 734(Part B), p.032027_1 - 032027_4, 2016/09

 Times Cited Count:0 Percentile:0.03

A neutron diffraction measurement was performed to reveal microstructural aspects of the ductile fracture in ferritic steel. The diffraction patterns were continuously measured at the center of the reduced area while a tensile specimen was loaded under tension until the end of the fracture process. The measurement results showed that the volume fraction of (110)-oriented grains increased when the texture evolved as a result of plastic deformation. But the mechanism of texture evolution may be changed during necking, decreasing an increase rate of the volume fraction.

Journal Articles

Non-destructive texture measurement of steel sheets with compact neutron source "RANS"

Takamura, Masato*; Ikeda, Yoshimasa*; Sunaga, Hideyuki*; Taketani, Atsushi*; Otake, Yoshie*; Suzuki, Hiroshi; Kumagai, Masayoshi*; Hama, Takayuki*; Oba, Yojiro*

Journal of Physics; Conference Series, 734(Part B), p.032047_1 - 032047_4, 2016/08

 Times Cited Count:4 Percentile:86.54

Neutron diffraction is well known to be a useful technique for measuring a bulk texture of metallic materials taking advantage of a large penetration depth of the neutron beam. However, this technique has not been widely utilized for the texture measurement because large facilities like a reactor or a large accelerator are required in general. In contrast, RANS (Riken Accelerator-driven Compact Neutron Source) has been developed as a neutron source which can be used easily in laboratories. In this study, texture evolution in steel sheets with plastic deformation was successfully measured using RANS. The results show the capability of the compact neutron source for the analysis of the crystal structure of metallic materials, which leads us to a better understanding of plastic deformation behavior.

Journal Articles

Improvement of INVS measurement uncertainty for Pu and U-Pu nitrate solution

Makino, Risa; Swinhoe, M. T.*; Suzuki, Yoshimasa; Mukai, Yasunobu; Menlove, H. O.*; Marlow, J. B.*; Nakamura, Hironobu

Proceedings of INMM 55th Annual Meeting (Internet), 9 Pages, 2014/07

The Inventory Verification Sample systems (INVS) is a non-destructive assay (NDA) system for small inventory samples to quantify the Pu amount in Pu and U-Pu nitrate solutions and MOX powder with 31.3% counting efficiency (for Cf). It has been used for IAEA safeguards measurement for many years at the Plutonium Conversion Development Facility (PCDF) for the samples taken at the time of Random Interim Inspection (RII) and Physical Inventory Verification (PIV), and is currently used as partial defects verification equipment with uncertainty about 3$$sim$$5% accuracy for solution samples. The INVS is a inline detector therefore it is very convenient to use since it can be used for a sample inside the glove box without bag-out. If the measurement uncertainty can be improved (to $$sim$$1%), it is expected that the usage can be extended to the operator's own measurements in MC&A to reduce effort and the number of destructive analyses (DA). In order to improve the measurement uncertainty, we have performed multiplicity measurements using a variety of solution samples (concentration, acidity and volume) to determine the Pu amount and uncertainty, although the multiplicity analysis is challenging. To control the measurement quality, a few MOX ceramic fuel pellets with known Pu amount are used. The results are evaluated by three kinds of methods (calibration curve, known-$$alpha$$ and multiplicity) to determine the best measurement method. In the range of concentration of typical samples, we could confirm good correlations between measured doubles and $$^{240}$$Pu effective mass in the three methods. Especially, the conventional calibration curve method showed a good performance with short measurement time and small uncertainty when the calibration standards were a good match to the unknown samples. In this paper, we present the INVS system design and measurement results with uncertainty using solution samples and comparison results among the three calibration methods.

JAEA Reports

Engineering scale development test of MOX fuel fabrication technology to establish commercialized fast reactor fuel, 1; The O/M ratio preparation tests of sintered pellets

Takato, Kiyoto; Murakami, Tatsutoshi; Suzuki, Kiichi; Shibanuma, Kimikazu; Hatanaka, Nobuhiro; Yamaguchi, Bungo; Tobita, Yoshimasa; Shinozaki, Masaru; Iimura, Naoto; Okita, Takatoshi; et al.

JAEA-Technology 2013-026, 42 Pages, 2013/10

JAEA-Technology-2013-026.pdf:3.17MB

In order to cope with making a commercial fast reactor fuel burn-up higher, oxygen-to-metal (O/M) ratio in the fuel specification is designed to 1.95. As the test for the fabrication of such low O/M ratio pellets, two kinds of O/M ratio preparation tests of different reduction mechanism were done. In the first test, we evaluated the technology to prepare the O/M ratio low by annealing the sintered pellets in production scale. In addition, we know from past experience that O/M ratio of the sintered pellets can be reduced by residual carbon when the de-waxed pellets with high carbon content are sintered. Thus, in another test, the green pellets containing a large amount of organic additives were sintered and we evaluated the technology to produce the low O/M ratio sintered pellets by the reduction due to residual carbon. From the first test results, we found a tendency that the higher annealing temperature or the longer annealing time resulted in the lower O/M ratio. However, the amount of O/M ratio reduction was small and it is estimated that a substantial annealing time is necessary to prepare the O/M ratio to 1.95. It is considered that reducing O/M ratio by annealing was difficult because atmosphere gas containing oxygen released from pellets remained and the O/M ratio was changed to the value equilibrated with the gas having high oxygen potential. From another test results, it was confirmed that O/M ratio was reduced by the reduction due to residual carbon. We found that it was important to manage an oxygen potential of atmosphere gas in a sintering furnace low to reduce the O/M ratio effectively.

JAEA Reports

Confirmation tests for fabrication of low density MOX pellet for FBR

Murakami, Tatsutoshi; Suzuki, Kiichi; Hatanaka, Nobuhiro; Hanawa, Yukio; Shinozaki, Masaru; Murakami, Shinichi; Tobita, Yoshimasa; Kawasaki, Takeshi; Kobayashi, Yoshihito; Iimura, Naoto; et al.

JAEA-Technology 2008-017, 97 Pages, 2008/03

JAEA-Technology-2008-017.pdf:2.76MB

Low density MOX pellets for FBR "MONJU" have not been fabricated in Plutonium Fuel Fabricating Facility (PFPF) for these 9 years since completion of the first reload fuel for "MONJU" in 1995. In this period, about 60 % of machines in the pellet fabrication process of PFPF have been replaced with new ones, and fabrication of MOX pellets for "JOYO" has been continued using these machines. Concerning the feed MOX powders for "MONJU", the amount of decay heat has been increased with increase of accumulated Am-241 in this period. In addition, powder characteristic of recycled MOX powder which is one of feed powders, MH-MOX powder, UO$$_{2}$$ powder and recycled MOX powder, was significantly changed by replacing former processing machine used for scrap recycling with improved one. Using MOX powder with increased decay heat and recycled MOX powder processed by new machine, a series of low density MOX pellet fabrication tests were conducted to confirm pellet fabrication conditions for current pellet fabrication machines from October in 2004 to August in 2006. As a conclusion, it was confirmed that low density MOX pellets could be fabricated using these feed powders and replaced machines by adjusting pellet fabrication conditions adequately. This report summarizes the results of a series of low density MOX pellet fabrication tests.

JAEA Reports

Determination of acidity in nitric acid solutions containing Plutonium and/or Uranium at high concentration by electric conductivity measurement

Kitagawa, Osamu; Suzuki, Yoshimasa; Kurosawa, Akira; Watahiki, Masaru; Hiyama, Toshiaki

JAEA-Technology 2006-031, 29 Pages, 2006/03

JAEA-Technology-2006-031.pdf:2.92MB

Using the correlation between electric conductivity and acidity in solution, we have investigated an analytical method that is able to determine acidity in the nitric acid solution by measuring electric conductivity of sample diluted with distilled water, and correcting the electric conductivity for plutonium(Pu) and uranium(U) using multivariate analysis method. We obtained good results as follows, (1) Acidity in the nitric acid solutions containing Pu and U obtained by this method was good agreement, within 10%, compared with the acidity measured by potentiometric titration method. (2) For plutonium nitrate solution and plutonium-uranium mixed nitrate solution, the repeatability and reproducibility for the measurement of electric conductivity at 25.0$$^{circ}$$C were less than 0.52%, and 1.53% respectively. (3) Impurities such as americium and iron in the solutions did not influence to the measurement of electric conductivity, if total amounts of these impurities were less than 1% compared with those of Pu and U. From the results described above, electric conductivity measuring method has been applying to analysis of acidity in the nitric acid solutions containing Pu and U at high concentration handled in Plutonium Conversion Development Facility. Furthermore, this method can be expected for the application to analysis of acidity in nitric acid solutions containing Pu and U for reprocessing process.

JAEA Reports

Hydraulic Test in DH-13 Borehole

Hirata, Yoichi*; Suzuki, Yoshimasa*; Ogawa, Ken*; Fujii, Makoto*

JNC TJ7440 2005-082, 459 Pages, 2001/12

JNC-TJ7440-2005-082.PDF:19.3MB

In this investigation, the hydraulic test, pumping up and analysis of the underground water were carried out in the deep geology of DH-13 borehole like rock mass or dislocation or broken layer that limits the flow of underground water as one of the study for that flow in the wide area.These investigations were executed to underground the properties of the deep hydraulics and underground water.In this hydraulic test, the method which is popular among foreign countries was applied - some unsteady and steady tests are carried in one test section continuously. By this method, the change of the rock or pore water pressure and the hydraulic conductivity of the main rock were obtained. The results of recovery in steady test (these were not effected by artificial or mechanical means) were applied for the representation. And the water pressure after all test applied for the pore water pressures.The underground water was used for analysis that was pumped up in the process of the steady test. These were no clear change in that results of the analysis among each test section.

Oral presentation

Test of neutralization treatment for radioactive liquid waste by using sodium hydroxide, 3; Behavior of moisture content in a calcined neutralization precipitate

Suzuki, Yoshimasa; Mukai, Yasunobu; Nakamura, Hironobu; Kurosawa, Akira; Fujiwara, Hideki*; Kamoshida, Shuichi*; Sugaya, Shinichi*

no journal, , 

no abstracts in English

Oral presentation

Preparation of the spike for isotope dilution mass spectrometry-optimization of mixing ratio of U and Pu for the measurement of U-Pu MOX powder

Horigome, Kazushi; Suzuki, Yoshimasa; Yamamoto, Masahiko; Taguchi, Shigeo; Kuno, Takehiko; Surugaya, Naoki

no journal, , 

no abstracts in English

Oral presentation

Cooperation of texture measurement study of steel materials between large-scale neutron facilities and RIKEN compact neutron source

Xu, P. G.; Takamura, Masato*; Ikeda, Yoshimasa*; Kakuta, Ryunosuke*; Takahashi, Susumu*; Hakoyama, Tomoyuki*; Iwamoto, Chihiro*; Otake, Yoshie*; Suzuki, Hiroshi

no journal, , 

no abstracts in English

Oral presentation

Neutron diffraction with RANS for industrial "on-site" applications

Takamura, Masato*; Iwamoto, Chihiro*; Xu, P. G.; Kakuta, Ryunosuke*; Kurihara, Ryo*; Hakoyama, Tomoyuki*; Ikeda, Yoshimasa*; Suzuki, Hiroshi; Otake, Yoshie*

no journal, , 

Oral presentation

In-house texture measurement using RIKEN accelerator-driven compact neutron source

Xu, P. G.; Takamura, Masato*; Ikeda, Yoshimasa*; Kakuta, Ryunosuke*; Iwamoto, Chihiro*; Hakoyama, Tomoyuki*; Otake, Yoshie*; Suzuki, Hiroshi

no journal, , 

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