KORAD (Korea Radioactive Waste Agency, http://www.korad.or.kr) has stored slightly contaminated ascon (asphalt coated concrete mixture) that was introduced to Gyeongju repository about a decade ago waiting for a final disposal. It is believed to be mainly contaminated by radioisotope 137Cs due to impurities introduced from the outside during the ascon manufacturing process. We studied characteristics of the radioactive waste to see whether this material would be proper enough to be disposed in Gyeongju LILW repository or be other ways to reduce the disposal volume including self-disposal before its final disposal otherwise. KORAD looked into the properness of characteristics of ascon in terms of WAC (Waste Acceptance Criteria) documented by KORAD that includes general chemical and physical properties of asphalt, density, size of grains, content of organic material and possibility of existence of chelate materials that qualitatively limited to be disposed by the criteria. And other associated characteristics such as gas generation and bio degradation were also investigated. Based on the data obtained from the study, we proposed various plausible solutions in associated with operational and disposal safety and economic view points. This study will be used for KORAD’s decision on how to control and safely dispose the spent ascon within a reasonable time period. And also those experiences may be applied for other LILW issues that require treatment or conditioning of radioactive wastes in the future.

해안지역에서 지하수 순환 특성 규명은 지하수 자원의 효율적 관리 측면에서 매우 중요하다. 본 연구에서는 물수지 분석법 을 이용하여 지하수 침누수량을 산정하였다. 증발산량은 Thornthwaite 방법으로 계산하였으며, 지표 직접유출량은 SCS-CN 방법으로 산정하였다. 지하수 저류량 변화는 229 mm/년로 30년 평균 강수량 1286 mm/년의 17.8%에 해당하며, 증발산량 은 693 mm/년 (53.9%), 지표 직접유출량은 124 mm/년 (9.6%)로 산정되었다. 강우량과 지하수 저류량 변화 사이에는 강우 량과 증발산량, 강우량과 지표 직접유출량에 비해 상관성이 높게 나타난다. 이는 증발산량 및 지표 직접유출량 보다 지하수 저류량 변화가 강우량에 대해서 더 민감하게 반응한다는 것을 반영한다.