A lead-bismuth alloy is promising as a coolant of the FBR and a spallation target material. An electromagnetic flow meter is used as a composition apparatus of that lead-bismuth testing device. As for the lead-bismuth, corrosion to the structure metal is a problem. Though stainless steel is the corrosion resistance metal, It was known that it corrode in the lead-bismuth of 500℃. Therefore, it is desirable to use it in less than 500℃. But, when temperature of lead-bismuth is less than 400℃, wettability of the lead-bismuth to the stainless steel get poor. The wettability of the electrode becomes unstable, too. Therefore, output of the EMF changes every time. The problem of the unstable wettability has already been solved by the Rh plating electrode. But, the Rh plating electrode, which improved wettability, has the possibility to make it produce the corrosion of the electrode. Therefore, we must evaluate rate of the corrosion about the Rh plating electrode. We soaked a Rh plating electrode into the melting lead-bismuth of 400℃, and rotated an electrode at a speed of 1m/s, and investigated the degree of the corrosion after the examination. As a result, after seventy-hour examination, 5μm corrosion was seen. After this, a long test will be done.
The present paper describes the damage behavior caused by cavitation in flowing liquid sodium using venturi test section. The venturi test section was made from 316 SS with an inner diameter of 6.5 mm and a length of 20 mm. The experiment was conducted with pressure of argon cover gas in the expansion tank ranging from 105-110 kPa. The liquid sodium temperature was kept at 200°C and the sodium flow rate was 27-28 L/min, which corresponded to developed cavitation condition with the cavitation coefficient of 0.59-0.51. This condition was kept for 600 hours during the experiment. The results showed that cavitation bubbles collapse created damage on the inner surface of the venturi test section in the form of pits due to eroded surfaces. Under SEM, most of the pits on the inner surface of the venturi test section were in the sizes of around 25 µm. Some pits with sizes larger than 25 µm were also observed with the largest diameter around 110 µm which indicated intense collapse of cavitation bubbles. Observation on the inner surface of the test section also indicated some micro cracks, which might be caused by the cyclic process of the formation and collapse of the bubbles during cavitation process.
A breeder blanket, whose purposes are to breed tritium and to produce thermal energy, is indispensable for a fusion reactor. In addition to demonstrating the physics of burning D-T plasmas, an experimental reactor such as the ITER will also conduct a verification test of a blanket design. An in-pile functional test has been considered to obtain above engineering data since 1992 in the JMTR project. The sweep gas system which is a system to measure and recover the tritium released from a blanket mock-up has been designed. From the results of the design, the sweep gas system will be sufficient for the in-pile functional test in the JMTR.
The carrier transport properties in metal-oxide (top oxide) nitride-oxide (tunnel oxide) silicon (MONOS) memory structures have been investigated in steady-state conditions under negative gate bias voltage. Carriers were separated into holes and electrons utilizing an induced junction of the p-channel MONOS transistors. Two-carrier transport is confirmed in the structure at negative gate polarity. It is found that the relatively thick top oxide acts as a potential barrier to the holes injected from the Si into the thin nitride. It is also found that a portion of the electrons injected from the gate at negative gate polarity recombine with the holes injected from the Si even in such a thin nitride and/or at the top-oxide/nitride interface.< >
Improvement of the sound quality for home VCRs has been strongly desired. As the tape velocity becomes smaller according to the high density recording, the conventional fixed sound head gives poor quality in S/N and frequency response. It is well known that the sound quality is greatly improved by recording the sound signal with rotary heads. Using this concept, FM sound multiplex recording system has been developed and standardized in the 8mm VCR system in March 1983. 1), 2)
We developed EBAS-100, which is available to 100 mm diameter SiC wafer, for post ion implantation annealing in order to realize silicon carbide (SiC) device with large volume production. EBAS-100 is able to perform the rapid thermal process due to the vacuum thermal insulation and small heat capacity of susceptor. Electrical power consumption density was 18.8 Wh/cm2 for EBAS-100, which is one-third smaller than that of our previous system (EBAS-50). Samples used in this study were p-type epitaxial 4H-SiC (0001) grown on 8o off SiC substrate. P+ ions (total dose; 2.0 x 1016 /cm2, thickness; 350 nm) were implanted into SiC samples at 500 oC. The root-mean-square (RMS) of surface roughness is estimated to be 0.21 nm for the sample annealed at 1700 oC for 5 min, which is much smooth than that of the sample annealed by the conventional RF inductive annealing (RMS value: 5.97 nm). Averaged sheet resistance (RS) value of 63.3 ohm/sq. is obtained with the excellent non-uniformity of RS (+/- 1.4 %) for the diameter of 76.0 mm.
