Concrete structure for nuclear power plant is mass concrete structure with large wall depth and easily permits cracking in early age due to hydration heat and drying shrinkage. It always needs cooling water so that usually located near to sea shore. The crack on concrete surface permits rapid chloride intrusion and also causes more rapid corrosion in the steel. In the study, the effect of age and crack width on chloride diffusion is evaluated for the concrete for nuclear power plant with 6000 psi strength. For the work, various crack widths with 0.0~1.4 mm are induced and accelerated diffusion test is performed for concrete with 56 days, 180days, and 365 days. With increasing crack width over 1.0mm, diffusion coefficient is enlarged to 2.7~3.1 times and significant reduction of diffusion is evaluated due to age effect. Furthermore, apparent diffusion coefficient and surface chloride content are evaluated for the concrete with various crack width exposed to atmospheric zone with salt spraying at the age of 180 days. The results are also analyzed with those from accelerated diffusion test.

Abstract
 1. 서 론
 2. 염화물 확산계수의 시간의존성에 따른거동 해석
 3. 사용재료 및 염화물 확산계수 실험계획
  3.1 사용재료 및 배합
  3.2 압축강도 실험
  3.3 정상상태 촉진 실험 및 겉보기 확산실험
 4. 고강도 원전콘크리트 확산계수의 시간 및균열특성
  4.1 압축강도 특성 변화
  4.2 균열 폭 및 재령에 따른 확산계수의 변화
  4.3 재령 및 균열폭에 따른 확산계수 변화 정량화
  4.4 균열 폭의 증가에 따른 겉보기 확산계수
 5. 결 론
 감사의 글
 References

• 천주현(한국건설생활환경 시험연구원, 선임연구원) | Ju-Hyun Chun
• 류화성((주)한양E&C 대표이사) | Hwa-Sung Ryu
• 윤용식(한남대학교 건설시스템공학과 석사과정) | Yong-Sik Yoon
• 권성준(한남대학교 건설시스템공학과 부교수) | Seung-Jun Kwon Corresponding author