Dr. Mainte, an integrated simulator for maintenance optimization of LWRs (Light Water Reactors) has been developed based on PFM (Probabilistic Fracture Mechanics) analyses in terms of safety, availability and economic efficiency, environmental impact and social acceptance. For the further improvement of maintenance activities, the importance of reducing human errors is often pointed out. Human errors are well recognized to be affected by mental stress conditions. Due to the amendment of Industrial Safe...
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Effects of Human Error and its Reduction Analyzed by Dr. Mainte, Integrated Simulator of Maintenance Optimization of LWRs 2

Dr. Mainte, an integrated simulator for maintenance optimization of LWRs (Light Water Reactors) has been developed based on PFM (Probabilistic Fracture Mechanics) analyses. The concept of the simulator is to provide a decision-making system to optimize maintenance activities for representative components and piping systems in nuclear power plants totally and quantitatively in terms of safety, availability and economic efficiency, environmental impact and social acceptance. For the further improvement ...
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Effects of Human Error and its Reduction Analyzed by Dr. Mainte, Integrated Simulator of Maintenance Optimization of LWRs

日立 GE 安藤 浩二 Kouji ANDOU Non-Member The new dry-well cooler (DWC) for a severe accident has been developed to avoid release of radioactive materials to environment caused by primary containment vessel failure. The DWC can be operated using natural driving force to remove decay heat. The element tests using copper tube bundle with 3 rows and 5 levels were conducted under existing nuclear power plant conditions to estimate heat removal ratio with non-condensable gas (N2) and to confirm occurrence of natu...
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Heat Removal Characteristics of Dry-well Cooler for a Severe Accident

This report describes an elasto-plastic analysis method which can be applied for the actual aseismic design of nuclear carbon steel piping systems. This analysis method follows the one developed by the related JSME tasks. Using this analysis method, the test result has been reproduced to the safe side for the strain range used as the intensity evaluation index of carbon steel piping. Furthermore, fatigue life has also been reproduced to the safe side by using the curve of fatigue of carbon steel piping upon...
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Investigation on Method of Elasto-Plastic Analysis for Piping System (No.1)

This paper discusses the feasibility of characterization of graphite morphology in gray cast irons based on electromagnetic method. For the pur pose, gray cast iron with different graphite morphology was systematically evaluated. In order to discuss electromagnetic property of gray cast iron with different graphite morphology, conductivity and permeability were measured. It was found that both conductivity and permeability mai nly depend on graphite morphology. It was shown that the graphite morphology of ...
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Characterization of graphite morphology of gray cast irons using electromagnetic method

In this study, we propose a novel EMAT-ECT multi sensor aiming at advanced structural health monitoring. For the purpose, proto-type EMAT-ECT multi-sensor was developed and their functions both as ECT and EMAT prove were evaluated. Experimental results of pulse ECT using the EMAT-ECT multi-sensor showed that the pr oposed sensor has a capability of detection and sizing of flaws. Experimental results of EMAT evaluation using the EMAT-ECT multi-sensor showed that ultrasoni c wave was transmitted by EMAT-ECT ...
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Development of novel EMAT-ECT multi-sensor and verification of its feasibility

Surface oxide behavior on alloys in high temperature plays an important role in the stress corrosion clacking (SCC) mechanism according to plausibl e existing SCC models. In this investigation, roughness analysis of oxide/alloy interface on stainless steels after exposure in oxygenated high pur ity water under high stress conditions. A special emphasis was placed on how the oxidation penetration localized and went through the surface harde ned layer. It was pronounced that SCC initiation on hardened layer ...
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Oxidation Behavior of Austenitic Alloys under High Stress Condition in High Temperature Water-Effect of Surface Hardened Layer

In this study, nickel-chromium binary alloys are used on the oxidation test in high temperature water to reveal the effect of chromium conten t on the oxidation behavior under high stress condition. It was shown that the oxidation behavior was affected by chromium content, stress co ndition and surface hardened layer. The feature which induced the localization of oxidation behavior was found on the oxide film of low chro mium alloys. It was thought that the presence of threshold conditions about chromium c...
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The Oxidation Behavior of Austenitic Alloys under High Stress Condition in High Temperature Water-Effect of Chromium Content

A sodium cooled fast breeder reactor (FBR) has unique systems and components and different degradation mechanism from light water reactor (LWR) so that need to establish maintenance technology in accordance with its features. The examination of the FBR maintenance technology is carried out in the special committee for considering the maintenance for Monju established in the Japan Society of Maintenology (JSM). As a result of the study such as extraction of Monju maintenance feature, maintenance technol...
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Principles of MONJU Maintenance - Characteristic of MONJU maintenance and reflection of LWR maintenance experience to FBR-