Safety considerations in the disposal of disused sealed radioactive sources in borehole facilities

Sealed radioactive sources are used in medicine, industry and research for a wide range of purposes. They can contain different radionuclides in greatly varying amounts. At the end of their useful lives, they are termed 'disused sources' but their activity levels can still be quite high. They are, for all practical purposes, another type of radioactive waste that needs to be disposed of safely. Disused sealed radioactive sources can represent a significant hazard to people if not managed properly. Many countries have no special facilities for the management or disposal of radioactive waste, as they have no nuclear power programmes requiring such facilities. Even in countries with developed nuclear programmes, disused sealed sources present problems as they often fall outside the common categories of radioactive waste for which disposal options have been identified. As a result, many disused sealed sources are kept in storage. Depending on the nature of the storage arrangements, this situation may represent a high potential risk to workers and to the public. The IAEA has received numerous requests for assistance from Member States faced with the problem of safely managing disused sealed sources. The requests have related to both technical and safety aspects. Particularly urgent requests have involved emergency situations arising from unsafe storage conditions and lost sources. There is therefore an important requirement for the development of safe and cost-effective final disposal solutions. Consequently, a number of activities have been initiated by the IAEA to assist Member States in the management of disused sealed sources. The objective of this report is to address safety issues relevant to the disposal of disused sealed sources, and other limited amounts of radioactive waste, in borehole facilities. It is the first in a series of reports aiming to provide an indication of the present issues related to the use of borehole disposal facilities to safely disp radioactive sources and other smaller quantities of radioactive waste and to identify areas were further work needs to be undertaken. This report discusses the general considerations related to the safe disposal of disused sealed sources, and other limited quantities of radioactive waste, in boreholes facilities. It is particularly aimed at Member States who do not plan to develop other types of disposal facility for nuclear fuel cycle waste. It is recognized that internationally agreed safety guidance is needed in this area but further development and consultation is required to establish broad international consensus on the appropriate technology and safety requirements