１．まえがき東海第二発電所（1978年11月営業運転開始）は、第21回定期事業者検査中の2005年（平成17年）5月、図１に示すシュラウドサポートシリンダ軸方向溶接継手（以下「V8」という）3箇所に応力腐食割れ（SCC）と推定される割れが確認され、（社）日本機械学会（以下JSME）の維持規格、及び（社）日本原子力技術協会（以下原技協）の炉内構造物点検評価ガイドライン（以下ガイドライン）を適用した評価により一定期間内の構造健全性を示し、割れを補修することなく継続使用し、3年、7年、10年経過後の最初の定......

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

After 2002, Stress Corrosion Cracking (SCC) came to be detected in the low carbon stainless steel PLR Piping of BWR plants. However, it worked on the improvement of ultrasonic examination technology for PLR Piping in Japan BWR Owners Group (JBOG) , because the mistake of the evaluation was caused as a rare case. In this study, it introduces the improvement of ultrasonic testing technology and evaluation....
英字タイトル:
Know-How for the Ultrasonic Examination Practice & Evaluation of PLR Piping

An effective countermeasure against stress corrosion cracks in nozzle welds is to improve the surface residual stress. A new tec hnique of the ultrasonic shot peening (USP) for steam generator (SG) nozzles will be introduced as a method to improve the residu al stress on Alloy 600 Welds. This method changes the compressive stress by applying plastic strain to the surface via the impac t force of the shot material during the shot peening. We have successfully performed 14 USP operations in actual plants in ...
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Application of Ultrasonic Shot Peening To Steam Generator Nozzles

Cracks were found at shroud support of Tokai II Power Station in 24th outage. Flaw evaluation of these cracks was performed applying Co des for Nuclear Power Generation Facilities - Rules on Fitness-for-Service ? (FFS Code) of Japan Society of Mechanical Engineers (JSME) and Guideline for Inspection and Evaluation of Reactor Internals of Japan Nuclear Technology Institute (JANTI). Evaluation methods and r esults are outlined in this report. Issues to be studied for better improvement of JSME FFS Code and J...
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Application of JSME Fitness-for-Service Code and JANTI Guideline for Inspection and Evaluation of ReactorInternals to Cracks found at Shroud Support of Tokai II Power Station

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...
英字タイトル:
Development and application of Monitoring and Diagnosis Techniques for Condition Based Maintenance in Nuclear Power Plant

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