Structural investigation of borosilicate glasses by using XAFS measurement in soft X-ray region, 3 (Joint research)

Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Shibata, Daisuke*; Kojima, Kazuo*; Hasegawa, Takehiko*; Sato, Seiichi*; Fukaya, Akane*; Hatakeyama, Kiyoshi*

JAEA-Research 2023-004, 45 Pages, 2023/09

JAEA-Research-2023-004.pdf:6.07MB

The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. To understand the chemical stability of simulated waste glasses, XANES spectra of B K-edge, Fe L, L-edge, and Cs M, M-edge were measured on the glass surface exposed to the leachate. As a result, it was found that the glass surface exposed to the leachate was changed and it was difficult to obtain a clear XANES spectrum. From the B K-edge XANES spectra on glass surfaces exposed to the leachate, an increase in three-coordination of B-O (BO) and a decrease in four-coordination of B-O (BO) were observed compared to the glass surfaces before immersion. The XANES spectra of Fe L, L-edge, and Cs M, M-edge show that as the exposure time in the leachate increases, the Cs present on the glass surface dissolves into the leachate. The XANES spectra of Si K-edge were measured on simulated waste glass surfaces before immersion, and it was confirmed that the change in XANES spectra given by NaO concentration had a larger effect than the waste component concentration.

Structural investigation of borosilicate glasses by using XAFS measurement in soft X-ray region, 2 (Joint research)

Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*

JAEA-Research 2022-008, 37 Pages, 2022/10

JAEA-Research-2022-008.pdf:5.27MB

The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of simulated waste glass surfaces after immersion test to investigate the long chemical stability. (1) As the leaching time of glass samples in immersion test passed, the Cs M, M-edge XANES spectra disappeared and the Fe L, L-edge spectra changed. (2) A new compound was formed on the sample surface after the immersion test, and these changes in the surface state were confirmed by Raman spectroscopy. However, it became difficult to obtain a clear B K-edge XANES spectrum by forming a compound on glass surfaces. The Si K-edge XANES spectra of borosilicate glass frits with different NaO content were measured, and following was confirmed. (1) As the NaO concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The intensity of the Si K-edge peak is maximum when the NaO content in glass frits was about 7wt%.

MIRS: an imaging spectrometer for the MMX mission

Barucci, M. A.*; Reess, J.-M.*; Bernardi, P.*; Doressoundiram, A.*; Fornasier, S.*; Le Du, M.*; Iwata, Takahiro*; Nakagawa, Hiromu*; Nakamura, Tomoki*; Andr, Y.*; et al.

Earth, Planets and Space (Internet), 73(1), p.211_1 - 211_28, 2021/12

https://doi.org/10.1186/s40623-021-01423-2

The MMX InfraRed Spectrometer (MIRS) is an imaging spectrometer on board of MMX JAXA mission. MIRS is built at LESIA-Paris Observatory in collaboration with four other French laboratories, collaboration and financial support of CNES and close collaboration with JAXA and MELCO. The instrument is designed to fully accomplish MMX's scientific and measurement objectives. MIRS will remotely provide near-infrared spectral maps of Phobos and Deimos containing compositional diagnostic spectral features that will be used to analyze the surface composition and to support the sampling site selection. MIRS will also study Mars atmosphere, in particular to spatial and temporal changes such as clouds, dust and water vapor.

XAFS measurement of simulated waste glass samples (Joint research)

Nagai, Takayuki; Sasage, Kenichi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamagishi, Hirona*; Ota, Toshiaki*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*; Takahashi, Tomoe*; et al.

JAEA-Research 2019-003, 94 Pages, 2019/09

JAEA-Research-2019-003.pdf:7.92MB

The local structures of glass-forming elements and waste elements would change by the chemical composition of waste glass including those elements. In this study, simulated waste glass samples were prepared from borosilicate glass frit including phosphorus (P) or vanadium (V), and we investigated local structures of boron, sodium, and waste elements in these P glass and V glass samples by using synchrotron XAFS measurements in soft and hard X ray region.

