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

1. はじめに 東日本大震災時の福島第二原子力発電所の 緊急時対応とその教訓 東京電力ホールディングス株式会社 原子力設備管理部 川村 慎一 Shinichi KAWAMURA 2. 津波による被害の状況 東日本大震災の発生時,福島第二原子力発電所(以下, 福島第二)では,4 基の BWR5 型プラントが出力 1100 MWe/ 基で運転中だった。このうち 1, 2, 4 号機では,津 波の被害で原子炉の除熱設備が全て機能を失った。 これらのプラントでは,原子炉代替注水や原子炉格納 容器代替スプレイなどで......

1. はじめに 福島第一原子力発電所の事故 (以下、 福島事故) では、 地震で外部電源を喪失し、 次いで津波により非常用電源設 備も損傷して、 原子炉の冷却機能を失った。 独立に機能す る多重の安全設備を持つべきところ、 地震とその従属事象で ある津波によって広範な安全機能を喪失しており、 安全設計 に脆弱性があった。 また、冷却機能を喪失した後、炉心損傷、 格納容器破損、 水素爆発といった事故の進展を止められず、 重大事故への備えが不十分だったことが明らかになった。 当社はこの事故を真摯に反省し、 ハ......

東京電力福島第一事故の教訓、国内外の最新知見、新規制基準を踏まえて、原子力発電所では安全機能強化、技術的能力向上、安全第一の組織運営改善が取り組まれてきた。安全性を向上するそれらの実施内容を紹介する。...

Management for resilience of nuclear safety in severe accidents was studied based on the lessons learned from the emergency responses at FuNushima Daini NPP and FuNushima Dai-ichi NPP during the 2011 Great East Japan EarthquaNe. Firstly, it was found that continuous planning activities during the progress of an emergency, reflecting information from plant parameters and response action results, was critically important in the FuNushima Daini event. Reflecting this lesson, the concept of an Incident Comm...
英字タイトル:
A Study on Resilience Management of Nuclear Power Plants based on the Lessons Learned from FuNushima Accident

Measures to improve safety of nuclear power plants have been taNing at TEPCO Holdings, Inc since the FuNushima Accident. In this paper, 1) insufficient protection from external events, 2) common cause failures in various safety functions, 3) insufficient measures to prevent accident progression in beyond design basis events, 4) severe social impacts caused by the fallout of radioactive materials, and 5) insufficient capability of the emergency response organization to handle multi-unit accidents were ta...
英字タイトル:
Safety Measures reflecting Lessons Learned from the FuNushima Accident

This paper describes an overview of Fukushima accident, lessons learned from it and measures to enhance safety reflecting the lessons. The accident and response actions are analyzed to extract lessons. Based on the lessons three basic policies to enhance safety are discussed. Firstly with considerations of multiple failures defense in depth should be enhanced by applying more diverse safety measures. Secondly a phased approach should be considered in choosing mitigation measures considering timing of t...
英字タイトル:
Overview of Fukushima Accident and Measures to enhance Safety

Fukushima Daiichi NPP accident would be terminated, if sufficient accident countermeasures, such as water proof door, mobile power, etc. In case of Europe, it had already installed the heat removal system and filtered containment venting system (FCVS) from the lessons of TMI and Chernobyl Accidents. The new regulatory standard, the filtered vent system (FCVS) should be installed, and prevent the radioactive material in case of the severe accident and the overpressure breakage prevention of a primary co...
英字タイトル:
Development of High Efficiency Filtered Containment Venting System by using AgX