• Title/Summary/Keyword: Radioactive soil

Search Result 207, Processing Time 0.032 seconds

The Modified Eulerian-Lagrangian Formulation for Cauchy Boundary Condition Under Dispersion Dominated Flow Regimes: A Novel Numerical Approach and its Implication on Radioactive Nuclide Migration or Solute Transport in the Subsurface Environment

  • Sruthi, K.V.;Suk, Heejun;Lakshmanan, Elango;Chae, Byung-Gon;Kim, Hyun-su
    • Journal of Soil and Groundwater Environment
    • /
    • v.20 no.2
    • /
    • pp.10-21
    • /
    • 2015

  • The present study introduces a novel numerical approach for solving dispersion dominated problems with Cauchy boundary condition in an Eulerian-Lagrangian scheme. The study reveals the incapability of traditional Neuman approach to address the dispersion dominated problems with Cauchy boundary condition, even though it can produce reliable solution in the advection dominated regime. Also, the proposed numerical approach is applied to a real field problem of radioactive contaminant migration from radioactive waste repository which is a major current waste management issue. The performance of the proposed numerical approach is evaluated by comparing the results with numerical solutions of traditional FDM (Finite Difference Method), Neuman approach, and the analytical solution. The results show that the proposed numerical approach yields better and reliable solution for dispersion dominated regime, specifically for Peclet Numbers of less than 0.1. The proposed numerical approach is validated by applying to a real field problem of radioactive contaminant migration from radioactive waste repository of varying Peclet Number from 0.003 to 34.5. The numerical results of Neuman approach overestimates the concentration value with an order of 100 than the proposed approach during the assessment of radioactive contaminant transport from nuclear waste repository. The overestimation of concentration value could be due to the assumption that dispersion is negligible. Also our application problem confirms the existence of real field situation with advection dominated condition and dispersion dominated condition simultaneously as well as the significance or advantage of the proposed approach in the real field problem.

  • https://doi.org/10.7857/JSGE.2015.20.2.010 인용 PDF KSCI KPUBS HTML

Geochemical Evolution of Mixing Zone with Freshwater and Seawater near the Coast Area during Underground Space Construction (지하공간건설 시 해안인근 담수-해수 혼합대의 지화학적 진화)

  • Kim, Jiyeon;Kim, Byung-Woo;Kwon, Jang-Soon;Koh, Yong-Kwon
    • Journal of Soil and Groundwater Environment
    • /
    • v.20 no.7
    • /
    • pp.90-102
    • /
    • 2015

  • To understand the hyrogeochemical variation of bedrock aquifer during underground space construction, various graphical methods including multiple-component plots and chemical trends were used to estimate the mixing rate between seawater and freshwater and to investigate the evolution of water quality. The water chemistry and mixing rate between fresh and sea waters, which are generally localized in the construction area (MW-7, in land), shows typical characteristics of freshwater that doesn’t affect its validity as seawater intrusion. Especially, the water chemistry of a MW-4 (coastline) was classified as Na-Cl type, Na-HCO3 type, and Ca-Cl type due to the influence of the seawater intrusion. And hydrogeochemical and isotopic data show that local freshwater is subjected to geochemical processes, such as reverse ion-exchange. Throughout the Chadha’s diagrams, four different case histories with the temporal and spatial variation of groundwaters in the study area were proposed, which is recommended to interpret the hydrogeochemical reactions effectively.

  • https://doi.org/10.7857/JSGE.2015.20.7.102 인용 PDF KSCI KPUBS HTML