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...

Nowadays, companies and educational institutions are required to prepare and respond to natural disasters with Business Continuity Plans (BCP). However, many of the BCP currently being formulated focused only on the natural disasters. Therefore, this study aims to develop the framework of BCP and its formulation method considering the compound risk of nuclear and natural disasters by utilizing the IRIDM process. The IRIDM process is to optimize decision-making for continuously improving the safety of Nuclea...
英字タイトル:
Development of Business Continuity Plan Considering the Compound Risk of Nuclear Disaster Based on IRIDM process

Debris remelting may play an important role in the progression analysis of severe accidents and the safety design of nuclear power plants. This paper developed a multiphase moving particle semi-implicit (MPS) method by coupling the fluid-solid interaction, solid-solid interaction, heat transfer and phase change models. Then, the debris remelting in reactor pressure vessel (RPV) is simulated, and the influence of debris size and decay heat power via local hot spots is investigated....

これまで、原子炉の運転差し止め裁判が数多く行われ、裁判所は運転を認める判断、禁止する判断のいずれも示している。原発裁判では、原子力安全に係る専門的かつ高度な事柄に関する論争が行われている。原発裁判で、安全確保の理解が進まない要因の1つに、「リスク」の理解が社会に進まないことが挙げられる。本 では、「リスク」とは んなことなのか、について自 と考えることのできるような議論、討論の手法を提案する。 Many lawsuits have been filed to stop the operation of nuclear power plants. Judgments in court show various decisions. In such lawsuits, some controversy over technical issues related to nuclear safety have taken place but it is hard to say that various efforts to ensure nuclear safety has been understood prop...
英字タイトル:
Nuclear Power Trials, Issue and Arguments No.4 Comprehension of Risk -Cognition Method-

The Fukushima Daiichi accident has affected nuclear energy strategy in different countries in different ways and to different extents. Global community continued to discuss and update concepts and actions for continuous improvement of nuclear safety based upon excellent level of management in nuclear sectors. Some examples of outcomes in international organizations are discussed in this paper to contribute management systems to cope with complexity of the issues in Japan. Considering responsibility and impu...
英字タイトル:
Management of Nuclear Safety from Global Viewpoints

The mission of decommissioning of Fukushima Dai-ichi NPP is the long-term, complicated and difficult task. In this paper, a new method to retrieve fuel debris using geopolymer will be discussed....
英字タイトル:
A new method of fuel debris retrieval with geopolymer for Fukushima Dai-ichi NPP (Phase-2)

On a power plant, the water quality of system water needs to be properly monitored and controlled. On this study proposes a monitoring method for the concentration of Chloride, one of the main impurities dissolved in feed water of a power plant. The proposed method is based on soft sensor, and variable selection through GAVDS contributes the predictive models to higher prediction accuracy....

In the future social infrastructure diagnosis for concrete structures such as bridges, tunnels and buildings, it is expected that the digital hammering inspection, which is objective, quantitative, and recordable to the conventional hammering inspection, will play a significant role. However, since there are a wide variety of defects due to poor construction and age-related deteriorations in the concrete structures, they have not been quantitatively identified enough by the digital hammering inspection in t...
英字タイトル:
A study on internal structure diagnosis of concrete structures incorporated with digital hammering inspection, AI and simulation technologies (1) Direct problem analysis using AI

One of the most common inspection methods for concrete structures is hammering inspection. While this method makes it possible to quickly inspect a vast number of inspection targets, it has the problem of lacking objectivity of judgment results and recordability. In this study, we aimed to develop a technology to quantitatively diagnose the internal structure of concrete structures by digital hammering inspection. The approach of the research was to build an AI trained by CNN with a database that relates th...
英字タイトル:
A study on internal structure diagnosis of concrete structures incorporated with digital hammering inspection, AI and simulation technologies (2) Inverse problem analysis using AI

We propose an advanced digital twin of artifact systems (DTAS) in which physical and numerical models of structural materials at several time scales and length scales are constructed and integrated, while monitoring and inspection data of structural materials are used as input parameters. As DTAS can reproduce the current state of structural materials and predict their degradation through their service life, it can improve the resilience and give plasticity to artifact systems. A portion of the results rela...
英字タイトル:
A digital-twin of artifact systems by synthesizing multiscale modeling and monitoring