Quantitation of long-lived radionuclide by ICP-MS

Asai, Shiho*; Horita, Takuma

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

https://doi.org/10.2116/bunsekikagaku.73.569

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.

Determination of 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, , 

Pd is a long-lived radionuclide that can be found in HLW. The estimation of the amount of Pd in HLW is considered crucial for long-term safety evaluation of HLW. However, experimentally determined concentrations of 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 Pd with ICP-MS. The amount of Pd per 1 mg of U in the sample was 2399 ng/mg-U.

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 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 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.

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

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.

Study on pretreatment methods of seawater for determination of ultra-trace radionuclide Cs

Tajima, Taiyo*; Asai, Shiho*; Saito, Kyoichi*; Seko, Noriaki*; Hoshina, Hiroyuki*; Horita, Takuma; Yamasaki, Shinya*; Takaku, Yuichi*; Sueki, Keisuke*; Sakaguchi, Aya*

no journal, , 

Cs is a radionuclide introduced into the environment by human nuclear activities. The use of Cs as an oceanic circulation tracer and the need for monitoring around nuclear facilities require the establishment of a measurement method for this nuclide. In this study, the appropriate adsorption and desorption conditions of Cs in seawater using the insoluble cobalt ferrocyanide-impregnated adsorbent synthesized by graft polymerisation were investigated. A chemical separation method of Cs for mass spectrometry was also investigated.