بررسی اجمالی فعالیت های تحقیق و توسعه ژاپنی ها در رابطه با ایمنی هسته ای

An overview is given about currently on-going activities on nuclear structural components in Japan. The content comprises six national projects on R&D. Four movements of codes and standards and two replacement plans for nuclear components are introduced.

Fifty two commercial light water reactors (LWR) plants are operating in Japan. Twenty eight units are BWRs, 23 are PWRs and one unit is a gas cooled reactor (the gas cooled reactor was shut down in March 1998). The current nuclear power generation capacity is about 44 900 MWe. Steady supply of electric power is essential for nuclear power generation in Japan. Nuclear power plants in Japan commissioned in the early period have now been in service for more than 25 years. The recent major concern is directed towards the reliability of aged plants, accompanying the increase of the number of aged plants. From technical and social viewpoints, comprehensive technological tasks are brought up to maintain and improve the reliability of operating nuclear plants. The present paper gives an overview of the following activities: 1. Activities of research and development (R&D). 2. Movement of codes and standards. 3. Replacement plans of nuclear components. The author gives a brief introduction to the above items, i.e. the basic framework, current scope, some results and future developments.

While the operating years of light water reactors are accumulating, the major concerns are directed towards the development of technologies for aged components. Many national R&D projects related to this field are actively running. In addition, codes and standards are being reviewed in Japan. On the other hand, replacements of nuclear components are being planned to enhance the reliability and improve cost efficiency.