Experimental Study of Leaching Phenomena of Cs-137 From a Cement Matrix Generated at PWR Plant

가압 경수로에서 생성된 시멘트 고화체로부터 Cs-137의 용출 현상의 실험적 연구

  • Doh, Jeong-Yeul (Department of Nuclear Engineering Korea Advanced Institute of Science and Technology) ;
  • Lee, Kun-Jai (Department of Nuclear Engineering Korea Advanced Institute of Science and Technology)
  • 도정열 (한국과학기술원 핵공학과) ;
  • 이건재 (한국과학기술원 핵공학과)
  • Published : 1986.12.15

Abstract

Experimental study for the leaching behavior of Cs-137 was carried out using the simulated evaporator bottom product of PWR plant. The method of leach test proposed by the IAEA was partially modified using ANS method. The effect of various factors, i.e., sampling method, curing temperature, curing time, leachant temperature, vermiculite addition and volume-to-surface ratio, was considered in this experiment. Diffusion model in semi-infinite slab was in a good agreement with the data obtained from 4-weeks cured specimens. The effective diffusion coefficient of the specimens which were cured at the temperature of $24^{\circ}C$ for 4 weeks was found to be $1.20{\sim}1.47{\times}10^{-11}cm^2/sec$. With the experimentally obtained diffusion coefficient ($1.47{\times}10^{-11}cm^2/sec$), long-term prediction for the leaching of Cs-137 was carried out using finite-slab approximation. The estimated fraction of Cs-137 which remains in the environment is found to be less than 0.25 percent of initial amount after 100 years. About 25 years after the beginning of leaching, its fractional amount in the environment reachs the maximum value, 0.66 percent of initial amount.

Keywords