Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 25

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Direct quantitation of $$^{135}$$Cs in spent Cs adsorbent used for the decontamination of radiocesium-containing water by laser ablation inductively coupled plasma mass spectrometry

Asai, Shiho*; Ohata, Masaki*; Hanzawa, Yukiko; Horita, Takuma; Yomogida, Takumi; Kitatsuji, Yoshihiro

Analytical Chemistry, 92(4), p.3276 - 3284, 2020/02

 Times Cited Count:1 Percentile:27.48(Chemistry, Analytical)

The long-term safety assessment of spent Cs adsorbents produced during the decontamination of radiocesium-containing water at the Fukushima Daiichi nuclear power plant requires one to estimate their $$^{135}$$Cs content prior to final disposal. $$^{135}$$Cs is usually quantified by inductively coupled plasma mass spectrometry (ICP-MS), which necessitates the elution of Cs from Cs adsorbents. However, this approach suffers from the high radiation dose from $$^{137}$$Cs. To address this challenge, we herein employed laser ablation ICP-MS for direct quantitation of $$^{135}$$Cs in Cs adsorbents and used a model Cs adsorbent prepared by immersion of a commercially available Cs adsorbent into radiocesium-containing liquid waste to verify the developed technique. The use of the $$^{135}$$Cs/$$^{137}$$Cs ratio and $$^{137}$$Cs radioactivity obtained by gamma spectrometry achieved simple and precise quantitation of $$^{135}$$Cs and the resulting $$^{135}$$Cs activity of 0.36 Bq agreed well with that in the original radiocesium-containing liquid waste.

Journal Articles

Determination of $$^{107}$$Pd in Pd purified by selective precipitation from spent nuclear fuel by laser ablation ICP-MS

Asai, Shiho; Ohata, Masaki*; Yomogida, Takumi; Saeki, Morihisa*; Oba, Hironori*; Hanzawa, Yukiko; Horita, Takuma; Kitatsuji, Yoshihiro

Analytical and Bioanalytical Chemistry, 411(5), p.973 - 983, 2019/02

 Times Cited Count:2 Percentile:45.8(Biochemical Research Methods)

Determination of radiopalladium $$^{107}$$Pd is required for ensuring the radiation safety of Pd extracted from spent nuclear fuel for recycling or disposal. We employed laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to simplify an analytical procedure of $$^{107}$$Pd. Pd was separated through selective Pd precipitation reaction from spent nuclear fuel. Laser ablation allows direct measurement of the Pd precipitates, skipping the dissolution and dilution procedure. In this study, $$^{102}$$Pd in natural Pd standard solution was used as an internal standard, taking advantage of its absence in spent nuclear fuel. The Pd precipitate was uniformly embedded on the surface of the centrifugal filter, forming a microscopically thin flat surface of Pd. The resulting homogeneous Pd layer is suitable for obtaining a stable signal ratio of $$^{107}$$Pd/$$^{102}$$Pd. The amount of $$^{107}$$Pd obtained by LA-ICP-MS corresponds to the values obtained by conventional solution nebulization measurement.

Journal Articles

Non-contact and selective Pd separation based on laser-induced photoreduction for determination of $$^{107}$$Pd by ICP-MS; The Relation between separation conditions and Pd recovery

Yomogida, Takumi; Asai, Shiho; Saeki, Morihisa*; Hanzawa, Yukiko; Horita, Takuma; Esaka, Fumitaka; Oba, Hironori*; Kitatsuji, Yoshihiro

Bunseki Kagaku, 66(9), p.647 - 652, 2017/09

 Times Cited Count:1 Percentile:92.51(Chemistry, Analytical)

Palladium-107 is a long-lived fission product, which can be found in high-level radioactive liquid wastes (HLLW). Determination of the $$^{107}$$Pd contents in HLLW is essential to evaluate the long-term safety of HLLW repositories. However, the $$^{107}$$Pd content in HLLW has not been reported because of difficulties in pretreatment for the measurement. In this study, we investigated applicability of laser-induced photoreduction to HLLW solution: it enables a simple and non-contact separation of Pd. The results showed the recovery of 60% was achieved at the conditions: 40% ethanol, 20 min irradiation, 100 mJ of pulse energy. Additionally, major radionuclides and potentially interfering components in ICP-MS were removed from the simulated HLLW over a wide concentration range of Pd from 0.24 to 24 mg L$$^{-1}$$, showing the applicability of the proposed separation technique to HLLW samples.

