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

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. 4

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. 5

6. 6 In this project we will develop analytical solutions for the two-dimensional couple multi-species reactive transport of radionuclide sequential decay chains through a finite-length geological media.

7. 7 Establish the initial and boundary conditions, derivation of two-dimensional advection dispersion equation Finite Fourier cosine transform General integral transform technique (GITT) Decouple technique in combination Solve the particular solution for differential equation Inverse transform, Analytical solution obtained

8. 8 Establish the initial and boundary conditions, derivation of two-dimensional advection dispersion equation

9. 9 Finite Fourier cosine transform

10. 10 Establish the initial and boundary conditions, derivation of two-dimensional advection dispersion equation Finite Fourier cosine transform General integral transform technique (GITT) Decouple technique in combination Solve the particular solution for differential equation Inverse transform, Analytical solution obtained General integral transform technique (GITT) Decouple technique in combination Solve the particular solution for differential equation Inverse transform, Analytical solution obtained Analytical solutions HYDROGEOCHEM 4.0

11. 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 11

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