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Journal Articles

Isotopic analysis of single uranium and plutonium particles by chemical treatment and mass spectrometry

Shinonaga, Taeko*; Esaka, Fumitaka; Magara, Masaaki; Klose, D.*; Donohue, D.*

Spectrochimica Acta, Part B, 63(11), p.1324 - 1328, 2008/11

 Times Cited Count:33 Percentile:83.94(Spectroscopy)

The isotopic composition of single uranium and plutonium particles was measured with an inductively coupled plasma mass spectrometer (ICP-MS) and a thermal ionization mass spectrometer (TIMS). The particles prepared on a carbon planchet were first analyzed with an energy dispersive X-ray spectrometer (EDX) attached to a scanning electron microscope (SEM) and then transferred on to a silicon wafer using a manipulator. The particle on the silicon wafer was dissolved with nitric acid and the isotopic ratios of U and Pu were measured with ICP-MS and TIMS. The results obtained by both methods showed good agreement with the certified values within the expected uncertainty. The measurement uncertainties obtained in this study were similar for both mass spectrometric methods. This study was performed to establish the method of particle analysis with SEM, EDX, the particle manipulation technique, and the measurement of isotope ratios of U and Pu in a single particle by mass spectrometry.

Journal Articles

Particle-chemical analysis of uranium and plutonium

Shinonaga, Taeko*; Donohue, D.*; Klose, D.*; Kuno, Takehiko*; Kuno, Yusuke*; Esaka, Fumitaka; Esaka, Konomi; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu

STI/PUB/1298 (CD-ROM), p.525 - 531, 2007/08

More precise, accurate and prompt analyses of uranium and plutonium in various types of environmental samples are increasingly requested from the Clean Laboratory Unit, Safeguards Analytical Laboratory of IAEA in recent years. Particles show unique information and up to now, the secondary ion mass spectrometry (SIMS) has been employed for the uranium and plutonium particle analysis. The SIMS that is the most rapid method for particle analysis has, however, disadvantages for the analysis of the minor isotopes like $$^{234}$$U and $$^{236}$$U, i.e., not precise enough. The SIMS measurement also has a difficulty on Pu determination because of the interference of U-based isobaric signals. In this study, a combination of techniques, picking-up particles by a manipulator attached to a scanning electron microscope (SEM), followed by uranium and plutonium chemical purification and measurement by an inductively coupled plasma mass spectrometer (ICP-MS) and thermal ionization mass spectrometer (TIMS), was demonstrated for particle analysis using standard materials (NBS U500 and NBS 947) to develop a particle-chemical analysis.

Oral presentation

Isotopic composition of uranium in aerosol samples collected at 120 km south-southwestern of Fukushima before and after the nuclear power plant accident

Shinonaga, Taeko*; Markus, L.*; Okura, Takehisa

no journal, , 

The isotopic composition of uranium (U) in aerosol samples collected before and after the accident of the Fukushima Daiichi Nuclear Power Plant (FDI-NPP), occurred on March 11, 2011, was studied. The aerosol samples were collected on filters by an air sampling system in Tokai, Japan (at 120 km south-southwestern of the FDI-NPP). The U isotopic composition in each filter was analyzed by sector field inductively coupled plasma mass spectrometry (SF-ICPMS). The compositions of U in the samples collected after the accident show that non-natural U existed in the aerosol. The results of series measurements of radioactive materials before and after the accident indicate that the radioactive materials released from the FDI-NPP into the atmosphere were transported to the sampling station in Tokai, a place at 120 km distance from the FDI-NPP, within a day.

Oral presentation

Review of the atmospheric radioactivity monitoring at Nuclear Science Research Institute, following the Fukushima accident

Okura, Takehisa; Feistenauer, P.*; Meisenberg, O.*; Shinonaga, Taeko*; Tschiersch, J.*

no journal, , 

The atmospheric radioactivity monitoring at Nuclear Science Research Institute, following the Fukushima accident was reviewed in this study. Comparison with measurement result of the filters at Helmholz Zentrum Muenchen (Germay) was made in order to discuss how to make an estimate of background under contaminated circumstance soon after the accident. Values of each other for samples with important level to estimate internal exposure was consistent; this points to that the adopted method to estimate background was appropriate. But some of samples with relative lower level were incompatible with each other. Penetration of radiocesium aerosols through HE-40TA was discussed with size distribution of radiocesium aerosols and characteristics of HE-40TA. Size distributions of radiocesium aerosols were evaluated experimentally, separated from HE-40TA and collected into a cascade impactor. The penetration was estimated by about 1% - 5%.

Oral presentation

Size distribution of radiocesium aerosols after the Fukushima accident collected at 120 km SSW of Fukushima Nuclear Power Plant

Okura, Takehisa; Meisenberg, O.*; Feistenauer, P.*; Shinonaga, Taeko*; Tschiersch, J.*

no journal, , 

Atmospheric radioactivity monitoring was made at Nuclear Science Research Institute, JAEA, following the Fukushima accident. Aerosol-bound radiocesium (Cs) was collected on paper filter (HE-40TA). In this study, to evaluate size distribution of the Cs, radioactive aerosols collected on HE-40TA was removed into distilled water, and then radioactive aerosols were extracted from the solution with a nebulizer and collected into a cascade impactor. The size distribution soon after the accident has one peak which is found around 0.3 $$mu$$m. Corresponded temporal decreasing Cs concentration, the second peak which has median of 1-2 $$mu$$m was developed besides ca. 0.3-$$mu$$m-median peak at sites around field. The size distribution collected at a site in woods has only one peak after also significant decreasing of Cs concentration. It is presumed that the coarser-median peak was attributed to resuspended radioactivity, considered on the basis of distribution of radioactive aerosols on the filters observed with autoradiography and reference articles.

Oral presentation

Contribution of internal dose to the exposure in the Fukushima exclusion zone

Tschiersch, J.*; Yoshimura, Kazuya; Spielmann, V.*; Iijima, Kazuki; Shinonaga, Taeko*; Miyahara, Kaname

no journal, , 

Oral presentation

Potential inhalation dose due to remediation activities in the Fukushima exclusion zone

Tschiersch, J.*; Yoshimura, Kazuya; Spielmann, V.*; Hurkamp, K.*; Iijima, Kazuki; Shinonaga, Taeko*; Miyahara, Kaname

no journal, , 

Inhalation dose depends on the kind and amount of inhaled radionuclides, but also on the size of radioactive particles and the solubility of the radionuclides in the lungs. Initial measurements during decontamination provide experimental data of the main parameters. These are particle size distribution with activity median aerodynamic diameter (AMAD) and geometric standard deviation and the solubility in the lungs. The dose assessment is performed according ICRP lung model using the computer code IMBA professional. Doses determined from measured parameters are compared to those using ICRP default values. Variability is studied and the range of potential inhalation dose is assessed.

Oral presentation

Inhalation dosimetry; Physicochemical differences between primary plume and resuspended material

Tschiersch, J.*; Spielmann, V.*; Shinonaga, Taeko*; Hurkamp, K.*; Yoshimura, Kazuya; Okura, Takehisa; Iijima, Kazuki; Miyahara, Kaname

no journal, , 

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