Transition of near surface resistivity of tunnel wall during drift closure test

Ozaki, Yusuke; Ishibashi, Masayuki; Matsushita, Tomoaki*; Masumoto, Kazuhiko*; Imasato, Takehiko*

Proceedings of 13th SEGJ International Symposium (USB Flash Drive), 4 Pages, 2018/11

In the Mizunami Underground Research Laboratory, Groundwater REcoverty Experiment in Tunnel (GREET) is performed to understanding the recovery process of geological environment after the closure of drift. In this experiment, we performed 2D electrical resistivity surveys three times. First survey was performed before the closure of test drift. Second and third surveys were performed after the closure test. The first survey detected two layers conformation that consists of conductive and resistive zones at shallower and deeper part from the drift surface, respectively. These layers correspond to the shotcrete and host rock, respectively. Second and third measurements show that the conductive zone expanded to deeper resistive part while the shallower conductive part did not change. We concluded that we captured the saturation process of dried fractures near the drift wall by closure of drift as an electrical resistivity response.

Development of U and Pu co-processing process; Demonstration of U, Pu and Np Co-recovery with centrifugal contactors

Kudo, Atsunari; Kurabayashi, Kazuaki; Yanagibashi, Futoshi; Sasaki, Shunichi; Sato, Takehiko; Fujimoto, Ikuo; Obu, Tomoyuki

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04

The Co-processing process is the extraction process to recover Pu/U mixed product solution with given Pu/U ratio for improving of nuclear proliferation resistance. In addition, Np is also recovered with U and Pu because Np is one of minor actinides and a long-lived radionuclide and Np has the extractability into TBP solvent. Development of its flowsheet achieves to decrease environmental effect of waste materials. The orientation of development about Co-processing process is to demonstrate of reprocessing the future spent fuels from a LWR, a LWR-MOX hybrid, and a FR-MOX with one cycle. We demonstrated by use of miniature reflux-type centrifugal contactors at the partitioning unit. The test conditions of the Pu/U ratio in the loaded solvents were 1%, 3%, and 5% considering the composition of spent fuels. We used the HAN as the reductant of Np (VI) for back extraction. The results of these tests were very good. We got the prospect of U, Pu, and Np Co-processing flowsheet.

Determination of electrochemical corrosion potential along the JMTR in-pile loop, 1; Evaluation of ECP of stainless steel in high-temperature water as a function of oxidant concentrations and exposure time

Uchida, Shunsuke; Hanawa, Satoshi; Nishiyama, Yutaka; Nakamura, Takehiko; Sato, Tomonori; Tsukada, Takashi; Kysela, J.*

Nuclear Technology, 183(1), p.119 - 135, 2013/07

https://doi.org/10.13182/NT13-A16997

In-pile loop experiments are one of the key technologies which can provide an understanding of corrosion behaviors of structural materials in nuclear power plants (NPPs). The experiments should be supported not only by reliable measurement tools to confirm corrosive conditions under neutron and ray irradiations but also by theoretical models for extrapolating the measured data to predict corrosion behaviors in NPPs. The relationships among electrochemical corrosion potential (ECP), metal surface conditions, exposure time and other environmental conditions have been determined from in situ measurements of corrosion behaviors of stainless steel specimens exposed to HO and O in high temperature water. Based on the relationships, a model to evaluate ECP of stainless steel was developed by coupling an electrochemical model and a double oxide layer model. Major conclusions obtained from the evaluation model are as follows. (1) The difference in ECP behaviors of the specimens exposed to HO and O were mainly from the thickness and developing rate of the inner oxide layers. (2) Calculated ECP behaviors, e.g., the different responses to HO and O and hysteresis and memory effects, agreed with the measured ones. (3) Neutron exposure might decrease ECP due to radiation-induced diffusion in the oxide layer. The ECP evaluation model will be applied to evaluation of corrosive conditions in the JMTR in-pile loop.

