new electromagnetic method for the nondestructive evaluation of electric pumps with ball bearings is roposed. A permanent magnet generates a static magnetic field and a coil of several hundred turns wrapped round it is used to pick up eddy currents induced inside rotating ball bearings and impellers. First, a method hat make use of the autocorrelation is applied to the signals of the ball bearings. A relation between therocessed signals and the size of the defects in the bearings is obtained. In a second...
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Electromagnetic Nondestructive Detection for Wounded Bearings and Impellers andCorrelation of Size of Defect and Signal

1. はじめに米国では、リスク概念を導入した確率論的安全評 価 (PSA) を原子力発電所の安全管理に利用し合理化を 進めている。ASME Section XI(維持規格) については、 すでに確率論を導入し合理的な保守管理に入っており、 Section II (設計・建設規格)についても、今後確率 論を導入した合理的な規格に改定していくことを計画 している。日本では、原子力配管設計においては、これまでASME Section IIを参考にして設計技術基準を定めてきた。 現行の ASME の手法は主に決定......
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Study on Prediction of Thickness in Nuclear Reactor Piping and Estimation of Inspection Intervals by Applying Reliability-base Method

A research project in ASME is developing a technical basis for reliability-based load and resistance factor design (LRFD) methods for piping in nuclear power plant. In LRFD, the probabilistic properties of load and resistance of components are taken into considerati on. There are several advantages in LRFD methods comparing to the traditional design methods based on the deterministic theory. In th is document theoretical basis of LRFD is discussed and the present research progress in ASME is reviewed based...
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Load and Resistance Factor Design For Piping of Nuclear Power Plant

In the present study, effect of spurious diagnostics to improvement of safety, and po ssibility of extension in the interval of TBM (Time-Based Maintenance) by introducing CBM (Condition-Based Maintenance) and necessity of TBM were investigated. From these investigations, improvement of safety and reduction of maintenance cost can be seen....
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Study on Best-Mix of CBM and TBM Considering Effect of Spurious Diagnostics Using State Transition Model

The epochal electromagnetic nondestructive detection method was proposed. In that method a permanent magnet is zed to generate static magnetic field and a several hundred turn coil is used to detect the eddy currents induced inside ball bea rings. In the present study the signal procedure method of a autocorrelation method is also proposed in tion to that detection method and these methods are applied to observe and evaluate ball bearings wounded by grinder. erimental validatio ns are carried out using a c...
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Lectromagnetic Nondestructive Detection for Wounded Bearings and Proposalof the Signal Procedure Method for Estimating the Wound Width