Accurate and precise measurement of uranium content in uranium trioxide by gravimetry; Comparison with isotope dilution mass spectrometry and its uncertainty estimation

Yamamoto, Masahiko; Horigome, Kazushi; Kuno, Takehiko

Applied Radiation and Isotopes, 190, p.110460_1 - 110460_7, 2022/12

https://doi.org/10.1016/j.apradiso.2022.110460

Gravimetric measurement of U content in UO with ignition in the air has been investigated. The ignition temperature, ignition time and aliquot sample mass are optimized as 900C, 60 minutes, and 1 g, respectively. The method is validated by IDMS with uncertainty estimation. The obtained result by gravimetry is 0.782360.00051 g/g (k=2) and agreed with IDMS value within its uncertainty. It has been found that U in UO can be measured accurately and precisely by gravimetry.

Investigation of physical properties of glove for glove-box and estimation of its life-time

Kobayashi, Daisuke; Yamamoto, Masahiko; Nishida, Naoki; Miyoshi, Ryuta; Nemoto, Ryo*; Hayashi, Hiroyuki*; Kato, Keisuke; Nishino, Saki; Kuno, Takehiko; Kitao, Takahiko; et al.

Nihon Hozen Gakkai Dai-18-Kai Gakujutsu Koenkai Yoshishu, p.237 - 240, 2022/07

All gloves attached to glove-box in Tokai Reprocessing Plant have a fixed expiration date and have to be replaced every 4-year. However, degrees of glove deterioration are different depending on its usage environment (frequency, chemicals, radiation, etc.), because of rubber products. Therefore, physical properties such as tensile strength, elongation, hardness of gloves are measured, and the life-time of gloves are estimated. As a result, gloves without any defects in its appearance have enough physical property for acceptance criteria of new glove. The extrapolated physical property of glove is sufficiently larger than the reported values of damaged glove. No deterioration in physical properties of gloves, that are periodically replaced without any defects in its appearance, is observed and the usable life-time of the glove is estimated to be 8 years.

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

https://doi.org/10.1038/s41550-020-01271-2

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Automation technique of analytical pre-treatment for radioactive sample measurement using the program written by visual basic for applications

Yamamoto, Masahiko; Karo, Yoshinori*; Kodaka, Noriyasu; Kuno, Takehiko

JAEA-Technology 2019-014, 68 Pages, 2019/10

JAEA-Technology-2019-014.pdf:2.93MB

Analytical devices like syringe pump, electric burette, fraction collector, and electric valve have been controlled by the program written with Visual Basic for Applications (VBA Macro) to automate the column separation of radioactive sample measurement. It is found that VBA Macro can control each device. Therefore, automatic conditioning and separation equipment were made by combining each device and sequentially controlling with the program. The automation conditioning equipment can repeatedly perform conditioning operation with maximum of 8 columns. The automation separation equipment can separate and recover Sr in simulated highly active liquid waste by using Eichrom Technologies Sr resin. It is found that the developed automation method, using commercially available VBA Macro, is effective to reduce labor work, operator's radiation exposure, and to prevent operational error of analysis, together with reducing the cost of automation.

Spectrochemistry of technetium by liquid electrode plasma optical emission spectrometry and its applicability of quantification for highly active liquid waste

Yamamoto, Masahiko; Do, V. K.; Taguchi, Shigeo; Kuno, Takehiko; Takamura, Yuzuru*

Spectrochimica Acta, Part B, 155, p.134 - 140, 2019/05

https://doi.org/10.1016/j.sab.2019.03.014

The emission spectra of technetium (Tc) by liquid electrode plasma optical emission spectrometry have been investigated in this study. From the spectra, 52 emission peaks of Tc were observed in the 250-500 nm wavelength range. All peaks were assigned to the neutral state or singly ionized state. The relative intensities of these peaks were similar to those excited by an electric spark. The strongest intensity peaks were found at 254.3 nm, 261.0 nm, and 264.7 nm. Spectral interferences of coexisting elements in highly active liquid waste of reprocessing stream on those three strongest peaks were investigated using simulated sample. No spectral interferences were observed around the 264.7 nm Tc peak. Therefore, analytical performance using 264.7 nm peak was evaluated. The detection limit, estimated on standard and blank samples in 0.4 M nitric acid, was 1.9 mg/L. The relative standard deviation of Tc standard sample (12.0 mg/L) was 3.8% (N = 5, 1).

New precise measurements of muonium hyperfine structure at J-PARC MUSE

Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.

EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01

https://doi.org/10.1051/epjconf/201919800003

Separation technique using column chromatography for safeguards verification analysis of uranium and plutonium in highly-active liquid waste by isotope dilution mass spectrometry

Yamamoto, Masahiko; Taguchi, Shigeo; Horigome, Kazushi; Kuno, Takehiko

Proceedings of IAEA Symposium on International Safeguards; Building Future Safeguards Capabilities (Internet), 8 Pages, 2018/11

In this study, the single-column extraction chromatographic separation has been developed for analysis of U and Pu in highly active liquid waste by isotope dilution mass spectrometry (IDMS). The commercially available TEVA resin is selected as an extraction chromatography resin. The U is chromatographically separated from fission products (FP) elements by nitric acid while Pu(IV) is adsorbed on the resin. After that, Pu is eluted by reducing to Pu(III). The method has been successfully achieved the separation with yielding the enough recovery and sufficient decontamination factors for subsequent IDMS analysis. The column dose rate after the FP removal is decreased to the background. The analytical results obtained by the developed method are in a good agreement with those of the conventional method. It provides simple and rapid separation and expected that the method can be applied to join IAEA/Japan on-site analytical laboratory.

Development of separation technique of Pu, Am, Np using solid phase extraction resin for the determination of impurity metal elements in plutonium nitrate solution by inductivity coupled plasma optical emission spectrometry

Taguchi, Shigeo; Yamamoto, Masahiko; Furuse, Takahiro*; Masaki, Yuji*; Kuno, Takehiko

JAEA-Technology 2018-005, 14 Pages, 2018/06

JAEA-Technology-2018-005.pdf:0.94MB

The method to remove Pu, Am and Np from plutonium nitrate solution recovered from spent nuclear fuel prior to ICP-OES measurement has been developed for the determination of 18 impurity metal elements (Fe, Cr, Ni, Mn, Al, Cd, V, Cu, Si, Zn, Mo, Sn, Ca, Mg, Na, Ag, Pb, B). In this method, two TRU resin packed columns were used for separation. In the first column, Pu and Am were mainly removed by adsorption. The recovered solution from the fist column was added to the second column after reduction of Np, and Am(III) and Np(IV) were removed by adsorption. The Pu nitrate solution (22g/L) of 2mL were treated by proposed method. The alpha emission nuclide was decreased to 5.8 Bq/mL in a solution diluted to 100mL. As a result of ICP-OES measurement, the recoveries of impurity metals separated by proposed method were almost 100%. This separation scheme can apply to the metal impurity elemental analysis in Pu nitrate solution recovered from spent nuclear fuel.

Online coupling of two-phase flow solvent extraction microfluidics with inductively coupled plasma mass spectrometry

Do, V. K.; Yamamoto, Masahiko; Taguchi, Shigeo; Kuno, Takehiko; Surugaya, Naoki

Current Analytical Chemistry, 14(2), p.111 - 119, 2018/00

https://doi.org/10.2174/1573411013666170421121927

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.

Preparation of uranium and plutonium mixed spike optimized for MOX analysis by isotope dilution mass spectrometry

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

JAEA-Technology 2017-016, 20 Pages, 2017/07

JAEA-Technology-2017-016.pdf:1.68MB

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.