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Presents a study that applied computer simulation to determine damage processes during ion implantation. Background on the Marlowe computer code; Development of a computational model for the code; Analysis of the results of impact-collision ion scattering spectroscopy.

We examined the plasma flow response to meso- and microscale magnetic dipoles by performing three-dimensional full particle-in-cell simulations. We particularly focused on the formation of a magnetosphere and its dependence on the intensity of the magnetic moment. The size of a magnetic dipole immersed in a plasma flow can be characterized by a distance L from the dipole center to the position where the pressure of the local magnetic field becomes equal to the dynamic pressure of the plasma flow under the magnetohydrodynamics (MHD) approximation. In this study, we are interested in a magnetic dipole whose L is smaller than the Larmor radius of ions riL calculated with the unperturbed dipole field at the distance L from the center. In the simulation results, we confirmed the clear formation of a magnetosphere consisting of a magnetopause and a tail region in the density profile, although the spatial scale is much smaller than the MHD scale. One of the important findings in this study is that the spatial profiles of the plasma density as well as the current flows are remarkably affected by the finite Larmor radius effect of the plasma flow, which is different from the Earth's magnetosphere. The magnetopause found in the upstream region is located at a position much closer to the dipole center than L. In the equatorial plane, we also found an asymmetric density profile with respect to the plasma flow direction, which is caused by plasma gyration in the dipole field region. The ion current layers are created in the inner region of the dipole field, and the electron current also flows in the region beyond the ion current layer because ions with a large inertia can closely approach the dipole center. Unlike the ring current structure of the Earth's magnetosphere, the current layers in the microscale dipole fields are not circularly closed around the dipole center. Since the major current is caused by the particle gyrations, the current is independently determined to be in the direction of the electron and ion gyrations, which are the same in both the upstream and downstream regions. The present analysis on the formation of a magnetosphere in the regime of a microscale magnetic dipole is significant for understanding the solar wind response to the crustal magnetic anomalies on the Moon surface, such as were recently observed by spacecraft. [ABSTRACT FROM AUTHOR]

A shielding benchmark experiment has been performed to obtain the experimental data of neutrons penetrated through iron and concrete shields by using 140-, 250-, and 350-MeV p-Li quasi-monoenergetic neutrons. The quasi-monoenergetic neutrons were emitted from a 1-cm-thick Li target bombarded with 140-, 250-, and 350-MeV protons. The neutrons emitted in the forward direction were extracted into the time-of-flight room through a collimator of 12- x 10-cm aperture embedded in a 150-cm-thick concrete wall. The concrete and iron shield blocks were set at the exit of the collimator. Neutron energy spectra behind the shields were measured by a multimoderator spectrometer (3He proportional counter covered with polyethylene moderator of various thicknesses). Neutron energy spectra behind concrete and iron shields with different thicknesses were obtained down to thermal energy. The experimental results were compared with calculation results by the Monte Carlo simulation code PHITS. These experimental results will be useful as benchmark data to investigate the accuracy of various transport calculation codes. [ABSTRACT FROM AUTHOR]

This study has summarised electromagnetic disturbances of control circuits in power stations and substations experienced in Japan for ten years from 1990. Altogether 330 disturbances informed from Japanese utilities are classified by disturbed equipments and causes, and the surge incoming routes and the characteristics of the disturbances are investigated. Also, case studies are demonstrated. Finally, the influence of the disturbances to power system operation, countermeasures carried out and costs are presented. [ABSTRACT FROM AUTHOR]

The present paper summarises the tests that have been performed on type B packages by CRIEPI in Japan to conditions different from the regulatory test standard for impact, fire and immersion. A drop test of a spent fuel package with transport frame was performed. The drop height was 7·8 m and the target was reinforced concrete floor. Drop tests of spent fuel packages without impact limiters were performed. The drop heights were 1·5, 5·0 and 17 m and the target was a reinforced concrete floor. Dynamic crash tests simulating accidental drop of heavy object onto a spent fuel transport/storage package without impact limiters were performed. The heavy object was a slab made of reinforced concrete. The drop heights were 5 to 17 m. A thermal test was performed using a spent fuel package specimen. During the thermal test in a furnace, the environmental temperature increased up to 1000°C. An immersion test under a head of water at 3000 m for one hour was performed. The specimens were packages of spent fuel and high level wastes. In all the cases, the integrity of the specimens was maintained. [ABSTRACT FROM AUTHOR]

The design of small-sized single pass boilers is usually based on the construction code for small-sized boilers, in Japan. Design methods in this construction code and other country codes have not been clearly defined, although most of small-sized boiler's headers are constructed from two concentric circular shells and cover plates. Therefore, Finite Element Analysis (FEA) with a PC and measurement by strain gauges are mainly used in strength design of these boilers. In this study, a T type welded joint of SS400 was adopted for the header of small-sized single pass boilers. Fatigue testing and FEA was carried out. The fatigue limit was greater for base metal than for weldment. For the weldment, the S-N curve decreased with decreasing ρ value. The stress concentration at the toe was evaluated by the FEA. S-N curves for different toe curvature radii were re-drawn using maximum elastic stress, Ktσmax. Crack initiation occurred in the vicinity of the toe. Several small cracks were observed on the surface of T type welded joint fatigue specimen at N/Nf=0.42. These cracks coalesced together at a crack length of 10mm. Fatigue crack growth rate lineally increased with increasing (crack length)1/2. [ABSTRACT FROM AUTHOR]