報告書番号

U97076

タイトル（和文）

放射性物質輸送の確率論的安全評価（その４）－専用運搬船の海難事故発生確率に関する検討－

タイトル（英文）

PROBABILISTIC SAFETY ASSESSMENT OF RADIOACTIVE MATERIALS TRANSPORT -ACCIDENT PROBABILITY FOR EXCLUSIVE SHIP-

概要 （図表や脚注は「報告書全文」に掲載しております）

本研究は，放射性物質専用運搬船の事故確率評価を目的とした。まず，海上輸送中の事故シナリオについて分析を行い，下記の４つの全損に至るシナリオを選定した。次に，専用運搬船と同クラスの３０００～５０００ＧＴの一般貨物船を対象として，日本の海難事故統計より各シナリオの発生確率を算出した。続いて，日本造船研究協会がとりまとめた沈没確率分析手法を用いて，破口が生じた場合の一般貨物船および専用運搬船の沈没確率を比較検討した。以上の結果，専用運搬船の全損に至る海難発生確率は，機関室火災に起因するもの１．７ｘ１０－６／航海，海面火災の場合２．６ｘ１０－７／航海，衝突による全損の場合８．８ｘ１０－７／航海，荒天による全損の場合２．３ｘ１０－５／航海を得た。なお，専用運搬船には構造的優位性の他にも様々な防護手段があるので，これらの確率値は，安全側の値であると考える。

概要 （英文）

RADIOACTIVE METERIALS, INCLUDING SPENT FUELSAND HIGH-LEVEL RADIOACTIVE WASTES, ARE TRANSPORTED BY EXCLUSIVE SHIPS BETWEEN JAPAN AND FRANCE OR ENGLAND. THIS REPORT DESCRIBES THE RESULTS OF ACCIDENT PROBABILITY EVALUATION FOR THESE EXCLUSIVE SHIPS. FIRST, A SCENARIO ANALYSIS WAS EXECUTED AND ENGINE-ROOM FIRE, AN SEA-SURFACE FIRE, AND SINKING CAUSED BY COLLISION OR STORMY WEATHER WERE EXTRACTED AS HYPOTHETICAL ACCIDENTS. THE PROTECTIVE FUNCTIONS OF THE EXCLUSIVE SHIP WERE ALSO CONSIDERED. SECOND, AN EXCLUSIVE SHIP AND AN ORDINARY 3,000 5,000GT CLASS CARGO SHIP OF EQUAL SIZE AND TONNAGE WERE SELECTED FOR COMPARISON, AND THE PROBABILITIES OF THE ABOVE HYPOTHETICAL ACCIDENTS WEREESTIMATED FROM THE CASUALTY STATISTICS FOR JAPAN. THIRD, THE PROBABILITY OF TOTAL LOSS OF ORDINARY CARGO SHIPS AND THE EXCLUSIVE SHIPS WERE CALCULATED AND COMPARED BY THE METHOD USED BY THE SHIPBUILDING RESEARCH ASSOCIATION OF JAPAN (JSRA) UNDER THE SOLAS90 INTERNATIONAL REGULATIONS. THE MARITIME ACCIDENT PROBABILITY CONSIDERING THE PROTECTION METHODS FOR THE EXCLUSIVE SHIP WAS FINALLY ESTIMATED FROM THE VIEWPOINT OF STRUCTURAL ADVANTAGE. THE FOLLOWING PROBABILITIES WERE OBTAINED; (I) COLLISION WITH OTHER SHIP LEADING TO TOTAL LOSS 8.8-7/VOYAGE(II) STORMY WEATHER LEADING TO TOTAL LOSS 2.3-5/VOYAGE (III) FIRE IN ENGINE ROOM:1.7-6/VOYAGE (IV) COLLISION WITH TANKER AND SEA-SURFACE FIRE2.6-7/VOYAGE FINALLY, IT SHOULD BE NOTED THAT THE PROBABILITIES ARE CONSERVATIVE BECAUSE OF OTHER PROTECTIVE FUNCTIONS NOT DISCUSSED IN THIS REPORT. TOTAL LOSS MEANS SINKING LOST AT SEA, FIRE, ETC., RENDERING THE SHIP ABSOLUTELY UNFIT FOR NORMAL OPERATIONS.

報告者

キーワード