Observation of aerosol particle capturing behavior near gas-liquid interface

Uesawa, Shinichiro; Yoshida, Hiroyuki

Mechanical Engineering Journal (Internet), 7(3), p.19-00539_1 - 19-00539_9, 2020/06

https://doi.org/10.1299/mej.19-00539

Upgrading of recovery method for radioactive microparticles by heavy liquid separation aiming to volume reduction of contaminated soil (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; University of Tsukuba*

JAEA-Review 2019-023, 33 Pages, 2020/01

JAEA-Review-2019-023.pdf:1.97MB

CLADS, JAEA, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the 'Upgrading of Recovery Method for Radioactive Microparticles by Heavy Liquid Separation Aiming to Volume Reduction of Contaminated Soil'. After the accident of the Fukushima Daiichi Nuclear Power Station, radioactive cesium has been heterogeneously distributed in surface soil due to the existence of radioactive microparticles and clay minerals. Therefore, the selective removal of these microparticles will lead to the volume reduction of contaminated soil. The present study examines methods for selectively removing radioactive microparticles from soil. Also, in order to reduce the volume of contaminated soil, we search a possibility to practically apply the separation method that uses the difference in specific gravity of particles (heavy liquid separation method).

Experimental evaluation of wall shear stress in a double contraction nozzle using a water mock-up of a liquid Li target for an intense fusion neutron source

Kondo, Hiroo*; Kanemura, Takuji*; Park, C. H.*; Oyaizu, Makoto*; Hirakawa, Yasushi; Furukawa, Tomohiro

Fusion Engineering and Design, 146(Part A), p.285 - 288, 2019/09

https://doi.org/10.1016/j.fusengdes.2018.12.047

Herein, the wall shear stress in a double contraction nozzle has been evaluated experimentally to produce a liquid lithium (Li) target as a beam target for intense fusion neutron sources such as the International Fusion Materials Irradiation Facility (IFMIF), the Advanced Fusion Neutron Source (A-FNS), and the DEMO Oriented Neutron Source (DONES). The boundary layer thickness and wall shear stress are essential physical parameters to understand erosion-corrosion by the high-speed liquid Li flow in the nozzle, which is the key component in producing a stable Li target. Therefore, these parameters were experimentally evaluated using an acrylic mock-up of the target assembly. The velocity distribution in the nozzle was measured by a laser-doppler velocimeter and the momentum thickness along the nozzle wall was calculated using an empirical prediction method. The resulting momentum thickness was used to estimate the variation of the wall shear stress along the nozzle wall. Consequently, the wall shear stress was at the maximum in the second convergent section in front of the nozzle exit.

SCHERN: Analysis program for chemical behavior of nitrogen oxide in accident of evaporation to dryness by boiling of reprocessed high level liquid waste in Fuel Reprocessing Facilities

Hiyama, Mina*; Tamaki, Hitoshi; Yoshida, Kazuo

JAEA-Data/Code 2019-006, 17 Pages, 2019/07

JAEA-Data-Code-2019-006.pdf:1.84MB

An accident of evaporation to dryness by boiling of high level liquid waste (HLLW) is postulated as one of the severe accidents caused by the loss of cooling function at a fuel reprocessing plant. In this case, volatile radioactive materials, such as ruthenium (Ru) are released from the tanks with water and nitric-acid mixed vapor into atmosphere. In addition to this, nitrogen oxides (NOx) are also released formed by the thermal decomposition of metal nitrates of fission products (FP) in HLLW. It has been observed experimentally that NOx affects strongly to the transport behavior of Ru at the anticipated atmosphere condition in cells and/or compartments of the facility building. Chemical reactions of NOx with water and nitric acid are also recognized as the complex phenomena to undergo simultaneously in the vapor and liquid phases. An analysis program has been developed to simulate chemical reaction coupled with the thermo-hydraulic condition in the flow paths in the facility building.

