The 2011 off the Pacific coast of Tohoku Pacific Earthquake and the Tsunami gave the serious damage to the Fukushima-Daiichi Nuclear Power Plants (NPPs). The lessons from the accidents, IAEA’s Integrated Regulatory Review Service (IRRS) team conducted review for NRA. The mission provided recommendations and suggestions for improvements in most of the areas covered by the review. include: 1) The NRA should work to attract competent and experienced staff, and enhance staff skills relevant to nuclear and r...
英字タイトル:
Improvement of NRA’s Inspection by IRRS recommendation and Innovative Integrated New Maintenance System for NPPs

During the Fukushima Daiichi Nuclear Power Plant accident, fuels in the each core in units 1, 3 and 2 melted, and the melted core might dropped down into the lower plenum of the RPV. The core debris heated the bottom structure of reactor vessels and dropped down onto the pedestal through the melted pass of the vessel bottom structure. High temperature core debris might attack concrete or PCV bottom. In order to protect core concrete reaction, several types of core catchers were developed, but they are...
英字タイトル:
Study on Compact-Type Core Catcher for Current Nuclear Power Plants

保全の体系化について（第4回）－最適化プロセスにおける定量化手法－ 今野 隆博,Takahiro KONNO,笠井 雅夫,Masao KASAI,清水 俊一,Toshikazu SHIMIZU......

保全の体系化について（第３回）－保全最適化の考え方－ 設楽 親,Chikashi SHITARA,岩見 裕,Hiroshi IWAMI,熊野 哲嗣,Tetsuji KUMANO,今野 隆博,Takahiro KONNO......

After the Great East Japan Earthquake, as for the nuclear power plant, addition and modifying of the facility to operate more safely are pushed forward under the thought of the new regulation standard. After the safety of the nuclear power plant being confirmed, and having operated again, an outage is carried out every 13 months. Efficiency of the inspection work is necessary to end outage during a same period as the past though facilities for safety enhancement are added to subject of inspections. In ...
英字タイトル:
Shortening of outage by advancement and the efficiency of the inspection techniques.

NRA demands that specific safety facility (SSF) shall be built because of the lesson and learn of the accident in the Fukushima Nuclear Power Plant. As for the completion of SSF, the postponement of five years was permitted from the enforcement of the regulation. However, it is the difficult situation to end SSF construction in the grace period by the delay of reviewing application documents. Therefore Japan society of maintenology demands the extension of the grace period on the regulation side and, o...
英字タイトル:
Issues of specific safe facility and short-term countermeasures.

In the Fukushima daiichi accident, molten core supposed to be leaked from the pressure vessel to the concreate floor in the containment vessel. To keep the integrity of the containment, development of small type of core catcher which can be installed in present nuclear power plant is needed. In this investigation, the thermal deterioration of concreate and Magnesia-Carbon brick was evaluated by the surface observation and the measurements of compressive strength, weight reduction, and difference of void r...
英字タイトル:
Investigation on thermal deterioration of concreate in severe accident