RSICC CODE PACKAGE PSR-415

1. NAME AND TITLE

USINT: Code System to Calculate Heat and Mass Transfer in Concrete.

2. CONTRIBUTORS

Sandia National Laboratories, Albuquerque, New Mexico,

Argonne National Laboratory, Argonne, Illinois,

through the Energy Science and Technology Software Center, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; CDC CYBER170; Lahey F77L; IBM PS/2 (P00415MNYCP00).

4. NATURE OF PROBLEM SOLVED

This version is designated USINTC and was developed to model the thermal response of concrete to very high heating rates such as might occur from sodium spills on concrete surfaces in a breeder reactor. The major phenomena treated are conductive energy transport; chemical decomposition of concrete; and two-phase, three-component heat and mass transfer of the decomposition products: steam, liquid water, and carbon dioxide. The USINT model provides for porosity to increase as water and carbon-dioxide are formed from the concrete. The concrete is treated generally as divided into two basic regions, wet and dry. In the wet region, steam, carbon-dioxide, and liquid water may co-exist, but in the dry region, there is no liquid water. There is also the possibility of a third region in which there is only liquid water and no gases.

5. METHOD OF SOLUTION

The finite difference representation of the partial differential equations include several models for Darcy's two-phase flow. The equations for energy and mass transfer of water and carbon-dioxide are solved by general implicit procedure that contains the Crank-Nicolson approximation. A modified Calusius-Clayperon equation is used as the equation of state in the wet region.

6. RESTRICTIONS OR LIMITATIONS

The limitations fo rthe PC version are: Maxima of 150 times for experimental temperature histories, 150 times for experimental pressure histories, 150 times for experimental water release, 20 thermal conductivities, 5 locations for experimental temperature histories, and 4 locations for experimental pressure histories. No restrictions or limitations are noted for the CDC version.

7. TYPICAL RUNNING TIME

NESC executed the sample problem in 1 minute on an IBM PS/2 Model 70 with a math coprocessor. The sample problem executed in 5 CPU seconds on a CDC Cyber 170. Notes indicate that the Lahey F77L compiler was used to run the PC version in 1991.

8. COMPUTER HARDWARE REQUIREMENTS

USINT required 177 Kbytes on an IBM PS/2 Model 70. 61,000 octal words were required on a CDC machine.

9. COMPUTER SOFTWARE REQUIREMENTS

The PC version ran under DOS 4.01. The CDC version ran under NOS 2.4. A Fortran compiler is required for execution. No executables are included in the package.

10. REFERENCES

a) Included in documentation:

J. V. Beck and R. L. Knight, "User's Manual for USINT," NUREG/CR-1375, SAND79-1694 (May 1980).

L. Eyberger, "USINT, NESC No. 1129.C170, USINT CDC Version Tape Description and Sample Problem Input and Output," NESC Note 92-17 (October 17, 1991).

L. Eyberger, "USINT, NESC No. 1129.PS2, USINT IBM PS/2 Version Tape Description and Sample Problem Input and Output," National Energy Software Center Note 92-18 (October 17, 1991).

b) Background information:

J. V. Beck, "Sensitivity Analysis for USINT - A Program for Calculating Heat and Mass Transfer in Concrete Subjected to High Heat Fluxes," NUREG/CR-2180, SAND81-0026 (October 1981).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one diskette containing a self-extracting compressed file, which contains the source code and test case.

12. DATE OF ABSTRACT

May 1999.

KEYWORDS: HEAT TRANSFER; REACTOR SAFETY; THERMAL HYDRAULICS