Abstract: A transportation assembly includes a single container having a primary confinement receptacle and a secondary confinement receptacle in which the primary confinement receptacle is retained. In the preferred embodiment the primary confinement receptacle has two reservoirs defined in it, one of which is for storing and transporting a radioactive substance and the other of which is for storing and transporting a diluting substance in which the radioactive substance is to be diluted at a location, such as a well site at which a radioactive tracer injection operation is to be performed. A system incorporating such a container and a method of using it are also disclosed.