Even after the accident of the Fukushima Daiichi Nuclear Power Plant, the Japanese government has positioned nuclear power as an important base load power source in terms of energy policies and has focused on safety operation of the nuclear power generation. This is because it is an indispensable power source for the use of renewable energy in Japan with limited resources. On the other hand, the first generation commercial reactors in the world generally have a designed life of 30 to 40 years, but most of them have been in existence for more than 20 years. Japan is no exception, and several NPPs aged already more than 40 years.
Analysis and research show that many commercial reactors leave enough capacity to operate beyond the designed service period. Replacement of the concrete members used in the reactor buildings is expensive making it difficult in many cases. Therefore, in order to continue nuclear power generation over the long term, it is necessary to maintain the performance of the concrete member during the designed service period. From this point of view, it is indispensable to conduct research on maintenance management, performance evaluation, and prediction of deterioration of concrete structures.
Research on concrete in the field of civil engineering and building science has been conducted for a long time, while reevaluation of concrete performance, physical properties and various problems in terms of nuclear field needs, i.e. Plant Life Management and Ageing Management, and addressing issues peculiar to the nuclear power field will be an important contribution from the field of concrete research to the field of nuclear power engineering. As discussed at OECD / NEA, alkali silica reactions and radiation influence are important issues for the maintenance of nuclear power plants, and many research on them has been reported.
Also in the past, research investment on concrete in the field of nuclear power has been carried out many times in Japan as well as in other developed countries. However, the international publication of the research results has been limited. In this ACT special issue, especially on advanced research in recent years, I widely urged stakeholders to make efforts to allow research trends in Japan to be forecast from other countries.
Based on these backgrounds, we applied for papers focusing on Plant Life Management at nuclear power plant facilities and related technologies in the research related to concrete. I think that it became a State of the Art report, which highlights the current problems. I also anticipate it could lead to a trust from the society concerning future nuclear power generation technology and a development of the concrete research field.