S nuclear magnetic resonance spectra of uranium disulfide -US

Sakai, Hironori; Tokunaga, Yo; Haga, Yoshinori; Kambe, Shinsaku; Ramakrishna, S. K.*; Reyes, A. P.*; Rosa, P. F. S.*; Ronning, F.*; Thompson, J. D.*; Fisk, Z.*; et al.

JPS Conference Proceedings (Internet), 30, p.011169_1 - 011169_6, 2020/03

https://doi.org/10.7566/JPSCP.30.011169

Uranium disulfide -US showing a semimetal-to-semiconductor crossover has been investigated by the nuclear magnetic resonance (NMR) technique for S nuclei with the nuclear spin of . Since the natural concentration 0.76% of NMR active S nuclei is too dilute, the isotopic enrichment to 50% has been carried out for the single crystal growth. The S NMR spectra have been successfully obtained using a single crystal of -US with external fields along the crystallographic axis. The S sites assignments have been made based on these NMR spectra.

Photophysical property of -bis(thiocyanato)aurate(I) complexes in ionic liquids

Aoyagi, Noboru; Shinha, Yusuke*; Ikeda, Atsushi*; Haga, Yoshinori; Shimojo, Kojiro; Brooks, N. R.*; Izuoka, Akira*; Naganawa, Hirochika; Kimura, Takaumi; Binnemans, K.*

Crystal Growth & Design, 15(3), p.1422 - 1429, 2015/03

https://doi.org/10.1021/cg501792m

The photochemistry of a gold(I) thiocyanate complex has been investigated to determine the coordination structure in both the solid and liquid states. The coordination geometries of the supramolecular complex and the concomitant exciplex have mainly been analyzed by crystallographic analysis and X-ray absorption spectroscopy. The Au-S bond distance and Au-Au separation of the compound in the ground state and in the phosphorescent excited state were compared. Upon irradiation with UV light, the excimeric interactions were enhanced, resulting in a contraction of the Au-Au aurophilic distance. A broad luminescence spectrum was observed for the one-dimensional chain suprastructure. The time-resolved luminescence spectra indicated the entity of several oligomeric species in the crude liquid without neutral solvent molecules. In addition, EXAFS spectroscopy exhibited a slight change in the nearest Au-S distance due to the photo-switched transformation. The deformation of the (Au-Au)* exciplexes was not apparently promoted in the liquid state with the asymmetrical imidazoium cations having a non-local charge distribution in the present observation. This is plausibly due to a flexible molecular structure and a property in the liquid state. In conclusion, the photo-excited nature of the pseudo-one dimensional complexes is emerged in controlling bond distances among the supramolecular networks.

Exotic superconducting properties in the electron-hole-compensated heavy-fermion "semimetal" URuSi

Kasahara, Yuichi*; Iwasawa, Takuya*; Shishido, Hiroaki*; Shibauchi, Takasada*; Behnia, K.*; Haga, Yoshinori; Matsuda, Tatsuma; Onuki, Yoshichika; Sigrist, M.*; Matsuda, Yuji*

Physical Review Letters, 99(116), p.116402_1 - 116402_4, 2007/09

https://doi.org/10.1103/PhysRevLett.99.116402

Higher-order collinear interaction and magnetic excitation in the 5f localized system UPdSi

Metoki, Naoto; Koike, Yoshihiro; Haga, Yoshinori; Kaneko, Koji; Araki, Shingo; McEwen, K. A.*; Kogi, Masafumi*; Aso, Naofumi*; Lander, G. H.; Komatsubara, Takemi*; et al.

Journal of Physics; Condensed Matter, 15(28), p.S1957 - S1963, 2003/07

https://doi.org/10.1088/0953-8984/15/28/307

no abstracts in English

Optimization of neutron imaging plate

Haga, Yuko*; Neriishi, Keiko*; Takahashi, K.*; Niimura, Nobuo

Nuclear Instruments and Methods in Physics Research A, 487(3), p.504 - 510, 2002/07

https://doi.org/10.1016/S0168-9002(01)02204-5

no abstracts in English

Sodium Boiling Experiment in 37-Pin Bundle under Loss-of-Flow Conditions

Haga, K.*

PNC TN941 83-26, 11 Pages, 1983/02

PNC-TN941-83-26.pdf:0.84MB

A series of loss-of-flow experiments was conducted in an electrically heated 37-pin bundle which simulated a MONJU fuel subassembly. The flow was reduced exponentially by a pump power control system. The radial temperature profile at boiling inception showed a trapezoidal shape independent of the flow decay curve and heat flux. Boiling initiated at the top end of the heated section, then the bubble expanded mainly to the upstream central subchannels and to the downstream unheated section according to the expansion of the saturated temperature region. When the voided zone covered the whole flow cross-section, the growth and collapse of a piston-like bubble repeated and the inlet flow decreased rapidly keeping the oscillation expanding. Dryout occurred when the flow oscillation became large enough to cause temporary flow reversal. Although reentry of the liquid slug rewetted the dried pin surfaces, the subsequent flow reversal caused dryout again.

