Release procedures and disposal of radioactive residual substances at the Medical University Hanover (MHH)

The disposal of all radioactive residual packages of the MHH is regulated by the German radiation protection ordinance from 26th July 2001; shown in appendix III, table 1, column 5: unrestricted release of solid materials and liquids. All radioactive waste packages are collected and handled by the central MHH department for radiation protection. They are sorted for type, nuclide and specific radioactivity. A few packages can directly be released as conventional waste after performing incoming measurements showing very low activity concentrations. Longer living radionuclides with specific activities above the release limits have to be delivered to the national waste disposal. For direct measurements of gamma-emitting radionuclides we use two in-situ-measuring units (ISOCS, Canberra) and a special release unit with 9 plastic scintillators in a fixed geometry (FR-9 PVT, MED Medizintechnik). Fluid beta-emitting radionuclides are measured by taking a fraction and using liquid scintillation counting (LSC). Solid beta-emitting radionuclides activity are calculated. (orig.)