Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
*
JNC TJ8400 2000-017, 74 Pages, 2000/02
JNC-TJ8400-2000-017.pdf:1.71MB
The report concerns the improvement of the method measuring thermal conductivity of buffer materials using a thermistor probe and the measurement of thermal conductivity of compacted bentonites and mixtures of bentonite and silica sand using the proposed method measuring thermophysical properties. The method measuring thermal conductivity is improved in accuracy and the apparatus is improved so as to measure easily with more short time. The calculated values of the conventional correlations predicting thermal conductivity of bentonite and mixture were compared with the exising and present data of thermal conductivity of bentonites and mixtures. The correlation proposed by Sakashita and Kumada can predict the best fitted values with the data of the bentonites and Fricke and Bruggeman correlations are fitted with the data for the mixtures with practical accuracy.
; Hirakawa, Yasushi; Kano, Shigeki; Yoshida, Eiichi
PNC TN9410 98-048, 56 Pages, 1998/03
Planar specimens of functionally gradient material (FGM) for thermal stress relaxation in fast reactor environment were formed and evaluated. FGMs of Al
O
-SUS316L system and YO-SUS316L system were deposited on SUS316L substrates by low pressure plasma spraying. The deposited coatings with 6 layers in which the ratio of ceramics/SUS316FR changes from 0 to 100% by 20% were successfully formed. Cross-sectional observation of the coatings showed no cracks and the hardness in the coating increased continuously from the substrate to the surface. From the results of X-ray diffraction, there were no changes in the structure of SUS316L and YO between the powder and the coating. On the contrary, in the case of AlO, 
- AlO phase was detected in the coating formed from 
_
_
$ powder. The specimens were exposed in liquid sodium at 823K or 923K for 3.6Ms(1000h). The coatings were damaged with many cracks in liquid sodium. It was revealed that the bonding strength between the sprayed particles were not sufficient. To improve the stability in liquid sodium, another specimens were formed with changing the chamber pressure during deposition. From the microstructural inspections of the specimens, the coating formed at higher chamber pressure showed less porosity.
Wakai, Takashi; Aoto, Kazumi
PNC TN9420 97-003, 11 Pages, 1996/12
Generally, it is required several periods for the damage initiation due to erosion. Such periods are called incubation time. This report describes the calculation of incubation time for erosion of a carbon steel subjected to dripping liquid sodium at elevated temperature, assuming fatigue plays the significant role in the early stage of erosion. It is clalified that the incubation time is remarkably long and it is needless to consider the damage due to erosion if there is no material property degradation. However, taking the material property degradation of carbon steel and liquid sodium into account, the incubation time may be short less than 1 hour in the most pessimistic case. So in this case, erosion must be considered as one of the damage mechanisms of carbon steel.