[en] Problems of seismic safety and stability of the NPP components are discussed. Main provisions of safety standards being in force in Japan since 1978 are considered. Main specifications of the large-scale vibration-testing machine constructed for testing the mockups of the main components of NPPs with PWP and BWR reactors are given. In accordance with the rules of aseismic component design each element of a reactor must preserve its integrity under any possible seismic effects. Depending on the degree of radioactive contamination of environment resulted from the earthquake, the nuclear reactor equipment is divided into four classes. All buildings, accessories, pipelines and other equipment are also devided into four classes. The rules involve the estimation of seismic stability of components by the statical method on the base of the seismic stability coefficient established by the building standards. The method of ''time historical analysis'', in which the seismic design waves are used as input signals, is applied for the dynamic analysis of buildings; and for the equipment, pipelines and other elements the method of ''spectral analysis'' is used. In the future it is suggested to carry out the fundamental investigations of the NPP equipment safety and reliability, supported by corresponding experimental data, both from the point of view of arizing stresses and serviceability of all components directly at the moment of the earthquake beginning

[en] Since the first operation of the first Japanese nuclear power plant with a gas-cooled reactor of 160 MWe questions about safety and solidity of nuclear power plants in case of earthquakes kept taking an important part in the consultation committee for nuclear safety in Japan. On the basis of latest success in seismology and geology, of experience in construction, and of results from experimental research, respective standards have been worked out and published in 1978. (orig.)

[en] The state of the art on the latest aseismic design guidelines, design procedures, and the aseismic safety evaluation for nuclear power stations in Japan are outlined. Details are also given of a new series of tests on equipment and components to be performed on a large-scale vibration table now under construction. It is expected to be completed this year. (author)

No abstract available

[en] As the input earthquake motion for seismic design of nuclear power plant structures and equipments, an artificial time history compatible with smoothed design response spectrum is frequently used. This paper deals with a wave generation technique based on phase characteristics in earthquake accelerograms as an alternate of envelope time function. The concept of 'phase differences' distribution' is defined to represent phase characteristics of earthquake motion. The procedure proposed in this paper consists of following steps; (1) Specify a design response spectrum and derive a corresponding initial modal amplitude. (2) Determine a phase differences' distribution corresponding to an envelope function, the shape of which is dependent on magnitude and epicentral distance of an earthquake. (3) Derive the phase angles at all modal frequencies from the phase differences' distribution. (4) Generate a time history by inverse Fourier transeform on the basis of the amplitudes and the phase angles thus determined. (5) Calculate the response spectrum. (6) Compare the specified and calculated response spectra, and correct the amplitude at each frequency so that the response spectrum will be consistent with the specified. (7) Repeat the steps 4 through 6, until the specified and calculated response spectra become consistent with sufficient accuracy. (orig.)

[en] In probabilistic seismic risk assessment for Zion nuclear power plant in USA, structural fragility analysis based on SRSS method (Square Root of Sum of Square method) was adopted for calculation of response factors of which safety factor consists. The advantage of adopting SRSS method is that it is possible, however approximately, to get maximum response value simply by using data of vibrational characteristics for system when spectrum characteristics for an earthquake are decided. In this paper, response factors relating to material properties of soil and structure, which make up safety factor, are calculated by simple method based on SRSS method and by detailed method based on MCS method (Monte Carlo Simulation method) respectively, and then the influence on probability of fragility for reactor building caused by the difference between both methods are investigated. As the result of comparison for response factors calculated by simple method and detailed method, it is cleared that, judging from engineering point of view, the difference of response factors between both methods are small enough, that is, the difference influences only a little on probability of fragility, so it is confirmed that SRSS method is available as simple method. (author)

[en] The intensity of gallium-67 scintiscans, lymphocyte counts in bronchoalveolar lavage fluid, and pathologic changes were studied in 26 patients with untreated pulmonary sarcoidosis. Noncaseating granulomas were recognized with significantly greater frequency in stage 2 (80 percent; 8/10 cases) than in stage 1 (43 percent; 6/14 cases). Alveolitis showed little relation to the roentgenographic stage. There was a strong correlation between the intensity of gallium uptake in pulmonary parenchyma and the detection rate of granuloma; however, the detection rate of alveolitis was not statistically different from the intensity of gallium uptake. A highly significant correlation was revealed between the lymphocyte counts in bronchoalveolar lavage fluid and the intensity of alveolitis. These observations suggest that the gallium uptake reflects mainly the presence of granuloma, and the lymphocyte count in bronchoalveolar lavage fluid reflects the intensity of alveolitis in patients with pulmonary sarcoidosis

[en] The criteria is composed of the following six chapters. 1. General 2. Design 3. Materials for Reinforced Concrete and Prestressed Concrete 4. Construction of Reinforced Concrete and Prestressed Concrete 5. Liner 6. Structural Integrity Test of Concrete Containment This paper describes the gists of the drafted criteria, placing emphasis on the items peculiar to Japan. The draft is not intended to be a final one, but shall be corrected as the experiences concerning design and construction are accumulated in the future. (orig./HP)

[en] One of the earthquake motion simulations computer generated is termed the wave superposition method. Its elemental wave amplitudes are determined by target convergent calculation on some smoothed response spectra. Phases are usually given with uniform random numbers. We seldom experienced on response spectrum over the level of the target response spectrum with lower damping. We therefore established a generation method to fit the response spectra simultaneously with 2 kinds of damping. (orig.)

[en] The paper provides a methodology for generating simulated earthquake ground motions, whose response spectra of different damping ratios are fitted to respective target response spectra. A parametric study was performed to investigate the influence of phase difference probability distribution breadth upon the low damping response spectra. Then, it was found that the greater the phase difference distribution breadth, the higher the 1% response spectrum value tends to be, while the simulated motion 5% response spectrum is well matched to that for the target. In practical procedures, narrower phase difference distributions in several frequency bands can be employed to reduce the response spectrum value for low damping without changing the time history envelope form. This technique could lead to considerable improvement in fitness to the target response spectra with various damping ratios, which was confirmed in comparison with a simulated motion generated by the conventional method and one generated by utilizing the impulse phase for a certain frequency range. These simulated motions are exemplified in figures showing time histories and response spectra and also in terms of floor response spectra for a nuclear power plant. (orig./HP)