RADIOLOGICAL IMPACT OF TRANSPORT ACCIDENTS AND INCIDENTS IN THE UNITED KINGDOM OVER A 1WENTY YEAR PERIOD

A review has been performed in the United Kingdom (UK) of the radiological impact resulting from accidents and incidents occurring during transport over the period 1964 to 1983. This work was jointly commissioned by the UK Health and Safety Executive and the Department of Transport. The materials transported consisted of nuclear fuel cycle materials, and radionuclides for medicine and industrial use. The modes of transport studied were road, rail, sea and 811'. Information in this paper should be used with caution because the database is likely to be incomplete and selective owing to the difficulties of data collation for the review. These difficulties arise because information is sparse as a result of the low frequency of occurrence of such events and to the lack of published information on their impact. In the 20 year period a total of about 330 events were recorded for an estimated 720 000 shipments. Of these events only 42 had the potential to exceed or did exceed the radiological impact associated with normal transport conditions. Over 98% of the total collective dose of about 5 man· Sv may be attributed to 15 events. It is in part due to regulatory control that there has never been a serious accident involving the dispersal of radioactivity during transport in the UK. The regulations are directed to ensuring that safeguards appropriate to the nature and quantity are built into the design of the package in which the material is to be transported. A review extending over a twenty year period cannot be used to derive the probability of occurrence of severe accidents which have very low probabilities. The review has demonstrated that the mlijority of significant events in the UK are related to procedural and quality assurance failures. These failures are aspects which should be addressed in a comprehensive assessment of the radiological impact of transport operations.