1995年阪神・淡路大震災における放射性同位元素使用施設の被害と対応

兵庫県南部地震は、大都市直下の断層を震源とするため被災地は惨状を呈した。この地域には約330程度の放射線施設が存在しており、地震に関わる放射線施設の被害状況を詳細に調査・分析する事により、今後の地震災害時における放射線施設への被害を最小限にくい止めるための対策の立案に資する事を目的に(社)日本アイソトープ協会に調査委員会が設けられ、調査を実施した。主要な調査項目は、①放射線施設設備の被害状況、②地震時における通報連絡体制の状況、③施設等の点検の状況、④放射線安全管理の状況などとした。その結果、災害救助法適用地域内で調査し得た229施設(全数331)のうち、1)建物それ自体に何らかの被害があったのは耐震性の高いRI発生取扱施設の36.0%、非密封RIの54.5% (但し、いずれも外部への放射能汚染なし)。II )施設内での物品の移動、転倒、転落ありが、それぞれ41.7%、81.8%。III) 非密封RI施設での給水・給ガス設備の被害が約50%、排水関係の被害は27.0%の発生率である。施設点検を当日中に行ったケースは約74%と危険物を取扱っているだけに高いが、法で定められている科学技術庁への通報は約8%と極めて低い。なお、医療機関でのX線・CT装置など重量医療機器の損傷が20～30%発生し、使用中であったら人命に関わる被害状況も認められた。それも含め使用時間帯の地震であったら人的被害や他の別の被害が発生したと推定される。また、この危険かつ重量物の保管・使用階が高層化するなど建築上の問題点も指摘しておかねばならない。

Since the hypocenter of the Southern Hyogo-Prefecture Earthquake was the active faults directly under urban areas，the damage situations were serious in the affected regions. There are about 330 of the radio-istotope facilities in the regions where were applicated the disaster relief law. The objectives of this survey are finding and drafting the measures of prevention of damage due to earthquakes in those dangerous urban facilities. Main investigating subjects are (1) the damage situations of the facilities and equipments，(2) the actual states of communication /notification at the earthquake，(3) the actual conditions of inspection on the facilities/equipments，(4) on the safety management as to them，etc.. The findings through this survey are as follows : I) The facilities themselves of which aseismic strength are very high suffered any kinds of damage were 36.0% of the closed RI generating treatment them and their open systems were 54.5% of them (contaminations of radioactivity to outside were not recognized in every case). II) The movement，overturn and fall down of things in these facilities occurred 41.7% and 81.8% both of them，respectively. III) The damage of water and gas supply equipments in the open RI treatment facilities were about 50% of them (draining equipments :27.0% ) etc.. Inspections on facilities/equipments were carried out about 74% (high rate) of them within that day from their sense of responsibility for treating the dangerous objects. But the notifications the Science and Technology Agency of the damage situations were only executed about 8% (low rate) in spite of specified in law. The heavy medical apparatuses such as X-ray and CT equipment were damaged 20-30% in the hospita1s and it was recognized that the accidents concerned human lives might occurred if they were used. Besides，it is necessary to point out the recent problems that the places which are the storage and treatment of these dangerous / heavy materials have been adopted the upper stories of buildings and so on.