According to the past edition of “Guideline of Inspection and Evaluation for Core Internals (Core Spray Sparger & Piping Jet Pum p]” issued by Japan Nuclear Technology Institute (JANTI), fully penetrated flaw should be assumed for uninspected region, for ev aluating their integrity. This assumption was considered to be too conservative. Then, this study was performed on the better as sumption of flaw existence in the uninspected region to develop more appropriate flaw modeling by using statistical evaluati...
英字タイトル:
The Guideline of BWR Inspection Program Study on Flaw Characterization of Core Internals Piping for Uninspected Region

Seal welding is a repair method when crack by Stress Corrosion Cracking (SCC) is found in weld rtion of core internals including pressure b oundary component in nuclear power plant. Seal lding is welded directly on surface of existing SCC crack and prevents SCC propagation by la ting SCC crack from reactor water environment. In this study, development of seal welding hnology using automatic TIG Welding was executed, and the applicability of seal welding method CRD stub-tube weld portion was confirmed by ex...
英字タイトル:
Development of Seal Welding Repair Technology for CRD Stub-tube

“Guidelines for Inspection and Evaluation of Reactor Internals”, published by Thermal and Nuclear Power Engineering Society (TENPES) and taken over by Japan Nuclear Technology Institute (JANTI), adopted a very conservative assumption on flaw characterization for uninspected region of cylindrical components. Fully penetrated flaw should be assumed for uninspected region, when SCC is found and flaw evaluation is performed on cylindrical core internals such as core shroud. The authors suggested a modified me...
英字タイトル:
Technical Basis for Revision of Guidelines for Inspection and Evaluation of Reactor Internals on Flaw Characterization for Uninspected Region of Cylindrical Components

地震を受けた機器における塑性ひずみ検出方法の適用について 米谷 豊,Yutaka KOMETANI,伊東 敬,Takashi ITO,野中 善夫,Yoshio NONAKA,高木 愛夫,Yoshio TAKAGI,黒崎 裕一,Yuichi KUROSAKI,羽鳥 正訓,Yoshio TAKAGI, １．はじめに東京電力株式会社　柏崎刈羽原子力発電所は、2007年7月16日に発生した中越沖地震により被災したが、原子炉は安全に停止するとともに、耐震設計グレードの高い機器では外見上の損傷は認められなかった。ま......

One year has passed since Electronic Journal of Advanced Maintenance (EJAM) was started on the website of Japan Society of M aintenology (ISM) May 25“, 2009. “New Technology' (NT) is one of the EJAM categories, and introduces widely advanced techniqu es developed or modified for maintenance. Twenty-two NT articles have been introduced on EJAM website so far as of May 25t“, 2010. This report describes the concept of NT, general features of NT articles, actual performance and future wishes for NT....
英字タイトル:
Current Status of EJAM ‘New Technology

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...
英字タイトル:
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

Water environment improvement (ex. Hydrogen Water Chemistry (HWC)) is carried out for Stress Corrosion Cracking (SCC) mitigation in some of BWR plants. Japan Nuclear Technology Institute (JANTI) has the guideline on the inspection programs based on effectiveness of environmental SCC mitigation technique for BWR core internals. The guideline provides the crack growth rate (CGR) under HWC. Although CGR is defined by ECP (electroch emical corrosion potential), a dealing of evaluation of ECP and the HWC avail...
英字タイトル:
The Guideline of evaluating the effectiveness of environmental improvementby Hydrogen Water Chemistry

This paper introduces the applied experience of Inspection and Evaluation Guideline for Japanese BWR plants' core shroud. This report includes the compari son of evaluation performed by using Guideline's method and actual inspection results for several plants. Evaluation was performed at the time when SCC wa s found. After one cycle operation, actual inspections were done to confirm the amount of existing crack growth. It was confirmed that actual crack growth is less than predicted value by the evaluation...
英字タイトル:
Applied experience of Inspection and Evaluation Guideline to actual BWR internals

1. 概要我が国の原子力発電プラントは,運転開始 から 20 年を経過しようとするプラントも少 なくなく,基幹電力として,安全かつ安定的 な電力供給を維持していくために,総合的な 保全策の適用検討がなされている。保全策の 二本柱は,予防保全と,適切な頻度の点検と 「点検結果の評価に基づく維持管理であり,点 検により万一欠陥が確認された場合には,そ の部位,程度によっては補修が必要になる場 合がある。炉内構造物で,万一補修を実施する場合に は,基本的に工事は遠隔操作による実施が要 求されることから,一般的に......
英字タイトル:
Repair Technologies applied to BWR Core Internals

Stress improvement is one of the most effective methods to cope with Stress Corrosion Cracking (SCC) in Nuclear Power Plants . Therefore, there should be prepared many alternatives to choose according to various conditions, for the purpose of practic al maintenance activity. This paper introduces stress improvement by polishing, which has been applied to reactor internal c omponents of Japan NPPs as a mitigation of SCC, and shows preliminary study to prepare Guideline for the application of that....
英字タイトル:
Preliminary study to prepare Guideline for the application of stress improvement by polishing