JAEA Reports

Preliminary missions for the decommissioning of the laboratory building No.1 for the plutonium research program

Segawa, Yukari; Horita, Takuma; Kitatsuji, Yoshihiro; Kumagai, Yuta; Aoyagi, Noboru; Nakada, Masami; Otobe, Haruyoshi; Tamura, Yukito*; Okamoto, Hisato; Otomo, Takashi; et al.

JAEA-Technology 2016-039, 64 Pages, 2017/03

JAEA-Technology-2016-039.pdf:5.24MB

The laboratory building No.1 for the plutonium research program (Bldg. Pu1) was chosen as one of the facilities to decommission by Japan Atomic Energy Agency Reform in September, 2013. The research groups, users of Bldg. Pu1, were driven by necessity to remove used equipment and transport nuclear fuel to other facilities from Bldg. Pu1. Research Group for Radiochemistry proactively established the Used Equipment Removal Team for the smooth operation of the removal in April, 2015. The team classified six types of work into the nature of the operation, removal of used equipment, disposal of chemicals, stabilization of mercury, stabilization of nuclear fuel, transportation of nuclear fuel and radioisotope, and survey of contamination status inside the glove boxes. These works were completed in December, 2015. This report circumstantially shows six works process, with the exception of the approval of the changes on the usage of nuclear fuel in Bldg. Pu1 to help prospective decommission.

Journal Articles

Preparation of Sr adsorptive fiber by impregnating with crown ether derivative for $$^{90}$$Sr measurement

Horita, Takuma; Asai, Shiho; Konda, Miki; Hanzawa, Yukiko; Saito, Kyoichi*; Fujiwara, Kunio*; Sugo, Takanobu*; Kitatsuji, Yoshihiro

Bunseki Kagaku, 66(3), p.189 - 193, 2017/03

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

A Sr-selective adsorption fiber was prepared for rapid analysis of $$^{90}$$Sr content by using radiation-induced emulsion graft polymerization and subsequent chemical modification. A polyethylene fiber with a diameter of 13 $$mu$$m was first immersed in a methanol solution of an epoxy-group-containing vinyl monomer, glycidyl methacrylate (GMA), and polyoxyethylene sorbitol ester (Tween20) as a surfactant for graft-polymerization of GMA. Octadecylamine was then bound to a polymer chain extending from the fiber surface providing hydrophobicity to the polymer chain. Dicyclohexano-18-crown-6 (DCH18C6) was finally impregnated onto the polymer chain via a hydrophobic interaction between the octadecyl moiety of the polymer chain and the cyclohexyl moiety of DCH18C6. The fiber surface structure, characterized by DCH18C6 molecules loosely entangled with polymer chains, afforded realizes the rapid and selective adsorption of Sr ions with an adsorption rate approximately 100 times higher than that of a commercially available Sr-selective resin (Sr Resin).

Journal Articles

Determination of $$^{107}$$Pd in Pd recovered by laser-induced photoreduction with inductively coupled plasma mass spectrometry

Asai, Shiho; Yomogida, Takumi; Saeki, Morihisa*; Oba, Hironori*; Hanzawa, Yukiko; Horita, Takuma; Kitatsuji, Yoshihiro

Analytical Chemistry, 88(24), p.12227 - 12233, 2016/12

 Times Cited Count:7 Percentile:57.18(Chemistry, Analytical)

Safety evaluation of a radioactive waste repository requires credible activity estimates confirmed by actual measurements. A long-lived radionuclide, $$^{107}$$Pd, which can be found in radioactive wastes, is one of the difficult-to-measure nuclides and results in a deficit in experimentally determined contents. In this study, a precipitation-based separation method has been developed for the determination of $$^{107}$$Pd with ICP-MS. The photoreduction induced by laser irradiation at 355 nm provides short-time and one-step recovery of Pd. The proposed method was verified by applying it to a spent nuclear fuel sample. In order to efficiently recover Pd, a natural Pd standard was employed as the Pd carrier. The chemical yield of Pd was about 90% with virtually no impurities, allowing accurate quantification of $$^{107}$$Pd.

