Developing suitable strategies for the disposal of disused sealed radioactive sources (DSRS) and assessing the safety of disposal facilities for DSRS declared as waste were the focus of a technical meeting held recently in Vienna.
Depending on the type of DSRS they have, countries should consider the full range of disposal options and select the most appropriate form or forms of disposal, concluded experts from 15 countries attending the meeting. They discussed the status of DSRS management in their countries, the use of the IAEA Code of Conduct guidance on the management of DSRS, the development of safety cases and safety assessments for disposal facilities, and areas for possible future work.
Radioactive sources are used for many beneficial purposes in areas such as health, industry, research and agriculture. At the end of their lives, sealed radioactive sources that will not decay to safe levels within a few weeks and cannot be recycled, returned to their manufacturers, or transferred to another national programme, need to be disposed of in the country of their use. IAEA safety standards recognise three disposal options: near surface disposal, borehole disposal and deep geological disposal.
A DSRS may be small, but it can have exceedingly high levels of radioactivity. While some short-lived and lower-activity DSRSs may be disposed of in near surface disposal facilities, longer-lived and higher activity DSRSs require greater degrees of isolation and containment, which can be achieved through borehole disposal or geological disposal.
“A common assumption in Member States is that a proportion of DSRS will need to be disposed of in near surface disposal facilities, but so far safety assessments have only been developed in a few countries,” said Richard Little, Managing Director of Quintessa, a scientific consultancy in the United Kingdom specializing in research and modelling of radioactive waste disposal. “Other DSRS might require geological disposal, but few countries currently have advanced plans for such facilities.”
