A new approach to characterize very-low-level radioactive waste produced at hadron accelerators

Radioactive waste is produced as a consequence of preventive and corrective maintenance during the operation of high-energy particle accelerators or associated dismantling campaigns. Their radiological characterization must be performed to ensure an appropriate disposal in the disposal facilities. The radiological characterization of waste includes the establishment of the list of produced radionuclides, called “radionuclide inventory”, and the estimation of their activity. The present paper describes the process adopted at CERN to characterize very-low-level radioactive waste with a focus on activated metals. The characterization method consists of measuring and estimating the activity of produced radionuclides either by experimental methods or statistical and numerical approaches. We adapted the so-called Scaling Factor (SF) and Correlation Factor (CF) techniques to the needs of hadron accelerators, and applied them to very-low-level metallic waste produced at CERN. For each type of metal we calculated the radionuclide inventory and identified the radionuclides that most contribute to hazard factors. The methodology proposed is of general validity, can be extended to other activated materials and can be used for the characterization of waste produced in particle accelerators and research centres, where the activation mechanisms are comparable to the ones occurring at CERN

Analyse de la mortalité dans la cohorte Française des mineurs d'uranium

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocSudocFranceF

Mortality risk in the French cohort of uranium miners: Extended follow-up 1946-1999

International audienceObjectives: This paper presents the risk of death from lung cancer and from other causes of death for the French cohort of uranium miners through 1999 and estimates associations with radon exposure. Methods: The cohort includes men employed as uranium miners for at least 1 year between 1946 and 1990. For each miner, vital status and cause of death were obtained from the national registry, and radon exposure was reconstructed for each year. Standardised mortality ratios were computed with national mortality rates as references. Exposure-risk relationships were estimated by Poisson regression, with a linear excess relative risk (ERR) model and a 5-year lag. Results: The cohort included 5086 miners and 153 063 person-years of exposure. The mean duration of follow-up was 30.1 years. In all 4140 miners exposed to radon, the average cumulative exposure was 36.6 working level months (WLM). There were 1411 deaths of miners <85 years of age. The miners did not differ significantly in overall mortality from the general male population. The analysis confirmed an excess risk of lung cancer death (n = 159; SMR = 1.43; 95% CI: 1.22 to 1.68), which increased significantly with cumulative radon exposure (ERR per 100 WLM = 0.71; 95% CI: 0.29 to 1.35). The ERR per unit exposure was much higher after 1955, when the accuracy of exposure measurement improved substantially (ERR per 100 WLM = 2.00; 95% CI: 0.91 to 3.65). A significant excess of kidney cancer deaths was observed (n = 20; SMR = 2.0; 95% CI: 1.22 to 3.09), which was not associated with cumulative radon exposure. No excess was observed for other causes of death, except silicosis (n = 23; SMR = 7.12; 95% CI: 4.51 to 10.69). Conclusions: The analysis confirmed the excess risk of death from lung cancer associated with low radon exposure. An excess risk of death from kidney cancer was also observed, apparently not associated with cumulative radon exposure