1. NAME AND TITLE

2DBS: Two-Dimensional Multigroup Neutron Diffusion Shielding Code System.

AUXILIARY ROUTINES:

ANISN Library Routine.

2DBS Plot Routine.

2DBS is a revision and extension of 2DB, a fast reactor analysis code.

2. CONTRIBUTOR

Battelle Memorial Institute, Pacific Northwest Laboratories, Richland, Washington.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; UNIVAC 1108.

4. NATURE OF PROBLEM SOLVED

2DBS is a flexible, two-dimensional (X-Y, R-Z, R-Theta geometry) diffusion code designed for calculating the performance of in-vessel shields typical of reactors in the LMFBR program. The compactness of such cores often necessitates the 2-dimensional treatment and diffusion theory is deemed adequate because the exclusion of hydrogenous media from the liquid metal environment relaxes the dependence of the total flux on the high energy scattering treatment where anisotropy is so important.

Included in the output is pointwise convergence information, reaction or activation rates; and, from a coupled routine, Calcomp plots of the flux, power, fission rates, or spectra.

5. METHOD OF SOLUTION

Standard source-iteration techniques are used in 2DBS. Group rebalancing and successive over-relaxation with line inversion are used to accelerate convergence. Special features are built in to accelerate flux convergence, particularly for points far from the source. Cross section libraries in the ANISN (CCC-82, -253, -254, -255) format may be used.

6. RESTRICTIONS OR LIMITATIONS

Since variable dimensioning is used, no simple bounds can be stated. The current version, however, is normally restricted to 50 energy groups in a 65K memory.

7. TYPICAL RUNNING TIME

No study has been made by RSIC of typical running times for 2DBS.

8. COMPUTER HARDWARE REQUIREMENTS

2DBS was designed for and is operable on the UNIVAC 1108. A 65K memory and three peripheral storage devices are required.

9. COMPUTER SOFTWARE REQUIREMENTS

The code was in FORTRAN IV and may be compiled and executed on a compatible FORTRAN IV Monitor System. The packaged version has been run on the UNIVAC 1108.

10. REFERENCES

D. R. Marr, "A User's Manual for 2DBS, A Diffusion Theory Shielding Code," BNWL-1291 (February 1970).

W. W. Little, Jr., and R. W. Hardie, "2DB, A Two-Dimensional Diffusion-Burnup Code for Fast Reactor Analysis," BNWL-640 (January 1968).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source code and sample problem input, plus output from the sample problem.

12. DATE OF ABSTRACT

August 1971; revised August 1982.