Oral presentation

Preparation of crown ether derivative-impregnated fiber based on the radiation-induced emulsion graft polymerization for rapid analysis of Sr-90

Horita, Takuma; Asai, Shiho; Hanzawa, Yukiko; Saito, Kyoichi*; Fujiwara, Kunio*; Sugo, Takanobu*; Kitatsuji, Yoshihiro

no journal, , 

There has been an increasing demand for rapid analysis of $$^{90}$$Sr to ensure a prompt action against the contaminated water in the Fukushima Daiichi NPP. Precedent works demonstrated that Cs adsorption fibers prepared by utilizing graft polymerization technology achieved high-speed removal of $$^{137}$$Cs in the contaminated water. In this study, we have investigated the applicability of such proven technology to the preparation of a Sr adsorption fiber specialized for the selective extraction of Sr. In the prepared fiber, an extractant for Sr$$_{2+}$$,dicyclohexano-18-crown-6-ether (DCH18C6) was impregnated via hydrophobic interaction between DCH18C6 and the hydrophobic polymer chains attached onto the surface of the fiber. To increase the adsorption capacity, emulsion graft polymerization which promotes the polymer chains to grow longer was applied. The densely-packed DCH18C6 inside the interfacial phase formed by the polymer chains facilitates the efficient adsorption. The amounts of Sr adsorbed is comparable to those of conventional adsorbents, indicating that the prepared fiber has a feasible performance for Sr adsorption.

Oral presentation

Preparation of 18-crown-6-ether derivative-impregnated fiber based on the radiation-induced graft polymerization

Horita, Takuma; Asai, Shiho; Konda, Miki; Hanzawa, Yukiko; Saito, Kyoichi*; Fujiwara, Kunio*; Sugo, Takanobu*; Kitatsuji, Yoshihiro

no journal, , 

High activity concentrations of $$^{90}$$Sr, which greatly exceed the regulatory limit (30 Bq/L), are detected in contaminated waters sampled in Fukushima Daiichi NPP. However, analytical method for $$^{90}$$Sr associated with time-consuming procedure causes delay in understanding the current status of $$^{90}$$Sr contamination. In this study, we have prepared a Sr adsorption fiber (Sr Fiber) based on radiation-induced graft polymerization technique to achieve a rapid adsorption of Sr ions. Dicyclohexano-18-crown-6 ether that has high affinity for Sr was impregnated in the hydrophobic interfacial phase provided by hydrophobic polymer chains attached on the fiber surface through graft polymerization. The time required to reach the Sr adsorption equilibrium for the Sr Fiber is approximately 180 times shorter than that for a commercially available Sr adsorbent (Sr Resin), showing that the Sr Fiber has a potential to efficiently reduce the analytical time of $$^{90}$$Sr.

Oral presentation

Determination of $$^{107}$$Pd in Pd recovered from spent nuclear fuel solution by laser induced photoreduction

Asai, Shiho; Yomogida, Takumi; Saeki, Morihisa*; Oba, Hironori*; Hanzawa, Yukiko; Horita, Takuma; Kitatsuji, Yoshihiro

no journal, , 

$$^{107}$$Pd is a long-lived radionuclide that can be found in HLW. The estimation of the amount of $$^{107}$$Pd in HLW is considered crucial for long-term safety evaluation of HLW. However, experimentally determined concentrations of $$^{107}$$Pd in HLW has not been reported due to the difficulty in recovering significant amount of Pd from HLW which has high radioactivity. In this study, we have focused on remotely operated separation technique based on laser-induced photoreduction, which allows to keep the distance from samples. To validate the applicability of the proposed method, spent nuclear fuel with a traceable irradiation history was employed instead of HLW. The resulting Pd precipitate contained almost no impurities, such as actinides (U, Np, Pu, Am, Cm), major fission products (Zr, Mo, Tc, Ru, Rh, Ba, Cs, Ce), resulting in the interference-free measurement of $$^{107}$$Pd with ICP-MS. The amount of $$^{107}$$Pd per 1 mg of $$^{238}$$U in the sample was 239$$pm$$9 ng/mg-$$^{238}$$U.

Oral presentation

Direct beta-ray measurement of $$^{90}$$Sr adsorbed on fiber surface; Preparation of 18-crown 6-ether derivative-impregnated Sr adsorption fiber based on the radiation-induced graft polymerization

