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.
It is shown that the motion of the plane rotator model should be described by a set of equations \(\ddot{\varphi}_{i}{=}I^{-1}\sum_{j}J_{ij}\sin(\varphi_{j}-\varphi_{i}),\quad i{=}1,2,\cdots,N\), and that the Hamiltonian should be H =∑ i p j 2 /2 I +∑ i < j J i j (1-cos (ϕ i -ϕ j )). To this Hamiltonian one can apply the method of molecular dynamics. For the case of the nearest neighbor interaction, energy-temperature curve is calculated for one, two and three dimensions. In one dimension our result agrees well with the exact solution. In two dimension a sharp peak of specific heat is found at T ∼1.1 J / k . In three dimension a singularity is observed at T ∼2.2 J / k .
