Current numbers of qubits and their uses

Ichikawa, Tsubasa*; Hakoshima, Hideaki*; Inui, Koji*; Ito, Kosuke*; Matsuda, Ryo*; Mitarai, Kosuke*; Miyamoto, Koichi*; Mizukami, Wataru*; Mizuta, Kaoru*; Mori, Toshio*; et al.

Nature Reviews Physics (Internet), 6(6), p.345 - 347, 2024/06

https://doi.org/10.1038/s42254-024-00725-0

Parity assignment for low-lying dipole states in Ni

Shizuma, Toshiyuki*; Omer, M.; Hayakawa, Takehito*; Minato, Futoshi*; Matsuba, Shunya*; Miyamoto, Shuji*; Shimizu, Noritaka*; Utsuno, Yutaka

Physical Review C, 109(1), p.014302_1 - 014302_7, 2024/01

https://doi.org/10.1103/PhysRevC.109.014302

Feasibility study of reactor radiation photon spectroscopy in Fugen for nuclear decommissioning

Kaburagi, Masaaki; Miyamoto, Yuta; Mori, Norimasa; Iwai, Hiroki; Tezuka, Masashi; Kurosawa, Shunsuke*; Tagawa, Akihiro; Takasaki, Koji

Journal of Nuclear Science and Technology, 9 Pages, 2024/00

https://doi.org/10.1080/00223131.2024.2417786

Document collection of the 39th Technical Special Committee on Fugen Decommissioning

Sato, Yuji; Miyamoto, Yuta; Awatani, Yuto; Yamamoto, Kosuke; Hatakeyama, Takumi

JAEA-Review 2023-002, 59 Pages, 2023/08

JAEA-Review-2023-002.pdf:8.75MB

"Fugen Decommissioning Engineering Center", in planning and carrying out our decommissioning technical development, organizes "Technical special committee on Fugen decommissioning" which consists of the members well-informed, aiming to make good use of Fugen as a place for technological development which is opened domestic and international, as the central place in research and development base of Fukui prefecture, and to utilize the outcome in our decommissioning to the technical development effectively. This report consists of presentation paper are "Achievements and Considerations for Sampling and Analysis of Reactor Core Components", "Treatment of liquid scintillator waste liquid" and "Results and issues of rationalization of decontamination related to the clearance and considerations related to surface contamination monitoring" which is presented in the 39th Technical Special Committee on Fugen Decommissioning.

Variation of crystallinity and secondary ion quantity of uranium particles with heating temperature of Sample preparation

Tomita, Ryohei; Tomita, Jumpei; Yomogida, Takumi; Suzuki, Daisuke; Yasuda, Kenichiro; Esaka, Fumitaka; Miyamoto, Yutaka

KEK Proceedings 2022-2, p.108 - 113, 2022/11

https://lib-extopc.kek.jp/preprints/PDF/2022/2225/2225002.pdf

Automated Particle Measurement (APM) is the first measurement of environmental sample for safeguard purpose. APM tells us the number of particles in sample, their enrichment and their location. Precision and accuracy of APM is easily affected by particle condition. We have investigated how influential baking temperature in sample preparation are for uranium secondary ion quantity, uranium hydride generation and particle crystallinity. Our experimental results showed that baking temperature of 800C reduced uranium secondary ion quantity to 33% compared with baking at 350C. Uranium hydride generation ratio of the sample baked at 850C was also 4 times higher than the sample baked at 350C. Baking at 850C raised only crystallinity of uranium particles. Baking sample at too high temperature caused less uranium secondary ion generation and much more uranium hydride generation. It made precision and accuracy of APM worse. In our experiment, baking at 350C is suitable for uranium particles in the safeguards sample.

