[en] With use of the numerical simulation code for homogeneous turbulence (Trans5), which was optimized for a vector computer, parallelizing tools, techniques, and environments for parallel systems such as Paragon XP/S, vector system VPP500, and the other vector system Monte-4, which was developed by JAERI, are investigated. Parallel optimization effect of FFT on these different architectures is also reported. (author)

[en] The kpx is a program analyzer, developed as a common technological basis for promoting parallel processing. The kpx consists of three tools. The first is ktool, that shows how much execution time is spent in program segments. The second is ptool, that shows parallelization overhead on the Paragon system. The last is xtool, that shows parallelization overhead on the VPP system. The kpx, designed to work for any FORTRAN cord on any UNIX computer, is confirmed to work well after testing on Paragon, SP2, SR2201, VPP500, VPP300, Monte-4, SX-4 and T90. (author)

[en] A huge amount of gaseous tritium is used as fusion fuel in the fusion reactors. Fusion reactor materials are exposed to various chemical species of molecular, atomic, ionic tritium. A part of the tritium species adsorbs on the surface of materials and it diffuses into bulk. On the contrary, it diffuses from bulk toward the surface and releases from the surface of materials, when the chemical potential of tritium species in gas phase lowers. From the economical and safe view points, it is important to examine a tritium depth distribution caused by elemental processes such as adsorption, absorption, diffusion, and reemission. From this view point, the depth profile and total amount of tritium charged thermally into stainless steel were examined by -ray-induced X-ray spectrometry (BIXS) and a chemical etching method. The former method is able to measure nondestructively tritium trapped in surface layers of materials and it is very sensitive for changes in the surface tritium concentration, while the later method is a conventional method and it enable to evaluate the total distribution and amount of tritium in materials. When stainless steel was exposed to tritium gas under the given temperature and pressure conditions, both analysis Methods indicated that tritium concentration in the bulk was almost uniform, but the enrichment of tritium appeared in surface layers thinner than 200 nm. The tritium concentration in surface layers was higher 100 times and more than that in bulk. Namely, the former tritium distribution indicates that an equilibrium state of dissolution was achieved, while the latter one indicates that a large amount of trapping sites existed in surface layers. Such a different tritium distribution has a possibility affecting the dynamic behavior of tritium in materials. (authors)

[en] The measurement of level in the liquid nitrogen vessel has been carried out by the weight conversion method using weigher or by putting directly a stick in the vessel. On a large CE tank, the pressure difference was read by manometer. These methods can not be used when the vessel does not put on the weigher or the pipe for manometer is stopped. We noticed the interaction between radiation (γ-ray) and substance and applied it to determine the liquid nitrogen level. The results proved it the easy method for measurement of the level in the large CE tank. Cesium 137 (γ-ray energy: 662 keV) was used as the radiation source. γ-ray transmission dose was determined by GM survey meter. The liquid nitrogen level could be determined by using the change of the transmission dose with amount of liquid nitrogen. (S.Y.)