Working Group on Application Enhancement of Repair Replacement Technology has been established since September 2015, for the purpose of studying specific measures to create an environment that Japanese utilities can easily make corrective actions such as repair replacement technology applicable to Nuclear Power Plant to improve the safety of their own plants, and meetings have been held five times until the end of April 2016. In this paper, discussions on the WG meetings so far are shown, as well as th...
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Current Status of WG on Application Enhancement of Repair Replacement Technology

This paper discusses maintenance optimization by the automatic planning tool for regular plant outage work in nuclear power plant using the logic programmin g language “Prolog”. As a result of consideration, the following results were obtained. (1) The automatic planning tool for regular plant outage in nuclear power plant was developed. (2) Using this tool, the work plan for BWR primary recirculation system and residual heat removal systemwas automatically made on the condition of flattening man loading o...
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A Study on Maintenance Optimization by the Automatic Planning Tool for Regular Plant OutageWork in Nuclear Power Plant Using the Logic Programming Language “Prolog”

軽水炉炉内構造物の点検評価ガイドラインの体系化－ガイドラインの評価および構造と体系－ 山下 裕宣,Hironobu YAMASHITA,酒井 和夫,Kazuo SAKAI,青木 孝行,Takayuki AOKI......

軽水炉炉内構造物の点検評価ガイドラインの体系化－将来の技術課題とその改善、高度化の方向性－ 山下 裕宣,Hironobu YAMASHITA,千種 直樹,Naoki CHIGUSA,青木 孝行,Takayuki AOKI,小山 幸司,Koji KOYAMA,元良 裕一Yuuichi MOTORA,藤森 治男,Haruo FUJIMORI......

System safety is considered to secure safety in a comprehensive manner as an entire plant by multiple elemen ts serving an entire plant for a common purpose of safety and an interdependent relationship among elements. nder this concept, we considered how the scheme of fatigue crack management in nuclear power plants should b e and also considered the problems to be solved to establish the effective and efficient management system....
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Conderation onHow to Manage Fatigue Cracking in Nuclear Power Plants from the viewpoint of Non-destructive Evaluation

In order to solve the problems of the thickness measurement, we have developed a thin-film UT sensor having excellent high-temperature durability and conformability in thin film form. In this paper, it was confirmed that the accuracy of thickness measurement for both complex geometries and plates at high-temperature was equivalent to the accuracy of conventional thickness measurement methods. It was also confirmed that the durability at high temperature and for temperature change in the actual equipmen...
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technology using high-temperature thin-film UT sensor

This paper reports an outline of the prototype database system which can provide with information on needs and seeds for new inspection and mon itoring technology, which is applicable to the actual nuclear power plan ts for understanding ageing degradation conditions of plant components....
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Needs and seeds database of new inspection and monitoring technology for ageing equipment

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-

Because a fast breeder reactor (FBR) uses sodium as a coolant and there exist systems and components unique to FBR, aging phenomena to be considered in FBR are quite different from ones in a light water reactor (LWR). Therefore it is required to make a maintenance plan for FBR by considering the characteristics of FBR. In the Japanese LWRs, aging phenomena which occur in every part of all safety-related components have been extracted based on the O&M experiences and the technical evaluation on aging pheno...
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Principles of MONJU Maintenance - Ageing phenomena of FBR for maintenance-

A Ni-base alloy weld, including cracks due to stress corrosion cracking found in the reactor internal of the oldest BWR in Japan, Tsuruga unit 1, in 1999, was examined by three (3) types of UT method. After this examination, a depth of each crack was confirmed by carrying out a little excavation with a grinder and PT examination by turns until each crack disappeared. Then, the depth measured by the former method was compared with the one measured by the latter method. In this fashion, performances of...
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Evaluation on Ultrasonic Examination Methods applied to Ni-base Alloy Weld including Cracks due to Stress Corrosion Cracking found in BWR Reactor Internal