Severity, Probability and Risk of Accidents during Maritime Transport of Radioactive Material

This analysis is based on Lloyd's database concerning sea transport accidents for the 1994–1997period and completes the previous analysis based on 1994 data. It gives an accurate description of theworld fleet and the most severe ship accidents (total losses), as well as the frequencies of accident (inaverage on the 1994–1997 period the frequency of accident for cargo carrying ships is 2.57 . 10 loss/ship.year). Furthermore, an analysis has been performed on the ship casualties recorded by the MarineAccident Investigation Branch (MAIB) for UK vessels for the 1990–1996 period, this databaseincluding all accidents for which a declaration has been made to authorities (for example, the averagefrequency of fires derived from this analysis is 1.36 . 10 per ship.year, this occurrence correspondingto the occurrence of initiating events of fire). Concerning fire accidents aboard ships supposed to berepresentative of the radioactive material transporters, a specific analysis was achieved by the FrenchBureau Veritas, on a selection of the world casualties (total losses) for the 1978–1988 period. Thisanalysis related to the origin of the fire points out that it originates mainly in the machinery room andquarters. In a few cases the fire duration recorded is more than one day. 1. SCOPE OF THE STUDY AND REFERENCE DATABASES The aim of this study is to provide a statistical analysis of sea transport accidents for theperiod 1994–1997. A detailed analysis has been performed for the Lloyd database (world fleetand records of the ship casualties). The accidents considered in this first analysis concernthose leading to severe damages to the ship inducing a total loss. Although the severity of theaccident maybe discussed as far as it is defined from the insurance point of view, it isinteresting to analyse the different characteristics of the accident collected in the Lloyddatabase as well as the main factors influencing the occurrence of the accident. A second analysis has been performed on the ship casualties recorded by the Marine AccidentInvestigation Branch (MAIB) for UK vessels. This analysis is limited to the frequencies ofcollision and of fire for the 1990–1996 period. It should be noted that this second database isnot limited to total loss but to accidents for which a declaration has been made to authorities.Thus, the frequencies derived from this second analysis should be useful for determining theoccurrence of initiating events in the perspective of performing a probabilistic safety analysis. In addition, an analysis using fire accident databases provided by the French Bureau Veritas ispresented. This analysis is based on fire accidents aboard ships supposed to be representativeof the radioactive material transporters on a selection of the world casualties (total losses) forthe 1978–1988 period.