Horita, Takuma; Asai, Shiho; Konda, Miki; Hanzawa, Yukiko; Saito, Kyoichi*; Fujiwara, Kunio*; Kitatsuji, Yoshihiro

no journal, , 

There has been an increasing importance of the development of rapid separation techniques for $$^{90}$$Sr analysis, responding to needs in Fukushima Daiichi NPP. However, conventional $$^{90}$$Sr analytical methods require two different separation steps for Sr and Y, respectively, resulting in a long processing time of about one month. In this study, we prepared a Sr adsorptive fiber (Sr fiber) that has a high density Sr adsorption phase on its surface, allowing to highly efficient $$beta$$-ray counting by minimizing the self-attenuation effects. The adsorption capacity of the prepared Sr fiber was about 14 g/mol, which is equivalent to that of a commercially available Sr adsorptive resin (Sr Resin). The selectivity of the Sr fiber was nearly the same as that of the Sr resin. Considering that the Sr fiber has a specific surface area 1000 times smaller than that of the Sr Resin, the Sr ions can be concentrated to 1000 times on its surface, capable of achieving highly-efficient $$beta$$-ray counting. From these result, we confirmed that Sr fiber has adsorption capacity and selectivity necessary for highly efficient $$beta$$-ray counting of $$^{90}$$Sr.

Oral presentation

Direct measurement of $$^{107}$$Pd in Pd metal recovered from spent nuclear fuel with laser ablation ICP-MS

Asai, Shiho; Ohata, Masaki*; Yomogida, Takumi; Saeki, Morihisa*; Oba, Hironori*; Hanzawa, Yukiko; Horita, Takuma; Kitatsuji, Yoshihiro

no journal, , 

Oral presentation

Development of Pd separation technique based on photoreduction and precipitation; The Relationship between ethanol concentration and Pd recovery

Yomogida, Takumi; Asai, Shiho; Saeki, Morihisa*; Hanzawa, Yukiko; Horita, Takuma; Esaka, Fumitaka; Oba, Hironori*; Kitatsuji, Yoshihiro

no journal, , 

Recently, we developed a precipitation-based separation method for the determination of $$^{107}$$Pd with ICP-MS. However, a pulsed-laser light source is indispensable to form Pd precipitation in the separation method. There were difficulties in handling of a pulsed-laser light source. Simplified irradiation procedure is desirable to facilitate a Pd separation procedure. In this study, we developed a simple Pd separation technique based on photoreduction with Xe lamp irradiation and applied the technique to a simulated HLW solution. The Pd recovery from a simulated HLW solution reached 50%, while 99% of the other 13 elements were removed. These results indicate that selective separation of Pd is achieved with the simplified irradiation procedure.

Oral presentation

Preparation of Sr adsorption fiber for beta-ray measurement

Horita, Takuma; Asai, Shiho; Hanzawa, Yukiko; Saito, Kyoichi*; Sugo, Takanobu*; Fujiwara, Kunio*; Kitatsuji, Yoshihiro

no journal, , 

There has been an increasing importance of the development of rapid $$^{90}$$Sr analysis technique, responding to needs in Fukushima Daiichi NPP. We have been trying to achieve a rapid analysis using a fibrous Sr adsorbent which has high selectivity for Sr$$^{2+}$$. The fiber we prepared that has a high-density Sr adsorption phase on its surface, and so it can adsorb Sr$$^{2+}$$ on the fiber surface. On the other hand, base material of a conventional Sr adsorptive resin for $$^{90}$$Sr analysis (Sr Resin) is bead-shaped resin, and $$^{90}$$Sr is adsorbed inside pores. The fiber allows highly efficient $$beta$$ counting by minimizing the self-attenuation effects. The adsorption capacity and selectivity of the fiber was nearly the same as those of the Sr Resin. From these results, we confirmed that the fiber has performance for efficient $$beta$$ counting of $$^{90}$$Sr.

Oral presentation

Development of in-situ analytical method of $$^{90}$$Sr in contaminated water using Sr adsorptive fiber

Konda, Miki; Horita, Takuma; Asai, Shiho; Matsueda, Makoto; Hanzawa, Yukiko; Saito, Kyoichi*; Fujiwara, Kunio*; Sugo, Takanobu*; Kameo, Yutaka

no journal, , 

no abstracts in English

Oral presentation

Isotope ratio measurement of Pd recovered from spent nuclear fuel with LA-ICP-MS

Asai, Shiho; Ohata, Masaki*; Yomogida, Takumi; Saeki, Morihisa*; Oba, Hironori*; Hanzawa, Yukiko; Horita, Takuma; Kitatsuji, Yoshihiro

no journal, , 

Safe and cost-effective disposal of radioactive wastes requires reliable evaluation of the amount of the radionuclides found in such wastes. Measurement of $$^{107}$$Pd, one of the radionuclides that are necessary to be evaluated, is associated with highly radioactive sample (e.g., spent nuclear fuel sample), resulting in only a few data in published forms. We separated Pd as a precipitate from a spent nuclear fuel sample and then determined the precise amount of $$^{107}$$Pd. However, the method needed dissolution of the Pd precipitate to carry it to the sample introduction system of ICP-MS. In this study, we tried direct measurement of the Pd precipitate with laser-ablation (LA)-ICP-MS that enables solid sample measurement. The diameters of the recovered Pd precipitates were less than 500 nm, which is much smaller than the ablation spot. This allowed Pd to be uniformly vaporized, leading to sufficiently stable signals with high precisions equivalent to those of conventional ICP-MS.

