報告書番号

S99001

タイトル（和文）

ウラン加工工場臨界事故に関するﾋｭｰﾏﾝﾌｧｸﾀｰ的分析 -― 臨界事故発生に係る行為の分析（中間報告） －-

タイトル（英文）

An Analysis on Human Factor Issues in Criticality Accident at a Uranium Processing Plant- Investigation on human behavior contributing to the criticality accident (Interim Report)-

概要 （図表や脚注は「報告書全文」に掲載しております）

1999年9月30日に茨城県東海村のウラン加工工場で起きた臨界事故に関して、現時点までに選られた情報をもとに、臨界事故の直接的な原因となった「16kgのウランを沈殿槽に入れたこと」ならびに「裏マニュアルを作成・使用していたこと」の2点の背景要因を、J-HPESの原因関連図を用いてヒューマンファクターの観点から分析した。その結果、企業としての安全に対する姿勢・風土に係る問題、、企業としての具体的安全活動に関する問題、設備・装置等のハードに係る問題、企業の経営方針に係る問題が、この事故の背景にあることが示唆された。特に、安全に対する姿勢・風土や企業の経営方針が、様々な問題の根底に横たわっていることが推測された。今回の事故に直接的あるいは間接的に関与した作業員やその上司らは、この安全を軽視した経営方針、企業風土の被害者であるともみなされる。

概要 （英文）

At 10:30 am, September 30th, 1999, a criticality accident occurred in a conversion building of a uranium processing plant in Tokai, Ibaraki prefecture. 69 people including 3 workers who then worked at the building, 3 fire fighters who dispatched to rescue them were exposed to the radiation. People within a 350m-radius of the site were recommended to evacuate themselves from the region to a temporarily prepared evacuation center. And about one hundred thousand people within a 10 km-radius were also advised to stay inside of their home. Nuclear Safety Commission's Accident Investigation Committee is investigating causes of this accident and have been revealing that deviation from government-authorized processing method and negligence of its illegal procedure had contributed to the accident. The influence of this accident is expanding not only to the plant operating company, local people but also to Japanese nuclear power policy, the whole nuclear industry in Japan. Especially pervasion of "Safety Culture" is strongly being required. This report analyses latent factors of some human behavior directly contributing to the criticality accident. It also mentions that 4 critical points on the poor climate for safety in the work place, the inadequate safety management, the unsuitable equipment and the production-biased company's policy are the latent factors of this accident. It also finds that the poor climate and the production-biased policy are the most important factors. It can be said that some people directly or indirectly having caused the accident are the victims of them.

報告者

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