Atom probe tomography (APT) has been performed on Fe-1.4Mn0.6Ni (at%) model alloy to study solute elements behavior under 2.8 MeV Fe ions at 400 0C. Orientation imaging microscopy (OIM) analysis is applied on the detector hit map to determine the pole figure supporting for orientation calculation. The three-dimensional images show that Mn and Ni solute atoms are distributed close to some certain planes, namely <111> and <100> families. This arrangement of solute atoms on the habit planes of interstitial loo...
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Anisotropic distribution of solute elements in ion － irradiated reactor pressure vessel model alloy

To assess radiological consequences, first an evaluation of the source term (i.e. activity release into the environment) has to be performed. This is followed by atmospheric dispersion calculations and dose assessment for the population. There are different purposes for a radiological consequence analysis, among which is the design and licensing of a nuclear installation as well as emergency preparedness and emergency response. For the different purposes, dedicated software tools are needed, which have...
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AREVA Computer Codes for Radiological Consequence Analysis

In recent years, inverter controlled rotating machines are becoming major for saving energy and maintenance labor. Up to now many kinds of methods about diagnosing rotating machines are proposed, but most of them are applicable only for machines rotating at constant speed. When rotating speed change, the acceleration signal measured for diagnosis becomes quite different. And applying the reviously proposed methods to invertercontrolled machines is difficult. So, in this paper, the method in which the diagno...
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Automatic Diagnosis Method for Inverter Controlled Rotating Machinery Using DP Matching, Histogram of Frequency Domain and Principal Component Analysis

The present study discusses electromagnetic characteristics of modeling thermal fatigue crack in numerical simulation from view point of eddy current testing. Two thermal fatigue cracks introduced into SUS304 stainless steel plates are investigated. Eddy current signals are gathered by a differential plus point probe with several frequencies, 50 kHz, 100 kHz and 400 kHz. In the numerical simulation thermal fatigue crack is modeled as a region with constant width, true profile revealed by results of destruc...
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Investigation on electromagnetic characteristics numerical simulation by eddy current testing

The PD Center of Central Research Institute of Electric Power Industry (CRIEPI) commenced performance demonstration examinations (PD examination) for flaw depth sizing of austenitic stainless steel pipes in March 2006. At the end of FY 2015, 44 examination sessions have been completed and 58 candidates have passed the examination. The total number of PD examinee including re-tests and re-certification was 104. Passed candidates can perform depth sizing of SCC flaws with a high level of accuracy during ...
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Implementation report for 10 years after the start of Japanese performance demonstration examination

Temper bead welding (TBW) is one effective repair welding method for the large-scale nuclear power plants instead of post weld heat treatment (PWHT). Consistent Layer (CSL) technique is the theoretically most authoritative method among the five temper bead welding techniques. For TBW, toughness is the key criteria to evaluate the tempering effect. A neural network-based method for toughness prediction in heat affected zone (HAZ) of low-alloy steel has been investigated to evaluate the tempering effect...
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Prediction of Toughness in HAZ produced by Temper Bead Welding of Consistent Layer Technique

Abstract : In this research, the performance and efficiency of a centrifugal pump under operation are diagnosed with high precision by measurement of electric current, voltage, flow rate, and pressure. Moreover, mechanical faults (misalignment etc.) and the faults in fluid (cavitation etc.) were diagnosed precisely with the vibration signals, and the reason of efficiency fall was clarified theoretically and experimentally. In this report, we proposed the condition diagnosis method for pump equipment by...
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Condition Diagnosis Method and of Efficiency Trend in Fault State for a Centrifugal Pump

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

Progressive deformation (ratcheting) is one of the failure modes by excessive seismic loadings. These occurrence conditions seem to be similar to the conditions for thermal ratcheting which is called Bree’s diagram. After experiments for ratcheting have done, there were similar results with Bree diagram in some frequency of input waves and not in other frequency. This paper shows detail results by numerical analysis and gives three frequency regions to clarify different characteristics in dynamic load...
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Progressive deformation by dynamic loadings and effects of frequency

Abstract : Structural faults are often occurring in a rotating machine, such as, u nbalance, misalignment and looseness etc., and their feature spectra of vibration signal appear in the low frequency area. The precise diagnosis for the structural faults type is difficult in the real plant, because of the noise in the vibratio n signal and the complex structure of the plant machine. In this study, we propose d the precise diagnosis method of structural fault for rotating machinery using en veloped wave spec...
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Precise Diagnosis Method of Structural Fault for Rotating Machinery Using Enveloped Wave Spectra, Signal Fusion and LSM Principal Component Analysis