Introduction

Transport containers for radioactive materials are tested to demonstrate compliance with national and international standards. At Winfrith, there are facilities that include drop-test cranes and targets (up to 700 tonne), and equipment to simulate pool fires. The protocols employed are normally IAEA Safety Series 6, or ST1 for transport containers, although tests have also been conducted to US DoE 10CFR71. Containers that are to be used entirely within a nuclear facility are tested to ensure compliance with relevant safety cases. The impact and fire test facilities have also been extensively used for investigation of the performance of components of transport packages, such as the shock absorbers, or the intended payloads.

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Drop Test Facilities
The principal facility used for drop tests comprises a 150 tonne crawler crane and a 700 tonne concrete target. The crane is capable of dropping a 90 tonne load from a height of 30 m, or a 50 tonne load from a hook height of 55 m. The target consists of a buried reinforced concrete block, with the upper 6 m square steel face located 0.5 m above ground level. Tests have been conducted on a number of different types of containers (e.g. flasks, drums, ISOs), some with unusual configurations.

Indoor facilities, used for the testing of smaller packages or scale models in conditions independent of the weather, have a maximum drop height of 10 m. Tests are conducted on packages weighing from between 2 and 50 kg.

Instrumentation routinely employed in impact testing includes high-speed video or cine cameras, accelerometers, strain gauges and pressure transducers. Data are collected using transient recorders, operating at sample rates of up to 300,000 per second. A large co-ordinate measuring machine is available for metrology. Techniques for leak testing of containers range from soap bubble testing to gas mass spectrometry.

Fire Test Facilities
The Pool Fire Test Facility comprises a specially designed waterproof pool, measuring approximately 9.5 m ´ 6.5 m, and capable of holding up to 30,000 litres of liquid hydrocarbon fuel. It is designed for testing of packages or structures up to 7 m long and weighing up to 100 tonne. It is filled with water to the required depth, and fuel is floated on the surface. The package being tested is supported 1 m above the surface of the fire on steel supports.

It should be noted that pool fire tests conducted to specifications drawn up to meet individual requirements generally employ a wide range of instrumentation. The minimum instrumentation required for pool fires is four directional flame thermometers, arranged at 90 degrees to each other in a horizontal plane on the centre line of the package. Measurement of pressure, strain, fuel weight, toxic and combustion gases, radiant heat flux and smoke density can also be performed, with up to 40 thermocouples attached to a test piece.