RSICC CODE PACKAGE PSR-466

1. NAME AND TITLE

MAEROS: Multicomponent Aerosol Time Evolution.

2. CONTRIBUTORS

Sandia National Laboratories, Albuquerque, New Mexico, through the NEA Data Bank, Issy-les-Moulineaux, France.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; CDC7600 (P00466C760000).

4. NATURE OF PROBLEM SOLVED

MAEROS calculates aerosol composition and mass concentration as a function of particle size and time. The processes that may be considered are coagulation due to Brownian motion, gravity, and turbulence; particle deposition due to gravitational settling, diffusion, and thermophoresis; particle growth due to condensation of a gas, typically water vapor; and time-varying sources of particles of different sizes and chemical compositions.

5. METHOD OF SOLUTION

The numerical technique used is based upon dividing the particle size domain into m sections and imposing the condition of mass conservation for each chemical component for the processes considered. Aerosol mass concentrations are grouped into sections (i.e., size classes) for which an average composition is determined. For m sections, a set of 2m(m+2) sectional coefficients must be calculated before integrating in time. These coefficients are determined from the basic coagulation, condensation, and deposition coefficients. Since the sectional coefficients depend on the physical properties of the containment chamber (e.g., temperature, pressure, chamber volume, and deposition surface area), they will generally need to be recalculated for a particular application. However, for a given containment chamber, the sectional coefficients will probably vary only with temperature and pressure. Consequently, the code has been developed so that sectional coefficients are stored at a user-specified upper and lower bound for both temperature and pressure, and linear interpolation is used to determine the appropriate sectional coefficients for a given temperature and pressure. A Runge-Kutta-Fehlberg method is used to integrate in time.

6. RESTRICTIONS OR LIMITATIONS

Maxima of 20 sections, 8 components, 50 rows for plotting, and 101 columns for plotting.

7. TYPICAL RUNNING TIME

NESC ran the sample problem on a CDC CYBER175 in approximately 12 CP seconds. Note that the sample problem is included in the main program. See page 25 of the referenced manual for a description of the problem.

8. COMPUTER HARDWARE REQUIREMENTS

NESC noted that 55,100 (octal) words of memory were required on a CDC Cyber 175. 1983. The CDC7600 version was submitted to NESC in October 1982. MAEROS was not tested when it was transferred to RSICC in 1999.

9. COMPUTER SOFTWARE REQUIREMENTS

The code was run under the SCOPE (CDC7600) and NOS 1.4 (CDC CYBER175) operating systems.

10. REFERENCES

a:) Included in documentation:

F. Gelbard, "MAEROS User Manual," NUREG/CR-1391 SAND 80-0822 (December 1982).

b:) Background information:

J.C. Helton, R.L. Iman, J.D. Johnson, and C.D. Leigh, "Uncertainty and Sensitivity Analysis of a Dry Containment Test Problem for the MAEROS Aerosol Model," NUREG/CR-4487 SAND85-2795 (June 1986).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document in (10.a) and one DS/HD diskette which includes the source code transmitted as an ASCII file written in DOS format.

12. DATE OF ABSTRACT

April 2000.

KEYWORDS: AEROSOL; REACTOR SAFETY