１． はじめに最近10年ほどの間に原子力発電をめぐる状況は大きく変わってきた。新興国でのエネルギー需要の増大、石油・天然ガス等の将来的価格高騰に対する懸念、環境問題等が引き金となり、世界的に原子力発電を見直す国が増えるとともに、新興国による原子力発電導入の動きも活発化してきた。また、米、仏、日等の原子力先進国では自国内の原子力発電プラントの信頼性向上、稼働率向上、供用期間の延長等を図るために、広範な技術検討、研究開発、管理面での改善および安全規制の高度化が進められてきた。他方国際的には、2008年7月......

Although Kashiwazaki-Kariwa Nuclear Power Station was affected by Chuetsu-Oki Earthquake, the important components in the reactor building were hardly damaged, and fundamental nuclear safety was ensured. However, as the mass communication media reported the pictures o f the black smoke of fire accident of the transformer, sloshing of the pool, etc. without declaration of “Safety“ by the Central Government or sufficient explanation, the habitants on the site and the Japan's people were put into anxiety and ...
英字タイトル:
Necessity of Radiation Education Suggested from Press Report during Earthquake Damage ofKashiwazaki-Kariwa Nuclear Power Station

The outlines of Fukushima-daiichi accident were shown in this report. The outline is composed of two parts. On e part is the period from the earthquake to the tsunami, and the other is after the tsunami. Fist part shows t hat the mitigation system and the barrier integrity of Fukushima-daiichi unit 1 to 3 were operable during this period. This result shows that the cause of the Fukushima-daiich accidents were an influence by the tsunami....
英字タイトル:
Outline of the Fukushima-Daiichi Accident

The Fukushima Daiichi nuclear power plant's units 1/2/3 which were under operation when the Tohoku - Pacific Ocean Earthquake occurred at 14:46 March 11, 2011, were analyzed by time series evaluation from the earthquake occurrence to the tsunami invasion as to whether safety functions were effective. The shutdown function and containment function were analyzed in this paper, and it showed both the safety functions were kept effective during the earthquake occurrence to the tsunami invasion....
英字タイトル:
Time-series evaluation on Fukushima Daiichi NPP units 1/2/3 from Tohoku - Pacific Ocean Earthquake to the related tsunami invasion (1)

The Fukushima Daiichi Nuclear Power Plant units 1, 2, and 3 were evaluated to determine whether their safety functions were effective. These units, which were under operation when the Tohoku - Pacific Ocean Earthquake occurred at 14:46 JST on March 11, 2011, were analyzed via a time series evaluation from the time the earthquake occurred to the subsequent tsunami attack. The cooling function of each unit was analyzed and the results show that the cooling functions were effective during the evaluation...
英字タイトル:
Time series evaluation on Fukushima Daiichi NPP units 1/2/3 from Tohoku - Pacific Ocean Earthquake to the tsunami invasion(2)

我が国では原子力発電所の保守に関する規制は、定期検査、定期安全管理審査、保安検査などにより行われている。米国においては、保守規則（メンテナンスルール）を制定し、保守に関する規制を行っている。本解説では、リスク情報の活用が進んでいる米国において、保守に関する規制にリスク情報がどのように活用されているかを述べる。１．米国の保守規則について既にご承知の方も多いと思うが、先ず米国の保守規則に関する概要を述べる。下図に日本と米国の原子力発電所の設備利用率と計画外停止頻度の1980年からの推移を示す。1980年代、米......

In many countries, online maintenance has been already introduced. Especially in US, online maintenance has been introduced to many nuclear plants which has (N+1) redundant safety systems as Japanese plants. There experience will contribute us to discuss how to introduce online maintenance in Japan. In IAEA's nuclear safety criteria and guidance, it is recognized that the outage of one safety system for maintenance is usual operation. This is normal sense in the world. In US, the ris k when online maintena...
英字タイトル:
Status of Online Maintenance in the world

The purpose of this report is clarification of the handling of online maintenance in important system for nuclear safety of nuclear power plant in Japan, and discusses future tasks of online maintenance in Japan. Now, online maintenance is limited few cases in Japan. But, the needs and importance of online maintenance will be increase near future. It is necessary to evaluate safety at the online maintenance, and if necessary PSA results were used. It will be safety to do online maintenance within AOT , bu...
英字タイトル:
Discussion on allowed outage time at Online Maintenance in Japan