1. NAME AND TITLE

EQUIVA-2.0: Generation of Environment-Insensitive Equivalent Diffusion Theory Parameters for PWR Reflector Regions.

2. CONTRIBUTOR

Atomic Energy Corporation of South Africa (Ltd), Pretoria, Republic of South Africa.

3. CODING LANGUAGE AND COMPUTER/OPERATING SYSTEM

Fortran 77; IBM 370, and IBM PC.

4. NATURE OF PROBLEM SOLVED

EQUIVA-2 generates environment-insensitive equivalent diffusion theory parameters for pressurized water (PWR) reflector regions from the results of simple one-dimensional (slab) multigroup transport calculations. Two one-dimensional reflector models have been implemented, namely the few-group NGET-RM method and the two-group KOEBKE-RM method. Equivalent parameters can be generated for one homogenized region only, although this region itself may be constituted by any number of component regions.

5. METHOD OF SOLUTION

Analytic functions of non-symmetric real matrices are computed by means of a spectral analysis method. Component region slab response matrices are combined using rigorous addition rules to obtain a global response matrix for a single region/node.

6. RESTRICTIONS OR LIMITATIONS

EQUIVA2.0 is a variably dimensioned code and there is no restriction on the number of energy groups, etc. The size of the problem is restricted only by the computer core storage available.

7. TYPICAL RUNNING TIME

The running time for a single PWR radial reflector problem consisting of group condensation from 69 to 2 energy groups, spatial homogenization of 2 regions, and computation of the NGET-RM parameters for the homogenized node is on the order of a few seconds on a mainframe computer.

8. COMPUTER HARDWARE REQUIREMENTS

EQUIVA-2.0 has run routinely on IBM mainframes and on 32-bit 80386/80486 class personal computers.

9. COMPUTER SOFTWARE REQUIREMENTS

The code is written in Fortran 77 and has run under MVS on IBM mainframes. The executable file for the PC included in the package was created with the Lahey F77L-EM/32 Version 5.0 compiler.

10. REFERENCES

E. Z. Muller, "EQUIVA-2: A Code for Generating Environment-Insensitive Equivalent Nodal Parameters for PWR Reflector Regions," PEL 307 (1991).

E. Z. Muller, "Environment-Insensitive Equivalent Diffusion Theory Group Constants for Pressurized Water Reactor Radial Reflector Regions," Nucl. Sci. Eng., 103, 359-376 (1989).

E. Z. Muller, "Improved Pressurized Water Reactor Radial Reflector Modeling in Nodal Analysis," Nucl. Sci. Eng., 109, 200-214 (1991).

11. CONTENTS OF CODE PACKAGE

Included in the package are the referenced documents and 1 DS/HD disk which includes the source files, PC executable file, test case input data and output in DOS format.

12. DATE OF ABSTRACT

March 1993.