Yamamoto, Masahiko; Taguchi, Shigeo; Do, V. K.; Kuno, Takehiko; Surugaya, Naoki
Applied Radiation and Isotopes, 152, p.37 - 44, 2019/10
An online measurement system using an alpha liquid scintillation counter (-LSC) coupled to microchip solvent extraction has been developed. A flow-through cell of -LSC has been prepared by packing PTFE tube into glass tube to combine microchip. Two-phase flow in microchannel has been stabilized by using coiled tube. The Pu in organic phase has been mixed with scintillation cocktail by T-junction connectors. The system separates and detects Pu by online with detection limit of 6.5 Bq/mL, generating only L-level wastes.
Do, V. K.; Yamamoto, Masahiko; Taguchi, Shigeo; Takamura, Yuzuru*; Surugaya, Naoki; Kuno, Takehiko
Talanta, 183, p.283 - 289, 2018/06
We develop a novel analytical method employing liquid electrode plasma optical emission spectrometry for measurement of total cesium in highly active liquid wastes. Limit of detection and limit of quantification are 0.005 mg/L and 0.02 mg/L, respectively. The method is validated and applied to the real samples.
Do, V. K.; Yamamoto, Masahiko; Taguchi, Shigeo; Kuno, Takehiko; Surugaya, Naoki
Current Analytical Chemistry, 14(2), p.111 - 119, 2018/00
A direct coupling of two-phase flow solvent extraction microfluidics with ICP-MS for element-selective analysis is successfully established. Two-phase flow in microchannels of two combined glass chips for continuous extraction and back-extraction is stabilized through balancing the pressure by using an external coiled tube that functions as a flow resistor. The difference of fluid flow rate between microchannels and ICP-MS is adjusted by a proposed interface system including T-junction mixer and a switching valve. An online measurement of rhenium is successfully demonstrated. The calibration curve for Re is carried out in the range of 1 g/L to 20 g/L. The limit of detection is 0.2 g/L with a needed sample volume of one milliliter. Total time including extraction, back-extraction, and measurement is less than one hour. The development of the online coupling is a first step towards future applications to the selective measurement of highly radioactive elements.
Horigome, Kazushi; Taguchi, Shigeo; Yamamoto, Masahiko; Kuno, Takehiko; Surugaya, Naoki
JAEA-Technology 2017-016, 20 Pages, 2017/07
Mixed spikes of uranium and plutonium have been prepared for the determination of uranium and plutonium in dissolved MOX solution by isotope dilution mass spectrometry. Enriched uranium metal NBL CRM116 and plutonium metal NBL CRM126 were accurately weighed and then dissolved in nitric acid, respectively. Their dissolved solutions were mixed in a mass ratio of 1 to 2. The preparation values of uranium and plutonium were 1.0530 0.0008 mg/g (k=2) of uranium with a U relative mass fraction of 93.114 wt% and 2.0046 0.0019 mg/g (k=2) of plutonium with a Pu relative mass fraction of 97.934 wt%, respectively. The concentrations of uranium and plutonium in spike were confirmed by reverse isotope dilution mass spectrometry using tracer of U and Pu. Finally, the prepared spike was validated by parallel analysis of simulated sample of dissolved MOX solution. This spike was applied to measure the uranium and plutonium amount content of dissolved MOX solutions using isotope dilution mass spectrometry.
Yamamoto, Masahiko; Holland, M. K.*; Cordaro, J. V.*; Kuno, Takehiko; Surugaya, Naoki
JAEA-Technology 2017-014, 63 Pages, 2017/06
In this study, the controlled-potential coulometry has been applied as a primary method for characterizing the Pu master solutions being used as alternative source material for IDMS spikes. The coulometry system compliance with ISO12183 has been used for measurement. It has been calibrated using equipment traceable to the SI units. Plutonium standard samples have been measured to confirm the accuracy. The relative standard deviation is below 0.05%. The results agree with the reference value within 0.05%. It is found that the Pu can be precisely analyzed by the coulometry system. Then, the Pu nitrate solution, which has been purified from mixed oxide powder containing relatively high Pu, has been measured. The relative standard deviation is below 0.05%. The relative expanded uncertainty is less than 0.074% at the 95% confidence interval (k=2). It is indicated that coulometric assay of Pu is fit for the purpose of characterizing reference materials.
Horigome, Kazushi; Taguchi, Shigeo; Ishibashi, Atsushi; Inada, Satoshi; Kuno, Takehiko; Surugaya, Naoki
JAEA-Technology 2017-008, 14 Pages, 2017/05
The plutonium solution had been converted into MOX powder to mitigate the potential hazards of storage plutonium solution such as hydrogen generation at the Plutonium Conversion Development Facility. The plutonium conversion operations had been started in April, 2014, and had been finished in July, 2016. With respect to the samples taken from the conversion process, about 2,200 items of plutonium/uranium solutions and MOX powders had 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 December, 2015 to October, 2016.
Yamamoto, Masahiko; Holland, M. K.*; Cordaro, J. V.*; Kuno, Takehiko; Surugaya, Naoki
Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2017/02
Precise and accurate determination of plutonium is necessary. The high reliability is required for standard materials used in the plutonium determination. In this study, JAEA and SRNL have collaborated on a mission to apply controlled-potential coulometry as a primary method for characterizing the plutonium master solution being used for reference materials of isotope dilution mass spectrometry. The measurement cell and electrodes were upgraded and optimized compliance with ISO12183. The instruments were calibrated traceable to the SI. The samples of plutonium standard solution were measured to confirm the accuracy of the method. The results have been in good agreement with the reference values. Therefore, the plutonium solution which were purified from MOX powder have been characterized. The total measurement uncertainty was less than 0.07%. The results indicated that coulometry assay of plutonium are fit for the purpose of characterizing reference material.
Furuse, Takahiro*; Taguchi, Shigeo; Kuno, Takehiko; Surugaya, Naoki
JAEA-Technology 2016-028, 19 Pages, 2016/12
Metal impurities in MOX powder obtained from uranium and plutonium recovered from reprocessing process of spent nuclear fuel are needed to be determined for its characterization. Direct current arc atomic emission spectroscopy (DCA-AES) is one of the useful methods for direct analysis of powder sample without dissolving the analyte into aqueous solution. However, the selection of standard material, which can overcome concerns such as matrix matching, is quite important to create adequate calibration curves for DCA-AES. In this study, we apply standard addition method using the certified UO containing known amounts of metal impurities to avoid the matrix problems. The proposed method provides good results for determination of Fe, Cr and Ni at a significant quantity level contained in MOX samples.
Horigome, Kazushi; Suzuki, Hisanori; Suzuki, Yoshimasa; Ishibashi, Atsushi; Taguchi, Shigeo; Inada, Satoshi; Kuno, Takehiko; Surugaya, Naoki
JAEA-Technology 2016-026, 21 Pages, 2016/12
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.
Masui, Kenji; Yamamoto, Masahiko; Kuno, Takehiko; Surugaya, Naoki
Nihon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.25 - 30, 2016/07
no abstracts in English
Goto, Yuichi; Yamamoto, Masahiko; Kuno, Takehiko; Surugaya, Naoki
Nihon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.31 - 34, 2016/07
Chloroprene rubber gaskets are often used to seal the glove box body and its panels. Such gaskets are deformed with compressive pressure and its elastic restoring force keeps sealing property. Therefore, gaskets play an important role in glove box sealing. However, physical properties of those used in glove box have not reported so far. In this study, hardness, elongation, tensile strength and compression set are investigated and its sealing performances are evaluated. The gaskets samples are taken from the glove box, which is used for 37 years. It is found that hardness, elongation and tensile strength of gaskets are changed due to the aging but its values are within the specification of chloroprene rubber. Also, the compression-set is less than the value that sealing performance is decreased. The results show that even the gaskets are used for long time, it has the property to keep sealing performances of glove box.
