Quantitation of long-lived radionuclide by ICP-MS

Asai, Shiho*; Horita, Takuma

Bunseki Kagaku, 73(10-11), p.569 - 578, 2024/10

The accurate estimation of the quantities and composition of long-lived radionuclides in radioactive waste is crucial for assessing the long-term safety of its disposal. Traditionally, theoretical predictions of the quantities of long-lived radionuclides obtained from burn-up calculation codes with evaluated nuclear data have been used especially for the safety assessment of high-level radioactive waste. However, such nuclear data used in theoretical predictions have not been sufficiently validated due to the scarcity of the reported measurement data. In this study, we aim to contribute to the improvement of the reliability of theoretical predictions by confirming them with the measured quantities of long-lived radionuclides per unit mass of uranium in spent nuclear fuel, which are output data obtained from the burnup calculation code. This involves measuring the long-lived radionuclides present in nuclear fuel pellets used in commercial nuclear reactors. Specifically, we focused on Zr, Pd, and Cs, which can be effectively measured using an inductively coupled plasma mass spectrometer (ICP-MS). Besides the purpose of validating the nuclear data, this article also highlights viable measurement techniques for these radionuclides, along with examples demonstrating their applicability to long-lived radionuclides, including the preparation procedures for their measurement.

Improvement of adsorption performances of Sr adsorption fiber and investigation for realizing simple Sr analysis

Horita, Takuma; Asai, Shiho*; Konda, Miki; Matsueda, Makoto; Hanzawa, Yukiko; Kitatsuji, Yoshihiro

Bunseki Kagaku, 69(10/11), p.619 - 626, 2020/10

https://doi.org/10.2116/bunsekikagaku.69.619

We have developed a Sr adsorption fiber for rapid analysis of Sr. The prepared Sr adsorption fiber has a Sr-extraction layer that densely retains a Sr-selective extractant, an 18-crown-6 ether derivative, on the fiber surface. Hydrophobic group-containing polymer chains embedded onto the surface of the fiber allow to form a hydrophobic phase, incorporating Sr-selective extractants. This unique surface structure provides high adsorption capacity, leading to rapid and highly efficient adsorption of Sr. The adsorption capacity of the Sr adsorption fiber was 3 times higher than commercially available 18-crown-6 ether derivative-impregnated resin (Sr Resin). The equilibrium adsorption capacity of the Sr adsorption fiber was comparable to the Sr Resin. The retained Sr was finally determined by a GM counter. The total analysis time including the Sr adsorption and measurement was about 1 hour.

Determination of 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

https://doi.org/10.1007/s00216-018-1527-3

Determination of radiopalladium 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 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, 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 Pd/Pd. The amount of Pd obtained by LA-ICP-MS corresponds to the values obtained by conventional solution nebulization measurement.

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.

Determination of 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

https://doi.org/10.1021/acs.analchem.6b03286

Safety evaluation of a radioactive waste repository requires credible activity estimates confirmed by actual measurements. A long-lived radionuclide, 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 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 Pd.

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.

Direct measurement of Cs in Cs adsorbent used for water decontamination by laser-ablation ICP-MS

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

no journal, , 

A large amount of spent Cs adsorbents used for decontaminating water in Fukushima Daiichi Nuclear Power Station are stored in the site. To dispose them safely, the estimation of Cs activity along with that of Cs is indispensable. Cs is generally measured by ICP-MS, which required the sample to be prepared in liquid form and thus the elution of Cs from the Cs adsorbents is essential. However, this approach suffers from the high radiation dose from Cs. In this study, we quantified Cs in a Cs adsorbent using the Cs/Cs ratio obtained by LA-ICP-MS and Cs radioactivity obtained by gamma spectrometry. To evaluate the applicability, we employed a Cs -containing water sample to prepare a model spent Cs adsorbent with a certified Cs activity. The resulting Cs activity of 0.36 Bq calculated by Cs /Cs ratio of 0.41 0.02 and Cs activity agreed well with that of the originally determined Cs activity in the model spent Cs adsorbent, demonstrating that the proposed technique has high validity to Cs determination of a real sample.

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 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 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,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.

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 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.

Development of crown-ether-derivative impregnated fiber for in-situ analysis of 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