Observation of aerosol particle behavior near gas-liquid interface

Uesawa, Shinichiro; Miyahara, Naoya; Horiguchi, Naoki; Yoshida, Hiroyuki; Osaka, Masahiko

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 5 Pages, 2019/05

Spectrochemistry of technetium by liquid electrode plasma optical emission spectrometry and its applicability of quantification for highly active liquid waste

Yamamoto, Masahiko; Do, V. K.; Taguchi, Shigeo; Kuno, Takehiko; Takamura, Yuzuru*

Spectrochimica Acta, Part B, 155, p.134 - 140, 2019/05

https://doi.org/10.1016/j.sab.2019.03.014

The emission spectra of technetium (Tc) by liquid electrode plasma optical emission spectrometry have been investigated in this study. From the spectra, 52 emission peaks of Tc were observed in the 250-500 nm wavelength range. All peaks were assigned to the neutral state or singly ionized state. The relative intensities of these peaks were similar to those excited by an electric spark. The strongest intensity peaks were found at 254.3 nm, 261.0 nm, and 264.7 nm. Spectral interferences of coexisting elements in highly active liquid waste of reprocessing stream on those three strongest peaks were investigated using simulated sample. No spectral interferences were observed around the 264.7 nm Tc peak. Therefore, analytical performance using 264.7 nm peak was evaluated. The detection limit, estimated on standard and blank samples in 0.4 M nitric acid, was 1.9 mg/L. The relative standard deviation of Tc standard sample (12.0 mg/L) was 3.8% (N = 5, 1).

Conceptual design and verification of long-distance laser-probe system for Li target diagnostics of intense fusion neutron source

Kondo, Hiroo*; Kanemura, Takuji*; Hirakawa, Yasushi; Furukawa, Tomohiro

Fusion Engineering and Design, 136(Part A), p.24 - 28, 2018/11

https://doi.org/10.1016/j.fusengdes.2017.12.015

In the IFMIF-EVEDA project, we designed and constructed the IFMIF-EVEDA Li Test Loop (ELTL), and we performed experiments to validate the stability of the Li target. This project required a diagnostic tool to be developed in order to examine the Li target; as such, we developed a unique laser-based method that we call the laser-probe method; this method combines a high-precision laser distance meter with a statistical data analysis method. Following the successful development of the laser-probe method, we proposes a long-distance-measurement of the laser probe method (long-distance LP method) as a diagnostics tool in off-beam conditions for IFMIF or the relevant neutron sources. In this study, the measurement uncertainty resulting from coherency of the laser in a long-distance-measurement has been verified by using stationary objects and a water jet simulating the liquid Li target.

Development on high-power spallation neutron sources with liquid metals

Futakawa, Masatoshi

Proceedings of 13th International Symposium on Advanced Science and Technology in Experimental Mechanics (13th ISEM'18) (USB Flash Drive), 6 Pages, 2018/10

Issues on the engineering technologies relating to high-power spallation neutron sources with liquid metals are introduced. The present status on research activities and results was reviewed.

Local gas-liquid two-phase flow characteristics in rod bundle geometry

Xiao, Y.*; Shen, X.*; Miwa, Shuichiro*; Sun, Haomin; Hibiki, Takashi*

Konsoryu Shimpojiumu 2018 Koen Rombunshu (Internet), 2 Pages, 2018/08

In order to develop constitutive equations of two-fluid model in rod bundle flow channels, experiments of adiabatic air-water upward two-phase flow in 66 rod bundle flow channel were performed. Local flow parameters such as void fraction, interfacial area concentration (IAC) and so on were measured by a double-sensor optical probe. The area-averaged void fraction and IAC data were compared with the predictions from a drift-flux model and an IAC correlation.

Quantitative determination of total cesium in highly active liquid waste by using liquid electrode plasma optical emission spectrometry

Do, V. K.; Yamamoto, Masahiko; Taguchi, Shigeo; Takamura, Yuzuru*; Surugaya, Naoki; Kuno, Takehiko

Talanta, 183, p.283 - 289, 2018/06

https://doi.org/10.1016/j.talanta.2018.02.023

We develop a novel analytical method employing liquid electrode plasma optical emission spectrometry for measurement of total cesium in highly active liquid wastes. Limit of detection and limit of quantification are 0.005 mg/L and 0.02 mg/L, respectively. The method is validated and applied to the real samples.