This paper reports the results of an experimental examination using X-rays to test annealing materials for lapped bearing steel (STB2), to confirm the validity of the weighted averaging analysis method. The distribution behavior for the sin diagram and the presence or absence of differences in the peak method, half-value breadth method, and centroid method were investigated. When lapping the annealed bearing steel (STB2) material, a residual stress state with a non-directional steep gradient appeared in the surface layer, and it was found that the weighted averaging analysis method was effective. If there is a steep stress gradient, the sin diagram is curved and the diffraction intensity distribution curve becomes asymmetric, resulting in a difference between the peak method, half-value breadth method, and centroid method. This phenomenon was evident when the stress gradient was more than 2~3 kg/mm2/μm. In this case, if the position of the diffraction line is determined using the centroid method and the weighted averaging analysis method is applied, the stress value on the surface and the stress gradient under the surface can be obtained more accurately. When the stress gradient becomes a problem, since the curvature of the sin diagram appears clearly in the region of sin > 0.5, it is necessary to increase the inclination angle  as much as possible. In the case of a lapping layer, a more accurate value can be obtained by considering  in the weighted averaging analysis method. In an isotropic biaxial residual stress state, the presence or absence of  can be determined as the presence or absence of strain for sin≈0.4.

Recently, many people have become interested in seismic stability enhancement and a chain of research and development be proceed for application of nuclear power plant according to increase the frequency and magnitude of earthquake event. Such as seismic isolation system is applied to general structure (architecture, bridge and LNG tank etc.) from ancient times. But the application results is limited for Nuclear power plant. In this paper, we proposed a stability of variable axial load from beyond design basis earthquake in Nuclear power plant. Also, the change of stiffness in isolator from the application of generally design equation is not equal to according to change in axial load compare with the experimental result in variable axial load. Therefore we proposed the empirical formula of design equation from test result of full-scale multi-lead rubber bearing for seismic analysis with real behavior (variable axial load) in the earthquake motion.

This paper presents the basic data for the structural safety study of the extension wall by evaluating the bending stresses of the existing and extension walls varying according to the plan change of the extension building through the numerical analysis on the horizontal load as follows: 1) the stress variation of the divided wall when the wall opening due to a partial demolition is evaluated by comparing the result of analysis on whether or not the opening of the bearing wall is demolished as a variable; 2) the stress variation of the existing wall due to the increase of the stiffness of the extension wall is also evaluated by comparing the result of analysis on the thickness of the extension wall as a variable.