Piping and Instrumentation Diagrams (P&IDs) contain information about the piping and process equipment together with the instrumentation and control devices, which is essential to the design and management of Nuclear Power Plants (NPPs). There are abundant complex objects on P&IDs, with imbalanced distribution of these objects and their linked information across different diagrams. The complexity of P&IDs thus is increased which make automatic identification difficult. Therefore, the content of P&IDs is gen...

次世代高速炉の合理的な設計や保全の最適化を実現するためには，もんじゅにおける点検長期化の要因を分析し，課題の整理と対策案を検討することが重要となる．本論文では，高速炉の稼働率向上を目的に，保全合理化検討のための概略的分析の結果を報告する． 具体的には，もんじゅの保全に関する全体傾向の把握及び保全合理化の余地が大きいと考えられる保全内容を抽出するため，もんじゅ保全計画に記載されている点検タスクの情報を分析した．また，得られた分析結果に対し，保全合理化の提案を行った．...
英字タイトル:
Proposal of Maintenance Rationalization for Next-Generation Fast Reactors based on the Analysis of the Prolonged Maintenance of the Prototype Fast-Breeder Reactor in Japan, “Monju” (2) ～Analysis of Maintenance Plan of “Monju” in Reactor Cold Shutdown～

本論文では、点検自体の期間も長く、その遅延が直接プラント工程に影響を及ぼすクリティカルパスの点検に着目し、もんじゅの点検に要する期間が長期化した要因を分析する。この要因に対し、次世代高速炉における合理的な保全を実現し、稼働率を向上させることを目的とした、次世代高速炉の設計や運用に反映すべき対策を検討した。...
英字タイトル:
Proposal of Maintenance Rationalization for Next-Generation Fast Reactors based on the Analysis of the Prolonged Maintenance of the Prototype Fast-Breeder Reactor in Japan, “Monju”? (1) ～Analysis of Plant Schedule of “Monju” in Cold Shutdown～

Creep tests for energy structural materials of austenitic stainless steel SUS316FR were performed. And degradation mechanism of welded specimen was investigated by using microcharacterization technique of magnetic force microscopy. In as-received specimen, magnetic phases of S-ferrite were interconnected at weld metal region. While in crept specimen, the magnetic phases at weld metal region were isolated, and the amount of magnetic phases decreased. It was found that creep da mage of welded specimen could ...
英字タイトル:
Microcharacterization of damage degradation for energy structural materialsof advanced fast breeder reactor

Magnetic characterization of creep-fatigue damage for welded specimens of austenitic stainless steel (SUS316FR) and high-chronium steel (Mod.9Cr-1Mo) steel was performed using magnetic force microscope an d Hall sensor. In SUS316FR volume fraction of d-ferrite at weld metal region decreased by creep or creep-fatigue and the remanent magnetic flux density at weld metal region also decreased. In Mod.9Cr-1Mo steel magnetic characteristics at weld metal region were different from those at base metal initially,...
英字タイトル:
Magnetic Characterization of Creep-fatigue Damagefor Energy Structural Materials

Probabilistic fracture mechanics (PFM) evaluation requires information on the probabilistic distributions of the number and size of initial defects, material properties such as crack growth rate due to fatigue and creep, and load to evaluate the failure probability of components. In this study, ultrasonic testing was conducted on the welds of the test equipment used in the research and development of fast reactors, and the number and size of defects were evaluated. The results could be used as conservative ...
英字タイトル:
Evaluation of Defect Number Density in Sodium Equipment Stainless Steel Welds

If components can be maintained according to a target reliability of nuclear power plants, plant safety and economic efficiency could be improved by avoiding excessive or insufficient margins. This approach can rationalize the maintenance of low target reliability components and concentrate resources (people, money, and time) on the maintenance of high target reliability components. It would take a long time to evaluate the target reliability for all components in the plant by quantitatively using probabili...
英字タイトル:
Proposal of a Simple Screening Method Which Determines Necessity of Quantitative Risk Assessment for Maintenance Rationalization Using Risk Information

In this paper, we propose a new method for extracting design issues on maintenance. Maintenance periods might be prolonged due to design issues. In the proposed method, maintenance preconditions are extracted by organizing the design information. A maintenance schedule is created by using extracted maintenance preconditions. If the created maintenance schedule doesn't achieve target periods, design issues could be extracted from the viewpoint of maintenance precondition. A simple example using "Monju" desig...
英字タイトル:
Proposal of a Method of Extracting Design Issues on Maintenance for the Rational Design of Next-Generation Reactors

JAEA has started the development of Advanced Reactor Knowledge-and AI-aided Design Integration Approach through the whole plant lifecycle (ARKADIA) that performs integrated design evaluation and optimization from various viewpoints such as safety, economy, and maintainability using risk information, in order to dramatically improve the development efficiency of innovative reactors. In this paper, we report the concept of a knowledge management system to support integrated design evaluation and optimization,...
英字タイトル:
Development of knowledge management system contributing to integrated design evaluation and optimization of innovative reactors

In order to achieve both safety and economic efficiency of a nuclear power plant, it is necessary to realize rational maintenance based on characteristics of the plant. The fast breeder prototype reactor, Monju, spent most of the year for the maintenance. It is important to identify causes of the prolonged maintenance of Monju and to investigate countermeasures for implementation of rational maintenance of a next fast reactor. In this study, causes of the prolonged maintenance of Monju during reactor cold s...
英字タイトル:
Analysis of issues related to maintenance period of the fast breeder prototype reactor Monju (1) Analysis of plant operation for maintenance of cold shutdown Monju