Depleted uranium contains a lower fraction of 235U than natural uranium. It has a lower radiation risk due to its lower fraction of 235U. In the 1980s, it was used as a catalyst for producing acrylonitrile in Korea. It has no longer been used after the 2000s. However, approximately 7,000 drums of radioactive waste containing depleted uranium has been stored factory site since that time. In this report, a radiation risk assessment of radioactive waste containing depleted uranium was conducted to search for disposal schemes in the near future. RESRAD was used to calculate the dose of workers from the radioactive waste tank. Furthermore, the effective dose equation from an IAEA report was used to calculate the dose from the waste. The storage tank geometric features and activity was measured using samples from a tank. Work hours were assumed to be 2,000 hours per year. Distance from the tank during the work was assumed to be 1 m. Default values provided by the RESRAD program were applied to other factors. Dose calculation was conducted by both a RESRAD and the dose equation. Table 1 shows the effective dose results of both methods. The effective dose limit value in the Korean Nuclear Safety Law is 100 mSv per 5 years for workers and 1mSv for the public. Compared to the dose results, both are quite low values. The radiation risk from the tank thus could be deemed safe for workers. Although the radiation risk was assessed to be low, depleted uranium has chemical toxicity because it is a heavy metal element and it could thereby cause problems when storing large amounts of radioactive waste over a long-term period at a factory site. In addition, it contains radionuclides, and hence can lead to concerns among citizens around the storage site. Furthermore, for the systematic management of radioactive waste, the depleted uranium should be delivered to low-level waste disposal site. However, this radioactive waste is not included as a disposal subject in the current low-level waste disposal site delivery and disposal scheme. Depleted uranium is mixed with waste in sludge form, and it should be transformed to a solid form to be delivered. To manage the radioactive waste, specifically including waste transformation and volume reduction, the disposal subject scheme should be revised in the near future.

Assessment of radiation dose to workers from depleted uranium containing radioactive waste

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.