This study evaluates the radioactivity of concrete waste that occurs due to large amounts of decommissioned nuclear wastes and then determines the surface dose rate when the waste is packaged in a disposal container. The radiation assessment was conducted under the presumption that impurities included in the bio-shielded concrete contain the highest amount of radioactivity among all the concrete wastes. Neutron flux was applied using the simplified model approach in a sample containing the most Co and Eu impurities, and a maximum of 9.8×104 Bq·g−1 60Co and 2.63×105 Bq·g−1 152Eu was determined. Subsequently, the surface dose rate of the container was measured assuming that the bio-shield concrete waste would be packaged in a newly developed disposal container. Results showed that most of the concrete wastes with a depth of 20 cm or higher from the concrete surface was found to have less than 1.8 mSv·hr−1 in the surface dose of the new-type disposal container. Hence, when bio-shielded concrete wastes, having the highest radioactivity, is disposed in the new disposal container, it satisfies the limit of the surface dose rate (i.e., 2 mSv·hr−1) as per global standards.

1. Introduction
2. Evaluation methods
    2.1 Analysis on the characteristics of decommissioningwastes of overseas commercialnuclear power plants
    2.2 Properties of radioactive concrete waste
    2.3 Radioactive evaluation method
    2.4 Evaluation method of surface radiationdose rate
3. Evaluation result
    3.1 Evaluation result of radioactivity
    3.2 Evaluation of disposal container surfacedose ratio
4. Conclusion
REFERENCES

• Gi-Woong Kang(Korea Radioactive Waste Agency)
• Rin-Ah Kim(Korea Radioactive Waste Agency)
• Ho-Seok Do(Korea Radioactive Waste Agency)
• Tae-Man Kim(Korea Radioactive Waste Agency) Corresponding Author
• Chun-Hyung Cho(Korea Radioactive Waste Agency)