1. NAME AND TITLE

3DB: A Three-Dimensional Multigroup Diffusion Theory Code System for Fast Reactor Criticality and Burnup Analysis.

2. CONTRIBUTOR

Battelle Northwest Laboratory, Richland, Washington.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; CDC.

4. NATURE OF PROBLEM SOLVED

3DB is a three-dimensional (X-Y-Z, R-theta-Z, triangular-Z), multigroup diffusion code for use in detailed fast reactor criticality and burnup analysis. The code can be used to: 1) compute k_eff and perform criticality searches on buckling, time absorption, reactor composition, and reactor dimensions by means of either a flux or an adjoint model, 2) compute material burnup using a flexible material shuffling scheme, 3) compute flux distributions for an arbitrary extraneous source.

5. METHOD OF SOLUTION

3DB can perform criticality searches on buckling, time absorption, material concentrations, and region dimensions. Alpha and k_eff can be used as parametric eigenvalues. Criticality searches can be performed during burnup to compensate for fuel depletion.

Variable dimensioning is used to make maximum use of the available fast memory. Since data for only one energy group and one plane are in the fast memory at any given time, the storage requirements are insensitive to the number of energy groups and the number of Z intervals.

6. RESTRICTIONS OR LIMITATIONS

Since variable dimensioning is employed, no simple restrictions on problem complexity can be stated.

7. TYPICAL RUNNING TIME

Running time (for a k_eff calculation) on a UNIVAC 1108 is about 1/2 hour for a 20 × 20 × 20 mesh problem using 2 energy groups. Each successive burnup time step takes about 1/4 of the above time. No study has been made by RSIC of typical running times for 3DB on the CDC computer.

8. COMPUTER HARDWARE REQUIREMENTS

3DB is operable on the CDC computer. It requires a 65 K memory storage and eleven peripheral storage units.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCE

R. W. Hardie and W. W. Little, Jr., "3DB, A Three-Dimensional Diffusion Theory Burnup Code," BNWL-1264 (March 1970).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source codes and sample problem input.

12. DATE OF ABSTRACT

January 1982.