Holland, M. K.*; Cordaro, J. V.*; Morales-Arteaga, M. E.*; Yamamoto, Masahiko; Kuno, Takehiko; Surugaya, Naoki
Proceedings of INMM 57th Annual Meeting (Internet), 10 Pages, 2016/07
Since 2007, the laboratory at the Japan Atomic Energy Agency (JAEA) and Savannah River National Laboratory (SRNL) have collaborated on a new mission to apply controlled-potential coulometry as a primary method for characterizating plutonium master solutions. Measurement results are being used to prepare traceable and certifiable large-size dry (LSD) spike standards for safeguards measurements by isotope dilution mass spectrometry. The collaboration activities performed by JAEA and SRNL were authorized and funded under the JAEA & United States NNSA/DOE Permanent Coordinating Group. This report will chronicle the collaboration activities of JAEA and SRNL, and provide the detail on the periodic coulometer component calibration, the coulometric plutonium measures and measure practices, including the uncertainty propagation for the most recent plutonium master solution used for LSD Spike preparation.
Yamamoto, Masahiko; Shirozu, Hidetomo; Mori, Eito; Surugaya, Naoki
JAEA-Technology 2016-009, 58 Pages, 2016/05
The panels of glove box installed at Tokai Reprocessing Plant have been deteriorated and transparencies have been decreased due to the long-term use. Therefore, the panels have been replaced from the view point of preventive maintenance. In the new regulation formulated since the Fukushima Daiichi Nuclear Power Plant accident, it is demanded that the glove box consists of incombustible or inflammable materials. In this replacement, new panels have been manufactured with polycarbonate which satisfied the UL94 V-0 incombustible class. The inside of glove box has been contaminated with radioactive materials. Thus, the contamination and operator's exposure have been investigated. Then radiation protection equipment have been selected. Also, it is necessary to maintain the glove box enclosure during the replacement. The replacement has been conducted by covering the opening parts with vinyl sheets. The enclosure function has been verified by the inspection of the new panels and glove box.
Kinuhata, Hiroshi*; Yamamoto, Masahiko; Taguchi, Shigeo; Surugaya, Naoki; Sato, Soichi; Kodama, Takashi*; Tamauchi, Yoshikazu*; Shibata, Yuki*; Anzai, Kiyoshi*; Matsuoka, Shingo*
Nuclear Technology, 192(2), p.155 - 159, 2015/11
Experiments using a small-scale apparatus with 30 ml actual high-level liquid waste from the Tokai Reprocessing Plant were carried out to show that the hydrogen concentration in the gas phase reaches a steady-state value of much less than 4% (lower explosive limit) in the absence of sweeping-air. The H concentration reached a steady-state value as was expected and it was compared with a value predicted from an equation with parameters which had been obtained using the simulated solution. Satisfactory agreement showed that the Pd-ion catalytic H consumption reaction previously found in the simulated solution proceeded equally well in the actual solution.
Yamamoto, Masahiko; Surugaya, Naoki; Mori, Eito; Taguchi, Shigeo; Sato, Soichi
JAEA-Research 2015-013, 27 Pages, 2015/10
The H concentration generating from Highly Active Liquid Waste (HALW) of Tokai Reprocessing Plant is measured in a closed experimental system. The experimental results show that H concentration gradually increases at first and then approaches a steady-state due to the H consumption reaction by Pd ions. The highest H concentration is 1200 ppm (0.1%) when the solution temperature is at 23C. It is found that H generating from HALW is equilibrated one order of magnitude lower than the H combustion lower limit. Moreover, a model based on H generation from HALW by the radiolysis and H consumption reaction by Pd ions is proposed and applied to evaluate H concentration behavior in the gas phase. The calculated H concentrations from proposed model agreed well with the experimental values. It is demonstrated that the behavior of H generating from HALW can be evaluated quantitatively by applying the proposed model in this study.
Yamamoto, Masahiko; Mori, Eito; Surugaya, Naoki
JAEA-Technology 2015-024, 19 Pages, 2015/09
Environmental Sampling from the hot cell in the Operating Testing Laboratory (OTL) of the Tokai Reprocessing Plant is implemented as an inspection of International Atomic Energy Agency (IAEA) for the first time. The specified sampling place requested from IAEA inspector is a device inside the hot cell. Since it is expected to be highly radioactive, the dose rates of samples and inside the hot cell are evaluated in advance. Also, the threshold dose rates of samples are determined. Subsequently, the sampling procedure describing radiation protection has been prepared. The environmental sampling from OTL hot cell is safely performed in accordance with the procedure and the radioactivity of sample is measured. The samples are categorized as Excepted Package according to the transport regulation and are transported to Safeguards Analytical Services of IAEA.
Yamamoto, Masahiko; Taguchi, Shigeo; Sato, Soichi; Surugaya, Naoki
Journal of Separation Science, 38(10), p.1807 - 1812, 2015/05
The extraction of Pu with tri--butyl phosphate (TBP) is performed using a glass microchip to evaluate the extraction rate. The parallel two-phase laminar flow is constructed in a microchannel by introducing plutonium nitrate solution and TBP diluted with -dodecane as aqueous and organic phase, respectively. It was found that extraction ratio of Pu increases with increasing the contact time of two phases. A numerical model based on the diffusion in the microchannel and the reaction at the interface was incorporated to evaluate the extraction rate. The experimental data points were subjected to least-squares fitting and the forward extraction rate of Pu(IV) was determined.
Mori, Eito; Yamamoto, Masahiko; Taguchi, Shigeo; Sato, Soichi; Kitao, Takahiko; Surugaya, Naoki
Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.132 - 138, 2014/07
The contamination of the radioactive material was observed on the filter casing surface of the glove box installed at the analytical laboratory in Tokai Reprocessing Plant. The cause of the contamination was investigated with visual inspection, penetrant testing and ultrasonic thickness measurement. It was found that a micro through-hole due to the corrosion of stainless-steel was generated in the glove box filter casing. The repair work of the filter casing was performed keeping the glove box negative pressure. The corrosion part of filter casing was replaced and newly fabricated casing was connected to the glove box with Tungsten Inert Gas welding method.
Suzuki, Hisanori; Nagayama, Tetsuya; Horigome, Kazushi; Ishibashi, Atsushi; Kitao, Takahiko; Surugaya, Naoki
Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.214 - 219, 2014/07
The Tokai Reprocessing Plant (TRP) is developing the technology to recover uranium and plutonium from spent nuclear fuel. There is an analytical laboratory which was built in 1978, as one of the most important facilities for process and material control analyses at the TRP. Samples taken from each process are analyzed by various analytical methods using hot cells, glove boxes and hume-hoods. A large number of maintenance work have been so far done and different types of experience have been accumulated. This paper describes our achievements in the maintenance activities at the analytical laboratory at the TRP.
Taguchi, Shigeo; Yamamoto, Masahiko; Surugaya, Naoki
Journal of Radioanalytical and Nuclear Chemistry, 299(3), p.1539 - 1545, 2014/03
A flow-based electrochemical detection system coupled to a solid-phase extraction column was developed for the determination of neptunium. A Np(V) was oxidized completely to Np(VI) by electrolysis using a column electrode composed of carbon fibers. The effluent was loaded onto a TEVA column, and then onto UTEVA column with 3 mol L HNO. The Np(VI) was eluted with 0.01 mol L HNO, and then introduced directly into a flow-through electrolysis cell. An electrochemical detection with a working potential of +0.1 V (vs. Ag/AgCl) was used to detect Np(VI). The current produced on reduction of Np(VI) was monitored continuously, and the Np(VI) concentration was calculated from the peak area. The relative standard deviation of ten analyses was 2.4 % for a Np(VI) solution (0.50 mg L) containing 1.0 g of Np. The detection limit calculated from three-times the standard deviation was 35 g L (70 ng Np).