Preparation of the particles containing isotope reference uranium for the determination of the low abundant U isotope ratios

Tomita, Jumpei; Tomita, Ryohei; Suzuki, Daisuke; Yasuda, Kenichiro; Miyamoto, Yutaka

KEK Proceedings 2022-2, p.154 - 158, 2022/11

https://lib-extopc.kek.jp/preprints/PDF/2022/2225/2225002.pdf

Precise determination of minor U isotopes (U and U) of particles from the safeguard environmental samples is powerful method for detecting the undeclared nuclear activities. In this study, preparation method of U particle was examined to utilize for the minor U isotope determination. The porous silica particles were used as the particle matrix and lutetium was mixed to the impregnation solution as U impregnation indicator for the particle picking. The result of the Scanning Electron Microscope indicated that the contacting the solution with Si particles overnight gently could produce the impregnated particles effectively rather than the mixing them with PFA stick.

Improvement of the return mapping algorithm based on the implicit function theorem with application to ductile fracture analysis using the GTN model

Mano, Akihiro; Imai, Ryuta*; Miyamoto, Yuhei*; Lu, K.; Katsuyama, Jinya; Li, Y.

International Journal of Pressure Vessels and Piping, 199, p.104700_1 - 104700_13, 2022/10

https://doi.org/10.1016/j.ijpvp.2022.104700

Elastic-plastic analyses based on finite element methods are widely applied to simulate the nonlinear behaviors of materials. When the analysis is conducted by an implicit method, the stress values are generally updated with a time increment by using the so-called return mapping algorithm. This algorithm requires solving simultaneous nonlinear equations related to a constitutive model. In the present paper, we proposed a general method to reduce the number of equations in the return mapping algorithm based on the implicit function theorem. In addition, the proposed method was applied to the Gurson-Tvergaard-Needleman (GTN) model that considers the influence of damage due to nucleation and growth of microscopic void in materials in the simulation of the nonlinear behaviors. By using the GTN model with the proposed method, an elastic-plastic analysis was performed by the implicit method for a 4-point bending test of pipe with a through-wall crack. The numerical solution of the variation of the load-load line displacement from the analysis agreed with experimental result. Thus, we concluded that the proposed method is useful for simulating nonlinear behaviors, including void nucleation and growth in materials.

An Examination of rapid analysis of Ra in natural water samples by ICP-MS

Tomita, Jumpei; Ozawa, Mayumi; Ohara, Yoshiyuki; Miyamoto, Yutaka

KEK Proceedings 2021-2, p.130 - 134, 2021/12

https://lib-extopc.kek.jp/preprints/PDF/2021/2125/2125002.pdf

no abstracts in English

Age determination analysis of a single uranium particle for safeguards

Suzuki, Daisuke; Tomita, Ryohei; Tomita, Jumpei; Esaka, Fumitaka; Yasuda, Kenichiro; Miyamoto, Yutaka

Journal of Radioanalytical and Nuclear Chemistry, 328(1), p.103 - 111, 2021/04

https://doi.org/10.1007/s10967-021-07626-x

An analytical technique was developed to determine the age of uranium particles for safeguards. After the chemical separation of uranium and thorium, the Th/U ratio was measured using single-collector inductively coupled plasma mass spectrometry and a U-based reference material comprising a certain amount of Th as a progeny nuclide of U. The results allowed us to determine the purification age of two certified materials, i.e., U-850 and U-100, which was in good agreement with the reference purification age (61 y). Moreover, the age of a single U-850 particle was determined with a difference of -28 to 2 years from the reference date.

Technology demonstration of sampling from reactor core structure of FUGEN Decommissioning Engineering Center

Iwai, Hiroki; Soejima, Goro; Takiya, Hiroaki; Awatani, Yuto; Aratani, Kenta; Miyamoto, Yuta; Tezuka, Masashi

Dekomisshoningu Giho, (61), p.12 - 19, 2020/03

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_61.pdf

FUGEN Decommissioning Engineering Center received the approval of the decommissioning plan in 2008, and we have been progressing the decommissioning. The first phase of decommissioning (Heavy Water and Other System Decontamination Period) finished in March 2018, and FUGEN has entered into the second phase of decommissioning (Reactor Periphery Facilities Dismantling Period). This report outlines the technology demonstration of sampling from reactor core structure of FUGEN that to prepare for reactor dismantlement in the third phase.