1. NAME AND TITLE

1DB: One-Dimensional Diffusion Code System for Nuclear Reactor Analysis.

2. CONTRIBUTOR

Battelle-Northwest Laboratory, Richland, Washington

3. CODING LANGUAGE AND COMPUTER

Fortran 77, many computers.

4. NATURE OF PROBLEM SOLVED

1DB is a multipurpose, one-dimensional (plane, cylinder, sphere) diffusion theory code for use in reactor analysis. The code is designed to do the following: to compute keff and perform criticality searches on time absorption, reactor composition, reactor dimensions, and buckling by means of either a flux or an adjoint model; to compute collapsed microscopic and macroscopic cross sections averaged over the spectrum in any specified zone; to compute resonance-shielded cross sections using data in the shielding factor format; and to compute isotopic burnup using decay chains specified by the user.

5. METHOD OF SOLUTION

The 1DB code has 3 essential capabilities: 1) preparation of multigroup shielded cross sections using the shielding factor technique, 2) calculation of neutronics eigenvalue using source-iteration technique, and 3) computation of isotopic burnup using transmutation chains specified by user. Transmutation can be by capture, fission, n,2n, or decay, with fractional yields for each.

6. RESTRICTIONS OR LIMITATIONS

Variable dimensioning - no limitations on groups or mesh points.

7. TYPICAL RUNNING TIME

Time's dependent on size of problem. A 24 spatial mesh, 89 energy group problem with complete up and down scattering required .14 min on the Hanford CRAY X-MP EA/232. RSIC tested the sample case on a PC 486/33; it took only a few seconds of CPU time.

8. COMPUTER HARDWARE REQUIREMENTS

1DB has been run on many computers, including CRAY, IBM PS/2, VAX, and PC 486, and has no special requirements.

9. COMPUTER SOFTWARE REQUIREMENTS

The Microsoft FORTRAN Compiler, Version 5.0, was used to create the executable file included in package.

10. REFERENCES

W. W. Little, "1DB, A One-Dimensional Diffusion Code for Nuclear Reactor Analysis," WHC-EP-0435 (September 1991).

11. CONTENTS OF CODE PACKAGE

The code package includes FORTRAN source deck, PC executable, INCLUDE file, and sample case on one DS/HD diskette written in DOS format.

12. DATE OF ABSTRACT

March 1993.