in a process for injecting a radioactive sample of a substance into a reaction vessel , the sample is first enclosed in a first container in which it is irradiated , and then the first container with sample is placed in a second container which is separated from the reaction vessel by way of a closed valve . the second container is heated , and the sample is then conveyed out of the containers into the reaction vessel through the valve which is opened . the sample is enclosed within the first container by plugs or is frozen therein for which purpose the first container may possibly by put into intermediate storage in a storage container . an apparatus comprises the first container for receiving the sample , to be arranged and fixed within the second heatable pressure - resistant container which can be communicated with the reaction vessel through a valve .