Environmental radiation monitoring resulting from the accident at the Fukushima Daiichi Nuclear Power Plant, conducted by Oarai Research and Development Center, JAEA; Results of ambient gamma-ray dose rate, atmospheric radioactivity and meteorological observation

Yamada, Junya; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Numari, Hideyuki*; Sato, Naomitsu*; Nemoto, Koji*; Takasaki, Hiroichi*; Shimizu, Takehiko; Takasaki, Koji

JAEA-Data/Code 2013-006, 100 Pages, 2013/06

JAEA-Data-Code-2013-006.pdf:12.04MB

This report presents the results of emergency radiation monitoring, including ambient -ray dose rate, atmospheric radioactivity, meteorological observation and estimation of internal exposure resulting from the accident at the Fukushima Daiichi Nuclear Power Plant triggered by the earthquake off the pacific coast of Tohoku on 11th March 2011, conducted by Oarai Research and Development Center (ORDC), Japan Atomic Energy Agency (JAEA) from March to May, 2011. ORDC is located in the central part of Ibaraki prefecture and approximately 130 km southwest of the Fukushima Daiichi Nuclear Power Plant. From around 15th to 21st March, 2011, the ambient -ray dose rate increased and many radioactive nuclides were detected in the atmosphere.

Composition of insoluble materials in highly active liquid waste at Tokai Reprocessing Plant

Kuno, Takehiko; Nakamura, Yoshinobu; Okano, Masanori; Sato, Soichi; Watahiki, Masaru

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 3 Pages, 2005/10

The elemental composition and amount of insoluble materials in highly active liquid waste (HALW) were measured at the Tokai Reprocessing Plant. To evaluate the composition of the insoluble material between the treatment and storage processes, samples from the evaporator and two vessels which differ in the storage period, were taken. The concentration of insoluble material evaluated by both its weight on filter paper after filtration as well as by filtration volume showed no difference for three different samples. Inductively coupled plasma atomic emission spectrometry and isotope dilution mass spectrometry were used to determine the elements in samples dissolved by sulfate fusion. Analytical data revealed that Zr and Mo were the main components of the insoluble material in three samples, but low levels of Rh, Ru and Pd were also present. These results suggest that most of insoluble material had re-precipitated from the HALW solution during the concentration process.

Confirmation of the availability of an analytical technique, Pu(VI) spectrophotometry for HALW; Technical Support for the Joint IAEA/Japan On-site Analytical Laboratory at the Rokkasho Reprocessing Plant (JASPAS JU-01-01)

Kitao, Takahiko; Sato, Soichi; Kuno, Takehiko; Keiji, Yamada,; Watahiki, Masaru; Kamata, Masayuki

JNC TN8410 2003-014, 29 Pages, 2003/11

JNC-TN8410-2003-014.pdf:1.82MB

The Agency requested the Tokai Reprocessing Plant(TRP) to confirm the applicability of three kinds of analytical procedure for Pu(VI) spectrophotometry in On-Site Analytical Laboratory (OSL) at Rokkasho, in order to obtain accurate plutonium(Pu) concentration in High Active Liquid Waste (HALW). Three analytical procedures, (1) Calibration method, (2) Nd internal standard method and (3) Reduction method, were tested. The measurement sample was prepared by adding the known amount of plutonium in the actual HALW after removing original Pu by solid extraction. We measured the Pu concentration in the sample by three methods and calculated the accuracy and precision. The results of each method are summarized as follows:(1) Calibration method Plutonium concentration calculated by the calibration method agreed with that by adjusted concentration. (2) Nd internal standard method Accurate results were obtained by this method. The error of pretreatment, especially dilution, has not influenced on the Pu measurements. (3) Reduction method The measured Pu concentrations were higher than those by adjusted. From the comparison with these results, the calibration method is the most simple and rapid in the three methods. Analysis time was within 1 hour including sample preparation. The detection limit, with the calibration method, was 1.3 mgPu/L in the actual HALW measurements.