18：00
19：30

ZHENG ZHIWEI

Development of Rapid and Efficient Extraction for Inert Platinum Group Metals by Designing Inner Sphere Coordination and Outer Sphere Interactions

High level radioactive waste (HLW) always contains several platinum group metals (PGMs) like Pd, Rh, and Ru. Separation of them is highly required, because they cause the serious problems in vitrification of HLW and have some isotopes showing long-lasting radioactivity. Additionally, high demands and limited availability of PGMs are concerned recently. It is highly relevant to recover and recycle PGMs from wasted materials like electronic devices and automotive catalysts. Solvent extraction is a promising method for the separation and recovery of PGMs, while extraction of some PGMs like Ru(III) and Rh(III) always shows slow kinetics and low efficiency. Based on these backgrounds and current issues, this presentation presents how to rapidly and efficiently extract inert PGMs from practical aqueous systems like HNO₃(aq) and HCl(aq).
In this study, I employed the thermal-assisted technique to accelerate the extraction of inert PGMs from aqueous solutions to ordinary organic solvents like 1-octanol. The ligands including pyridinediamides, picolinic acids and bipyridines were used as potential extractants. A realistic method named as complexation-distribution separated extraction process was proposed and demonstrated for the extraction of inert PGMs. As a result, extractability (E%) of Ru(III) and Rh(III) was more than 90% in 0.5 M HNO₃(aq)/1-octanol system employing a selected pyridinediamides as a ligand and bis(trifluoromethylsulfonyl)amide (Tf₂N⁻) as an anionic phase transfer catalyst (PTC). I also developed the extraction of inert PGMs in another practical aqueous system, HCl(aq). Even in this system, E% of Ru(III) and Rh(III) reached up to 79% with selected picolinic acid and bipyridine, respectively, under the presence of appropriate PTCs and salting-out agents. Eventually, I proposed and demonstrated process flows for separation and recovery of PGMs including Pd(II), Pt(IV), Ru(III) and Rh(III) from the acidic aqueous systems

10：00
11：30

CHIN Kim Wei

Non-destructive assay technology development using photofission reactions with bremsstrahlung photons for multi-nuclide composition assay in nuclear material

Strengthening the nuclear security is one of the essential issues in the world, and the development of non-destructive assay technologies are strongly demanded to detect the illegal transfer of nuclear material in the export control. One of the important technical challenges is to detect the non-intensive radio-ray emitting nuclear material such as highly enriched uranium, difficult to be measured by passive neutron or photon signals. A non-destructive assay technology was developed using photofission reactions with bremsstrahlung photons to detect the unauthorized nuclear material transfer. High energy photons can penetrate shields easily and the ratio of the photofission reaction by two distinct energies are correlated with the uranium enrichment. First, the principle of photofission reaction ratio was developed by expanding the interrogating photons to bremsstrahlung photons spectrum to detect highly enriched uranium. The neutron measurement noise caused by the (γ, 2n) reaction was studied too. Second, a new numerical methodology was proposed to assay a multi-nuclide system in nuclear material using multiple energy photons. The methodology was applied to detect U-Th multi-nuclide system using bremsstrahlung photons and its accuracy was evaluated on 19 different photon energy combinations. 7 – 11 – 13.5 MeV bremsstrahlung photons have successfully estimated the nuclides composition with relative composition error below 0.2%. Lastly, the measurement system requirement was deduced with neutron coincidence counting method, distinguishing photofission signal from the background neutron noise caused by bremsstrahlung photon source creation, photo-nuclear reactions by surrounded materials, and accidental injection to the neutron detectors.

11：45
13：15

大泉 昭人

加速器駆動システムを用いたTRU燃料サイクルの核不拡散性に関する研究

放射性廃棄物処分による環境負荷の低減に向けた加速器駆動システム(ADS)の開発が進められ
ているが、包括的な核不拡散性研究がなされていない。本研究では、ADSサイクルの潜在的核拡散リスクを定量化し、それを活用した核セキュリティ及び保障措置の設計要求と成立性を明らかにした。ADSサイクルの潜在的核拡散リスクの定量化評価手法を開発し、評価した結果、ADS燃料中のUやPuは既存のMOX燃料中のものとは異なる特性を有することを定量的に明らかにした。次に、潜在的核拡散リスク情報を活用し、核セキュリティ及び保障措置の設計要求と成立性を明らかにした。最後に、ADSサイクルの核セキュリティ及び保障措置の規制において、法律的、並びに技術的な課題を指摘した。

13：00
15：00

Thijs van
der Gaag

A study on continuum emission electron diagnostics in atmospheric pressure plasma

Atmospheric-pressure plasma studies have expanded the application fields of non-thermal equilibrium plasmas significantly. Numerous applications for this plasma have been found in medical treatments, agriculture, food processing, surface treatment and many other fields. However, diagnostics for this plasma are not yet fully developed. Due to its non-equilibrium characteristics, electron diagnostics of atmospheric-pressure plasma is essential, not only for understanding the state of the plasma but also for estimation of reactive radical densities in the plasma. A new electron diagnostics method is introduced that is capable of determining a partial electron energy distribution function (EEDF) from an optical emission spectroscopy (OES) measurement. For this, the continuum spectrum is used, which is dominated by electron-neutral bremsstrahlung emission at atmospheric pressure. This continuum spectrum is isolated from the OES measurement. A machine learning scheme is created to efficiently and accurately reconstruct this experimental continuum spectrum through simulation of the EEDF. From a visible-range OES measurement over the 300-800 nm wavelength range, a partial EEDF can be determined with high resolution in the 1.5-4 eV electron energy region. The potential of this novel diagnostics method is investigated, considering both experimental as well as computational limitations.

17：00
19：00

SARDINI SAYIDATUN NISA SAILELLAH

Study on Remote Elemental Analysis System for Aqueous Solutions using Sonoluminescence

After TEPCO's Fukushima Daiichi nuclear power plant accident, contaminated water has become an essential issue, and the harsh environment complicates the challenges. A study on a remote elemental analysis system for aqueous solutions contributes to the analysis of contaminated water is proposed. The analysis was based on a well-known ultrasonic phenomenon in liquid, sonoluminescence (SL). The study is divided into four steps. First, a study focused on the SL characteristics for elemental analysis in closed and stagnant conditions. An analysis of SL using an external transducer was conducted to confirm the performance for mobile analysis. Furthermore, an investigation of SL behavior in a flowing condition and its effect on the flow. Finally, a spectroscopic analysis using an optical fiber system was conducted to confirm the feasibility of remote elemental analysis using SL. The visualization and analysis using SL showed that specific light and wavelength were observed from each element. The study reveals the effect of each parameter changing on SL behavior, including the optimum working parameters. Further observation of the flowing condition indicates the effect of SL on the flow condition. Finally, the SL spectrum analysis using an optical system and SL using an external transducer in various conditions confirmed the remote elemental analysis.