The current edition of “Guideline of Inspection and Evaluation for Reactor Internals issued by Japan Nuclear Safety Institute (JANSI) consists of inspection target, inspection method, and evaluation. Recently, the guideline is revised based on the safety function of the Reactor Internals, domestic operation experience, and the new knowledge. In this report, summary of “Guidelines of Inspection and Evaluation for Reactor Internals [Core Shroud] and [Shroud Support]....
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Guideline for BWR Inspection Program Revision Policy of Guidelines for Core Shroud and Shroud Support

JSME シビアアクシデント時の構造健全性評価ガイドラインのうち BWR 鉄筋コンクリート製格納容器（RCCV）編について、RCCV のコンクリート部、ライナ部、鋼製耐圧部についての耐圧・耐漏えい性評価概要を記述する。 ...
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Summary of Structural Integrity Evaluation Guideline under Severe Accident Condition (BWR Reinforced Concrete Containment)

In order to optimize plant maintenance, it is important to diagnose an integrity of equipment and use it for maintenance planning. We developed the integrity diagnostic method combining statistical model and physical model. The statistical model detects abnormality from process data and estimates abnormal parameters. The physical model estimates failure equipment from abnormal parameters. As a result of test data evaluation, it was confirmed that the proposed method can detect anomalies and estimate faulure...
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Development of integrity diagnosis technique for plant equipment

Eddy current testing (ECT) with multi coil probe has been developing for enhancing surface inspection. Defect extraction method based on phase angle of lissajous waveform was effective to identify between defects and noises. This paper describes applicability of crack extraction method for magnetic material. The criteria based on feature of phase angle on magnetic material could extract defects to separate from noises like liftoff using experiment and simulation....
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Crack Extraction technique for Magnetic Materials by Eddy Current Testing with Multi Coil Probe

Flaw evaluation method for riser brace arm weld was investigated in case of a flaw is detected in in-service inspection. Weld residual stress was evaluated using 3-D finite element model considering structure of riser brace. Fatigue and SCC crack growth evaluation was performed using evaluated residual stress and stress due to normal operation. Two methods, which are JSME fitness-for-service code and influence function method, were applied to estimation of stress intensity factor to investigate effect of st...
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Structural Integrity Assessment for Riser Brace Arm Weld

Underwater inspection vehicles for nuclear power plants were selected as the third maintenance heritage. Hitachi- GE Nuclear Energy, Ltd and Toshiba Energy Systems & Solutions Corporation have been working on miniaturization and weight reduction of vehicles for many years, and enabling visual inspection of narrow space and bottom of the nuclear reactors, which were not accessible with the conventional hanging cameras. This article describes the developed vehicles by each company and their contribution to ma...
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The Third Maintenance Heritage Underwater Inspection Vehicles for Nuclear Power Plants

Rapid growth in renewable energy (RE) is essential for achieving carbon neutrality. However, the resilience of bulk power system is decreased due to the installation of large amount of RE, and there is a possibility that the transmission accident causes disasters such as a large-scale blackout. As a result, the amount of RE is limited in order not to cause such disasters. In such a situation, nuclear power plants will be useful items to reinforce the resilience of bulk power system. In this research, we eva...
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Study of utilization of nuclear power plants for increasement of renewable energy installation

We have developed a method using mobile devices to identify plant equipments, especially for repair. After the accident of March 2011 at Fukushima, many nuclear plant operations have still been downed and it leads to the insufficiency of mature experience. The work assistance with IT is getting required under this situation. The IT device can provide appropriate information, e.g. operating instructions, to workers depending on the situation. In order to recognize the current location the arrangement informa...
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Development of Identification Method of Equipments for Repair in Nuclear Plant

Operator’s initiatives are important to achieve high level safety under the new nuclear regulatory inspection program, which was developed based on experiences in the United States and its Reactor Oversight Process. In the United States the performance of nuclear power plants was significantly improved in 1990’s and it has been continuously maintained at a high level since then. Some improvements in the management systems with risk- informed decision-making process were identified as key success factors. Th...
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Importance of Operators’ Initiatives under the New Nuclear Regulatory Inspection Program

Safety of existing nuclear power plants has been enhanced by reflecting lessons learned from the Fukushima Daiichi Accident. For nuclear new builds, safety can be further enhanced in more rational ways. Hitachi GE Nuclear Energy (HGNE) developed an ABWR design for the United Kingdom in which Fukushima lessons were reflected. Some additional safety improvements were identified and realized by using the results of full-scope probabilistic risk assessments. In addition, collaborating with GE Hitachi Nuclear En...
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Technology Evolution for Nuclear New Build to realize Improved Safety in more Rational Ways