10：00
12：00

蛯沢 貴

自由表面液体リチウムターゲットを用いる加速器の真空特性に関する実験的研究

自由表面液体リチウムターゲットは、中性子生成量、ビーム熱負荷の冷却、ターゲット交換不要などの利点から、大強度中性子源加速器への利用が検討されているが、加速器部分は運転性能の維持のために10^-5 Pa以下の高真空を、ターゲット部分は液体リチウムの沸騰防止のために10^-4 Pa以上の圧力を維持する必要があることから、差圧維持やリチウム流入抑制の技術の確立が課題となっている。そして、さらなる大強度化に向けて超伝導高周波加速器を用いる場合には、高い清浄度と10^-6 Pa以下の超高真空を維持しなければならない。本論文研究では、差圧維持とリチウム流入抑制を両立する高エネルギービーム輸送系の設計をシミュレーションによりおこない、その加速器・ターゲット接続部を模擬する試験体系を準備して、実際に液体リチウムを流動させることで、研究目的である設計性能の実証と真空特性の変化を明らかにした。

13：30
15：30

STAFIE CATALIN ALEXANDRU

Study on small Rotational Fuel-shuffling Breed-and-Burn fast reactor with nitride fuel and lead coolant

This thesis explores the design of the equilibrium core and the implementation of a start-up core for a lead-cooled, nitride-fueled fast reactor utilizing the Rotational Fuel-shuffling Breed-and-Burn (RFBB) strategy. This innovative approach, rooted in initial equilibrium-state studies, aims to maximize fuel utilization and sustainability by enabling continuous breeding and burning of natural uranium. Based on the Westinghouse Lead Fast Reactor (WH-LFR), the RFBB reactor design initially uses High-Assay Low-Enriched Uranium (HALEU) nitride fuel, transitioning to natural uranium. The study confirms that this reactor configuration can sustain criticality with a refueling interval of 1050 Effective Full Power Days (EFPD), achieving an equilibrium discharge burnup of approximately ~230 MWd/kgHM.

17：00
19：00

小野 遼真

U(VI)-Pu(IV)選択的同時沈殿剤としての架橋ピロリドン誘導体の開発と次世代再処理への適用

10：00
12：00

Wang Jingting

Study on Stability Analysis of Non-axisymmetric Tokamak Plasma Equilibrium by 3-D Multi-layers Method

Tokamak-type magnetic field confinement fusion devices, such as ITER, are at the center of fusion research and development in the world, and thus far, analyzes have been based on toroidal axisymmetry. In recent years, the significance of non-axisymmetry in tokamaks has been acknowledged, leading to the growing importance of diverse three-dimensional effects in practical applications.
Hence, it is inevitable to use analysis codes developed for stellarator plasmas to examine the equilibrium and stability of three-dimensionality magnetohydrodynamic (MHD) in tokamaks. Currently, the most widely used 3D MHD balance code is the VMEC code, which uses the spectral method with a Fourier expansion for the angular variables over the magnetic surface. The VMEC code is presently used for 3D MHD balance calculations on most tokamaks. In contrast, VMEC uses magnetic coordinates, so it cannot be operated in the presence of a separatrix which is very important for tokamak devices. VMEC also does not compute stability.

18：30
20：30

ZHANG Yiwei

Investigation on Separation, Dissolution, and Aggregation Behaviors of Radioactive Elements Using Functional Microporous Microfluidic Devices

In order to ensure the safety of waste management and disposal of nuclear fuel debris generated by the accident of TEPCO’s Fukushima-Daiichi NPP, it is essential to understand the dissolution and denaturation behavior of colloidal radioactive particles derived from fuel debris, and to develop novel techniques and methodologies which enables precise separation and analysis of the radionuclides. General bulk-scale separation and analysis methods have disadvantages such as time-consuming operations and production of large amounts of secondary wastes, and difficult to examine the dissolution and denaturation behavior of the colloidal particles generated from fuel debris retrieval processes. To overcome such issues, this study aims to gain fundamental understanding of the unusual thermodynamic and kinetic phenomena underpinning the dissolution, aggregation, and denaturation process of simulated radioactive nanoparticles such as CeO₂ under various solution environments, and development of novel surface-functionalized porous materials, called as PDMS sponges, designed to enable selective adsorption and desorption of target lanthanide and molybdenum ions through controlling chemical-mechanical stresses, and clarify the superior adsorption-desorption abilities.

10：00
12：00

CHEN JINGDE

Study of Fission Product Yield by Deep Learning

Fission product yield (FPY), one of the most essential types of nuclear data, provides fundamental insights into the fission process and has various practical applications in nuclear engineering. However, due to discrepancies in theoretical calculations and limitations in experimental measurements, achieving consistent and systematic evaluations of the energy dependence of fission product yields still remains challenging. To address this issue, we developed a new method for predicting and evaluating FPY data using a Bayesian neural network (BNN) model, which integrates current evaluated nuclear data with prior nuclear physics knowledge and information. Specifically, we designed a shell factor representing the interaction between the shell effect and neutron multiplicities as prior physics information in the input layer to enhance the reliability of the BNN model. To further improve the model's versatility, the Watanabe-Akaike Information Criterion (WAIC) was applied to optimize the BNN model's configuration. Finally, by presenting the prediction results for FPY data of ²³²Th, ^233,235,238U and ^239,241Pu, as well as assessing indirect evaluations such as charge distributions and delayed neutron yields, the BNN model demonstrates its effectiveness and constructiveness in predicting unknown FPY data in the nuclear data field. Also, there is still room for improvement in the evaluation of FPY data between 8 MeV and 14 MeV, where the multi-chance fission effect becomes significant, and there is a lack of measured FPY due to the difficulty in creating a stable mono-energetic neutron source.

18：00
20：00

MILAI ENKHBAATAR

Whole genome sequencing-based mutation analysis of human cells in culture

DNA damage, if not repaired, can lead to mutations. Germline mutations cause hereditary effects and somatic mutations lead to cancer. While mutations have long been studied mainly through specific locus test (SLT) approach, the next generation sequencing (NGS) technology has enabled whole genome sequencing (WGS). Whereas there are an increasing number of mutation studies based on WGS in individual contexts for human and animal subjects, there have been a limited number of studies in cellular contexts. This study aimed to establish an experimental scheme enabling to apply WGS-based mutation analysis to cells in culture and, through it, to conduct quantitative and qualitative analysis of mutations induced by various types with varying dose rates. The primary clone was generated from a single cell and, then, the secondary clones were generated from a single cell in the primary clone. The comparison of the WGS results from the primary clone and secondary clones shows the mutations induced during the growth of the primary clone. WGS analysis revealed the mutation rates and spectra under varying radiation conditions, including γ-rays, X-rays and mixture of neutron and γ-rays in nuclear reactor at high dose rates and low dose rates. The results of this study provide novel insights into the mechanisms of radiation-induced mutagenesis and its impact on genomic stability over time.