Condition-based maintenance(CBM) is maintenance performed on the basis of the condition of the equipment. The transition to CBM being considered, it is necessary to make appropriate decision, such as judgment of normality or abnormality. The threshold approach has generally been used for the judgment, but it provides ambiguous decisions due to individual variability of the equipment. Diagnosis using Data Analysis is a promising method to detect variations of the condition of rotating machinery. In this meth...
英字タイトル:
Development of Diagnosis Method for Rotating Machinery by Data Analysis

Phased array ultrasonic testing (PAUT) has performed an important role for plant maintenances. However, many parts of cast austenitic stainless steels are difficult to be inspected by UT owing to their noises from large grains. We have been noticing that depending on the PAUT conditions, (e.g. incident angles and focal depths), the tendency of echoes from defects are different from that of grain noises. Thus we have developed new PAUT system which can analyze the tendency of echoes from comprehensive PA...
英字タイトル:
Sizing Accuracy Improvement of Defects in Cast Austenitic Stainless Steel Using Post Processing Phased Array UT

Abstract In operation of nuclear power plants (NPPs), it is required not only to preserve and improve the reliability and safety, but also to introduce more efficient and lower cost maintenance strategy simultaneously, due to the power trading deregulation in recent years. For this purpose, Condition Based maintenance (CBM), which has been extensively applied i n the nuclear power plant of U.S., is introduced as a maintenance method for rotating machines in Japanese nuclear power plant. TOSHIBA develops t...
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Development and application of Monitoring and Diagnosis Techniques for Condition Based Maintenance in Nuclear Power Plant

This paper introduces the simply applicable vibration diagnostic technique to a vertical type pump in nuclear power pla nts. This technique is the combination of simple shaft vibration measurement by an ultrasonic vibrometer and a rotor dy namics simulation. By using this technique, for vertical type pump, a simple and high-precision diagnosis is attained. It is expected that this technique has effect in cost reduction and improvement of reliability in nuclear power plants....
英字タイトル:
Vertical type pump diagnosis using an ultrasonic vibrometer

Abstract In operating of nuclear power plants, it is required not only to preserve and improve the reliability and safety, but also to introduce more efficient and lower cost maintenance strategy simultaneously, due to t he power trading deregulation in recent years. In addition, as the number of experienced operators / maintenance personnel decreases, comprehensive implementation of objective and transparent information provision syste m on plant operation and maintenance (O&M) being compliant with the la...
英字タイトル:
Development of Remote Operation & Maintenance Support service system

As use of condition-based maintenance is allowed in the new regulatory inspection system employed in Japan's nuclear pow er plants in 2009, development of advanced diagnostic technologies for motor-operated valves (MOVs) is now required. This report discusses advanced technologies in valve-setup verification, valve performance evaluation, monitoring of valve/ac tuator conditions by performance diagnostic system and moreover detection of stem crack by ultrasonic diagnostic system....
英字タイトル:
Development of Advanced Diagnostic Technologies for Motor-operated Valves