Scope of Presentations(3) : Third Specialists Meeting on Reactor Noise SMORN-3,1981 ASME Winter Annual Meeting,1981,ANS Winter Meeting

H.Inuji*; T.Ogino*; Haga, K.*; Kikuchi, Y.*

PNC TN941 82-53, 120 Pages, 1982/02

PNC-TN941-82-53.pdf:3.07MB

Out-of-pile experiments were carried out to study the feasibility of the local sodium boiling detection by use of temperature, flow and acoustic noises. The studies showed that the temperature fluctuation transferred the information of local sodium boiling to the end of the bundle, but little to the outlet. A new anomaly detection method, which used the algorithm of whiteness test of the residual time series data of autoregressive model, especially using flow fluctuation, was effective detecting the anomaly such as local sodium boiling. On the other hand, acoustic noises with local sodium boiling became much higher than the background such as the mechanical and flow noises. A waveguide method, which was utilized for the present experiments, was useful for the boiling detection.

Experiments on Local Core Anomaly Detection by Fluctuations of Temperature and Flow Rate at LMFBR FuelSubassembly Outlets

Haga, K.*; T.Ogino*; H.Inuji*

PNC TN941 81-18, 36 Pages, 1981/02

PNC-TN941-81-18.pdf:2.18MB

Several series of out-of pile safety experiments have been conducted using heater pin bundles. Sodium boiling, fission product (FP) gas release and local flow blockage phenomena were measured in the test sections of a sodium loop named SIENA at the Oarai Engineering Center, PNC. In almost all test sections an eddy current flow-meter and Chromel-Alumel thermocouples were installed at the outlet of the bundle for the convenience of monitoring. The alternating current components of the recorded signals were examined from the view point of local core anomaly detection. The simulated LMFBR fuel subassemblies were 37-pin or 61-pin bundle geometries, in which 6.5 mm diameter pins were heated for the axial length of around 450 mm. A 5 mm thick stainless steel plate was inserted in the heated region to form a blockage. The root mean square (RMS) value, and power spectral density (PSD) of the temperature and flow fluctuations, and the transfer function and coherence between temperature fluctuations were examined. The studies showed that the temperature fluctuation transferred the information on local boiling toward the end of the bundle, but hardly to the outlet. The temperature fluctuation at the outlet may be generated mainly by the turbulent mixing of the coolant flowing through the passage from the end of the bundle to the measured position. Consequently, it can be considered that the local boiling may be detected only when the local boiling region is large enough to affect the temperature distribution at the outlet of the bundle or generate global flow oscillations due to void formation and collapse. The burst type one-pin failure can be detected by the flow fluctuation.

Local Temperature Rise and Boiling Behavior Behind a Central Blockage in a Wire-Wrapped Pin Bundle

Haga, K.*; M.Uotan*; Yamaguchi, K.*; M.hori*

PNC TN941 80-131, 11 Pages, 1980/08

PNC-TN941-80-131.pdf:3.46MB

The succeeding series of central-type blockage experiments were completed by the present one with 61-pin bundle test section. The interpretations of the present test results and those of our previous bundle configurations were summarized in the present paper. Concerning the single-phase flow, an empirical formula was derived to estimate the temperature rises behind various central-type blockages: τU/d = 35.3 (D/p), where τU/d is the dimensionless residence time and D/p is the Ring Parameter newly introduced here. This formula was validated to be effective within the region up to x mockup scale (3.0<d<16.1 mm) and was also supported by the data of KfK and ORNL. It was guessed that the apparent peaking factor of temperature rises in the wake region that would be observed in case of bare bundle was about 1.5 and that the effect of three-dimensional distortion due to spacer wires was from 0.9 to 1.2. The estimation of peak temperature rise by the present formula and two kinds of constants led the conclusion that the central-type blockage will not cause local boiling without being detected by an in-core flow-meter. In case of sodium boiling two-phase flow, existence of a large boiling window could be identified through the experimental knowledge on oscillatory boiling and dry-out mechanism: the stable oscillatory behavior of a single bubble (or a cluster of bubbles) was never terminated untill the saturated region being widely built up enough to yeild the one-sided expansion of bubbly region and following clad melting. The oscillation improved the mass exchange between localized bubbly region and surrounding subcooled free stream region in compared with that under non-oscillatory conditions, and often relieved clads from melting.

Local Flow Blockage Experiments in 37-Pin Sodium Cooled Bundles with Grid Spacers

M.Uotan*; Haga, K.*; Kikuchi, Y.*; M.hori*

PNC TN941 78-141, 15 Pages, 1978/10

PNC-TN941-78-141.pdf:0.68MB

A series of out-of-pile experiments were conducted on local temperature rises due to non-heat generating blockages in 37-pin bundles. In the central blockage experiment, the central 24 subchannels of the bundle were blocked with a 5 mm thick stainless-steel plate at up-stream end of a grid spacer. The blocked area was 27% of the total flow area. In the edge blockage experiment, a stainless-steel plate blocked 39 subchannels of a 1/2 edge part of the cross-sectional area. In both cases of the central and the edge blockage, the pin surface temperature attained a local peak in the grid spacer behind the blockage and decreased with the distance from the blockage. The mass exchange rate and the coolant residence time in the wake rigions were evaluated from the observed temperature rises. The mass exchange rate per unit interface area behind the edge blockage agreed fairly well with that behind the central blockage. The dimensionless coolant residence time was found independent of Reynolds number except in the low number range, and the value obtained in the edge blockage experiment was about 2.4 times as much as that obtained in the central blockage experiment. when experimental results were extrapolated to the reactor condition, an edge blockage of more than 30% might cause local boiling in the wake region, while a central one would not cause local boiling in any blockage ratio less than 60 %. The temperature rises in the blocked grid spacer were also discussed.