報 告 者：林 建 文 指導教授：陳 瑞 昇 博士 1 Jesús S. Pérez Guerrero · Todd H. Skaggs · M. Th. van Genuchten {Transp Porous Med (2010) 85:171–188.}

OUTLINE 2 TAIPOWER, 2009)

INTRODUCTION 3 how to deal with …? examples of common international

INTRODUCTION 4 (USEPA, 2010) Radioactive decay often involves a sequence of steps (decay chain). For example, Pu-238 decays to U-234 which decays to Th-230 which decays, and so on, to Ra-226. Decay products are important in understanding radioactive decay and the management of radioactive waste.

INTRODUCTION 5 Analytical solutions for transport problems involving sequential decay reactions have been developed mostly for steady-state boundary conditions and for infinite or semi-infinite spatial domains. Relatively very little literature is available about analytical solutions for multispecies transport problems for either finite media or time-dependent boundary conditions.

OBJECTIVES The objective of this study is to extend the CITT procedure to obtain an analytical solution for a sequential decay reaction transport problem with time-varying boundary conditions and a finite domain. 6

METHODS 7 7 First-order sequentially decaying species Homogeneous finite porous media Subject to linear equilibrium adsorption processes Constant advective velocity

8 CONCLUSIONS Using the CITT in combination with a filter function with separable space and time- dependencies, the superposition principle, and a classic algebraic substitution The analytical solution is general and permits different values for the retardation coefficients of each species.

Establish the initial and boundary conditions, derivation of two-dimensional advection dispersion equation Variables and equations dimensionless FINITE HANKEL transform General integral transform technique (GITT) Solve the particular solution for differential equation Inverse transform, Analytical solution obtained 9 FUTURE WORK Analytical solutions HYDROGEOCHEM 5.0

10 FUTURE WORK Transport safety assessment of nuclear substances Risk assess -ment Project plann- ing Geochemical transfer mode (HYDROGEOCHEM) Biogeo chemical Transfer Heat Transfer Groundwater Flow Numerical solutions Analytical solutions

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12 FUTURE WORK

13 METHODS