1. NAME AND TITLE

WHATIF-AQ: A Computer Program For Speciation Calculation.

2. CONTRIBUTOR

Riso National Laboratory, Roskilde, Denmark, through NEA Data Bank, France.

3. CODING LANGUAGE AND COMPUTER

ALGOL; Burroughs 7800.

4. NATURE OF PROBLEM SOLVED

WHATIF-AQ is part of a family of programs for calculations of geochemistry in the near-field of radioactive waste with temperature gradients.

5. METHOD OF SOLUTION

The program calculates speciation and saturation indices for an aqueous solution at temperatures in the range 0-125 degrees Centigrade. The chemical equilibrium is determined by solving a set of nonlinear equations consisting of the equilibrium constant and mass balance constraints. WHATIF-AQ takes into account the following components: Si, Al, Ca, Mg, K, Na, Fe2+, Fe3+, Cl, SO4, and total HCO3 or carbon dioxide pressure. Construction of 37 different aqueous species and saturation state of 84 minerals are calculated. The set of equations is solved using a generalized Newton-Rhapson technique.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

The sample input was tested on the Burroughs 7800 and took about 10 CPU seconds.

8. COMPUTER HARDWARE REQUIREMENTS

WHATIF-AQ runs on the Burroughs 7800 computer.

9. COMPUTER SOFTWARE REQUIREMENTS

The code was written in ALGOL.

10. REFERENCE

B. Skytte-Jensen, H. Jensen, O. J. Nielsen. "WHATIF-AQ: A Computer Programme for Speciation Calculation," EUR 10119 EN; NEA 1147/01 (May 1987).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (360 K) DOS diskette.

12. DATE OF ABSTRACT

November 1990.