Inspection technique for complex surface profiles has been required in order to ensure the reliable operation and high operating rate of nuclear power plants, because many parts due to inspection have complex geometry. We have developed Pha sed Array (PA) ultrasonic testing with immersion technique which suitable to complex geometry. In this paper, we developed precise inspection technique for curvature surface profile such as a nozzle of pressure vessel. For curved surface pro file, Synthesis Aperture Foc...
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Development of Phased Array Inspection Technique for Nozzle Pipes with Curved Surface

Phased Array Ultrasonic Testing (PAUT) techniques for complex geometries are greatly progressing. We developed an immersion PAUT which is suitable for complex surface profiles such as nozzles and deformed welded areas. Furthermore, we have developed a shape adaptive beam steering technique for 3D complex surface structures with conventional array probe and flexible coupling gel which makes the immersion beam forming technique usable under dry conditions. This system consists of 3 steps. Step1 is surfac...
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Verification and Application of Beam Steering Phased Array UT Technique for Complex Structures

Abstract This study proposes the risk-informed classification of structures, systems, and components (SSCs) and the possibility of applying risk-informed evaluation for operation and maintenance improvement. The resul ts of the risk importance ranking of SSCs are potentially formed into engineering databases to rationalize m anagement processes of the plant operation/maintenance by appropriate re-distribution of available resources....
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Study on the Possibility of Applying Risk-Informed Evaluation for Operation and Maintenance Improvement at Tokai-2

Non-destructive examination (NDE) methods for joint interfaces between different materials in high heat flux components of ITER divertor should be urgently developed to assure qualit y and reliability of joining techniques. This paper reports the present R&Ds status of NDE for ITER divertor and its outlook. The detection ability of joint defect by using ultrasonic wave and thermography NDE are examined in the joint interface between armor tiles and a cooling tubes of divertor mock-ups. The results of both ...
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Development of Non-destructive technique for ITER divertor high heat flux component

Abstract Adverse events that have occurred at overseas nuclear power plants can be studied to provide an indication of how to improve the safety and the reliability of nuclear power plants in Japan. The Institute of Nuclear Safety Systems (INSS) obtains all information related to overseas adverse events and incidents at power stations, evaluates them in an attempt to prevent similar occurrences in Japanese PWR plants, and proposes recommendations to Japanese PWR utilities. Through su ch INSS evaluation act...
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Analysis of Tendency on Adverse Events Occurred at Overseas Nuclear Power Plants in 2003

This study aims at proposing a novel magnetic testing method, eddy current magnetic signature method for evaluation of residual strain in carbon steels. This method characterize the eddy current magnetic signatures that is eddy current signals in an impedance plain during magnetization process. In order to discuss the feasibility of this method, eddy current magnetic signatures of a set of tensile test specimens are investigated. The relationship between eddy current signature and plastic deformation is di...
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Nondestructive Evaluation of Residual Strain in Carbon Steels by Eddy Current Magnetic Signature Method

In a previous study, authors showed experimentally the correlation between leakage magnetic flux density and irradiation assisted stress corrosion cracking susceptibility of high purity model austenitic stainless ste els. This study aimed to investigate mechanism of the correlation. Tensile test at elevated temperature and aging test were conducted on materials simulating irradiation-induced segregation, and leakage magnetic flux density was measured before and after these tests in order to study the influ...
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Evaluation of Sensitivity to Irradiation Assisted Stress Corrosion Crackingby Measurement of Leakage Magnetic Flux Density

It has been clarified that the fatigue life is reduced in the fatigue test of high-temperature and high-pressure water that simulates PWR reactor coolant environment compared to that in the tmosphere, and temperature, strain rate，etc. affect the decrease of fatigue life. In this study, the influence of crack growth behavior on fatigue life of SUS316 in simulated PWR reactor coolant environment of different temperature was investigated. Fatigue tests were conducted under different temperatures (325℃ and 200℃...
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Influence of Temperature on the Fatigue Crack Initiation and Growth in Reactor Coolant Environment

Laser peening is a surface enhancement process that introduces compressive residual stress on materials by irradiating laser pulses under aqueous environment. The process utilizes the impulsive effect of high-pressure plasma generated by ablative interaction of each laser pulse. It is very beneficial to shorten ou tage period if laser peening is available during refueling work. It is confirmed that laser peening can be available in the situation by experiment and analys is. This report describes detail of ...
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Study on availability of laser peening during refueling work- Preventive maintenance to shorten outage period

高温ガス炉は、基本構成要素である耐熱性の高いセラミックス製被覆燃料粒子や黒鉛減速材、不活性ヘリウム冷却材の特長を活用することで、高温熱を原子炉の外に取り出すことが可能である。図 1に高温ガス炉供給熱の温度範囲と熱利用が想定される産業プロセスの温度条件を示す。高温ガス炉供給熱の温度範囲は 100℃から 1000℃と幅広いため、発電のみならず種々の産業分野での熱利用が想定されている。例えば、エネルギー転換分野における原子力エネルギー利用の高効率化に資するヘリウム冷却材を用いたガスタービン発電、製鉄分野での還元剤・燃料や運輸分野における燃料電池自動車に供給する水素の熱化学水分解法やメタン水蒸気改質法による製造、炭酸ガス排出量の削減を目的としたスチレン等の化学製品製造やオイルシェール等の非在来型化石資源回収、石油精製プラントの熱源に用いる高温蒸気製造、発電システムでの排熱を利用した海水淡水化や地域暖房などでの多様な熱利用が期待される。 本稿では、高温ガス炉の熱利用技術として、発電熱電併給、再生可能エネルギーハイブリッドシステム及び熱化学法 ISプロセスの概要を述べる。...