SMASH HIT ! MAGNOX LESSON FOR TODAY

On July 17 1984 at Old Dalby in Leicestershire, UK, a spectacular staged rail crash took place between a 100mph train and a Magnox spent fuel flask. Often replayed on the media, this event makes a lasting impression on the viewer of what a “worst case” impact accident scenario would look like which might be imagined could cause a release of radioactive material during the transport of irradiated nuclear fuel by rail. It is less well remembered that this crash test was but one part of a comprehensive programme of work carried out by the then Central Electricity Generating Board, spanning 4 years and costing some £4M of early 1980’s money. This programme clearly met a number of key objectives, to mention just a few it:- - demonstrated the practicality and effectiveness of scale model testing to prove the impact integrity of spent fuel flasks made of ductile materials; - showed how simple analytical and more complex computer solutions could alternatively or additionally be used to estimate and refine predictions of impact forces and damage; - showed how route specific analysis might be used to determine the likelihood and potential magnitude of various impact scenarios, enabling typical, credible, “worst case” scenarios to be postulated and their probabilities estimated; - enabled the severity of the IAEA regulatory tests to be compared with that of a realistic severe impact scenario; and - produced a large body of data and developed techniques which are applicable to other designs of radioactive material packages. This paper reviews the results of that work and recalls the major conclusions which have continuing relevance to present day programmes which are aimed at ensuring that radioactive material continues to be transported under the highest practical standards of safety.