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Suzuki, Satoru; Kawamura, Katsuyuki*
JNC TN8400 2001-005, 41 Pages, 2001/04
A correlation between molecular structure and a vibrational spectrum of interlayer water in Na-smectite was investigated by means of Molecular Dymamics (MDs) simulations. Detailed comparison of simulation results with IR spectroscopic observations for the water-smectite system indicated good agreement. Internal vibrational spectra of water were obtained by the Fourier transformation of velocty auto-correlation function of hydrogen atom. A stretching vibrational spectrum of interlayer water consisted of a broad band with a peak top around 3400cm
and a sharp peak around 3650 to 3700cm. The fomer broad band was assigned to O-H vibrations between water molecules as bulk water, while the latter band was attributed to O-H ones oriented to siloxane surface through hydrogen bonding. The hydrogen bond distance, determined as the shortest O-O distance by the radial distribution function (RDF), revealed that hydrogen bond distance between water and siloxane surface (O
-O
3.0 
-O = ca. 2.8 AA ). These results suggested that interaction between water molecule and siloxane surface weaker than that between water molecules, although they were forced to be oriented.
PNC TN9410 98-013, 48 Pages, 1998/03
Thermal striping phenomena characterized by stationary random temperature fluctuation are observed in the region immediately above the core exit of liquid-metal-cooled fast breeder reactors (LMFBRs) due to the interactions of cold sodium flowing out of a control rod (C/R) assembly and hot sodium flowing out of adjacent fuel assemblies (F/As). Therefore the in-vessel components located in the core outlet region, such as upper core structure (UCS), flow guide tube, C/R upper guide tube, etc., must be protected against the stationary random thermal process which might induce high-cycle fatigue. In this study, frequency characteristics of stationary random temperature fluctuations were investigated by the use of the time-series data from parallel impinging jet experiments, TIFFSS-I. From the investigations, the following results have been obtained; [Auto-Power Spectral Density Functions] (1)Higher frequency componets were decreased drastically with the close to the test piece surface, due to the presence of filtering effect by the laminar sub-layer and heat tansfer to the surface from coolant. (2)Dependence to the nozzle velocities was observed at the outside and inside positions of the laminar sub-layer region. It was due to the increasing of turbulent intensities with increase of the nozzle velocities. [Coherence Functions] (1)Coherency between outer temperatures of the laminar sub-layer was very small. 0ne of the main reasons is that the outer temperatures of the laminar sub-1ayer were dominated by the stationary random phenomena of turbulence flows. (2)It was confirmed that the coherency between immediate positions of different thermocouples had relatively higher values. [Transfer Functions] (1)The dominant frequency band of the gain was about 3 - 10 Hz for the transfer functions of the outer position to the inner position of the laminar sub-layer, and of the inner position of the laminar sub-layer to the test piece surface. (2)There wasno dependence of ...
