Re: a fundamental question!

["David L Parkhurst" <dlpark@xxxxxxxx>]

The following file is a rough example of uranium rollfront simulation.

David



TITLE  Rollfront

SOLUTION 0 Rainwater
        units            mmol/kgw
        temp           25.0
        pH              7.0     charge
        pe               4.0
        Ca  1
        S(6) 1
EQUILIBRIUM_PHASES 0
 CO2(g) -3 10
 O2(g)  -0.7 10
Save Solution 0
END

solution 1
EQUILIBRIUM_PHASES 1-2
 Schoepite 0.0 0.1
 Calcite  0.0 0.1
 Goethite 0.0 0.1
SAVE solution 1-10
END
EQUILIBRIUM_PHASES 3-10
 Calcite  0.0 0.1
 Goethite 0.0 0.1
 Uraninite(c)     0     0
KINETICS 3-10
      Organic_C
        -formula  CH2O
  -tol 1e-8
  -m0 .005
  -m .005

RATES
  Organic_C
   -start
    10 if (m <= 0) then goto 200
    20  mO2 = mol("O2")
    30  mNO3 = tot("N(5)")
    40  mSO4 = tot("S(6)")
    50   rate = 1.57e-7*mO2/(2.94e-4 + mO2)
    60   rate = rate + 1.e-7*mSO4/(1.e-4 + mSO4)
    70  moles = rate * m * (m/m0) * time
    80 if (moles > m) then moles = m
    200 save moles
   -end
END
ADVECTION
      -cells 10
      -shifts 10
      -time 5184000
SELECTED_OUTPUT
        -file      Roll-front122.csv
        -reset     false
        -time   false
   -distance    true
        -totals    U
    -pH    true
      -pe    true

END


David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225

Project web page: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled