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....
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Know-How for the Ultrasonic Examination Practice & Evaluation of PLR Piping

2002, Stress Corrosion Cracking (SCC) came to be detected in the low carbon stainless steel PLR ; of BWR plants. These SCC were detected and evaluated by the Procedure for adding creeping wave ar wave of angle of 45° based on ultrasonic examination guidelines in In-service inspection (JEAG . However, it worke d on the improvement of ultrasonic examination technology for PLR Piping in BWR Owners Group (JBOG), because the mistake of the evaluation was caused as a rare case. In this it introduces the improvem...
英字タイトル:
Know-How for the Ultrasonic Examination Practice & Evaluation of PLR Piping

原子炉圧力容器の監視試験および破壊靱性の確認試験方法に係わる日本電気協会電気技術規程（JEAC4201，4206）の改定 山下 理道,Norimichi YAMASHITA,米原 晃,Akira YONEHARA,冨松 実,Minoru TOMIMATSU _ １．はじめに(社)日本電気協会の電気技術規程「原子炉構造材の監試験方法（JEAC 4201）」は発電用軽水型原子炉圧力容器鋼材の中性子照射による機械的特性の変化（主として脆化）を調査し評価するための監視試験方法を規定している。一方、電気技術規程「原......

Neutron irradiation embrittlement of reactor pressure vessel (RPV) steels is one of the important material ageing issues. The Japan Electric Association Code, JEAC 4201-2007 “Method of Surveillance Tests for Structur al Materials of Nuclear Reactors,” was revised in December 2007. A new mechanism-guided embrittlement correlation method was adopted. The surveillance program was modified for the long term operation of nuclear plan ts by introducing the “long-term surveillance program”, which is to be applied...
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Industry Practice for the Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels in Japan

In order to cool the melted fuel in reactors, circulating water system was installed. This system continually provides coolant inside the pressure vessel at Unit 1 to 3. After cooling fuel debris in RPVs or PCVs, injected water goes to turbine buildings. Cesium is then removed and this water flows to desalination plant with reverse osmosis membrane. After this step, purified water is recycled as coolant. Contaminated water of 300 m3 per day is created and stored in tanks. This contaminated water is tre...
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Summary of contaminated water management at Fukushima Daiichi NPS

1.はじめに 解説記事 東日本大震災発生当時(3 月 11 日 14 時 46 分の地震 プ、非常ガス処理系に電源を供給することが可能となっ 発生時)、福島第一原子力発電所 5 号機は定期検査中で た。さらに、健全性確認が完了した 5 号機低圧電源盤の あり、原子炉内に燃料を装荷した状態で、原子炉圧力 一部に仮設電源ケーブルを敷設するなど、順次電源を復 容器の耐圧漏えい試験(原子炉圧力容器満水、原子炉 旧していった。 圧力約 7MPa[gage]、原子炉水温度約 90°C)を実施中で さらに、主蒸気逃がし......

1. 緒 言電気事業法の改正により、2003年10月より原子力発電設備の維持基準が導入された。これに伴い発電事業者は法定の「定期事業者検査」を実施すること、また、き裂等の欠陥を発見した場合、当該機器の運転を継続するためには、欠陥の進展を予測し、機器の構造健全性を確認することが義務付けられた［1］。本稿では、近年、国内の沸騰水型原子力発電プラント（以下、BWR）の低炭素ステンレス鋼製炉心シュラウドで多くの事例が確認された応力腐食割れ（以下、SCC）を例に、機械学会維持基準［2］に基づく構造健全性評価の考え方......

It is revealed that Stress Corrosion Cracking (SCC) on the surface of the L-grade stainless steels in Nuclear Power Plants is caused by heavily cold work of the materials. The microstructure, hardness and residual stress on the surface of the material are factors for SCC initiation. There are surface treatment methods that is effective reduction on SCC such as Flap Wheel (FW) polishing, Clean N Strip (CNS) polishing, Water Jet Peening (WJP) and Shot Peening(SP). In this paper, the characteristics of the su...
英字タイトル:
Effects of Surface Treatments on Microstructure in Stainless Steel