Oral presentation

Application of ICP-MS to analysis of samples from 1F site at Radioactive Material Analysis and Research Facility

Do, V. K.; Horita, Takuma; Miura, Katsue; Iwasaki, Maho

no journal, , 

Radioactive Material Analysis and Research Facility has been recently established to support the analysis of samples including fuel debris and radioactive wastes from the decommissioning of Fukushima Daiichi Nuclear Power Station (1F). ICP-MS is considered as a potential analytical tool for long-lived nuclides in fuel debris because of its superior sensitivity. Moreover, the use of ICP-MS is aimed to increase the analysis capacity, which make possible to repeat measurements in order to obtain precise results and to reduce exposed dose of analysts because ICP-MS is much more rapid than radiometric methods. Employing latest advanced technologies, a triple quadrupole ICP-MS, Agilent 8900 (ICP-QQQ-MS), enables to suppress the isobaric interference. In this presentation, we report some demonstrative separations of difficult-to-measure nuclides using the ICP-QQQ-MS system. The obtained results indicate that the separations are possible with suitable reaction gases.

Oral presentation

Separation of platinum-group metals from radioactive waste liquid by laser induced particle formation

Saeki, Morihisa*; Asai, Shiho; Yomogida, Takumi; Hanzawa, Yukiko; Taguchi, Tomitsugu*; Horita, Takuma; Kitatsuji, Yoshihiro; Oba, Hironori*

no journal, , 

Platinum-group metals (PGMs), such as Pd, Ru, and Rh are generated by nuclear fission of U and can be found in spent nuclear fuel (SNF) and high-level radioactive waste (HLW). Separation techniques for PGMs from HLW have been investigated for the safety assessment of HLW and the reuse of PGMs as resources. Among such PGMs, only Pd has a long-lived radionuclide $$^{107}$$Pd. Accordingly, the precise measurement of the amount of $$^{107}$$Pd in HLW is essential for the long-term safety management of HLW. The determination of $$^{107}$$Pd requires a reliable separation technique that allows selective Pd recovery with high purity. We developed a new separation technique specialized for PGMs. The technique involves UV-laser irradiation that induces selective reduction of ions of PGMs. The reduced PGMs can be readily recovered as precipitates. At the conference, the separation performances of PGMs and some applications of our technique will be discussed.

Oral presentation

Study on applicability of ICP-QQQ-MS to the analysis of Np-237 at Okuma Analysis and Research Center

Horita, Takuma; Iwasaki, Maho

no journal, , 

no abstracts in English

Oral presentation

Development of crown-ether-derivative impregnated fiber for in-situ analysis of $$^{90}$$Sr; Study of safe Sr adsorption with no nitric acid

Konda, Miki; Horita, Takuma; Asai, Shiho; Hanzawa, Yukiko; Saito, Kyoichi*; Fujiwara, Kunio*; Sugo, Takanobu*; Ishimori, Kenichiro; Kameo, Yutaka

no journal, , 

no abstracts in English

Oral presentation

Development of an analytical method for nickel isotopes using an automated sample preparation system and ICP-QQQ-MS

Do, V. K.; Kitamura, Kiyoshi; Horita, Takuma; Furuse, Takahiro

no journal, , 

We report an application of automated devices for multi-step chemical separation for nickel and an idea of subsequent quantification for Ni-59 using ICP-QQQ-MS. Nickel is separated on our selected automated instruments applying a conventional separation scheme. The obtained chemical recovery for Ni standard carrier was 89.8% (relative standard deviation, RSD of 2.9%, n = 3), which is consistent with the manually obtained recovery of 87.0% (RSD = 2.2%, n = 3). The quantification of Ni-59 by ICP-QQQ-MS was examined. Accordingly, the intensity of 59Ni could be deduced from an intensity correction curve for natural isotopes of nickel. The proposed analytical method is more rapid and less laborious, being expected to reduce radiation exposure to workers.

25 (Records 1-20 displayed on this page)