Qualification of radium sources packaging by the measurement of the radon escape rate

The extensive use of radium sources in radiotherapy and in industry during the first half of the 20th century has yielded waste of different types (needles, tubes, luminescent paints etc.) with various concentrations of radium. These waste products have the characteristic to produce radon, a radioactive gas and its progeny radionuclides. These are of natural origin, but they still require precaution to be taken in order not to increase significantly the radiological risk to workers and to present and future populations. The management of these waste products implies the use of specific packaging that reduces as much as possible the radon transfer from the radium source to the storage facility, in order to comply with the different regulations. So, the efficiency of the packaging as a radon barrier must be controlled. We have developed a test method to estimate the radon leakage of different containers by the measurement of radon degassing from the packaging. With this methodology, we can measure radon leakage rates as low as 10-5 Bq.s-1. (author)